at86rf230: remove multiple dereferencing for ctx

[deliverable/linux.git] / drivers / net / ieee802154 / at86rf230.c

/*
 * AT86RF230/RF231 driver
 *
 * Copyright (C) 2009-2012 Siemens AG
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Written by:
 * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
 * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
 * Alexander Aring <aar@pengutronix.de>
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/spi/spi.h>
#include <linux/spi/at86rf230.h>
#include <linux/regmap.h>
#include <linux/skbuff.h>
#include <linux/of_gpio.h>
#include <linux/ieee802154.h>

#include <net/mac802154.h>
#include <net/cfg802154.h>

struct at86rf230_local;
/* at86rf2xx chip depend data.
 * All timings are in us.
 */
struct at86rf2xx_chip_data {
        u16 t_sleep_cycle;
        u16 t_channel_switch;
        u16 t_reset_to_off;
        u16 t_off_to_aack;
        u16 t_off_to_tx_on;
        u16 t_frame;
        u16 t_p_ack;
        int rssi_base_val;

        int (*set_channel)(struct at86rf230_local *, u8, u8);
        int (*get_desense_steps)(struct at86rf230_local *, s32);
};

#define AT86RF2XX_MAX_BUF               (127 + 3)
/* tx retries to access the TX_ON state
 * if it's above then force change will be started.
 *
 * We assume the max_frame_retries (7) value of 802.15.4 here.
 */
#define AT86RF2XX_MAX_TX_RETRIES        7

struct at86rf230_state_change {
        struct at86rf230_local *lp;
        int irq;

        struct spi_message msg;
        struct spi_transfer trx;
        u8 buf[AT86RF2XX_MAX_BUF];

        void (*complete)(void *context);
        u8 from_state;
        u8 to_state;

        bool irq_enable;
};

struct at86rf230_local {
        struct spi_device *spi;

        struct ieee802154_hw *hw;
        struct at86rf2xx_chip_data *data;
        struct regmap *regmap;

        struct completion state_complete;
        struct at86rf230_state_change state;

        struct at86rf230_state_change irq;

        bool tx_aret;
        s8 max_frame_retries;
        bool is_tx;
        /* spinlock for is_tx protection */
        spinlock_t lock;
        u8 tx_retry;
        struct sk_buff *tx_skb;
        struct at86rf230_state_change tx;
};

#define RG_TRX_STATUS   (0x01)
#define SR_TRX_STATUS           0x01, 0x1f, 0
#define SR_RESERVED_01_3        0x01, 0x20, 5
#define SR_CCA_STATUS           0x01, 0x40, 6
#define SR_CCA_DONE             0x01, 0x80, 7
#define RG_TRX_STATE    (0x02)
#define SR_TRX_CMD              0x02, 0x1f, 0
#define SR_TRAC_STATUS          0x02, 0xe0, 5
#define RG_TRX_CTRL_0   (0x03)
#define SR_CLKM_CTRL            0x03, 0x07, 0
#define SR_CLKM_SHA_SEL         0x03, 0x08, 3
#define SR_PAD_IO_CLKM          0x03, 0x30, 4
#define SR_PAD_IO               0x03, 0xc0, 6
#define RG_TRX_CTRL_1   (0x04)
#define SR_IRQ_POLARITY         0x04, 0x01, 0
#define SR_IRQ_MASK_MODE        0x04, 0x02, 1
#define SR_SPI_CMD_MODE         0x04, 0x0c, 2
#define SR_RX_BL_CTRL           0x04, 0x10, 4
#define SR_TX_AUTO_CRC_ON       0x04, 0x20, 5
#define SR_IRQ_2_EXT_EN         0x04, 0x40, 6
#define SR_PA_EXT_EN            0x04, 0x80, 7
#define RG_PHY_TX_PWR   (0x05)
#define SR_TX_PWR               0x05, 0x0f, 0
#define SR_PA_LT                0x05, 0x30, 4
#define SR_PA_BUF_LT            0x05, 0xc0, 6
#define RG_PHY_RSSI     (0x06)
#define SR_RSSI                 0x06, 0x1f, 0
#define SR_RND_VALUE            0x06, 0x60, 5
#define SR_RX_CRC_VALID         0x06, 0x80, 7
#define RG_PHY_ED_LEVEL (0x07)
#define SR_ED_LEVEL             0x07, 0xff, 0
#define RG_PHY_CC_CCA   (0x08)
#define SR_CHANNEL              0x08, 0x1f, 0
#define SR_CCA_MODE             0x08, 0x60, 5
#define SR_CCA_REQUEST          0x08, 0x80, 7
#define RG_CCA_THRES    (0x09)
#define SR_CCA_ED_THRES         0x09, 0x0f, 0
#define SR_RESERVED_09_1        0x09, 0xf0, 4
#define RG_RX_CTRL      (0x0a)
#define SR_PDT_THRES            0x0a, 0x0f, 0
#define SR_RESERVED_0a_1        0x0a, 0xf0, 4
#define RG_SFD_VALUE    (0x0b)
#define SR_SFD_VALUE            0x0b, 0xff, 0
#define RG_TRX_CTRL_2   (0x0c)
#define SR_OQPSK_DATA_RATE      0x0c, 0x03, 0
#define SR_SUB_MODE             0x0c, 0x04, 2
#define SR_BPSK_QPSK            0x0c, 0x08, 3
#define SR_OQPSK_SUB1_RC_EN     0x0c, 0x10, 4
#define SR_RESERVED_0c_5        0x0c, 0x60, 5
#define SR_RX_SAFE_MODE         0x0c, 0x80, 7
#define RG_ANT_DIV      (0x0d)
#define SR_ANT_CTRL             0x0d, 0x03, 0
#define SR_ANT_EXT_SW_EN        0x0d, 0x04, 2
#define SR_ANT_DIV_EN           0x0d, 0x08, 3
#define SR_RESERVED_0d_2        0x0d, 0x70, 4
#define SR_ANT_SEL              0x0d, 0x80, 7
#define RG_IRQ_MASK     (0x0e)
#define SR_IRQ_MASK             0x0e, 0xff, 0
#define RG_IRQ_STATUS   (0x0f)
#define SR_IRQ_0_PLL_LOCK       0x0f, 0x01, 0
#define SR_IRQ_1_PLL_UNLOCK     0x0f, 0x02, 1
#define SR_IRQ_2_RX_START       0x0f, 0x04, 2
#define SR_IRQ_3_TRX_END        0x0f, 0x08, 3
#define SR_IRQ_4_CCA_ED_DONE    0x0f, 0x10, 4
#define SR_IRQ_5_AMI            0x0f, 0x20, 5
#define SR_IRQ_6_TRX_UR         0x0f, 0x40, 6
#define SR_IRQ_7_BAT_LOW        0x0f, 0x80, 7
#define RG_VREG_CTRL    (0x10)
#define SR_RESERVED_10_6        0x10, 0x03, 0
#define SR_DVDD_OK              0x10, 0x04, 2
#define SR_DVREG_EXT            0x10, 0x08, 3
#define SR_RESERVED_10_3        0x10, 0x30, 4
#define SR_AVDD_OK              0x10, 0x40, 6
#define SR_AVREG_EXT            0x10, 0x80, 7
#define RG_BATMON       (0x11)
#define SR_BATMON_VTH           0x11, 0x0f, 0
#define SR_BATMON_HR            0x11, 0x10, 4
#define SR_BATMON_OK            0x11, 0x20, 5
#define SR_RESERVED_11_1        0x11, 0xc0, 6
#define RG_XOSC_CTRL    (0x12)
#define SR_XTAL_TRIM            0x12, 0x0f, 0
#define SR_XTAL_MODE            0x12, 0xf0, 4
#define RG_RX_SYN       (0x15)
#define SR_RX_PDT_LEVEL         0x15, 0x0f, 0
#define SR_RESERVED_15_2        0x15, 0x70, 4
#define SR_RX_PDT_DIS           0x15, 0x80, 7
#define RG_XAH_CTRL_1   (0x17)
#define SR_RESERVED_17_8        0x17, 0x01, 0
#define SR_AACK_PROM_MODE       0x17, 0x02, 1
#define SR_AACK_ACK_TIME        0x17, 0x04, 2
#define SR_RESERVED_17_5        0x17, 0x08, 3
#define SR_AACK_UPLD_RES_FT     0x17, 0x10, 4
#define SR_AACK_FLTR_RES_FT     0x17, 0x20, 5
#define SR_CSMA_LBT_MODE        0x17, 0x40, 6
#define SR_RESERVED_17_1        0x17, 0x80, 7
#define RG_FTN_CTRL     (0x18)
#define SR_RESERVED_18_2        0x18, 0x7f, 0
#define SR_FTN_START            0x18, 0x80, 7
#define RG_PLL_CF       (0x1a)
#define SR_RESERVED_1a_2        0x1a, 0x7f, 0
#define SR_PLL_CF_START         0x1a, 0x80, 7
#define RG_PLL_DCU      (0x1b)
#define SR_RESERVED_1b_3        0x1b, 0x3f, 0
#define SR_RESERVED_1b_2        0x1b, 0x40, 6
#define SR_PLL_DCU_START        0x1b, 0x80, 7
#define RG_PART_NUM     (0x1c)
#define SR_PART_NUM             0x1c, 0xff, 0
#define RG_VERSION_NUM  (0x1d)
#define SR_VERSION_NUM          0x1d, 0xff, 0
#define RG_MAN_ID_0     (0x1e)
#define SR_MAN_ID_0             0x1e, 0xff, 0
#define RG_MAN_ID_1     (0x1f)
#define SR_MAN_ID_1             0x1f, 0xff, 0
#define RG_SHORT_ADDR_0 (0x20)
#define SR_SHORT_ADDR_0         0x20, 0xff, 0
#define RG_SHORT_ADDR_1 (0x21)
#define SR_SHORT_ADDR_1         0x21, 0xff, 0
#define RG_PAN_ID_0     (0x22)
#define SR_PAN_ID_0             0x22, 0xff, 0
#define RG_PAN_ID_1     (0x23)
#define SR_PAN_ID_1             0x23, 0xff, 0
#define RG_IEEE_ADDR_0  (0x24)
#define SR_IEEE_ADDR_0          0x24, 0xff, 0
#define RG_IEEE_ADDR_1  (0x25)
#define SR_IEEE_ADDR_1          0x25, 0xff, 0
#define RG_IEEE_ADDR_2  (0x26)
#define SR_IEEE_ADDR_2          0x26, 0xff, 0
#define RG_IEEE_ADDR_3  (0x27)
#define SR_IEEE_ADDR_3          0x27, 0xff, 0
#define RG_IEEE_ADDR_4  (0x28)
#define SR_IEEE_ADDR_4          0x28, 0xff, 0
#define RG_IEEE_ADDR_5  (0x29)
#define SR_IEEE_ADDR_5          0x29, 0xff, 0
#define RG_IEEE_ADDR_6  (0x2a)
#define SR_IEEE_ADDR_6          0x2a, 0xff, 0
#define RG_IEEE_ADDR_7  (0x2b)
#define SR_IEEE_ADDR_7          0x2b, 0xff, 0
#define RG_XAH_CTRL_0   (0x2c)
#define SR_SLOTTED_OPERATION    0x2c, 0x01, 0
#define SR_MAX_CSMA_RETRIES     0x2c, 0x0e, 1
#define SR_MAX_FRAME_RETRIES    0x2c, 0xf0, 4
#define RG_CSMA_SEED_0  (0x2d)
#define SR_CSMA_SEED_0          0x2d, 0xff, 0
#define RG_CSMA_SEED_1  (0x2e)
#define SR_CSMA_SEED_1          0x2e, 0x07, 0
#define SR_AACK_I_AM_COORD      0x2e, 0x08, 3
#define SR_AACK_DIS_ACK         0x2e, 0x10, 4
#define SR_AACK_SET_PD          0x2e, 0x20, 5
#define SR_AACK_FVN_MODE        0x2e, 0xc0, 6
#define RG_CSMA_BE      (0x2f)
#define SR_MIN_BE               0x2f, 0x0f, 0
#define SR_MAX_BE               0x2f, 0xf0, 4

