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

Andy Shevchenko
2016-09-07T11:36:04Z

On Wed, 2016-09-07 at 11:24 +0200, Bartosz Golaszewski wrote:
> 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>
> ---
>  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;
> + }

For sake of consolidation stuff can we move write_regs_16 variants here?
It might require to refactor patch 3 as well

>
>   if (PCA_CHIP_TYPE(chip->driver_data) == PCA953X_TYPE)
>   ret = device_pca953x_init(chip, invert);

--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy