[PATCH v2 5/5] gpio: pca953x: refactor pca953x_read_regs()

[Bartosz Golaszewski]

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 <bgolaszew...@baylibre.com>
---
 drivers/gpio/gpio-pca953x.c | 55 ++++++++++++++++++++++++++++++++-------------
 1 file changed, 39 insertions(+), 16 deletions(-)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 00bb2ea..e417c42 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -134,6 +134,7 @@ struct pca953x_chip {
        const struct pca953x_offset *offset;
 
        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,
@@ -219,24 +220,41 @@ 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;
@@ -766,10 +784,15 @@ static int pca953x_probe(struct i2c_client *client,
         */
        pca953x_setup_gpio(chip, chip->driver_data & PCA_GPIO_MASK);
 
-       if (chip->gpio_chip.ngpio <= 8)
+       if (chip->gpio_chip.ngpio <= 8) {
                chip->write_regs = pca953x_write_regs_8;
-       else if (chip->gpio_chip.ngpio >= 24)
+               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 {
+               chip->read_regs = pca953x_read_regs_16;
+       }
 
        if (PCA_CHIP_TYPE(chip->driver_data) == PCA953X_TYPE)
                ret = device_pca953x_init(chip, invert);
-- 
2.7.4