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