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>

2 files changed, 67 insertions, 70 deletions

diff --git a/arch/arm/mach-davinci/Kconfig b/arch/arm/mach-davinci/Kconfig
index 89548287ca0f..006144401c95 100644
--- a/arch/arm/mach-davinci/Kconfig
+++ b/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"
diff --git a/arch/arm/mach-davinci/board-da830-evm.c b/arch/arm/mach-davinci/board-da830-evm.c
index b433b22e1777..e7e97c90d4d0 100644
--- a/arch/arm/mach-davinci/board-da830-evm.c
+++ b/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);