gpio: syscon: retrive syscon node and regs offsets from dt

This patch adds handling of new "gpio,syscon-dev" DT property,
which allows to specify syscon node and data/direction registers
offsets in DT.

"gpio,syscon-dev" has following format:
	gpio,syscon-dev = <&syscon_dev data_reg_offset [direction_reg_offset]>;

where
 - syscon_dev - phandle on syscon node
 - data_reg_offset - offset of data register (in bytes)
 - direction_reg_offset - offset of dirrection register (optional, in bytes)

for example:
	gpio,syscon-dev = <&devctrl 0x254>;

In such way, the support of multiple Syscon GPIO devices is added.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 43 insertions, 8 deletions

diff --git a/drivers/gpio/gpio-syscon.c b/drivers/gpio/gpio-syscon.c
index d50ff9363c81..049391bf80ee 100644
--- a/drivers/gpio/gpio-syscon.c
+++ b/drivers/gpio/gpio-syscon.c
@@ -55,6 +55,8 @@ struct syscon_gpio_priv {
         struct gpio_chip                chip;
         struct regmap                   *syscon;
         const struct syscon_gpio_data   *data;
+        u32                             dreg_offset;
+        u32                             dir_reg_offset;
 };
 
 static inline struct syscon_gpio_priv *to_syscon_gpio(struct gpio_chip *chip)
@@ -65,9 +67,11 @@ static inline struct syscon_gpio_priv *to_syscon_gpio(struct gpio_chip *chip)
 static int syscon_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
         struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
-        unsigned int val, offs = priv->data->dat_bit_offset + offset;
+        unsigned int val, offs;
         int ret;
 
+        offs = priv->dreg_offset + priv->data->dat_bit_offset + offset;
+
         ret = regmap_read(priv->syscon,
                           (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, &val);
         if (ret)
@@ -79,7 +83,9 @@ static int syscon_gpio_get(struct gpio_chip *chip, unsigned offset)
 static void syscon_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
 {
         struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
-        unsigned int offs = priv->data->dat_bit_offset + offset;
+        unsigned int offs;
+
+        offs = priv->dreg_offset + priv->data->dat_bit_offset + offset;
 
         regmap_update_bits(priv->syscon,
                            (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
@@ -92,7 +98,10 @@ static int syscon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
         struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
 
         if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) {
-                unsigned int offs = priv->data->dir_bit_offset + offset;
+                unsigned int offs;
+
+                offs = priv->dir_reg_offset +
+                       priv->data->dir_bit_offset + offset;
 
                 regmap_update_bits(priv->syscon,
                                    (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
@@ -107,7 +116,10 @@ static int syscon_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int val)
         struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
 
         if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) {
-                unsigned int offs = priv->data->dir_bit_offset + offset;
+                unsigned int offs;
+
+                offs = priv->dir_reg_offset +
+                       priv->data->dir_bit_offset + offset;
 
                 regmap_update_bits(priv->syscon,
                                    (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
@@ -142,6 +154,8 @@ static int syscon_gpio_probe(struct platform_device *pdev)
         struct device *dev = &pdev->dev;
         const struct of_device_id *of_id = of_match_device(syscon_gpio_ids, dev);
         struct syscon_gpio_priv *priv;
+        struct device_node *np = dev->of_node;
+        int ret;
 
         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
         if (!priv)
@@ -149,10 +163,31 @@ static int syscon_gpio_probe(struct platform_device *pdev)
 
         priv->data = of_id->data;
 
-        priv->syscon =
-                syscon_regmap_lookup_by_compatible(priv->data->compatible);
-        if (IS_ERR(priv->syscon))
-                return PTR_ERR(priv->syscon);
+        if (priv->data->compatible) {
+                priv->syscon = syscon_regmap_lookup_by_compatible(
+                                        priv->data->compatible);
+                if (IS_ERR(priv->syscon))
+                        return PTR_ERR(priv->syscon);
+        } else {
+                priv->syscon =
+                        syscon_regmap_lookup_by_phandle(np, "gpio,syscon-dev");
+                if (IS_ERR(priv->syscon))
+                        return PTR_ERR(priv->syscon);
+
+                ret = of_property_read_u32_index(np, "gpio,syscon-dev", 1,
+                                                 &priv->dreg_offset);
+                if (ret)
+                        dev_err(dev, "can't read the data register offset!\n");
+
+                priv->dreg_offset <<= 3;
+
+                ret = of_property_read_u32_index(np, "gpio,syscon-dev", 2,
+                                                 &priv->dir_reg_offset);
+                if (ret)
+                        dev_err(dev, "can't read the dir register offset!\n");
+
+                priv->dir_reg_offset <<= 3;
+        }
 
         priv->chip.dev = dev;
         priv->chip.owner = THIS_MODULE;