#define CMD_REG         0x80
#define CMD_REG_MASK    0x3f
#define CMD_WRITE       0x40
#define CMD_FB          0x20

#define IRQ_BAT_LOW     (1 << 7)
#define IRQ_TRX_UR      (1 << 6)
#define IRQ_AMI         (1 << 5)
#define IRQ_CCA_ED      (1 << 4)
#define IRQ_TRX_END     (1 << 3)
#define IRQ_RX_START    (1 << 2)
#define IRQ_PLL_UNL     (1 << 1)
#define IRQ_PLL_LOCK    (1 << 0)

#define IRQ_ACTIVE_HIGH 0
#define IRQ_ACTIVE_LOW  1

#define STATE_P_ON              0x00    /* BUSY */
#define STATE_BUSY_RX           0x01
#define STATE_BUSY_TX           0x02
#define STATE_FORCE_TRX_OFF     0x03
#define STATE_FORCE_TX_ON       0x04    /* IDLE */
/* 0x05 */                              /* INVALID_PARAMETER */
#define STATE_RX_ON             0x06
/* 0x07 */                              /* SUCCESS */
#define STATE_TRX_OFF           0x08
#define STATE_TX_ON             0x09
/* 0x0a - 0x0e */                       /* 0x0a - UNSUPPORTED_ATTRIBUTE */
#define STATE_SLEEP             0x0F
#define STATE_PREP_DEEP_SLEEP   0x10
#define STATE_BUSY_RX_AACK      0x11
#define STATE_BUSY_TX_ARET      0x12
#define STATE_RX_AACK_ON        0x16
#define STATE_TX_ARET_ON        0x19
#define STATE_RX_ON_NOCLK       0x1C
#define STATE_RX_AACK_ON_NOCLK  0x1D
#define STATE_BUSY_RX_AACK_NOCLK 0x1E
#define STATE_TRANSITION_IN_PROGRESS 0x1F

