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 #include "padmux.h"
  18
  19 /*
  20  * The following is for the actual devices on the SSP/SPI bus
  21  */
  22 #ifdef CONFIG_MACH_U300_SPIDUMMY
  23 static void select_dummy_chip(u32 chipselect)
  24 {
  25         pr_debug("CORE: %s called with CS=0x%x (%s)\n",
  26                  __func__,
  27                  chipselect,
  28                  chipselect ? "unselect chip" : "select chip");
  29         /*
  30          * Here you would write the chip select value to the GPIO pins if
  31          * this was a real chip (but this is a loopback dummy).
  32          */
  33 }
  34
  35 struct pl022_config_chip dummy_chip_info = {
  36         /* available POLLING_TRANSFER, INTERRUPT_TRANSFER, DMA_TRANSFER */
  37         .com_mode = DMA_TRANSFER,
  38         .iface = SSP_INTERFACE_MOTOROLA_SPI,
  39         /* We can only act as master but SSP_SLAVE is possible in theory */
  40         .hierarchy = SSP_MASTER,
  41         /* 0 = drive TX even as slave, 1 = do not drive TX as slave */
  42         .slave_tx_disable = 0,
  43         .rx_lev_trig = SSP_RX_4_OR_MORE_ELEM,
  44         .tx_lev_trig = SSP_TX_4_OR_MORE_EMPTY_LOC,
  45         .ctrl_len = SSP_BITS_12,
  46         .wait_state = SSP_MWIRE_WAIT_ZERO,
  47         .duplex = SSP_MICROWIRE_CHANNEL_FULL_DUPLEX,
  48         /*
  49          * This is where you insert a call to a function to enable CS
  50          * (usually GPIO) for a certain chip.
  51          */
  52         .cs_control = select_dummy_chip,
  53 };
  54 #endif
  55
  56 static struct spi_board_info u300_spi_devices[] = {
  57 #ifdef CONFIG_MACH_U300_SPIDUMMY
  58         {
  59                 /* A dummy chip used for loopback tests */
  60                 .modalias       = "spi-dummy",
  61                 /* Really dummy, pass in additional chip config here */
  62                 .platform_data  = NULL,
  63                 /* This defines how the controller shall handle the device */
  64                 .controller_data = &dummy_chip_info,
  65                 /* .irq - no external IRQ routed from this device */
  66                 .max_speed_hz   = 1000000,
  67                 .bus_num        = 0, /* Only one bus on this chip */
  68                 .chip_select    = 0,
  69                 /* Means SPI_CS_HIGH, change if e.g low CS */
  70                 .mode           = SPI_MODE_1 | SPI_LOOP,
  71         },
  72 #endif
  73 };
  74
  75 static struct pl022_ssp_controller ssp_platform_data = {
  76         /* If you have several SPI buses this varies, we have only bus 0 */
  77         .bus_id = 0,
  78         /*
  79          * On the APP CPU GPIO 4, 5 and 6 are connected as generic
  80          * chip selects for SPI. (Same on U330, U335 and U365.)
  81          * TODO: make sure the GPIO driver can select these properly
  82          * and do padmuxing accordingly too.
  83          */
  84         .num_chipselect = 3,
  85 #ifdef CONFIG_COH901318
  86         .enable_dma = 1,
  87         .dma_filter = coh901318_filter_id,
  88         .dma_rx_param = (void *) U300_DMA_SPI_RX,
  89         .dma_tx_param = (void *) U300_DMA_SPI_TX,
  90 #else
  91         .enable_dma = 0,
  92 #endif
  93 };
  94
  95
  96 void __init u300_spi_init(struct amba_device *adev)
  97 {
  98         struct pmx *pmx;
  99
 100         adev->dev.platform_data = &ssp_platform_data;
 101         /*
 102          * Setup padmuxing for SPI. Since this must always be
 103          * compiled into the kernel, pmx is never released.
 104          */
 105         pmx = pmx_get(&adev->dev, U300_APP_PMX_SPI_SETTING);
 106
 107         if (IS_ERR(pmx))
 108                 dev_warn(&adev->dev, "Could not get padmux handle\n");
 109         else {
 110                 int ret;
 111
 112                 ret = pmx_activate(&adev->dev, pmx);
 113                 if (IS_ERR_VALUE(ret))
 114                         dev_warn(&adev->dev, "Could not activate padmuxing\n");
 115         }
 116
 117 }
 118
 119 void __init u300_spi_register_board_devices(void)
 120 {
 121         /* Register any SPI devices */
 122         spi_register_board_info(u300_spi_devices, ARRAY_SIZE(u300_spi_devices));
 123 }