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>
diff --git a/arch/arm/mach-u300/spi.c b/arch/arm/mach-u300/spi.c
new file mode 100644
index 0000000..307d007
--- /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));
+}