#define AT86RF2XX_NUMREGS 0x3F

static void
at86rf230_async_state_change(struct at86rf230_local *lp,
                             struct at86rf230_state_change *ctx,
                             const u8 state, void (*complete)(void *context),
                             const bool irq_enable);

static inline int
__at86rf230_write(struct at86rf230_local *lp,
                  unsigned int addr, unsigned int data)
{
        return regmap_write(lp->regmap, addr, data);
}

static inline int
__at86rf230_read(struct at86rf230_local *lp,
                 unsigned int addr, unsigned int *data)
{
        return regmap_read(lp->regmap, addr, data);
}

static inline int
at86rf230_read_subreg(struct at86rf230_local *lp,
                      unsigned int addr, unsigned int mask,
                      unsigned int shift, unsigned int *data)
{
        int rc;

        rc = __at86rf230_read(lp, addr, data);
        if (rc > 0)
                *data = (*data & mask) >> shift;

        return rc;
}

static inline int
at86rf230_write_subreg(struct at86rf230_local *lp,
                       unsigned int addr, unsigned int mask,
                       unsigned int shift, unsigned int data)
{
        return regmap_update_bits(lp->regmap, addr, mask, data << shift);
}

static bool
at86rf230_reg_writeable(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case RG_TRX_STATE:
        case RG_TRX_CTRL_0:
        case RG_TRX_CTRL_1:
        case RG_PHY_TX_PWR:
        case RG_PHY_ED_LEVEL:
        case RG_PHY_CC_CCA:
        case RG_CCA_THRES:
        case RG_RX_CTRL:
        case RG_SFD_VALUE:
        case RG_TRX_CTRL_2:
        case RG_ANT_DIV:
        case RG_IRQ_MASK:
        case RG_VREG_CTRL:
        case RG_BATMON:
        case RG_XOSC_CTRL:
        case RG_RX_SYN:
        case RG_XAH_CTRL_1:
        case RG_FTN_CTRL:
        case RG_PLL_CF:
        case RG_PLL_DCU:
        case RG_SHORT_ADDR_0:
        case RG_SHORT_ADDR_1:
        case RG_PAN_ID_0:
        case RG_PAN_ID_1:
        case RG_IEEE_ADDR_0:
        case RG_IEEE_ADDR_1:
        case RG_IEEE_ADDR_2:
        case RG_IEEE_ADDR_3:
        case RG_IEEE_ADDR_4:
        case RG_IEEE_ADDR_5:
        case RG_IEEE_ADDR_6:
        case RG_IEEE_ADDR_7:
        case RG_XAH_CTRL_0:
        case RG_CSMA_SEED_0:
        case RG_CSMA_SEED_1:
        case RG_CSMA_BE:
                return true;
        default:
                return false;
        }
}

static bool
at86rf230_reg_readable(struct device *dev, unsigned int reg)
{
        bool rc;

        /* all writeable are also readable */
        rc = at86rf230_reg_writeable(dev, reg);
        if (rc)
                return rc;

        /* readonly regs */
        switch (reg) {
        case RG_TRX_STATUS:
        case RG_PHY_RSSI:
        case RG_IRQ_STATUS:
        case RG_PART_NUM:
        case RG_VERSION_NUM:
        case RG_MAN_ID_1:
        case RG_MAN_ID_0:
                return true;
        default:
                return false;
        }
}

static bool
at86rf230_reg_volatile(struct device *dev, unsigned int reg)
{
        /* can be changed during runtime */
        switch (reg) {
        case RG_TRX_STATUS:
        case RG_TRX_STATE:
        case RG_PHY_RSSI:
        case RG_PHY_ED_LEVEL:
        case RG_IRQ_STATUS:
        case RG_VREG_CTRL:
                return true;
        default:
                return false;
        }
}

static bool
at86rf230_reg_precious(struct device *dev, unsigned int reg)
{
        /* don't clear irq line on read */
        switch (reg) {
        case RG_IRQ_STATUS:
                return true;
        default:
                return false;
        }
}

static const struct regmap_config at86rf230_regmap_spi_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .write_flag_mask = CMD_REG | CMD_WRITE,
        .read_flag_mask = CMD_REG,
        .cache_type = REGCACHE_RBTREE,
        .max_register = AT86RF2XX_NUMREGS,
        .writeable_reg = at86rf230_reg_writeable,
        .readable_reg = at86rf230_reg_readable,
        .volatile_reg = at86rf230_reg_volatile,
        .precious_reg = at86rf230_reg_precious,
};

static void
at86rf230_async_error_recover(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;

        at86rf230_async_state_change(lp, ctx, STATE_RX_AACK_ON, NULL, false);
        ieee802154_wake_queue(lp->hw);
}

static inline void
at86rf230_async_error(struct at86rf230_local *lp,
                      struct at86rf230_state_change *ctx, int rc)
{
        dev_err(&lp->spi->dev, "spi_async error %d\n", rc);

        at86rf230_async_state_change(lp, ctx, STATE_FORCE_TRX_OFF,
                                     at86rf230_async_error_recover, false);
}

/* Generic function to get some register value in async mode */
static void
at86rf230_async_read_reg(struct at86rf230_local *lp, const u8 reg,
                         struct at86rf230_state_change *ctx,
                         void (*complete)(void *context),
                         const bool irq_enable)
{
        int rc;

        u8 *tx_buf = ctx->buf;

        tx_buf[0] = (reg & CMD_REG_MASK) | CMD_REG;
        ctx->trx.len = 2;
        ctx->msg.complete = complete;
        ctx->irq_enable = irq_enable;
        rc = spi_async(lp->spi, &ctx->msg);
        if (rc) {
                if (irq_enable)
                        enable_irq(ctx->irq);

                at86rf230_async_error(lp, ctx, rc);
        }
}

static void
at86rf230_async_state_assert(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;
        const u8 *buf = ctx->buf;
        const u8 trx_state = buf[1] & 0x1f;

        /* Assert state change */
        if (trx_state != ctx->to_state) {
                /* Special handling if transceiver state is in
                 * STATE_BUSY_RX_AACK and a SHR was detected.
                 */
                if  (trx_state == STATE_BUSY_RX_AACK) {
                        /* Undocumented race condition. If we send a state
                         * change to STATE_RX_AACK_ON the transceiver could
                         * change his state automatically to STATE_BUSY_RX_AACK
                         * if a SHR was detected. This is not an error, but we
                         * can't assert this.
                         */
                        if (ctx->to_state == STATE_RX_AACK_ON)
                                goto done;

                        /* If we change to STATE_TX_ON without forcing and
                         * transceiver state is STATE_BUSY_RX_AACK, we wait
                         * 'tFrame + tPAck' receiving time. In this time the
                         * PDU should be received. If the transceiver is still
                         * in STATE_BUSY_RX_AACK, we run a force state change
                         * to STATE_TX_ON. This is a timeout handling, if the
                         * transceiver stucks in STATE_BUSY_RX_AACK.
                         *
                         * Additional we do several retries to try to get into
                         * TX_ON state without forcing. If the retries are
                         * higher or equal than AT86RF2XX_MAX_TX_RETRIES we
                         * will do a force change.
                         */
                        if (ctx->to_state == STATE_TX_ON) {
                                u8 state = STATE_TX_ON;

                                if (lp->tx_retry >= AT86RF2XX_MAX_TX_RETRIES)
                                        state = STATE_FORCE_TX_ON;
                                lp->tx_retry++;

                                at86rf230_async_state_change(lp, ctx, state,
                                                             ctx->complete,
                                                             ctx->irq_enable);
                                return;
                        }
                }

                dev_warn(&lp->spi->dev, "unexcept state change from 0x%02x to 0x%02x. Actual state: 0x%02x\n",
                         ctx->from_state, ctx->to_state, trx_state);
        }

done:
        if (ctx->complete)
                ctx->complete(context);
}

/* Do state change timing delay. */
static void
at86rf230_async_state_delay(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;
        struct at86rf2xx_chip_data *c = lp->data;
        bool force = false;

