Re: [PATCH] Add support for TCA6424

[Grant Likely <grant.likely@secretlab.ca>]

On Tue, 24 Apr 2012 15:48:31 +0200, Andreas Schallenberg <Andreas.Schallenberg@3alitytechnica.com> 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.