drivers/mfd/mc13xxx-spi.c

   1 /*
   2  * Copyright 2009-2010 Pengutronix
   3  * Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
   4  *
   5  * loosely based on an earlier driver that has
   6  * Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it under
   9  * the terms of the GNU General Public License version 2 as published by the
  10  * Free Software Foundation.
  11  */
  12
  13 #include <linux/slab.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/mutex.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/mfd/core.h>
  19 #include <linux/mfd/mc13xxx.h>
  20 #include <linux/of.h>
  21 #include <linux/of_device.h>
  22 #include <linux/of_gpio.h>
  23 #include <linux/err.h>
  24 #include <linux/spi/spi.h>
  25
  26 #include "mc13xxx.h"
  27
  28 static const struct spi_device_id mc13xxx_device_id[] = {
  29         {
  30                 .name = "mc13783",
  31                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13783,
  32         }, {
  33                 .name = "mc13892",
  34                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13892,
  35         }, {
  36                 .name = "mc34708",
  37                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc34708,
  38         }, {
  39                 /* sentinel */
  40         }
  41 };
  42 MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);
  43
  44 static const struct of_device_id mc13xxx_dt_ids[] = {
  45         { .compatible = "fsl,mc13783", .data = &mc13xxx_variant_mc13783, },
  46         { .compatible = "fsl,mc13892", .data = &mc13xxx_variant_mc13892, },
  47         { .compatible = "fsl,mc34708", .data = &mc13xxx_variant_mc34708, },
  48         { /* sentinel */ }
  49 };
  50 MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);
  51
  52 static struct regmap_config mc13xxx_regmap_spi_config = {
  53         .reg_bits = 7,
  54         .pad_bits = 1,
  55         .val_bits = 24,
  56         .write_flag_mask = 0x80,
  57
  58         .max_register = MC13XXX_NUMREGS,
  59
  60         .cache_type = REGCACHE_NONE,
  61         .use_single_rw = 1,
  62 };
  63
  64 static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size,
  65                                 void *val, size_t val_size)
  66 {
  67         unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0};
  68         unsigned char r[4];
  69         unsigned char *p = val;
  70         struct device *dev = context;
  71         struct spi_device *spi = to_spi_device(dev);
  72         struct spi_transfer t = {
  73                 .tx_buf = w,
  74                 .rx_buf = r,
  75                 .len = 4,
  76         };
  77
  78         struct spi_message m;
  79         int ret;
  80
  81         if (val_size != 3 || reg_size != 1)
  82                 return -ENOTSUPP;
  83
  84         spi_message_init(&m);
  85         spi_message_add_tail(&t, &m);
  86         ret = spi_sync(spi, &m);
  87
  88         memcpy(p, &r[1], 3);
  89
  90         return ret;
  91 }
  92
  93 static int mc13xxx_spi_write(void *context, const void *data, size_t count)
  94 {
  95         struct device *dev = context;
  96         struct spi_device *spi = to_spi_device(dev);
  97         const char *reg = data;
  98
  99         if (count != 4)
 100                 return -ENOTSUPP;
 101
 102         /* include errata fix for spi audio problems */
 103         if (*reg == MC13783_AUDIO_CODEC || *reg == MC13783_AUDIO_DAC)
 104                 spi_write(spi, data, count);
 105
 106         return spi_write(spi, data, count);
 107 }
 108
 109 /*
 110  * We cannot use regmap-spi generic bus implementation here.
 111  * The MC13783 chip will get corrupted if CS signal is deasserted
 112  * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller
 113  * has the following errata (DSPhl22960):
 114  * "The CSPI negates SS when the FIFO becomes empty with
 115  * SSCTL= 0. Software cannot guarantee that the FIFO will not
 116  * drain because of higher priority interrupts and the
 117  * non-realtime characteristics of the operating system. As a
 118  * result, the SS will negate before all of the data has been
 119  * transferred to/from the peripheral."
 120  * We workaround this by accessing the SPI controller with a
 121  * single transfert.
 122  */
 123
 124 static struct regmap_bus regmap_mc13xxx_bus = {
 125         .write = mc13xxx_spi_write,
 126         .read = mc13xxx_spi_read,
 127 };
 128
 129 static int mc13xxx_spi_probe(struct spi_device *spi)
 130 {
 131         struct mc13xxx *mc13xxx;
 132         struct mc13xxx_platform_data *pdata = dev_get_platdata(&spi->dev);
 133         int ret;
 134
 135         mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL);
 136         if (!mc13xxx)
 137                 return -ENOMEM;
 138
 139         spi_set_drvdata(spi, mc13xxx);
 140         spi->mode = SPI_MODE_0 | SPI_CS_HIGH;
 141
 142         mc13xxx->dev = &spi->dev;
 143         mutex_init(&mc13xxx->lock);
 144
 145         mc13xxx->regmap = devm_regmap_init(&spi->dev, &regmap_mc13xxx_bus,
 146                                            &spi->dev,
 147                                            &mc13xxx_regmap_spi_config);
 148         if (IS_ERR(mc13xxx->regmap)) {
 149                 ret = PTR_ERR(mc13xxx->regmap);
 150                 dev_err(mc13xxx->dev, "Failed to initialize register map: %d\n",
 151                                 ret);
 152                 spi_set_drvdata(spi, NULL);
 153                 return ret;
 154         }
 155
 156         if (spi->dev.of_node) {
 157                 const struct of_device_id *of_id =
 158                         of_match_device(mc13xxx_dt_ids, &spi->dev);
 159
 160                 mc13xxx->variant = of_id->data;
 161         } else {
 162                 const struct spi_device_id *id_entry = spi_get_device_id(spi);
 163
 164                 mc13xxx->variant = (void *)id_entry->driver_data;
 165         }
 166
 167         return mc13xxx_common_init(mc13xxx, pdata, spi->irq);
 168 }
 169
 170 static int mc13xxx_spi_remove(struct spi_device *spi)
 171 {
 172         struct mc13xxx *mc13xxx = spi_get_drvdata(spi);
 173
 174         mc13xxx_common_cleanup(mc13xxx);
 175
 176         return 0;
 177 }
 178
 179 static struct spi_driver mc13xxx_spi_driver = {
 180         .id_table = mc13xxx_device_id,
 181         .driver = {
 182                 .name = "mc13xxx",
 183                 .owner = THIS_MODULE,
 184                 .of_match_table = mc13xxx_dt_ids,
 185         },
 186         .probe = mc13xxx_spi_probe,
 187         .remove = mc13xxx_spi_remove,
 188 };
 189
 190 static int __init mc13xxx_init(void)
 191 {
 192         return spi_register_driver(&mc13xxx_spi_driver);
 193 }
 194 subsys_initcall(mc13xxx_init);
 195
 196 static void __exit mc13xxx_exit(void)
 197 {
 198         spi_unregister_driver(&mc13xxx_spi_driver);
 199 }
 200 module_exit(mc13xxx_exit);
 201
 202 MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
 203 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
 204 MODULE_LICENSE("GPL v2");