gpio: pca953x: refactor pca953x_read_regs()

Avoid the unnecessary if-else in pca953x_read_regs() by spltting the
routine into smaller, specialized functions and calling the right one
via a function pointer held in struct pca953x.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index e9defeb9c21275c9e5afd6c40fbd98e7e82bc16e..e7bf3b3cebcd1c13f3b66b378a913ac5a2524d3e 100644 (file)
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -137,6 +137,7 @@ struct pca953x_chip {
        const struct pca953x_reg_config *regs;
 
        int (*write_regs)(struct pca953x_chip *, int, u8 *);
+       int (*read_regs)(struct pca953x_chip *, int, u8 *);
 };
 
 static int pca953x_read_single(struct pca953x_chip *chip, int reg, u32 *val,
@@ -222,24 +223,41 @@ static int pca953x_write_regs(struct pca953x_chip *chip, int reg, u8 *val)
        return 0;
 }
 
-static int pca953x_read_regs(struct pca953x_chip *chip, int reg, u8 *val)
+static int pca953x_read_regs_8(struct pca953x_chip *chip, int reg, u8 *val)
 {
        int ret;
 
-       if (chip->gpio_chip.ngpio <= 8) {
-               ret = i2c_smbus_read_byte_data(chip->client, reg);
-               *val = ret;
-       } else if (chip->gpio_chip.ngpio >= 24) {
-               int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
+       ret = i2c_smbus_read_byte_data(chip->client, reg);
+       *val = ret;
 
-               ret = i2c_smbus_read_i2c_block_data(chip->client,
-                                       (reg << bank_shift) | REG_ADDR_AI,
-                                       NBANK(chip), val);
-       } else {
-               ret = i2c_smbus_read_word_data(chip->client, reg << 1);
-               val[0] = (u16)ret & 0xFF;
-               val[1] = (u16)ret >> 8;
-       }
+       return ret;
+}
+
+static int pca953x_read_regs_16(struct pca953x_chip *chip, int reg, u8 *val)
+{
+       int ret;
+
+       ret = i2c_smbus_read_word_data(chip->client, reg << 1);
+       val[0] = (u16)ret & 0xFF;
+       val[1] = (u16)ret >> 8;
+
+       return ret;
+}
+
+static int pca953x_read_regs_24(struct pca953x_chip *chip, int reg, u8 *val)
+{
+       int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
+
+       return i2c_smbus_read_i2c_block_data(chip->client,
+                                            (reg << bank_shift) | REG_ADDR_AI,
+                                            NBANK(chip), val);
+}
+
+static int pca953x_read_regs(struct pca953x_chip *chip, int reg, u8 *val)
+{
+       int ret;
+
+       ret = chip->read_regs(chip, reg, val);
        if (ret < 0) {
                dev_err(&chip->client->dev, "failed reading register\n");
                return ret;
@@ -784,13 +802,16 @@ static int pca953x_probe(struct i2c_client *client,
 
        if (chip->gpio_chip.ngpio <= 8) {
                chip->write_regs = pca953x_write_regs_8;
+               chip->read_regs = pca953x_read_regs_8;
        } else if (chip->gpio_chip.ngpio >= 24) {
                chip->write_regs = pca953x_write_regs_24;
+               chip->read_regs = pca953x_read_regs_24;
        } else {
                if (PCA_CHIP_TYPE(chip->driver_data) == PCA953X_TYPE)
                        chip->write_regs = pca953x_write_regs_16;
                else
                        chip->write_regs = pca957x_write_regs_16;
+               chip->read_regs = pca953x_read_regs_16;
        }
 
        if (chip->chip_type == PCA953X_TYPE)