spi.c

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/*
 * arch/arm/mach-u300/spi.c
 *
 * Copyright (C) 2009 ST-Ericsson AB
 * License terms: GNU General Public License (GPL) version 2
 *
 * Author: Linus Walleij <[email protected]>
 */
#include <linux/device.h>
#include <linux/amba/bus.h>
#include <linux/spi/spi.h>
#include <linux/amba/pl022.h>
#include <linux/err.h>
#include <mach/coh901318.h>
#include "dma_channels.h"

/*
 * The following is for the actual devices on the SSP/SPI bus
 */
#ifdef CONFIG_MACH_U300_SPIDUMMY
static void select_dummy_chip(u32 chipselect)
{
    pr_debug("CORE: %s called with CS=0x%x (%s)\n",
         __func__,
         chipselect,
         chipselect ? "unselect chip" : "select chip");
    /*
     * Here you would write the chip select value to the GPIO pins if
     * this was a real chip (but this is a loopback dummy).
     */
}

struct pl022_config_chip dummy_chip_info = {
    /* available POLLING_TRANSFER, INTERRUPT_TRANSFER, DMA_TRANSFER */
    .com_mode = DMA_TRANSFER,
    .iface = SSP_INTERFACE_MOTOROLA_SPI,
    /* We can only act as master but SSP_SLAVE is possible in theory */
    .hierarchy = SSP_MASTER,
    /* 0 = drive TX even as slave, 1 = do not drive TX as slave */
    .slave_tx_disable = 0,
    .rx_lev_trig = SSP_RX_4_OR_MORE_ELEM,
    .tx_lev_trig = SSP_TX_4_OR_MORE_EMPTY_LOC,
    .ctrl_len = SSP_BITS_12,
    .wait_state = SSP_MWIRE_WAIT_ZERO,
    .duplex = SSP_MICROWIRE_CHANNEL_FULL_DUPLEX,
    /*
     * This is where you insert a call to a function to enable CS
     * (usually GPIO) for a certain chip.
     */
    .cs_control = select_dummy_chip,
};
#endif

static struct spi_board_info u300_spi_devices[] = {
#ifdef CONFIG_MACH_U300_SPIDUMMY
    {
        /* A dummy chip used for loopback tests */
        .modalias       = "spi-dummy",
        /* Really dummy, pass in additional chip config here */
        .platform_data  = NULL,
        /* This defines how the controller shall handle the device */
        .controller_data = &dummy_chip_info,
        /* .irq - no external IRQ routed from this device */
        .max_speed_hz   = 1000000,
        .bus_num        = 0, /* Only one bus on this chip */
        .chip_select    = 0,
        /* Means SPI_CS_HIGH, change if e.g low CS */
        .mode           = SPI_MODE_1 | SPI_LOOP,
    },
#endif
};

static struct pl022_ssp_controller ssp_platform_data = {
    /* If you have several SPI buses this varies, we have only bus 0 */
    .bus_id = 0,
    /*
     * On the APP CPU GPIO 4, 5 and 6 are connected as generic
     * chip selects for SPI. (Same on U330, U335 and U365.)
     * TODO: make sure the GPIO driver can select these properly
     * and do padmuxing accordingly too.
     */
    .num_chipselect = 3,
#ifdef CONFIG_COH901318
    .enable_dma = 1,
    .dma_filter = coh901318_filter_id,
    .dma_rx_param = (void *) U300_DMA_SPI_RX,
    .dma_tx_param = (void *) U300_DMA_SPI_TX,
#else
    .enable_dma = 0,
#endif
};


void __init u300_spi_init(struct amba_device *adev)
{
    adev->dev.platform_data = &ssp_platform_data;
}

void __init u300_spi_register_board_devices(void)
{
    /* Register any SPI devices */
    spi_register_board_info(u300_spi_devices, ARRAY_SIZE(u300_spi_devices));
}