ARM: OMAP3: Add ADS7846 touchscreen support to Overo platform, v3

An upcoming Overo expansion board includes an ADS7846 touchscreen controller.

This patch adds support via the ads7846 driver when enabled in the
kernel config.
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/board-overo.c

@@ -57,6 +57,65 @@
 #define GPMC_CS0_BASE  0x60
 #define GPMC_CS_SIZE   0x30
 
+#if defined(CONFIG_TOUCHSCREEN_ADS7846) || \
+	defined(CONFIG_TOUCHSCREEN_ADS7846_MODULE)
+
+#include <mach/mcspi.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/ads7846.h>
+
+static struct omap2_mcspi_device_config ads7846_mcspi_config = {
+	.turbo_mode	= 0,
+	.single_channel	= 1,	/* 0: slave, 1: master */
+};
+
+static int ads7846_get_pendown_state(void)
+{
+	return !gpio_get_value(OVERO_GPIO_PENDOWN);
+}
+
+static struct ads7846_platform_data ads7846_config = {
+	.x_max			= 0x0fff,
+	.y_max			= 0x0fff,
+	.x_plate_ohms		= 180,
+	.pressure_max		= 255,
+	.debounce_max		= 10,
+	.debounce_tol		= 3,
+	.debounce_rep		= 1,
+	.get_pendown_state	= ads7846_get_pendown_state,
+	.keep_vref_on		= 1,
+};
+
+static struct spi_board_info overo_spi_board_info[] __initdata = {
+	{
+		.modalias		= "ads7846",
+		.bus_num		= 1,
+		.chip_select		= 0,
+		.max_speed_hz		= 1500000,
+		.controller_data	= &ads7846_mcspi_config,
+		.irq			= OMAP_GPIO_IRQ(OVERO_GPIO_PENDOWN),
+		.platform_data		= &ads7846_config,
+	}
+};
+
+static void __init overo_ads7846_init(void)
+{
+	if ((gpio_request(OVERO_GPIO_PENDOWN, "ADS7846_PENDOWN") == 0) &&
+	    (gpio_direction_input(OVERO_GPIO_PENDOWN) == 0)) {
+		gpio_export(OVERO_GPIO_PENDOWN, 0);
+	} else {
+		printk(KERN_ERR "could not obtain gpio for ADS7846_PENDOWN\n");
+		return;
+	}
+
+	spi_register_board_info(overo_spi_board_info,
+			ARRAY_SIZE(overo_spi_board_info));
+}
+
+#else
+static inline void __init overo_ads7846_init(void) { return; }
+#endif
+
 static struct mtd_partition overo_nand_partitions[] = {
 	{
 		.name           = "xloader",
@@ -230,6 +289,7 @@ static void __init overo_init(void)
 	twl4030_mmc_init(mmc);
 	overo_flash_init();
 	usb_musb_init();
+	overo_ads7846_init();
 
 	if ((gpio_request(OVERO_GPIO_W2W_NRESET,
 			  "OVERO_GPIO_W2W_NRESET") == 0) &&