[PATCH v2] pinctrl: rockchip: fix rk3288 gpio0 configuration

[Sonny Rao]

On rk3288, for gpio bank 0, the registers which configure pull-up,
iomux, and drive strength don't implement the enable bits in the upper
half of the register, unlike the other gpio configuration registers,
and so the kernel must perform a read-modify-write of the register to
update a particular gpio in that bank.

The current code is actually clobbering the contents of the register,
so this fixes it by using regmap_update_bits and masking out only the
bits which require updating.  In the case of bank0 on rk3288 the upper
enable bits will just get ignored, and the other configurations won't
get clobbered.

Signed-off-by: Sonny Rao <sonnyrao at chromium.org>
---
v2: rebase onto latest pinctrl with drive strength and fix this bug on
  iomux and drive strength as well.
 
 drivers/pinctrl/pinctrl-rockchip.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c
index c15f7f9..4ff5dc3 100644
--- a/drivers/pinctrl/pinctrl-rockchip.c
+++ b/drivers/pinctrl/pinctrl-rockchip.c
@@ -438,7 +438,7 @@ static int rockchip_set_mux(struct rockchip_pin_bank *bank, int pin, int mux)
 	int reg, ret, mask;
 	unsigned long flags;
 	u8 bit;
-	u32 data;
+	u32 data, rmask;
 
 	if (iomux_num > 3)
 		return -EINVAL;
@@ -478,8 +478,9 @@ static int rockchip_set_mux(struct rockchip_pin_bank *bank, int pin, int mux)
 	spin_lock_irqsave(&bank->slock, flags);
 
 	data = (mask << (bit + 16));
+	rmask = data | (data >> 16);
 	data |= (mux & mask) << bit;
-	ret = regmap_write(regmap, reg, data);
+	ret = regmap_update_bits(regmap, reg, rmask, data);
 
 	spin_unlock_irqrestore(&bank->slock, flags);
 
@@ -634,7 +635,7 @@ static int rk3288_set_drive(struct rockchip_pin_bank *bank, int pin_num,
 	struct regmap *regmap;
 	unsigned long flags;
 	int reg, ret, i;
-	u32 data;
+	u32 data, rmask;
 	u8 bit;
 
 	rk3288_calc_drv_reg_and_bit(bank, pin_num, &regmap, &reg, &bit);
@@ -657,9 +658,10 @@ static int rk3288_set_drive(struct rockchip_pin_bank *bank, int pin_num,
 
 	/* enable the write to the equivalent lower bits */
 	data = ((1 << RK3288_DRV_BITS_PER_PIN) - 1) << (bit + 16);
+	rmask = data | (data >> 16);
 	data |= (ret << bit);
 
-	ret = regmap_write(regmap, reg, data);
+	ret = regmap_update_bits(regmap, reg, rmask, data);
 	spin_unlock_irqrestore(&bank->slock, flags);
 
 	return ret;
@@ -722,7 +724,7 @@ static int rockchip_set_pull(struct rockchip_pin_bank *bank,
 	int reg, ret;
 	unsigned long flags;
 	u8 bit;
-	u32 data;
+	u32 data, rmask;
 
 	dev_dbg(info->dev, "setting pull of GPIO%d-%d to %d\n",
 		 bank->bank_num, pin_num, pull);
@@ -750,6 +752,7 @@ static int rockchip_set_pull(struct rockchip_pin_bank *bank,
 
 		/* enable the write to the equivalent lower bits */
 		data = ((1 << RK3188_PULL_BITS_PER_PIN) - 1) << (bit + 16);
+		rmask = data | (data >> 16);
 
 		switch (pull) {
 		case PIN_CONFIG_BIAS_DISABLE:
@@ -770,7 +773,7 @@ static int rockchip_set_pull(struct rockchip_pin_bank *bank,
 			return -EINVAL;
 		}
 
-		ret = regmap_write(regmap, reg, data);
+		ret = regmap_update_bits(regmap, reg, rmask, data);
 
 		spin_unlock_irqrestore(&bank->slock, flags);
 		break;
-- 
1.8.3.2