arch/arm/mach-u300/spi.c

   1 /*
   2  * arch/arm/mach-u300/spi.c
   3  *
   4  * Copyright (C) 2009 ST-Ericsson AB
   5  * License terms: GNU General Public License (GPL) version 2
   6  *
   7  * Author: Linus Walleij <linus.walleij@stericsson.com>
   8  */
   9 #include <linux/device.h>
  10 #include <linux/amba/bus.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/amba/pl022.h>
  13 #include <linux/err.h>
  14 #include <mach/coh901318.h>
  15 #include <mach/dma_channels.h>
  16
  17 /*
  18  * The following is for the actual devices on the SSP/SPI bus
  19  */
  20 #ifdef CONFIG_MACH_U300_SPIDUMMY
  21 static void select_dummy_chip(u32 chipselect)
  22 {
  23         pr_debug("CORE: %s called with CS=0x%x (%s)\n",
  24                  __func__,
  25                  chipselect,
  26                  chipselect ? "unselect chip" : "select chip");
  27         /*
  28          * Here you would write the chip select value to the GPIO pins if
  29          * this was a real chip (but this is a loopback dummy).
  30          */
  31 }
  32
  33 struct pl022_config_chip dummy_chip_info = {
  34         /* available POLLING_TRANSFER, INTERRUPT_TRANSFER, DMA_TRANSFER */
  35         .com_mode = DMA_TRANSFER,
  36         .iface = SSP_INTERFACE_MOTOROLA_SPI,
  37         /* We can only act as master but SSP_SLAVE is possible in theory */
  38         .hierarchy = SSP_MASTER,
  39         /* 0 = drive TX even as slave, 1 = do not drive TX as slave */
  40         .slave_tx_disable = 0,
  41         .rx_lev_trig = SSP_RX_4_OR_MORE_ELEM,
  42         .tx_lev_trig = SSP_TX_4_OR_MORE_EMPTY_LOC,
  43         .ctrl_len = SSP_BITS_12,
  44         .wait_state = SSP_MWIRE_WAIT_ZERO,
  45         .duplex = SSP_MICROWIRE_CHANNEL_FULL_DUPLEX,
  46         /*
  47          * This is where you insert a call to a function to enable CS
  48          * (usually GPIO) for a certain chip.
  49          */
  50         .cs_control = select_dummy_chip,
  51 };
  52 #endif
  53
  54 static struct spi_board_info u300_spi_devices[] = {
  55 #ifdef CONFIG_MACH_U300_SPIDUMMY
  56         {
  57                 /* A dummy chip used for loopback tests */
  58                 .modalias       = "spi-dummy",
  59                 /* Really dummy, pass in additional chip config here */
  60                 .platform_data  = NULL,
  61                 /* This defines how the controller shall handle the device */
  62                 .controller_data = &dummy_chip_info,
  63                 /* .irq - no external IRQ routed from this device */
  64                 .max_speed_hz   = 1000000,
  65                 .bus_num        = 0, /* Only one bus on this chip */
  66                 .chip_select    = 0,
  67                 /* Means SPI_CS_HIGH, change if e.g low CS */
  68                 .mode           = SPI_MODE_1 | SPI_LOOP,
  69         },
  70 #endif
  71 };
  72
  73 static struct pl022_ssp_controller ssp_platform_data = {
  74         /* If you have several SPI buses this varies, we have only bus 0 */
  75         .bus_id = 0,
  76         /*
  77          * On the APP CPU GPIO 4, 5 and 6 are connected as generic
  78          * chip selects for SPI. (Same on U330, U335 and U365.)
  79          * TODO: make sure the GPIO driver can select these properly
  80          * and do padmuxing accordingly too.
  81          */
  82         .num_chipselect = 3,
  83 #ifdef CONFIG_COH901318
  84         .enable_dma = 1,
  85         .dma_filter = coh901318_filter_id,
  86         .dma_rx_param = (void *) U300_DMA_SPI_RX,
  87         .dma_tx_param = (void *) U300_DMA_SPI_TX,
  88 #else
  89         .enable_dma = 0,
  90 #endif
  91 };
  92
  93
  94 void __init u300_spi_init(struct amba_device *adev)
  95 {
  96         adev->dev.platform_data = &ssp_platform_data;
  97 }
  98
  99 void __init u300_spi_register_board_devices(void)
 100 {
 101         /* Register any SPI devices */
 102         spi_register_board_info(u300_spi_devices, ARRAY_SIZE(u300_spi_devices));
 103 }