[PATCH 0/5] gpio: pca953x: code refactoring

[PATCH 0/5] gpio: pca953x: code refactoring

[Bartosz Golaszewski]

I'm working on converting the pca953x driver to using regmap, but since
it's not a trivial task I figured I'd post a couple refactoring patches
I did so far for 4.9.

The first patch just fixes a couple coding style issues. The second
removes a couple unnecessary switches. Last three refactor the
read/write_regs functions to avoid if-elses by using function pointers
to smaller, specialized routines.

Tested with pca9534 and pca9535 chips.

Bartosz Golaszewski (5):
  gpio: pca953x: coding style fixes
  gpio: pca953x: code shrink
  gpio: pca953x: refactor pca953x_write_regs()
  gpio: pca953x: remove an unused variable
  gpio: pca953x: refactor pca953x_read_regs()

 drivers/gpio/gpio-pca953x.c | 270 ++++++++++++++++++++++----------------------
 1 file changed, 136 insertions(+), 134 deletions(-)

-- 
2.7.4

[PATCH 1/5] gpio: pca953x: coding style fixes

[Bartosz Golaszewski]

pca953x_gpio_set_multiple() has some coding style issues that make it
harder to read. Tweak the code a bit.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-pca953x.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 02f2a56..2312f8d 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -355,13 +355,13 @@ exit:
 }
 
 static void pca953x_gpio_set_multiple(struct gpio_chip *gc,
-		unsigned long *mask, unsigned long *bits)
+				      unsigned long *mask, unsigned long *bits)
 {
 	struct pca953x_chip *chip = gpiochip_get_data(gc);
 	u8 reg_val[MAX_BANK];
-	int ret, offset = 0;
+	int ret, bank, offset = 0;
 	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
-	int bank;
+	unsigned int bankmask, bankval;
 
 	switch (chip->chip_type) {
 	case PCA953X_TYPE:
@@ -374,15 +374,16 @@ static void pca953x_gpio_set_multiple(struct gpio_chip *gc,
 
 	memcpy(reg_val, chip->reg_output, NBANK(chip));
 	mutex_lock(&chip->i2c_lock);
-	for(bank=0; bank<NBANK(chip); bank++) {
-		unsigned bankmask = mask[bank / sizeof(*mask)] >>
-				    ((bank % sizeof(*mask)) * 8);
-		if(bankmask) {
-			unsigned bankval  = bits[bank / sizeof(*bits)] >>
-					    ((bank % sizeof(*bits)) * 8);
+	for (bank = 0; bank < NBANK(chip); bank++) {
+		bankmask = mask[bank / sizeof(*mask)] >>
+			   ((bank % sizeof(*mask)) * 8);
+		if (bankmask) {
+			bankval = bits[bank / sizeof(*bits)] >>
+				  ((bank % sizeof(*bits)) * 8);
 			reg_val[bank] = (reg_val[bank] & ~bankmask) | bankval;
 		}
 	}
+
 	ret = i2c_smbus_write_i2c_block_data(chip->client, offset << bank_shift, NBANK(chip), reg_val);
 	if (ret)
 		goto exit;
-- 
2.7.4

Re: [PATCH 1/5] gpio: pca953x: coding style fixes

[Linus Walleij]

On Mon, Sep 5, 2016 at 4:31 PM, Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:

> pca953x_gpio_set_multiple() has some coding style issues that make it
> harder to read. Tweak the code a bit.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Much better like this.

Patch applied.

Yours,
Linus Walleij

Re: [PATCH 1/5] gpio: pca953x: coding style fixes

[Linus Walleij]

On Wed, Sep 7, 2016 at 11:55 PM, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Mon, Sep 5, 2016 at 4:31 PM, Bartosz Golaszewski
> <bgolaszewski@baylibre.com> wrote:
>
>> pca953x_gpio_set_multiple() has some coding style issues that make it
>> harder to read. Tweak the code a bit.
>>
>> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>
> Much better like this.
>
> Patch applied.