        /* The force state changes are will show as normal states in the
         * state status subregister. We change the to_state to the
         * corresponding one and remember if it was a force change, this
         * differs if we do a state change from STATE_BUSY_RX_AACK.
         */
        switch (ctx->to_state) {
        case STATE_FORCE_TX_ON:
                ctx->to_state = STATE_TX_ON;
                force = true;
                break;
        case STATE_FORCE_TRX_OFF:
                ctx->to_state = STATE_TRX_OFF;
                force = true;
                break;
        default:
                break;
        }

        switch (ctx->from_state) {
        case STATE_TRX_OFF:
                switch (ctx->to_state) {
                case STATE_RX_AACK_ON:
                        usleep_range(c->t_off_to_aack, c->t_off_to_aack + 10);
                        goto change;
                case STATE_TX_ON:
                        usleep_range(c->t_off_to_tx_on,
                                     c->t_off_to_tx_on + 10);
                        goto change;
                default:
                        break;
                }
                break;
        case STATE_BUSY_RX_AACK:
                switch (ctx->to_state) {
                case STATE_TX_ON:
                        /* Wait for worst case receiving time if we
                         * didn't make a force change from BUSY_RX_AACK
                         * to TX_ON.
                         */
                        if (!force) {
                                usleep_range(c->t_frame + c->t_p_ack,
                                             c->t_frame + c->t_p_ack + 1000);
                                goto change;
                        }
                        break;
                default:
                        break;
                }
                break;
        /* Default value, means RESET state */
        case STATE_P_ON:
                switch (ctx->to_state) {
                case STATE_TRX_OFF:
                        usleep_range(c->t_reset_to_off, c->t_reset_to_off + 10);
                        goto change;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        /* Default delay is 1us in the most cases */
        udelay(1);

change:
        at86rf230_async_read_reg(lp, RG_TRX_STATUS, ctx,
                                 at86rf230_async_state_assert,
                                 ctx->irq_enable);
}

static void
at86rf230_async_state_change_start(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;
        u8 *buf = ctx->buf;
        const u8 trx_state = buf[1] & 0x1f;
        int rc;

        /* Check for "possible" STATE_TRANSITION_IN_PROGRESS */
        if (trx_state == STATE_TRANSITION_IN_PROGRESS) {
                udelay(1);
                at86rf230_async_read_reg(lp, RG_TRX_STATUS, ctx,
                                         at86rf230_async_state_change_start,
                                         ctx->irq_enable);
                return;
        }

        /* Check if we already are in the state which we change in */
        if (trx_state == ctx->to_state) {
                if (ctx->complete)
                        ctx->complete(context);
                return;
        }

        /* Set current state to the context of state change */
        ctx->from_state = trx_state;

        /* Going into the next step for a state change which do a timing
         * relevant delay.
         */
        buf[0] = (RG_TRX_STATE & CMD_REG_MASK) | CMD_REG | CMD_WRITE;
        buf[1] = ctx->to_state;
        ctx->trx.len = 2;
        ctx->msg.complete = at86rf230_async_state_delay;
        rc = spi_async(lp->spi, &ctx->msg);
        if (rc) {
                if (ctx->irq_enable)
                        enable_irq(ctx->irq);

                at86rf230_async_error(lp, ctx, rc);
        }
}

static void
at86rf230_async_state_change(struct at86rf230_local *lp,
                             struct at86rf230_state_change *ctx,
                             const u8 state, void (*complete)(void *context),
                             const bool irq_enable)
{
        /* Initialization for the state change context */
        ctx->to_state = state;
        ctx->complete = complete;
        ctx->irq_enable = irq_enable;
        at86rf230_async_read_reg(lp, RG_TRX_STATUS, ctx,
                                 at86rf230_async_state_change_start,
                                 irq_enable);
}

static void
at86rf230_sync_state_change_complete(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;

        complete(&lp->state_complete);
}

/* This function do a sync framework above the async state change.
 * Some callbacks of the IEEE 802.15.4 driver interface need to be
 * handled synchronously.
 */
static int
at86rf230_sync_state_change(struct at86rf230_local *lp, unsigned int state)
{
        unsigned long rc;

        at86rf230_async_state_change(lp, &lp->state, state,
                                     at86rf230_sync_state_change_complete,
                                     false);

        rc = wait_for_completion_timeout(&lp->state_complete,
                                         msecs_to_jiffies(100));
        if (!rc) {
                at86rf230_async_error(lp, &lp->state, -ETIMEDOUT);
                return -ETIMEDOUT;
        }

        return 0;
}

static void
at86rf230_tx_complete(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;

        enable_irq(ctx->irq);

        ieee802154_xmit_complete(lp->hw, lp->tx_skb, !lp->tx_aret);
}

static void
at86rf230_tx_on(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;

        at86rf230_async_state_change(lp, ctx, STATE_RX_AACK_ON,
                                     at86rf230_tx_complete, true);
}

static void
at86rf230_tx_trac_error(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;

        at86rf230_async_state_change(lp, ctx, STATE_TX_ON,
                                     at86rf230_tx_on, true);
}

static void
at86rf230_tx_trac_check(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;
        const u8 *buf = ctx->buf;
        const u8 trac = (buf[1] & 0xe0) >> 5;

        /* If trac status is different than zero we need to do a state change
         * to STATE_FORCE_TRX_OFF then STATE_TX_ON to recover the transceiver
         * state to TX_ON.
         */
        if (trac)
                at86rf230_async_state_change(lp, ctx, STATE_FORCE_TRX_OFF,
                                             at86rf230_tx_trac_error, true);
        else
                at86rf230_tx_on(context);
}

static void
at86rf230_tx_trac_status(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;

        at86rf230_async_read_reg(lp, RG_TRX_STATE, ctx,
                                 at86rf230_tx_trac_check, true);
}

static void
at86rf230_rx_read_frame_complete(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;
        u8 rx_local_buf[AT86RF2XX_MAX_BUF];
        const u8 *buf = ctx->buf;
        struct sk_buff *skb;
        u8 len, lqi;

        len = buf[1];
        if (!ieee802154_is_valid_psdu_len(len)) {
                dev_vdbg(&lp->spi->dev, "corrupted frame received\n");
                len = IEEE802154_MTU;
        }
        lqi = buf[2 + len];

        memcpy(rx_local_buf, buf + 2, len);
        enable_irq(ctx->irq);

        skb = dev_alloc_skb(IEEE802154_MTU);
        if (!skb) {
                dev_vdbg(&lp->spi->dev, "failed to allocate sk_buff\n");
                return;
        }

        memcpy(skb_put(skb, len), rx_local_buf, len);
        ieee802154_rx_irqsafe(lp->hw, skb, lqi);
}

static void
at86rf230_rx_read_frame(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;
        u8 *buf = ctx->buf;
        int rc;

        buf[0] = CMD_FB;
        ctx->trx.len = AT86RF2XX_MAX_BUF;
        ctx->msg.complete = at86rf230_rx_read_frame_complete;
        rc = spi_async(lp->spi, &ctx->msg);
        if (rc) {
                enable_irq(ctx->irq);
                at86rf230_async_error(lp, ctx, rc);
        }
}

