gpio: stm32f7: Add gpio bank holes management

In some STM32 SoC packages, GPIO bank has not always 16 gpios.
Several cases can occur, gpio hole can be located at the beginning,
middle or end of the gpio bank or a combination of these 3
configurations.

For that, gpio bindings offer the gpio-ranges DT property which
described the gpio bank mapping.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>

arch/arm/include/asm/arch-stm32/gpio.h

@@ -109,6 +109,9 @@ struct stm32_gpio_regs {
 
 struct stm32_gpio_priv {
 	struct stm32_gpio_regs *regs;
+	unsigned int gpio_range;
 };
 
+int stm32_offset_to_index(struct udevice *dev, unsigned int offset);
+
 #endif /* _GPIO_H_ */

arch/arm/mach-stm32mp/include/mach/gpio.h

@@ -110,5 +110,9 @@ struct stm32_gpio_regs {
 
 struct stm32_gpio_priv {
 	struct stm32_gpio_regs *regs;
+	unsigned int gpio_range;
 };
+
+int stm32_offset_to_index(struct udevice *dev, unsigned int offset);
+
 #endif /* _STM32_GPIO_H_ */

drivers/gpio/stm32f7_gpio.c

@@ -20,12 +20,41 @@
 #define MODE_BITS_MASK			3
 #define BSRR_BIT(gpio_pin, value)	BIT(gpio_pin + (value ? 0 : 16))
 
+/*
+ * convert gpio offset to gpio index taking into account gpio holes
+ * into gpio bank
+ */
+int stm32_offset_to_index(struct udevice *dev, unsigned int offset)
+{
+	struct stm32_gpio_priv *priv = dev_get_priv(dev);
+	int idx = 0;
+	int i;
+
+	for (i = 0; i < STM32_GPIOS_PER_BANK; i++) {
+		if (priv->gpio_range & BIT(i)) {
+			if (idx == offset)
+				return idx;
+			idx++;
+		}
+	}
+	/* shouldn't happen */
+	return -EINVAL;
+}
+
 static int stm32_gpio_direction_input(struct udevice *dev, unsigned offset)
 {
 	struct stm32_gpio_priv *priv = dev_get_priv(dev);
 	struct stm32_gpio_regs *regs = priv->regs;
-	int bits_index = MODE_BITS(offset);
+	int bits_index;
-	int mask = MODE_BITS_MASK << bits_index;
+	int mask;
+	int idx;
+
+	idx = stm32_offset_to_index(dev, offset);
+	if (idx < 0)
+		return idx;
+
+	bits_index = MODE_BITS(idx);
+	mask = MODE_BITS_MASK << bits_index;
 
 	clrsetbits_le32(&regs->moder, mask, STM32_GPIO_MODE_IN << bits_index);
 
@@ -37,12 +66,20 @@ static int stm32_gpio_direction_output(struct udevice *dev, unsigned offset,
 {
 	struct stm32_gpio_priv *priv = dev_get_priv(dev);
 	struct stm32_gpio_regs *regs = priv->regs;
-	int bits_index = MODE_BITS(offset);
+	int bits_index;
-	int mask = MODE_BITS_MASK << bits_index;
+	int mask;
+	int idx;
+
+	idx = stm32_offset_to_index(dev, offset);
+	if (idx < 0)
+		return idx;
+
+	bits_index = MODE_BITS(idx);
+	mask = MODE_BITS_MASK << bits_index;
 
 	clrsetbits_le32(&regs->moder, mask, STM32_GPIO_MODE_OUT << bits_index);
 
-	writel(BSRR_BIT(offset, value), &regs->bsrr);
+	writel(BSRR_BIT(idx, value), &regs->bsrr);
 
 	return 0;
 }
@@ -51,16 +88,26 @@ static int stm32_gpio_get_value(struct udevice *dev, unsigned offset)
 {
 	struct stm32_gpio_priv *priv = dev_get_priv(dev);
 	struct stm32_gpio_regs *regs = priv->regs;
+	int idx;
 
-	return readl(&regs->idr) & BIT(offset) ? 1 : 0;
+	idx = stm32_offset_to_index(dev, offset);
+	if (idx < 0)
+		return idx;
+
+	return readl(&regs->idr) & BIT(idx) ? 1 : 0;
 }
 
 static int stm32_gpio_set_value(struct udevice *dev, unsigned offset, int value)
 {
 	struct stm32_gpio_priv *priv = dev_get_priv(dev);
 	struct stm32_gpio_regs *regs = priv->regs;
+	int idx;
 
-	writel(BSRR_BIT(offset, value), &regs->bsrr);
+	idx = stm32_offset_to_index(dev, offset);
+	if (idx < 0)
+		return idx;
+
+	writel(BSRR_BIT(idx, value), &regs->bsrr);
 
 	return 0;
 }
@@ -69,10 +116,18 @@ static int stm32_gpio_get_function(struct udevice *dev, unsigned int offset)
 {
 	struct stm32_gpio_priv *priv = dev_get_priv(dev);
 	struct stm32_gpio_regs *regs = priv->regs;
-	int bits_index = MODE_BITS(offset);
+	int bits_index;
-	int mask = MODE_BITS_MASK << bits_index;
+	int mask;
+	int idx;
 	u32 mode;
 
+	idx = stm32_offset_to_index(dev, offset);
+	if (idx < 0)
+		return idx;
+
+	bits_index = MODE_BITS(idx);
+	mask = MODE_BITS_MASK << bits_index;
+
 	mode = (readl(&regs->moder) & mask) >> bits_index;
 	if (mode == STM32_GPIO_MODE_OUT)
 		return GPIOF_OUTPUT;
@@ -96,8 +151,11 @@ static int gpio_stm32_probe(struct udevice *dev)
 {
 	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
 	struct stm32_gpio_priv *priv = dev_get_priv(dev);
+	struct ofnode_phandle_args args;
 	fdt_addr_t addr;
 	const char *name;
+	int ret;
+	int i;
 
 	addr = dev_read_addr(dev);
 	if (addr == FDT_ADDR_T_NONE)
@@ -108,14 +166,27 @@ static int gpio_stm32_probe(struct udevice *dev)
 	if (!name)
 		return -EINVAL;
 	uc_priv->bank_name = name;
-	uc_priv->gpio_count = dev_read_u32_default(dev, "ngpios",
+
-						   STM32_GPIOS_PER_BANK);
+	i = 0;
-	debug("%s, addr = 0x%p, bank_name = %s\n", __func__, (u32 *)priv->regs,
+	ret = dev_read_phandle_with_args(dev, "gpio-ranges",
-	      uc_priv->bank_name);
+					 NULL, 3, i, &args);
+
+	while (ret != -ENOENT) {
+		priv->gpio_range |= GENMASK(args.args[2] + args.args[0] - 1,
+				    args.args[0]);
+
+		uc_priv->gpio_count += args.args[2];
+
+		ret = dev_read_phandle_with_args(dev, "gpio-ranges", NULL, 3,
+						 ++i, &args);
+	}
+
+	dev_dbg(dev, "addr = 0x%p bank_name = %s gpio_count = %d gpio_range = 0x%x\n",
+		(u32 *)priv->regs, uc_priv->bank_name, uc_priv->gpio_count,
+		priv->gpio_range);
 
 #ifdef CONFIG_CLK
 	struct clk clk;
-	int ret;
 	ret = clk_get_by_index(dev, 0, &clk);
 	if (ret < 0)
 		return ret;