Ah I see there was a later version and it was moved around.

OK backing this out. Let's go for latest version and also please
rebase it onto my devel branch.

Yours,
Linus Walleij

Re: [PATCH 1/5] gpio: pca953x: coding style fixes

[Bartosz Golaszewski]

2016-09-08 1:15 GMT+02:00 Linus Walleij <linus.walleij@linaro.org>:
> On Wed, Sep 7, 2016 at 11:55 PM, Linus Walleij <linus.walleij@linaro.org> wrote:
>> On Mon, Sep 5, 2016 at 4:31 PM, Bartosz Golaszewski
>> <bgolaszewski@baylibre.com> wrote:
>>
>>> pca953x_gpio_set_multiple() has some coding style issues that make it
>>> harder to read. Tweak the code a bit.
>>>
>>> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>>
>> Much better like this.
>>
>> Patch applied.
>
> Ah I see there was a later version and it was moved around.
>
> OK backing this out. Let's go for latest version and also please
> rebase it onto my devel branch.
>
> Yours,
> Linus Walleij

Done. The current, rebased version is v6.

Thanks,
Bartosz

[PATCH 2/5] gpio: pca953x: code shrink

[Bartosz Golaszewski]

There are multiple places in the driver code where a
switch (chip->chip_type) is used to determine the proper register
offset.

Unduplicate the code by adding a simple structure holding the possible
offsets that differ between the pca953x and pca957x chip families and
use it to avoid the checks.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-pca953x.c | 122 +++++++++++++++-----------------------------
 1 file changed, 42 insertions(+), 80 deletions(-)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 2312f8d..17cba0a 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -94,6 +94,24 @@ MODULE_DEVICE_TABLE(acpi, pca953x_acpi_ids);
 
 #define NBANK(chip) DIV_ROUND_UP(chip->gpio_chip.ngpio, BANK_SZ)
 
+struct pca953x_offset {
+	int direction;
+	int output;
+	int input;
+};
+
+static struct pca953x_offset pca953x_offsets = {
+	.direction = PCA953X_DIRECTION,
+	.output = PCA953X_OUTPUT,
+	.input = PCA953X_INPUT,
+};
+
+static struct pca953x_offset pca957x_offsets = {
+	.direction = PCA957X_CFG,
+	.output = PCA957X_OUT,
+	.input = PCA957X_IN,
+};
+
 struct pca953x_chip {
 	unsigned gpio_start;
 	u8 reg_output[MAX_BANK];
@@ -113,6 +131,8 @@ struct pca953x_chip {
 	const char *const *names;
 	int	chip_type;
 	unsigned long driver_data;
+
+	struct pca953x_offset *offset;
 };
 
 static int pca953x_read_single(struct pca953x_chip *chip, int reg, u32 *val,
@@ -222,20 +242,12 @@ static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
 {
 	struct pca953x_chip *chip = gpiochip_get_data(gc);
 	u8 reg_val;
-	int ret, offset = 0;
+	int ret;
 
 	mutex_lock(&chip->i2c_lock);
 	reg_val = chip->reg_direction[off / BANK_SZ] | (1u << (off % BANK_SZ));
 
-	switch (chip->chip_type) {
-	case PCA953X_TYPE:
-		offset = PCA953X_DIRECTION;
-		break;
-	case PCA957X_TYPE:
-		offset = PCA957X_CFG;
-		break;
-	}
-	ret = pca953x_write_single(chip, offset, reg_val, off);
+	ret = pca953x_write_single(chip, chip->offset->direction, reg_val, off);
 	if (ret)
 		goto exit;
 
@@ -250,7 +262,7 @@ static int pca953x_gpio_direction_output(struct gpio_chip *gc,
 {
 	struct pca953x_chip *chip = gpiochip_get_data(gc);
 	u8 reg_val;
-	int ret, offset = 0;
+	int ret;
 
 	mutex_lock(&chip->i2c_lock);
 	/* set output level */
@@ -261,15 +273,7 @@ static int pca953x_gpio_direction_output(struct gpio_chip *gc,
 		reg_val = chip->reg_output[off / BANK_SZ]
 			& ~(1u << (off % BANK_SZ));
 
