forked from Minki/linux
c7c8c78fdf
This adds a U300 board configuration for the PL022 SSP/SPI PrimeCell driver recently merged to the 2.6.31-rc series. Further it adds a dummy loopback SPI chip that can be used for testing the SPI functionality on a running system using the loopback mode of PL022. Signed-off-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
125 lines
3.5 KiB
C
125 lines
3.5 KiB
C
/*
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* arch/arm/mach-u300/spi.c
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*
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* Copyright (C) 2009 ST-Ericsson AB
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* License terms: GNU General Public License (GPL) version 2
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*
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* Author: Linus Walleij <linus.walleij@stericsson.com>
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*/
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#include <linux/device.h>
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#include <linux/amba/bus.h>
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#include <linux/spi/spi.h>
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#include <linux/amba/pl022.h>
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#include <linux/err.h>
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#include "padmux.h"
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/*
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* The following is for the actual devices on the SSP/SPI bus
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*/
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#ifdef CONFIG_MACH_U300_SPIDUMMY
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static void select_dummy_chip(u32 chipselect)
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{
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pr_debug("CORE: %s called with CS=0x%x (%s)\n",
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__func__,
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chipselect,
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chipselect ? "unselect chip" : "select chip");
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/*
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* Here you would write the chip select value to the GPIO pins if
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* this was a real chip (but this is a loopback dummy).
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*/
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}
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struct pl022_config_chip dummy_chip_info = {
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/* Nominally this is LOOPBACK_DISABLED, but this is our dummy chip! */
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.lbm = LOOPBACK_ENABLED,
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/*
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* available POLLING_TRANSFER and INTERRUPT_TRANSFER,
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* DMA_TRANSFER does not work
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*/
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.com_mode = INTERRUPT_TRANSFER,
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.iface = SSP_INTERFACE_MOTOROLA_SPI,
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/* We can only act as master but SSP_SLAVE is possible in theory */
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.hierarchy = SSP_MASTER,
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/* 0 = drive TX even as slave, 1 = do not drive TX as slave */
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.slave_tx_disable = 0,
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/* LSB first */
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.endian_tx = SSP_TX_LSB,
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.endian_rx = SSP_RX_LSB,
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.data_size = SSP_DATA_BITS_8, /* used to be 12 in some default */
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.rx_lev_trig = SSP_RX_1_OR_MORE_ELEM,
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.tx_lev_trig = SSP_TX_1_OR_MORE_EMPTY_LOC,
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.clk_phase = SSP_CLK_FALLING_EDGE,
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.clk_pol = SSP_CLK_POL_IDLE_LOW,
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.ctrl_len = SSP_BITS_12,
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.wait_state = SSP_MWIRE_WAIT_ZERO,
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.duplex = SSP_MICROWIRE_CHANNEL_FULL_DUPLEX,
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/*
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* This is where you insert a call to a function to enable CS
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* (usually GPIO) for a certain chip.
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*/
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.cs_control = select_dummy_chip,
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};
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#endif
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static struct spi_board_info u300_spi_devices[] = {
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#ifdef CONFIG_MACH_U300_SPIDUMMY
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{
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/* A dummy chip used for loopback tests */
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.modalias = "spi-dummy",
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/* Really dummy, pass in additional chip config here */
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.platform_data = NULL,
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/* This defines how the controller shall handle the device */
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.controller_data = &dummy_chip_info,
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/* .irq - no external IRQ routed from this device */
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.max_speed_hz = 1000000,
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.bus_num = 0, /* Only one bus on this chip */
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.chip_select = 0,
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/* Means SPI_CS_HIGH, change if e.g low CS */
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.mode = 0,
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},
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#endif
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};
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static struct pl022_ssp_controller ssp_platform_data = {
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/* If you have several SPI buses this varies, we have only bus 0 */
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.bus_id = 0,
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/* Set this to 1 when we think we got DMA working */
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.enable_dma = 0,
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/*
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* On the APP CPU GPIO 4, 5 and 6 are connected as generic
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* chip selects for SPI. (Same on U330, U335 and U365.)
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* TODO: make sure the GPIO driver can select these properly
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* and do padmuxing accordingly too.
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*/
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.num_chipselect = 3,
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};
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void __init u300_spi_init(struct amba_device *adev)
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{
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struct pmx *pmx;
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adev->dev.platform_data = &ssp_platform_data;
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/*
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* Setup padmuxing for SPI. Since this must always be
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* compiled into the kernel, pmx is never released.
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*/
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pmx = pmx_get(&adev->dev, U300_APP_PMX_SPI_SETTING);
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if (IS_ERR(pmx))
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dev_warn(&adev->dev, "Could not get padmux handle\n");
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else {
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int ret;
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ret = pmx_activate(&adev->dev, pmx);
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if (IS_ERR_VALUE(ret))
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dev_warn(&adev->dev, "Could not activate padmuxing\n");
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}
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}
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void __init u300_spi_register_board_devices(void)
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{
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/* Register any SPI devices */
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spi_register_board_info(u300_spi_devices, ARRAY_SIZE(u300_spi_devices));
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}
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