static void
at86rf230_rx_trac_check(void *context)
{
        /* Possible check on trac status here. This could be useful to make
         * some stats why receive is failed. Not used at the moment, but it's
         * maybe timing relevant. Datasheet doesn't say anything about this.
         * The programming guide say do it so.
         */

        at86rf230_rx_read_frame(context);
}

static void
at86rf230_irq_trx_end(struct at86rf230_local *lp)
{
        spin_lock(&lp->lock);
        if (lp->is_tx) {
                lp->is_tx = 0;
                spin_unlock(&lp->lock);

                if (lp->tx_aret)
                        at86rf230_async_state_change(lp, &lp->irq,
                                                     STATE_FORCE_TX_ON,
                                                     at86rf230_tx_trac_status,
                                                     true);
                else
                        at86rf230_async_state_change(lp, &lp->irq,
                                                     STATE_RX_AACK_ON,
                                                     at86rf230_tx_complete,
                                                     true);
        } else {
                spin_unlock(&lp->lock);
                at86rf230_async_read_reg(lp, RG_TRX_STATE, &lp->irq,
                                         at86rf230_rx_trac_check, true);
        }
}

static void
at86rf230_irq_status(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;
        const u8 *buf = ctx->buf;
        const u8 irq = buf[1];

        if (irq & IRQ_TRX_END) {
                at86rf230_irq_trx_end(lp);
        } else {
                enable_irq(ctx->irq);
                dev_err(&lp->spi->dev, "not supported irq %02x received\n",
                        irq);
        }
}

static irqreturn_t at86rf230_isr(int irq, void *data)
{
        struct at86rf230_local *lp = data;
        struct at86rf230_state_change *ctx = &lp->irq;
        u8 *buf = ctx->buf;
        int rc;

        disable_irq_nosync(irq);

        buf[0] = (RG_IRQ_STATUS & CMD_REG_MASK) | CMD_REG;
        ctx->trx.len = 2;
        ctx->msg.complete = at86rf230_irq_status;
        rc = spi_async(lp->spi, &ctx->msg);
        if (rc) {
                enable_irq(irq);
                at86rf230_async_error(lp, ctx, rc);
                return IRQ_NONE;
        }

        return IRQ_HANDLED;
}

static void
at86rf230_write_frame_complete(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;
        u8 *buf = ctx->buf;
        int rc;

        buf[0] = (RG_TRX_STATE & CMD_REG_MASK) | CMD_REG | CMD_WRITE;
        buf[1] = STATE_BUSY_TX;
        ctx->trx.len = 2;
        ctx->msg.complete = NULL;
        rc = spi_async(lp->spi, &ctx->msg);
        if (rc)
                at86rf230_async_error(lp, ctx, rc);
}

static void
at86rf230_write_frame(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;
        struct sk_buff *skb = lp->tx_skb;
        u8 *buf = ctx->buf;
        int rc;

        spin_lock(&lp->lock);
        lp->is_tx = 1;
        spin_unlock(&lp->lock);

        buf[0] = CMD_FB | CMD_WRITE;
        buf[1] = skb->len + 2;
        memcpy(buf + 2, skb->data, skb->len);
        ctx->trx.len = skb->len + 2;
        ctx->msg.complete = at86rf230_write_frame_complete;
        rc = spi_async(lp->spi, &ctx->msg);
        if (rc)
                at86rf230_async_error(lp, ctx, rc);
}

static void
at86rf230_xmit_tx_on(void *context)
{
        struct at86rf230_state_change *ctx = context;
        struct at86rf230_local *lp = ctx->lp;

        at86rf230_async_state_change(lp, ctx, STATE_TX_ARET_ON,
                                     at86rf230_write_frame, false);
}

static int
at86rf230_xmit(struct ieee802154_hw *hw, struct sk_buff *skb)
{
        struct at86rf230_local *lp = hw->priv;
        struct at86rf230_state_change *ctx = &lp->tx;

        void (*tx_complete)(void *context) = at86rf230_write_frame;

        lp->tx_skb = skb;

        /* In ARET mode we need to go into STATE_TX_ARET_ON after we
         * are in STATE_TX_ON. The pfad differs here, so we change
         * the complete handler.
         */
        if (lp->tx_aret)
                tx_complete = at86rf230_xmit_tx_on;

        lp->tx_retry = 0;
        at86rf230_async_state_change(lp, ctx, STATE_TX_ON, tx_complete, false);

        return 0;
}

static int
at86rf230_ed(struct ieee802154_hw *hw, u8 *level)
{
        BUG_ON(!level);
        *level = 0xbe;
        return 0;
}

static int
at86rf230_start(struct ieee802154_hw *hw)
{
        return at86rf230_sync_state_change(hw->priv, STATE_RX_AACK_ON);
}

static void
at86rf230_stop(struct ieee802154_hw *hw)
{
        at86rf230_sync_state_change(hw->priv, STATE_FORCE_TRX_OFF);
}

static int
at86rf23x_set_channel(struct at86rf230_local *lp, u8 page, u8 channel)
{
        return at86rf230_write_subreg(lp, SR_CHANNEL, channel);
}

static int
at86rf212_set_channel(struct at86rf230_local *lp, u8 page, u8 channel)
{
        int rc;

        if (channel == 0)
                rc = at86rf230_write_subreg(lp, SR_SUB_MODE, 0);
        else
                rc = at86rf230_write_subreg(lp, SR_SUB_MODE, 1);
        if (rc < 0)
                return rc;

        if (page == 0) {
                rc = at86rf230_write_subreg(lp, SR_BPSK_QPSK, 0);
                lp->data->rssi_base_val = -100;
        } else {
                rc = at86rf230_write_subreg(lp, SR_BPSK_QPSK, 1);
                lp->data->rssi_base_val = -98;
        }
        if (rc < 0)
                return rc;

        /* This sets the symbol_duration according frequency on the 212.
         * TODO move this handling while set channel and page in cfg802154.
         * We can do that, this timings are according 802.15.4 standard.
         * If we do that in cfg802154, this is a more generic calculation.
         *
         * This should also protected from ifs_timer. Means cancel timer and
         * init with a new value. For now, this is okay.
         */
        if (channel == 0) {
                if (page == 0) {
                        /* SUB:0 and BPSK:0 -> BPSK-20 */
                        lp->hw->phy->symbol_duration = 50;
                } else {
                        /* SUB:1 and BPSK:0 -> BPSK-40 */
                        lp->hw->phy->symbol_duration = 25;
                }
        } else {
                if (page == 0)
                        /* SUB:0 and BPSK:1 -> OQPSK-100/200/400 */
                        lp->hw->phy->symbol_duration = 40;
                else
                        /* SUB:1 and BPSK:1 -> OQPSK-250/500/1000 */
                        lp->hw->phy->symbol_duration = 16;
        }

        lp->hw->phy->lifs_period = IEEE802154_LIFS_PERIOD *
                                   lp->hw->phy->symbol_duration;
        lp->hw->phy->sifs_period = IEEE802154_SIFS_PERIOD *
                                   lp->hw->phy->symbol_duration;

        return at86rf230_write_subreg(lp, SR_CHANNEL, channel);
}

static int
at86rf230_channel(struct ieee802154_hw *hw, u8 page, u8 channel)
{
        struct at86rf230_local *lp = hw->priv;
        int rc;