-	switch (chip->chip_type) {
-	case PCA953X_TYPE:
-		offset = PCA953X_OUTPUT;
-		break;
-	case PCA957X_TYPE:
-		offset = PCA957X_OUT;
-		break;
-	}
-	ret = pca953x_write_single(chip, offset, reg_val, off);
+	ret = pca953x_write_single(chip, chip->offset->output, reg_val, off);
 	if (ret)
 		goto exit;
 
@@ -277,15 +281,7 @@ static int pca953x_gpio_direction_output(struct gpio_chip *gc,
 
 	/* then direction */
 	reg_val = chip->reg_direction[off / BANK_SZ] & ~(1u << (off % BANK_SZ));
-	switch (chip->chip_type) {
-	case PCA953X_TYPE:
-		offset = PCA953X_DIRECTION;
-		break;
-	case PCA957X_TYPE:
-		offset = PCA957X_CFG;
-		break;
-	}
-	ret = pca953x_write_single(chip, offset, reg_val, off);
+	ret = pca953x_write_single(chip, chip->offset->direction, reg_val, off);
 	if (ret)
 		goto exit;
 
@@ -299,18 +295,10 @@ static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
 {
 	struct pca953x_chip *chip = gpiochip_get_data(gc);
 	u32 reg_val;
-	int ret, offset = 0;
+	int ret;
 
 	mutex_lock(&chip->i2c_lock);
-	switch (chip->chip_type) {
-	case PCA953X_TYPE:
-		offset = PCA953X_INPUT;
-		break;
-	case PCA957X_TYPE:
-		offset = PCA957X_IN;
-		break;
-	}
-	ret = pca953x_read_single(chip, offset, &reg_val, off);
+	ret = pca953x_read_single(chip, chip->offset->input, &reg_val, off);
 	mutex_unlock(&chip->i2c_lock);
 	if (ret < 0) {
 		/* NOTE:  diagnostic already emitted; that's all we should
@@ -327,7 +315,7 @@ static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
 {
 	struct pca953x_chip *chip = gpiochip_get_data(gc);
 	u8 reg_val;
-	int ret, offset = 0;
+	int ret;
 
 	mutex_lock(&chip->i2c_lock);
 	if (val)
@@ -337,15 +325,7 @@ static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
 		reg_val = chip->reg_output[off / BANK_SZ]
 			& ~(1u << (off % BANK_SZ));
 
-	switch (chip->chip_type) {
-	case PCA953X_TYPE:
-		offset = PCA953X_OUTPUT;
-		break;
-	case PCA957X_TYPE:
-		offset = PCA957X_OUT;
-		break;
-	}
-	ret = pca953x_write_single(chip, offset, reg_val, off);
+	ret = pca953x_write_single(chip, chip->offset->output, reg_val, off);
 	if (ret)
 		goto exit;
 
@@ -359,19 +339,10 @@ static void pca953x_gpio_set_multiple(struct gpio_chip *gc,
 {
 	struct pca953x_chip *chip = gpiochip_get_data(gc);
 	u8 reg_val[MAX_BANK];
-	int ret, bank, offset = 0;
+	int ret, bank;
 	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
 	unsigned int bankmask, bankval;
 
-	switch (chip->chip_type) {
-	case PCA953X_TYPE:
-		offset = PCA953X_OUTPUT;
-		break;
-	case PCA957X_TYPE:
-		offset = PCA957X_OUT;
-		break;
-	}
-
 	memcpy(reg_val, chip->reg_output, NBANK(chip));
 	mutex_lock(&chip->i2c_lock);
 	for (bank = 0; bank < NBANK(chip); bank++) {
@@ -384,7 +355,9 @@ static void pca953x_gpio_set_multiple(struct gpio_chip *gc,
 		}
 	}
 
