ARM: 5667/3: U300 SSP/SPI board setup and test

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>

1 files changed, 124 insertions, 0 deletions

diff --git a/arch/arm/mach-u300/spi.c b/arch/arm/mach-u300/spi.c
new file mode 100644
index 000000000000..307d007ea7f3
--- /dev/null
+++ b/arch/arm/mach-u300/spi.c
@@ -0,0 +1,124 @@
+/*
+ * arch/arm/mach-u300/spi.c
+ *
+ * Copyright (C) 2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Author: Linus Walleij <linus.walleij@stericsson.com>
+ */
+#include <linux/device.h>
+#include <linux/amba/bus.h>
+#include <linux/spi/spi.h>
+#include <linux/amba/pl022.h>
+#include <linux/err.h>
+#include "padmux.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 = {
+        /* Nominally this is LOOPBACK_DISABLED, but this is our dummy chip! */
+        .lbm = LOOPBACK_ENABLED,
+        /*
+         * available POLLING_TRANSFER and INTERRUPT_TRANSFER,
+         * DMA_TRANSFER does not work
+         */
+        .com_mode = INTERRUPT_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,
+        /* LSB first */
+        .endian_tx = SSP_TX_LSB,
+        .endian_rx = SSP_RX_LSB,
+        .data_size = SSP_DATA_BITS_8, /* used to be 12 in some default */
+        .rx_lev_trig = SSP_RX_1_OR_MORE_ELEM,
+        .tx_lev_trig = SSP_TX_1_OR_MORE_EMPTY_LOC,
+        .clk_phase = SSP_CLK_FALLING_EDGE,
+        .clk_pol = SSP_CLK_POL_IDLE_LOW,
+        .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           = 0,
+        },
+#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,
+        /* Set this to 1 when we think we got DMA working */
+        .enable_dma = 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,
+};
+
+
+void __init u300_spi_init(struct amba_device *adev)
+{
+        struct pmx *pmx;
+
+        adev->dev.platform_data = &ssp_platform_data;
+        /*
+         * Setup padmuxing for SPI. Since this must always be
+         * compiled into the kernel, pmx is never released.
+         */
+        pmx = pmx_get(&adev->dev, U300_APP_PMX_SPI_SETTING);
+
+        if (IS_ERR(pmx))
+                dev_warn(&adev->dev, "Could not get padmux handle\n");
+        else {
+                int ret;
+
+                ret = pmx_activate(&adev->dev, pmx);
+                if (IS_ERR_VALUE(ret))
+                        dev_warn(&adev->dev, "Could not activate padmuxing\n");
+        }
+
+}
+void __init u300_spi_register_board_devices(void)
+{
+        /* Register any SPI devices */
+        spi_register_board_info(u300_spi_devices, ARRAY_SIZE(u300_spi_devices));
+}