[PATCH 3/3] gpio: support stmpe1801 18 bits enhanced port expander

[Jean-Nicolas Graux]

Provides support for 1801 variant of stmpe gpio port expanders.
This chip has 18 gpios configurable as GPI, GPO, keypad matrix,
special key or dedicated key function.

Note that special/dedicated key function is not supported yet.

Signed-off-by: Jean-Nicolas Graux <jean-nicolas.graux@xxxxxxxxxxxxxx>
---
 drivers/gpio/gpio-stmpe.c |   52 ++++++++++++++++++++++++++++++++-------------
 1 file changed, 37 insertions(+), 15 deletions(-)

diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
index 770476a..343dfe1 100644
--- a/drivers/gpio/gpio-stmpe.c
+++ b/drivers/gpio/gpio-stmpe.c
@@ -45,14 +45,25 @@ static inline struct stmpe_gpio *to_stmpe_gpio(struct gpio_chip *chip)
 	return container_of(chip, struct stmpe_gpio, chip);
 }
 
+static inline u8 stmpe_gpio_reg(struct stmpe *stmpe, u8 index, int offset)
+{
+	u8 reg;
+	if (stmpe->partnum == STMPE1801)
+		reg = stmpe->regs[index] + offset;
+	else
+		reg = stmpe->regs[index] - offset;
+	return reg;
+}
+
 static int stmpe_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
 	struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
-	u8 reg = stmpe->regs[STMPE_IDX_GPMR_LSB] - (offset / 8);
-	u8 mask = 1 << (offset % 8);
 	int ret;
+	u8 reg, mask;
 
+	reg = stmpe_gpio_reg(stmpe, STMPE_IDX_GPMR_LSB, offset / 8);
+	mask = 1 << (offset % 8);
 	ret = stmpe_reg_read(stmpe, reg);
 	if (ret < 0)
 		return ret;
@@ -65,8 +76,10 @@ static void stmpe_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
 	struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
 	int which = val ? STMPE_IDX_GPSR_LSB : STMPE_IDX_GPCR_LSB;
-	u8 reg = stmpe->regs[which] - (offset / 8);
-	u8 mask = 1 << (offset % 8);
+	u8 reg, mask;
+
+	reg = stmpe_gpio_reg(stmpe, which, offset / 8);
+	mask = 1 << (offset % 8);
 
 	/*
 	 * Some variants have single register for gpio set/clear functionality.
@@ -83,8 +96,10 @@ static int stmpe_gpio_direction_output(struct gpio_chip *chip,
 {
 	struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
-	u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
-	u8 mask = 1 << (offset % 8);
+	u8 reg, mask;
+
+	reg = stmpe_gpio_reg(stmpe, STMPE_IDX_GPDR_LSB, offset / 8);
+	mask = 1 << (offset % 8);
 
 	stmpe_gpio_set(chip, offset, val);
 
@@ -96,8 +111,10 @@ static int stmpe_gpio_direction_input(struct gpio_chip *chip,
 {
 	struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
-	u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
-	u8 mask = 1 << (offset % 8);
+	u8 reg, mask;
+
+	reg = stmpe_gpio_reg(stmpe, STMPE_IDX_GPDR_LSB, offset / 8);
+	mask = 1 << (offset % 8);
 
 	return stmpe_set_bits(stmpe, reg, mask, 0);
 }
@@ -177,6 +194,7 @@ static void stmpe_gpio_irq_sync_unlock(struct irq_data *d)
 		[REG_IE]	= STMPE_IDX_IEGPIOR_LSB,
 	};
 	int i, j;
+	u8 reg;
 
 	for (i = 0; i < CACHE_NR_REGS; i++) {
 		/* STMPE801 doesn't have RE and FE registers */
@@ -192,7 +210,8 @@ static void stmpe_gpio_irq_sync_unlock(struct irq_data *d)
 				continue;
 
 			stmpe_gpio->oldregs[i][j] = new;
-			stmpe_reg_write(stmpe, stmpe->regs[regmap[i]] - j, new);
+			reg = stmpe_gpio_reg(stmpe, regmap[i], j);
+			stmpe_reg_write(stmpe, reg, new);
 		}
 	}
 
@@ -232,18 +251,20 @@ static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
 {
 	struct stmpe_gpio *stmpe_gpio = dev;
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
-	u8 statmsbreg = stmpe->regs[STMPE_IDX_ISGPIOR_MSB];
 	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
 	u8 status[num_banks];
 	int ret;
 	int i;
+	bool lsb = stmpe->partnum == STMPE1801;
+	u8 statmsbreg = lsb ? stmpe->regs[STMPE_IDX_ISGPIOR_LSB] :
+			stmpe->regs[STMPE_IDX_ISGPIOR_MSB];
 
 	ret = stmpe_block_read(stmpe, statmsbreg, num_banks, status);
 	if (ret < 0)
 		return IRQ_NONE;
 
 	for (i = 0; i < num_banks; i++) {
-		int bank = num_banks - i - 1;
+		int bank = lsb ? i : num_banks - i - 1;
 		unsigned int enabled = stmpe_gpio->regs[REG_IE][bank];
 		unsigned int stat = status[i];
 
@@ -262,10 +283,11 @@ static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
 
 		stmpe_reg_write(stmpe, statmsbreg + i, status[i]);
 
-		/* Edge detect register is not present on 801 */
-		if (stmpe->partnum != STMPE801)
-			stmpe_reg_write(stmpe, stmpe->regs[STMPE_IDX_GPEDR_MSB]
-					+ i, status[i]);
+		/* Edge detect register is not present on 801 and 1801 */
+		if (stmpe->partnum != STMPE801 && stmpe->partnum != STMPE1801)
+			stmpe_reg_write(stmpe,
+				stmpe->regs[STMPE_IDX_GPEDR_MSB] + i,
+				status[i]);
 	}
 
 	return IRQ_HANDLED;
-- 
1.7.10

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