twl4030-gpio: pullup/pulldown init

From: David Brownell <[email protected]>

Finish moving initialization of pullups and pulldowns for twl4030 GPIOs into board specific init. Remove partial/incorrect init code for that from the hsmmc glue.

Doing this right requires some attention from board init logic, based on how the TWL chip is wired. Letting digital inputs float will waste power. Everyone with board schematics should update their board init code so it matches their boards; meanwhile, this returns to "current" behavior (all pullups disabled) but finally offers a way to do it "right".

Note that the ULPI pins won't need this attention (muxed against gpio{3-5,9-12,14} pins), and neither will ones with external pullups or pulldowns (conventional for MMC/SD card detect).

---
This partially reverses the effect of patch 0002 of the series Felipe has been refreshing, in the sense that all pullups (and pullups) are again disabled. HOWEVER it fills in that hole by providing a way boards can fix that -- example in patch #2.

 arch/arm/mach-omap2/hsmmc.c |    6 ---
 drivers/gpio/twl4030-gpio.c |   78 +++++++++++++++++++++---------------------
 include/linux/i2c/twl4030.h |    7 +++
 3 files changed, 46 insertions(+), 45 deletions(-)

@@ -27,7 +27,6 @@
 #define VMMC1_DEDICATED		0x2A
 #define VSEL_3V			0x02
 #define VSEL_18V		0x00
-#define TWL_GPIO_PUPDCTR1	0x13
 #define TWL_GPIO_IMR1A		0x1C
 #define TWL_GPIO_ISR1A		0x19
 #define LDO_CLR			0x00

@@ -65,11 +64,6 @@ static int hsmmc_late_init(struct device
 	if (ret)
 		goto err;
 
-	ret = twl4030_i2c_write_u8(TWL4030_MODULE_GPIO, 0x02,
-						TWL_GPIO_PUPDCTR1);
-	if (ret)
-		goto err;
-
 	ret = twl4030_set_gpio_debounce(MMC1_CD_IRQ, TWL4030_GPIO_IS_ENABLE);
 	if (ret)
 		goto err;

@@ -62,8 +62,13 @@ struct twl4030_gpio_platform_data {
 	int		gpio_base;
 	unsigned	irq_base, irq_end;
 
-	/* for gpio-N, bit (1 << N) is set if pullup should be used */
+	/* For gpio-N, bit (1 << N) in "pullups" is set if that pullup
+	 * should be enabled.  Else, if that bit is set in "pulldowns",
+	 * that pulldown is enabled.  Don't waste power by letting any
+	 * digital inputs float...
+	 */
 	u32		pullups;
+	u32		pulldowns;
 
 	int		(*setup)(struct device *dev,
 				unsigned gpio, unsigned ngpio);