Re: [PATCH] Add support for TCA6424

From: Grant Likely
Date: Thu May 17 2012 - 19:46:56 EST

On Tue, 24 Apr 2012 15:48:31 +0200, Andreas Schallenberg <Andreas.Schallenberg@xxxxxxxxxxxxxxxxxx> wrote:
> From: Andreas Schallenberg <aschallenberg@GWS026Linux.(none)>

<rant-mode>
This is getting ridiculous. Please, please, please write good
descriptions of your patches. Yes it is obvious that your adding
support for a new chip to an existing driver, but you haven't said a
word about what you had to change, any problems you encountered or how
it has been tested.

For instance, some of the data types change from uint16_t to uint
without any clue as to why. Why uint? Why not uint32_t (for
example)?

Give a poor review a break and give me some hints about what I should
be looking out for and any gotchas that might be in the code.
</rant-mode>

Andreas, I'm not singling you out. This is not the only patch by far
that shows up without a sufficient description. I just happened to
snap while reading this one.

g.

>
> ---
> drivers/gpio/gpio-pca953x.c | 43 ++++++++++++++++++++++++++++++-------------
> 1 files changed, 30 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
> index 0550dcb..58f9428 100644
> --- a/drivers/gpio/gpio-pca953x.c
> +++ b/drivers/gpio/gpio-pca953x.c
> @@ -28,6 +28,8 @@
> #define PCA953X_INVERT 2
> #define PCA953X_DIRECTION 3
>
> +#define REG_ADDR_AI 0x80
> +
> #define PCA957X_IN 0
> #define PCA957X_INVRT 1
> #define PCA957X_BKEN 2
> @@ -63,15 +65,15 @@ static const struct i2c_device_id pca953x_id[] = {
> { "pca6107", 8 | PCA953X_TYPE | PCA_INT, },
> { "tca6408", 8 | PCA953X_TYPE | PCA_INT, },
> { "tca6416", 16 | PCA953X_TYPE | PCA_INT, },
> - /* NYET: { "tca6424", 24, }, */
> + { "tca6424", 24 | PCA953X_TYPE | PCA_INT, },
> { }
> };
> MODULE_DEVICE_TABLE(i2c, pca953x_id);
>
> struct pca953x_chip {
> unsigned gpio_start;
> - uint16_t reg_output;
> - uint16_t reg_direction;
> + uint reg_output;
> + uint reg_direction;
> struct mutex i2c_lock;
>
> #ifdef CONFIG_GPIO_PCA953X_IRQ
> @@ -89,12 +91,20 @@ struct pca953x_chip {
> int chip_type;
> };
>
> -static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
> +static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint val)
> {
> int ret = 0;
>
> if (chip->gpio_chip.ngpio <= 8)
> ret = i2c_smbus_write_byte_data(chip->client, reg, val);
> + else if (chip->gpio_chip.ngpio > 16) {
> + ret = i2c_smbus_write_word_data(chip->client,
> + (reg << 2) | REG_ADDR_AI,
> + val & 0xffff);
> + ret = i2c_smbus_write_byte_data(chip->client,
> + (reg << 2) + 2,
> + (val & 0xff0000) >> 16);

Can these not be rolled up into a single i2c transaction? It looks
wrong to do two transfers for a single write.

> + }
> else {
> switch (chip->chip_type) {
> case PCA953X_TYPE:
> @@ -121,12 +131,17 @@ static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
> return 0;
> }
>
> -static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint16_t *val)
> +static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint *val)
> {
> int ret;
>
> if (chip->gpio_chip.ngpio <= 8)
> ret = i2c_smbus_read_byte_data(chip->client, reg);
> + else if (chip->gpio_chip.ngpio == 24) {
> + ret = i2c_smbus_read_word_data(chip->client, reg << 2);
> + ret |= (i2c_smbus_read_byte_data(chip->client,
> + (reg << 2) + 2)<<16);

Ditto here.

> + }
> else
> ret = i2c_smbus_read_word_data(chip->client, reg << 1);
>
> @@ -135,14 +150,14 @@ static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint16_t *val)
> return ret;
> }
>
> - *val = (uint16_t)ret;
> + *val = (uint)ret;

Blech! Why the cast?

> return 0;
> }
>
> static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
> {
> struct pca953x_chip *chip;
> - uint16_t reg_val;
> + uint reg_val;
> int ret, offset = 0;
>
> chip = container_of(gc, struct pca953x_chip, gpio_chip);
> @@ -173,7 +188,7 @@ static int pca953x_gpio_direction_output(struct gpio_chip *gc,
> unsigned off, int val)
> {
> struct pca953x_chip *chip;
> - uint16_t reg_val;
> + uint reg_val;
> int ret, offset = 0;
>
> chip = container_of(gc, struct pca953x_chip, gpio_chip);
> @@ -223,7 +238,7 @@ exit:
> static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
> {
> struct pca953x_chip *chip;
> - uint16_t reg_val;
> + uint reg_val;
> int ret, offset = 0;
>
> chip = container_of(gc, struct pca953x_chip, gpio_chip);
> @@ -253,7 +268,7 @@ static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
> static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
> {
> struct pca953x_chip *chip;
> - uint16_t reg_val;
> + uint reg_val;
> int ret, offset = 0;
>
> chip = container_of(gc, struct pca953x_chip, gpio_chip);
> @@ -386,7 +401,7 @@ static struct irq_chip pca953x_irq_chip = {
>
> static uint16_t pca953x_irq_pending(struct pca953x_chip *chip)
> {
> - uint16_t cur_stat;
> + uint cur_stat;
> uint16_t old_stat;
> uint16_t pending;
> uint16_t trigger;
> @@ -449,6 +464,7 @@ static int pca953x_irq_setup(struct pca953x_chip *chip,
> {
> struct i2c_client *client = chip->client;
> int ret, offset = 0;
> + uint temporary;
>
> if (irq_base != -1
> && (id->driver_data & PCA_INT)) {
> @@ -462,7 +478,8 @@ static int pca953x_irq_setup(struct pca953x_chip *chip,
> offset = PCA957X_IN;
> break;
> }
> - ret = pca953x_read_reg(chip, offset, &chip->irq_stat);
> + ret = pca953x_read_reg(chip, offset, &temporary);
> + chip->irq_stat = temporary;
> if (ret)
> goto out_failed;
>
> @@ -606,7 +623,7 @@ out:
> static int __devinit device_pca957x_init(struct pca953x_chip *chip, int invert)
> {
> int ret;
> - uint16_t val = 0;
> + uint val = 0;
>
> /* Let every port in proper state, that could save power */
> pca953x_write_reg(chip, PCA957X_PUPD, 0x0);
> --
> 1.7.3.4
>

--
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.
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