        rc = lp->data->set_channel(lp, page, channel);
        /* Wait for PLL */
        usleep_range(lp->data->t_channel_switch,
                     lp->data->t_channel_switch + 10);
        return rc;
}

static int
at86rf230_set_hw_addr_filt(struct ieee802154_hw *hw,
                           struct ieee802154_hw_addr_filt *filt,
                           unsigned long changed)
{
        struct at86rf230_local *lp = hw->priv;

        if (changed & IEEE802154_AFILT_SADDR_CHANGED) {
                u16 addr = le16_to_cpu(filt->short_addr);

                dev_vdbg(&lp->spi->dev,
                         "at86rf230_set_hw_addr_filt called for saddr\n");
                __at86rf230_write(lp, RG_SHORT_ADDR_0, addr);
                __at86rf230_write(lp, RG_SHORT_ADDR_1, addr >> 8);
        }

        if (changed & IEEE802154_AFILT_PANID_CHANGED) {
                u16 pan = le16_to_cpu(filt->pan_id);

                dev_vdbg(&lp->spi->dev,
                         "at86rf230_set_hw_addr_filt called for pan id\n");
                __at86rf230_write(lp, RG_PAN_ID_0, pan);
                __at86rf230_write(lp, RG_PAN_ID_1, pan >> 8);
        }

        if (changed & IEEE802154_AFILT_IEEEADDR_CHANGED) {
                u8 i, addr[8];

                memcpy(addr, &filt->ieee_addr, 8);
                dev_vdbg(&lp->spi->dev,
                         "at86rf230_set_hw_addr_filt called for IEEE addr\n");
                for (i = 0; i < 8; i++)
                        __at86rf230_write(lp, RG_IEEE_ADDR_0 + i, addr[i]);
        }

        if (changed & IEEE802154_AFILT_PANC_CHANGED) {
                dev_vdbg(&lp->spi->dev,
                         "at86rf230_set_hw_addr_filt called for panc change\n");
                if (filt->pan_coord)
                        at86rf230_write_subreg(lp, SR_AACK_I_AM_COORD, 1);
                else
                        at86rf230_write_subreg(lp, SR_AACK_I_AM_COORD, 0);
        }

        return 0;
}

static int
at86rf230_set_txpower(struct ieee802154_hw *hw, int db)
{
        struct at86rf230_local *lp = hw->priv;

        /* typical maximum output is 5dBm with RG_PHY_TX_PWR 0x60, lower five
         * bits decrease power in 1dB steps. 0x60 represents extra PA gain of
         * 0dB.
         * thus, supported values for db range from -26 to 5, for 31dB of
         * reduction to 0dB of reduction.
         */
        if (db > 5 || db < -26)
                return -EINVAL;

        db = -(db - 5);

        return __at86rf230_write(lp, RG_PHY_TX_PWR, 0x60 | db);
}

static int
at86rf230_set_lbt(struct ieee802154_hw *hw, bool on)
{
        struct at86rf230_local *lp = hw->priv;

        return at86rf230_write_subreg(lp, SR_CSMA_LBT_MODE, on);
}

static int
at86rf230_set_cca_mode(struct ieee802154_hw *hw,
                       const struct wpan_phy_cca *cca)
{
        struct at86rf230_local *lp = hw->priv;
        u8 val;

        /* mapping 802.15.4 to driver spec */
        switch (cca->mode) {
        case NL802154_CCA_ENERGY:
                val = 1;
                break;
        case NL802154_CCA_CARRIER:
                val = 2;
                break;
        case NL802154_CCA_ENERGY_CARRIER:
                switch (cca->opt) {
                case NL802154_CCA_OPT_ENERGY_CARRIER_AND:
                        val = 3;
                        break;
                case NL802154_CCA_OPT_ENERGY_CARRIER_OR:
                        val = 0;
                        break;
                default:
                        return -EINVAL;
                }
                break;
        default:
                return -EINVAL;
        }

        return at86rf230_write_subreg(lp, SR_CCA_MODE, val);
}

static int
at86rf212_get_desens_steps(struct at86rf230_local *lp, s32 level)
{
        return (level - lp->data->rssi_base_val) * 100 / 207;
}

static int
at86rf23x_get_desens_steps(struct at86rf230_local *lp, s32 level)
{
        return (level - lp->data->rssi_base_val) / 2;
}

static int
at86rf230_set_cca_ed_level(struct ieee802154_hw *hw, s32 level)
{
        struct at86rf230_local *lp = hw->priv;

        if (level < lp->data->rssi_base_val || level > 30)
                return -EINVAL;

        return at86rf230_write_subreg(lp, SR_CCA_ED_THRES,
                                      lp->data->get_desense_steps(lp, level));
}

static int
at86rf230_set_csma_params(struct ieee802154_hw *hw, u8 min_be, u8 max_be,
                          u8 retries)
{
        struct at86rf230_local *lp = hw->priv;
        int rc;

        rc = at86rf230_write_subreg(lp, SR_MIN_BE, min_be);
        if (rc)
                return rc;

        rc = at86rf230_write_subreg(lp, SR_MAX_BE, max_be);
        if (rc)
                return rc;

        return at86rf230_write_subreg(lp, SR_MAX_CSMA_RETRIES, retries);
}

static int
at86rf230_set_frame_retries(struct ieee802154_hw *hw, s8 retries)
{
        struct at86rf230_local *lp = hw->priv;
        int rc = 0;

        lp->tx_aret = retries >= 0;
        lp->max_frame_retries = retries;

        if (retries >= 0)
                rc = at86rf230_write_subreg(lp, SR_MAX_FRAME_RETRIES, retries);

        return rc;
}

static int
at86rf230_set_promiscuous_mode(struct ieee802154_hw *hw, const bool on)
{
        struct at86rf230_local *lp = hw->priv;
        int rc;

        if (on) {
                rc = at86rf230_write_subreg(lp, SR_AACK_DIS_ACK, 1);
                if (rc < 0)
                        return rc;

                rc = at86rf230_write_subreg(lp, SR_AACK_PROM_MODE, 1);
                if (rc < 0)
                        return rc;
        } else {
                rc = at86rf230_write_subreg(lp, SR_AACK_PROM_MODE, 0);
                if (rc < 0)
                        return rc;

                rc = at86rf230_write_subreg(lp, SR_AACK_DIS_ACK, 0);
                if (rc < 0)
                        return rc;
        }

        return 0;
}

static const struct ieee802154_ops at86rf230_ops = {
        .owner = THIS_MODULE,
        .xmit_async = at86rf230_xmit,
        .ed = at86rf230_ed,
        .set_channel = at86rf230_channel,
        .start = at86rf230_start,
        .stop = at86rf230_stop,
        .set_hw_addr_filt = at86rf230_set_hw_addr_filt,
        .set_txpower = at86rf230_set_txpower,
        .set_lbt = at86rf230_set_lbt,
        .set_cca_mode = at86rf230_set_cca_mode,
        .set_cca_ed_level = at86rf230_set_cca_ed_level,
        .set_csma_params = at86rf230_set_csma_params,
        .set_frame_retries = at86rf230_set_frame_retries,
        .set_promiscuous_mode = at86rf230_set_promiscuous_mode,
};