-	ret = i2c_smbus_write_i2c_block_data(chip->client, offset << bank_shift, NBANK(chip), reg_val);
+	ret = i2c_smbus_write_i2c_block_data(chip->client,
+					     chip->offset->output << bank_shift,
+					     NBANK(chip), reg_val);
 	if (ret)
 		goto exit;
 
@@ -516,7 +489,7 @@ static bool pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending)
 	bool pending_seen = false;
 	bool trigger_seen = false;
 	u8 trigger[MAX_BANK];
-	int ret, i, offset = 0;
+	int ret, i;
 
 	if (chip->driver_data & PCA_PCAL) {
 		/* Read the current interrupt status from the device */
@@ -541,15 +514,7 @@ static bool pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending)
 		return pending_seen;
 	}
 
-	switch (chip->chip_type) {
-	case PCA953X_TYPE:
-		offset = PCA953X_INPUT;
-		break;
-	case PCA957X_TYPE:
-		offset = PCA957X_IN;
-		break;
-	}
-	ret = pca953x_read_regs(chip, offset, cur_stat);
+	ret = pca953x_read_regs(chip, chip->offset->input, cur_stat);
 	if (ret)
 		return false;
 
@@ -609,20 +574,13 @@ static int pca953x_irq_setup(struct pca953x_chip *chip,
 			     int irq_base)
 {
 	struct i2c_client *client = chip->client;
-	int ret, i, offset = 0;
+	int ret, i;
 
 	if (client->irq && irq_base != -1
 			&& (chip->driver_data & PCA_INT)) {
 
-		switch (chip->chip_type) {
-		case PCA953X_TYPE:
-			offset = PCA953X_INPUT;
-			break;
-		case PCA957X_TYPE:
-			offset = PCA957X_IN;
-			break;
-		}
-		ret = pca953x_read_regs(chip, offset, chip->irq_stat);
+		ret = pca953x_read_regs(chip,
+					chip->offset->input, chip->irq_stat);
 		if (ret)
 			return ret;
 
@@ -685,6 +643,8 @@ static int device_pca953x_init(struct pca953x_chip *chip, u32 invert)
 	int ret;
 	u8 val[MAX_BANK];
 
+	chip->offset = &pca953x_offsets;
+
 	ret = pca953x_read_regs(chip, PCA953X_OUTPUT, chip->reg_output);
 	if (ret)
 		goto out;
@@ -710,6 +670,8 @@ static int device_pca957x_init(struct pca953x_chip *chip, u32 invert)
 	int ret;
 	u8 val[MAX_BANK];
 
+	chip->offset = &pca957x_offsets;
+
 	ret = pca953x_read_regs(chip, PCA957X_OUT, chip->reg_output);
 	if (ret)
 		goto out;
-- 
2.7.4

Re: [PATCH 2/5] gpio: pca953x: code shrink

[Geert Uytterhoeven]

On Mon, Sep 5, 2016 at 4:31 PM, Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:
> --- a/drivers/gpio/gpio-pca953x.c
> +++ b/drivers/gpio/gpio-pca953x.c
> @@ -94,6 +94,24 @@ MODULE_DEVICE_TABLE(acpi, pca953x_acpi_ids);
>
>  #define NBANK(chip) DIV_ROUND_UP(chip->gpio_chip.ngpio, BANK_SZ)
>
> +struct pca953x_offset {
> +       int direction;
> +       int output;
> +       int input;
> +};
> +
> +static struct pca953x_offset pca953x_offsets = {

const

> +       .direction = PCA953X_DIRECTION,
> +       .output = PCA953X_OUTPUT,
> +       .input = PCA953X_INPUT,
> +};
> +
> +static struct pca953x_offset pca957x_offsets = {

const

> +       .direction = PCA957X_CFG,
> +       .output = PCA957X_OUT,
> +       .input = PCA957X_IN,
> +};
> +
>  struct pca953x_chip {
>         unsigned gpio_start;
>         u8 reg_output[MAX_BANK];
> @@ -113,6 +131,8 @@ struct pca953x_chip {
>         const char *const *names;
>         int     chip_type;
>         unsigned long driver_data;
> +
> +       struct pca953x_offset *offset;

const

>  };

