davinci: DA830/OMAP-L137 EVM: use runtime detection for UI card

This patch supports runtime detection of DA830 UI card and
eliminates the need for DA830_UI config option. Successful
probe of GPIO expander present on the UI card is used to
detect its presence. For this reason, GPIO_PCF857X is auto-
selected when DA830 EVM is configured. In case the UI card
is absent, the probe fails in reasonable time.

As a side effect this patch also gets rid of the voilation
of Documentation/SubmittingPatches section 2.2 in function
da830_evm_ui_expander_setup()
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/mach-davinci/Kconfig

@@ -100,21 +100,18 @@ config MACH_DAVINCI_DA830_EVM
 	bool "TI DA830/OMAP-L137 Reference Platform"
 	default ARCH_DAVINCI_DA830
 	depends on ARCH_DAVINCI_DA830
+	select GPIO_PCF857X
 	help
 	  Say Y here to select the TI DA830/OMAP-L137 Evaluation Module.
 
-config DA830_UI
-	bool "DA830/OMAP-L137 UI (User Interface) board support"
-	depends on MACH_DAVINCI_DA830_EVM
-	help
-	  Say Y here if you have the DA830/OMAP-L137 UI
-	  (User Interface) board installed and you want to
-	  enable the peripherals located on User Interface
-	  board.
-
 choice
 	prompt "Select DA830/OMAP-L137 UI board peripheral"
-	depends on DA830_UI
+	depends on MACH_DAVINCI_DA830_EVM
+	help
+	  The presence of UI card on the DA830/OMAP-L137 EVM is detected
+	  automatically based on successful probe of the I2C based GPIO
+	  expander on that board. This option selected in this menu has
+	  an effect only in case of a successful UI card detection.
 
 config DA830_UI_LCD
 	bool "LCD"

arch/arm/mach-davinci/board-da830-evm.c

@@ -36,58 +36,6 @@
 #define DA830_EMIF25_ASYNC_DATA_CE3_BASE	0x62000000
 #define DA830_EMIF25_CONTROL_BASE		0x68000000
 
-static struct at24_platform_data da830_evm_i2c_eeprom_info = {
-	.byte_len	= SZ_256K / 8,
-	.page_size	= 64,
-	.flags		= AT24_FLAG_ADDR16,
-	.setup		= davinci_get_mac_addr,
-	.context	= (void *)0x7f00,
-};
-
-static int da830_evm_ui_expander_setup(struct i2c_client *client, int gpio,
-		unsigned ngpio, void *context)
-{
-	gpio_request(gpio + 6, "MUX_MODE");
-#ifdef CONFIG_DA830_UI_LCD
-	gpio_direction_output(gpio + 6, 0);
-#else /* Must be NAND or NOR */
-	gpio_direction_output(gpio + 6, 1);
-#endif
-	return 0;
-}
-
-static int da830_evm_ui_expander_teardown(struct i2c_client *client, int gpio,
-		unsigned ngpio, void *context)
-{
-	gpio_free(gpio + 6);
-	return 0;
-}
-
-static struct pcf857x_platform_data da830_evm_ui_expander_info = {
-	.gpio_base	= DAVINCI_N_GPIO,
-	.setup		= da830_evm_ui_expander_setup,
-	.teardown	= da830_evm_ui_expander_teardown,
-};
-
-static struct i2c_board_info __initdata da830_evm_i2c_devices[] = {
-	{
-		I2C_BOARD_INFO("24c256", 0x50),
-		.platform_data	= &da830_evm_i2c_eeprom_info,
-	},
-	{
-		I2C_BOARD_INFO("tlv320aic3x", 0x18),
-	},
-	{
-		I2C_BOARD_INFO("pcf8574", 0x3f),
-		.platform_data	= &da830_evm_ui_expander_info,
-	},
-};
-
-static struct davinci_i2c_platform_data da830_evm_i2c_0_pdata = {
-	.bus_freq	= 100,	/* kHz */
-	.bus_delay	= 0,	/* usec */
-};
-
 /*
  * USB1 VBUS is controlled by GPIO1[15], over-current is reported on GPIO2[4].
  */
@@ -425,7 +373,7 @@ static struct platform_device da830_evm_nand_device = {
 	.resource	= da830_evm_nand_resources,
 };
 
-static inline void da830_evm_init_nand(void)
+static inline void da830_evm_init_nand(int mux_mode)
 {
 	int ret;
 
@@ -437,13 +385,15 @@ static inline void da830_evm_init_nand(void)
 	ret = platform_device_register(&da830_evm_nand_device);
 	if (ret)
 		pr_warning("da830_evm_init: NAND device not registered.\n");
+
+	gpio_direction_output(mux_mode, 1);
 }
 #else
-static inline void da830_evm_init_nand(void) { }
+static inline void da830_evm_init_nand(int mux_mode) { }
 #endif
 
 #ifdef CONFIG_DA830_UI_LCD
-static inline void da830_evm_init_lcdc(void)
+static inline void da830_evm_init_lcdc(int mux_mode)
 {
 	int ret;
 
@@ -455,11 +405,65 @@ static inline void da830_evm_init_lcdc(void)
 	ret = da8xx_register_lcdc(&sharp_lcd035q3dg01_pdata);
 	if (ret)
 		pr_warning("da830_evm_init: lcd setup failed: %d\n", ret);
+
+	gpio_direction_output(mux_mode, 0);
 }
 #else
-static inline void da830_evm_init_lcdc(void) { }
+static inline void da830_evm_init_lcdc(int mux_mode) { }
 #endif
 
+static struct at24_platform_data da830_evm_i2c_eeprom_info = {
+	.byte_len	= SZ_256K / 8,
+	.page_size	= 64,
+	.flags		= AT24_FLAG_ADDR16,
+	.setup		= davinci_get_mac_addr,
+	.context	= (void *)0x7f00,
+};
+
+static int da830_evm_ui_expander_setup(struct i2c_client *client, int gpio,
+		unsigned ngpio, void *context)
+{
+	gpio_request(gpio + 6, "UI MUX_MODE");
+
+	da830_evm_init_lcdc(gpio + 6);
+
+	da830_evm_init_nand(gpio + 6);
+
+	return 0;
+}
+
+static int da830_evm_ui_expander_teardown(struct i2c_client *client, int gpio,
+		unsigned ngpio, void *context)
+{
+	gpio_free(gpio + 6);
+	return 0;
+}
+
+static struct pcf857x_platform_data da830_evm_ui_expander_info = {
+	.gpio_base	= DAVINCI_N_GPIO,
+	.setup		= da830_evm_ui_expander_setup,
+	.teardown	= da830_evm_ui_expander_teardown,
+};
+
+static struct i2c_board_info __initdata da830_evm_i2c_devices[] = {
+	{
+		I2C_BOARD_INFO("24c256", 0x50),
+		.platform_data	= &da830_evm_i2c_eeprom_info,
+	},
+	{
+		I2C_BOARD_INFO("tlv320aic3x", 0x18),
+	},
+	{
+		I2C_BOARD_INFO("pcf8574", 0x3f),
+		.platform_data	= &da830_evm_ui_expander_info,
+	},
+};
+
+static struct davinci_i2c_platform_data da830_evm_i2c_0_pdata = {
+	.bus_freq	= 100,	/* kHz */
+	.bus_delay	= 0,	/* usec */
+};
+
 static __init void da830_evm_init(void)
 {
 	struct davinci_soc_info *soc_info = &davinci_soc_info;
@@ -514,10 +518,6 @@ static __init void da830_evm_init(void)
 
 	da830_evm_init_mmc();
 
-	da830_evm_init_lcdc();
-
-	da830_evm_init_nand();
-
 	ret = da8xx_register_rtc();
 	if (ret)
 		pr_warning("da830_evm_init: rtc setup failed: %d\n", ret);