static struct at86rf2xx_chip_data at86rf233_data = {
        .t_sleep_cycle = 330,
        .t_channel_switch = 11,
        .t_reset_to_off = 26,
        .t_off_to_aack = 80,
        .t_off_to_tx_on = 80,
        .t_frame = 4096,
        .t_p_ack = 545,
        .rssi_base_val = -91,
        .set_channel = at86rf23x_set_channel,
        .get_desense_steps = at86rf23x_get_desens_steps
};

static struct at86rf2xx_chip_data at86rf231_data = {
        .t_sleep_cycle = 330,
        .t_channel_switch = 24,
        .t_reset_to_off = 37,
        .t_off_to_aack = 110,
        .t_off_to_tx_on = 110,
        .t_frame = 4096,
        .t_p_ack = 545,
        .rssi_base_val = -91,
        .set_channel = at86rf23x_set_channel,
        .get_desense_steps = at86rf23x_get_desens_steps
};

static struct at86rf2xx_chip_data at86rf212_data = {
        .t_sleep_cycle = 330,
        .t_channel_switch = 11,
        .t_reset_to_off = 26,
        .t_off_to_aack = 200,
        .t_off_to_tx_on = 200,
        .t_frame = 4096,
        .t_p_ack = 545,
        .rssi_base_val = -100,
        .set_channel = at86rf212_set_channel,
        .get_desense_steps = at86rf212_get_desens_steps
};

static int at86rf230_hw_init(struct at86rf230_local *lp, u8 xtal_trim)
{
        int rc, irq_type, irq_pol = IRQ_ACTIVE_HIGH;
        unsigned int dvdd;
        u8 csma_seed[2];

        rc = at86rf230_sync_state_change(lp, STATE_FORCE_TRX_OFF);
        if (rc)
                return rc;

        irq_type = irq_get_trigger_type(lp->spi->irq);
        if (irq_type == IRQ_TYPE_EDGE_RISING ||
            irq_type == IRQ_TYPE_EDGE_FALLING)
                dev_warn(&lp->spi->dev,
                         "Using edge triggered irq's are not recommended!\n");
        if (irq_type == IRQ_TYPE_EDGE_FALLING ||
            irq_type == IRQ_TYPE_LEVEL_LOW)
                irq_pol = IRQ_ACTIVE_LOW;

        rc = at86rf230_write_subreg(lp, SR_IRQ_POLARITY, irq_pol);
        if (rc)
                return rc;

        rc = at86rf230_write_subreg(lp, SR_RX_SAFE_MODE, 1);
        if (rc)
                return rc;

        rc = at86rf230_write_subreg(lp, SR_IRQ_MASK, IRQ_TRX_END);
        if (rc)
                return rc;

        /* reset values differs in at86rf231 and at86rf233 */
        rc = at86rf230_write_subreg(lp, SR_IRQ_MASK_MODE, 0);
        if (rc)
                return rc;

        get_random_bytes(csma_seed, ARRAY_SIZE(csma_seed));
        rc = at86rf230_write_subreg(lp, SR_CSMA_SEED_0, csma_seed[0]);
        if (rc)
                return rc;
        rc = at86rf230_write_subreg(lp, SR_CSMA_SEED_1, csma_seed[1]);
        if (rc)
                return rc;

        /* CLKM changes are applied immediately */
        rc = at86rf230_write_subreg(lp, SR_CLKM_SHA_SEL, 0x00);
        if (rc)
                return rc;

        /* Turn CLKM Off */
        rc = at86rf230_write_subreg(lp, SR_CLKM_CTRL, 0x00);
        if (rc)
                return rc;
        /* Wait the next SLEEP cycle */
        usleep_range(lp->data->t_sleep_cycle,
                     lp->data->t_sleep_cycle + 100);

        /* xtal_trim value is calculated by:
         * CL = 0.5 * (CX + CTRIM + CPAR)
         *
         * whereas:
         * CL = capacitor of used crystal
         * CX = connected capacitors at xtal pins
         * CPAR = in all at86rf2xx datasheets this is a constant value 3 pF,
         *        but this is different on each board setup. You need to fine
         *        tuning this value via CTRIM.
         * CTRIM = variable capacitor setting. Resolution is 0.3 pF range is
         *         0 pF upto 4.5 pF.
         *
         * Examples:
         * atben transceiver:
         *
         * CL = 8 pF
         * CX = 12 pF
         * CPAR = 3 pF (We assume the magic constant from datasheet)
         * CTRIM = 0.9 pF
         *
         * (12+0.9+3)/2 = 7.95 which is nearly at 8 pF
         *
         * xtal_trim = 0x3
         *
         * openlabs transceiver:
         *
         * CL = 16 pF
         * CX = 22 pF
         * CPAR = 3 pF (We assume the magic constant from datasheet)
         * CTRIM = 4.5 pF
         *
         * (22+4.5+3)/2 = 14.75 which is the nearest value to 16 pF
         *
         * xtal_trim = 0xf
         */
        rc = at86rf230_write_subreg(lp, SR_XTAL_TRIM, xtal_trim);
        if (rc)
                return rc;

        rc = at86rf230_read_subreg(lp, SR_DVDD_OK, &dvdd);
        if (rc)
                return rc;
        if (!dvdd) {
                dev_err(&lp->spi->dev, "DVDD error\n");
                return -EINVAL;
        }

        /* Force setting slotted operation bit to 0. Sometimes the atben
         * sets this bit and I don't know why. We set this always force
         * to zero while probing.
         */
        return at86rf230_write_subreg(lp, SR_SLOTTED_OPERATION, 0);
}

static int
at86rf230_get_pdata(struct spi_device *spi, int *rstn, int *slp_tr,
                    u8 *xtal_trim)
{
        struct at86rf230_platform_data *pdata = spi->dev.platform_data;
        int ret;

        if (!IS_ENABLED(CONFIG_OF) || !spi->dev.of_node) {
                if (!pdata)
                        return -ENOENT;

                *rstn = pdata->rstn;
                *slp_tr = pdata->slp_tr;
                *xtal_trim = pdata->xtal_trim;
                return 0;
        }

        *rstn = of_get_named_gpio(spi->dev.of_node, "reset-gpio", 0);
        *slp_tr = of_get_named_gpio(spi->dev.of_node, "sleep-gpio", 0);
        ret = of_property_read_u8(spi->dev.of_node, "xtal-trim", xtal_trim);
        if (ret < 0 && ret != -EINVAL)
                return ret;

        return 0;
}

static int
at86rf230_detect_device(struct at86rf230_local *lp)
{
        unsigned int part, version, val;
        u16 man_id = 0;
        const char *chip;
        int rc;

        rc = __at86rf230_read(lp, RG_MAN_ID_0, &val);
        if (rc)
                return rc;
        man_id |= val;

        rc = __at86rf230_read(lp, RG_MAN_ID_1, &val);
        if (rc)
                return rc;
        man_id |= (val << 8);

        rc = __at86rf230_read(lp, RG_PART_NUM, &part);
        if (rc)
                return rc;

        rc = __at86rf230_read(lp, RG_VERSION_NUM, &version);
        if (rc)
                return rc;

        if (man_id != 0x001f) {
                dev_err(&lp->spi->dev, "Non-Atmel dev found (MAN_ID %02x %02x)\n",
                        man_id >> 8, man_id & 0xFF);
                return -EINVAL;
        }

        lp->hw->flags = IEEE802154_HW_TX_OMIT_CKSUM | IEEE802154_HW_AACK |
                        IEEE802154_HW_TXPOWER | IEEE802154_HW_ARET |
                        IEEE802154_HW_AFILT | IEEE802154_HW_PROMISCUOUS;