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 2/5] gpio: pca953x: code shrink

[Linus Walleij]

On Mon, Sep 5, 2016 at 4:31 PM, Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:

> There are multiple places in the driver code where a
> switch (chip->chip_type) is used to determine the proper register
> offset.
>
> Unduplicate the code by adding a simple structure holding the possible
> offsets that differ between the pca953x and pca957x chip families and
> use it to avoid the checks.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

This doesn't apply beacuse of other changes made to the driver by
Phil Reid et al.

Can you please rebase your work on top of my gpio "devel" branch:
https://git.kernel.org/cgit/linux/kernel/git/linusw/linux-gpio.git/log/?h=devel
and at the same time fix Geert's reported const thing?

I'm overall happy with the patch series and would like to apply
also patches 2-5 for v4.9 soon.

Yours,
Linus Walleij

[PATCH 3/5] gpio: pca953x: refactor pca953x_write_regs()

[Bartosz Golaszewski]

Avoid the unnecessary if-else in pca953x_write_regs() by splitting
the routine into smaller, specialized functions and calling the right
one via a function pointer held in struct pca953x_chip.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-pca953x.c | 75 ++++++++++++++++++++++++++++-----------------
 1 file changed, 47 insertions(+), 28 deletions(-)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 17cba0a..b64a7bb 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -133,6 +133,8 @@ struct pca953x_chip {
 	unsigned long driver_data;
 
 	struct pca953x_offset *offset;
+
+	int (*write_regs)(struct pca953x_chip *, int, u8 *);
 };
 
 static int pca953x_read_single(struct pca953x_chip *chip, int reg, u32 *val,
@@ -172,38 +174,44 @@ static int pca953x_write_single(struct pca953x_chip *chip, int reg, u32 val,
 	return 0;
 }
 
-static int pca953x_write_regs(struct pca953x_chip *chip, int reg, u8 *val)
+static int pca953x_write_regs_8(struct pca953x_chip *chip, int reg, u8 *val)
 {
-	int ret = 0;
+	return i2c_smbus_write_byte_data(chip->client, reg, *val);
+}
 
-	if (chip->gpio_chip.ngpio <= 8)
-		ret = i2c_smbus_write_byte_data(chip->client, reg, *val);
-	else if (chip->gpio_chip.ngpio >= 24) {
-		int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
-		ret = i2c_smbus_write_i2c_block_data(chip->client,
-					(reg << bank_shift) | REG_ADDR_AI,
-					NBANK(chip), val);
-	} else {
-		switch (chip->chip_type) {
-		case PCA953X_TYPE: {
-			__le16 word = cpu_to_le16(get_unaligned((u16 *)val));
+static int pca953x_write_regs_16(struct pca953x_chip *chip, int reg, u8 *val)
+{
+	__le16 word = cpu_to_le16(get_unaligned((u16 *)val));
 
-			ret = i2c_smbus_write_word_data(chip->client, reg << 1,
-							(__force u16)word);
-			break;
-		}
-		case PCA957X_TYPE:
-			ret = i2c_smbus_write_byte_data(chip->client, reg << 1,
-							val[0]);
-			if (ret < 0)
-				break;
-			ret = i2c_smbus_write_byte_data(chip->client,
-							(reg << 1) + 1,
-							val[1]);
-			break;
-		}
-	}
+	return i2c_smbus_write_word_data(chip->client,
+					 reg << 1, (__force u16)word);
+}
+
+static int pca957x_write_regs_16(struct pca953x_chip *chip, int reg, u8 *val)
+{
+	int ret;
 
+	ret = i2c_smbus_write_byte_data(chip->client, reg << 1, val[0]);
+	if (ret < 0)
+		return ret;
+
+	return i2c_smbus_write_byte_data(chip->client, (reg << 1) + 1, val[1]);
+}
+
+static int pca953x_write_regs_24(struct pca953x_chip *chip, int reg, u8 *val)
+{
+	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
+
+	return i2c_smbus_write_i2c_block_data(chip->client,
+					      (reg << bank_shift) | REG_ADDR_AI,
+					      NBANK(chip), val);
+}
+
+static int pca953x_write_regs(struct pca953x_chip *chip, int reg, u8 *val)
+{
+	int ret = 0;
+
+	ret = chip->write_regs(chip, reg, val);
 	if (ret < 0) {
 		dev_err(&chip->client->dev, "failed writing register\n");
 		return ret;
@@ -645,6 +653,9 @@ static int device_pca953x_init(struct pca953x_chip *chip, u32 invert)
 
 	chip->offset = &pca953x_offsets;
 
+	if (!chip->write_regs)
+		chip->write_regs = pca953x_write_regs_16;
+
 	ret = pca953x_read_regs(chip, PCA953X_OUTPUT, chip->reg_output);
 	if (ret)
 		goto out;
@@ -672,6 +683,9 @@ static int device_pca957x_init(struct pca953x_chip *chip, u32 invert)
 
 	chip->offset = &pca957x_offsets;
 
+	if (!chip->write_regs)
+		chip->write_regs = pca957x_write_regs_16;
+
 	ret = pca953x_read_regs(chip, PCA957X_OUT, chip->reg_output);
 	if (ret)
 		goto out;
@@ -755,6 +769,11 @@ static int pca953x_probe(struct i2c_client *client,
 	 */
 	pca953x_setup_gpio(chip, chip->driver_data & PCA_GPIO_MASK);
 
+	if (chip->gpio_chip.ngpio <= 8)
+		chip->write_regs = pca953x_write_regs_8;
+	else if (chip->gpio_chip.ngpio >= 24)
+		chip->write_regs = pca953x_write_regs_24;
+
 	if (chip->chip_type == PCA953X_TYPE)
 		ret = device_pca953x_init(chip, invert);
 	else
-- 
2.7.4

[PATCH 4/5] gpio: pca953x: remove an unused variable

[Bartosz Golaszewski]

The chip_type variable in struct pca953x_chip is no longer required.

Remove it.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-pca953x.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index b64a7bb..86676dd 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -129,7 +129,6 @@ struct pca953x_chip {
 	struct i2c_client *client;
 	struct gpio_chip gpio_chip;
 	const char *const *names;
-	int	chip_type;
 	unsigned long driver_data;
 
 	struct pca953x_offset *offset;
@@ -760,8 +759,6 @@ static int pca953x_probe(struct i2c_client *client,
 		}
 	}
 
-	chip->chip_type = PCA_CHIP_TYPE(chip->driver_data);
-
 	mutex_init(&chip->i2c_lock);
 
 	/* initialize cached registers from their original values.
@@ -774,7 +771,7 @@ static int pca953x_probe(struct i2c_client *client,
 	else if (chip->gpio_chip.ngpio >= 24)
 		chip->write_regs = pca953x_write_regs_24;
 
-	if (chip->chip_type == PCA953X_TYPE)
+	if (PCA_CHIP_TYPE(chip->driver_data) == PCA953X_TYPE)
 		ret = device_pca953x_init(chip, invert);
 	else
 		ret = device_pca957x_init(chip, invert);
-- 
2.7.4

[PATCH 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 <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 86676dd..0ddcbbc 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -134,6 +134,7 @@ struct pca953x_chip {
 	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

Re: [PATCH 0/5] gpio: pca953x: code refactoring

[Linus Walleij]

On Mon, Sep 5, 2016 at 4:31 PM, Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:

> I'm working on converting the pca953x driver to using regmap, but since
> it's not a trivial task I figured I'd post a couple refactoring patches
> I did so far for 4.9.

I'm in. I'm also ready to merge more patches on top late, because
it is a noble goal.

Yours,
Linus Walleij