        lp->hw->phy->cca.mode = NL802154_CCA_ENERGY;

        switch (part) {
        case 2:
                chip = "at86rf230";
                rc = -ENOTSUPP;
                break;
        case 3:
                chip = "at86rf231";
                lp->data = &at86rf231_data;
                lp->hw->phy->channels_supported[0] = 0x7FFF800;
                lp->hw->phy->current_channel = 11;
                lp->hw->phy->symbol_duration = 16;
                break;
        case 7:
                chip = "at86rf212";
                lp->data = &at86rf212_data;
                lp->hw->flags |= IEEE802154_HW_LBT;
                lp->hw->phy->channels_supported[0] = 0x00007FF;
                lp->hw->phy->channels_supported[2] = 0x00007FF;
                lp->hw->phy->current_channel = 5;
                lp->hw->phy->symbol_duration = 25;
                break;
        case 11:
                chip = "at86rf233";
                lp->data = &at86rf233_data;
                lp->hw->phy->channels_supported[0] = 0x7FFF800;
                lp->hw->phy->current_channel = 13;
                lp->hw->phy->symbol_duration = 16;
                break;
        default:
                chip = "unknown";
                rc = -ENOTSUPP;
                break;
        }

        dev_info(&lp->spi->dev, "Detected %s chip version %d\n", chip, version);

        return rc;
}

static void
at86rf230_setup_spi_messages(struct at86rf230_local *lp)
{
        lp->state.lp = lp;
        lp->state.irq = lp->spi->irq;
        spi_message_init(&lp->state.msg);
        lp->state.msg.context = &lp->state;
        lp->state.trx.tx_buf = lp->state.buf;
        lp->state.trx.rx_buf = lp->state.buf;
        spi_message_add_tail(&lp->state.trx, &lp->state.msg);

        lp->irq.lp = lp;
        lp->irq.irq = lp->spi->irq;
        spi_message_init(&lp->irq.msg);
        lp->irq.msg.context = &lp->irq;
        lp->irq.trx.tx_buf = lp->irq.buf;
        lp->irq.trx.rx_buf = lp->irq.buf;
        spi_message_add_tail(&lp->irq.trx, &lp->irq.msg);

        lp->tx.lp = lp;
        lp->tx.irq = lp->spi->irq;
        spi_message_init(&lp->tx.msg);
        lp->tx.msg.context = &lp->tx;
        lp->tx.trx.tx_buf = lp->tx.buf;
        lp->tx.trx.rx_buf = lp->tx.buf;
        spi_message_add_tail(&lp->tx.trx, &lp->tx.msg);
}

static int at86rf230_probe(struct spi_device *spi)
{
        struct ieee802154_hw *hw;
        struct at86rf230_local *lp;
        unsigned int status;
        int rc, irq_type, rstn, slp_tr;
        u8 xtal_trim;

        if (!spi->irq) {
                dev_err(&spi->dev, "no IRQ specified\n");
                return -EINVAL;
        }

        rc = at86rf230_get_pdata(spi, &rstn, &slp_tr, &xtal_trim);
        if (rc < 0) {
                dev_err(&spi->dev, "failed to parse platform_data: %d\n", rc);
                return rc;
        }

        if (gpio_is_valid(rstn)) {
                rc = devm_gpio_request_one(&spi->dev, rstn,
                                           GPIOF_OUT_INIT_HIGH, "rstn");
                if (rc)
                        return rc;
        }

        if (gpio_is_valid(slp_tr)) {
                rc = devm_gpio_request_one(&spi->dev, slp_tr,
                                           GPIOF_OUT_INIT_LOW, "slp_tr");
                if (rc)
                        return rc;
        }

        /* Reset */
        if (gpio_is_valid(rstn)) {
                udelay(1);
                gpio_set_value(rstn, 0);
                udelay(1);
                gpio_set_value(rstn, 1);
                usleep_range(120, 240);
        }

        hw = ieee802154_alloc_hw(sizeof(*lp), &at86rf230_ops);
        if (!hw)
                return -ENOMEM;

        lp = hw->priv;
        lp->hw = hw;
        lp->spi = spi;
        hw->parent = &spi->dev;
        hw->vif_data_size = sizeof(*lp);
        ieee802154_random_extended_addr(&hw->phy->perm_extended_addr);

        lp->regmap = devm_regmap_init_spi(spi, &at86rf230_regmap_spi_config);
        if (IS_ERR(lp->regmap)) {
                rc = PTR_ERR(lp->regmap);
                dev_err(&spi->dev, "Failed to allocate register map: %d\n",
                        rc);
                goto free_dev;
        }

        at86rf230_setup_spi_messages(lp);

        rc = at86rf230_detect_device(lp);
        if (rc < 0)
                goto free_dev;

        spin_lock_init(&lp->lock);
        init_completion(&lp->state_complete);

        spi_set_drvdata(spi, lp);

        rc = at86rf230_hw_init(lp, xtal_trim);
        if (rc)
                goto free_dev;

        /* Read irq status register to reset irq line */
        rc = at86rf230_read_subreg(lp, RG_IRQ_STATUS, 0xff, 0, &status);
        if (rc)
                goto free_dev;

        irq_type = irq_get_trigger_type(spi->irq);
        if (!irq_type)
                irq_type = IRQF_TRIGGER_RISING;

        rc = devm_request_irq(&spi->dev, spi->irq, at86rf230_isr,
                              IRQF_SHARED | irq_type, dev_name(&spi->dev), lp);
        if (rc)
                goto free_dev;

        rc = ieee802154_register_hw(lp->hw);
        if (rc)
                goto free_dev;

        return rc;

free_dev:
        ieee802154_free_hw(lp->hw);

        return rc;
}

static int at86rf230_remove(struct spi_device *spi)
{
        struct at86rf230_local *lp = spi_get_drvdata(spi);

        /* mask all at86rf230 irq's */
        at86rf230_write_subreg(lp, SR_IRQ_MASK, 0);
        ieee802154_unregister_hw(lp->hw);
        ieee802154_free_hw(lp->hw);
        dev_dbg(&spi->dev, "unregistered at86rf230\n");

        return 0;
}

static const struct of_device_id at86rf230_of_match[] = {
        { .compatible = "atmel,at86rf230", },
        { .compatible = "atmel,at86rf231", },
        { .compatible = "atmel,at86rf233", },
        { .compatible = "atmel,at86rf212", },
        { },
};
MODULE_DEVICE_TABLE(of, at86rf230_of_match);

static const struct spi_device_id at86rf230_device_id[] = {
        { .name = "at86rf230", },
        { .name = "at86rf231", },
        { .name = "at86rf233", },
        { .name = "at86rf212", },
        { },
};
MODULE_DEVICE_TABLE(spi, at86rf230_device_id);

static struct spi_driver at86rf230_driver = {
        .id_table = at86rf230_device_id,
        .driver = {
                .of_match_table = of_match_ptr(at86rf230_of_match),
                .name   = "at86rf230",
                .owner  = THIS_MODULE,
        },
        .probe      = at86rf230_probe,
        .remove     = at86rf230_remove,
};

module_spi_driver(at86rf230_driver);

MODULE_DESCRIPTION("AT86RF230 Transceiver Driver");
MODULE_LICENSE("GPL v2");