Re: [PATCH 1/2] saa7115: move the autodetection code out of the probe function

[Ezequiel Garcia <ezequiel.garcia@free-electrons.com>]

On Fri, Apr 26, 2013 at 09:49:16AM -0300, Mauro Carvalho Chehab wrote:
> As we're now seeing other variants from chinese clones, like
> gm1113c, we'll need to add more bits at the detection code.
> 
> So, move it into a separate function.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
> ---
>  drivers/media/i2c/saa7115.c | 133 +++++++++++++++++++++++++++-----------------
>  1 file changed, 83 insertions(+), 50 deletions(-)
> 
> diff --git a/drivers/media/i2c/saa7115.c b/drivers/media/i2c/saa7115.c
> index 52c717d..2bc8b72 100644
> --- a/drivers/media/i2c/saa7115.c
> +++ b/drivers/media/i2c/saa7115.c
> @@ -1573,46 +1573,103 @@ static const struct v4l2_subdev_ops saa711x_ops = {
>  
>  /* ----------------------------------------------------------------------- */
>  
> +/**
> + * saa711x_detect_chip - Detects the saa711x (or clone) variant
> + * @client:		I2C client structure;
> + * @id:			I2C device ID structure;

Tiny nitpick: weird indentation and inconsistent
format ";" vs. "." trailing char.

> + * @name:		Name of the device to be filled.
> + * @size:		Size of the name var.
> + *
> + * Detects the Philips/NXP saa711x chip, or some clone of it.
> + * if 'id' is NULL or id->driver_data is equal to 1, it auto-probes
> + * the analog demod.
> + * If the tuner is not found, it returns -ENODEV.
> + * If auto-detection is disabled and the tuner doesn't match what it was
> + *	requred, it returns -EINVAL and fills 'name'.
> + * If the chip is found, it returns the chip ID and fills 'name'.
> + */
> +static int saa711x_detect_chip(struct i2c_client *client,
> +			       const struct i2c_device_id *id,
> +			       char *name, unsigned size)
> +{
> +	char chip_ver[size - 1];
> +	char chip_id;
> +	int i;
> +	int autodetect;
> +
> +	autodetect = !id || id->driver_data == 1;
> +
> +	/* Read the chip version register */
> +	for (i = 0; i < size - 1; i++) {
> +		i2c_smbus_write_byte_data(client, 0, i);
> +		chip_ver[i] = i2c_smbus_read_byte_data(client, 0);
> +		name[i] = (chip_ver[i] & 0x0f) + '0';
> +		if (name[i] > '9')
> +			name[i] += 'a' - '9' - 1;
> +	}
> +	name[i] = '\0';
> +
> +	/* Check if it is a Philips/NXP chip */
> +	if (!memcmp(name + 1, "f711", 4)) {
> +		chip_id = name[5];
> +		snprintf(name, size, "saa711%c", chip_id);
> +
> +		if (!autodetect && strcmp(name, id->name))
> +			return -EINVAL;
> +
> +		switch (chip_id) {
> +		case '1':
> +			if (chip_ver[0] & 0xf0) {
> +				snprintf(name, size, "saa711%ca", chip_id);
> +				v4l_info(client, "saa7111a variant found\n");
> +				return V4L2_IDENT_SAA7111A;
> +			}
> +			return V4L2_IDENT_SAA7111;
> +		case '3':
> +			return V4L2_IDENT_SAA7113;
> +		case '4':
> +			return V4L2_IDENT_SAA7114;
> +		case '5':
> +			return V4L2_IDENT_SAA7115;
> +		case '8':
> +			return V4L2_IDENT_SAA7118;
> +		default:
> +			v4l2_info(client,
> +				  "WARNING: Philips/NXP chip unknown - Falling back to saa7111\n");
> +			return V4L2_IDENT_SAA7111;
> +		}
> +	}
> +
> +	/* Chip was not discovered. Return its ID and don't bind */
> +	v4l_dbg(1, debug, client, "chip %*ph @ 0x%x is unknown.\n",
> +		16, chip_ver, client->addr << 1);
> +	return -ENODEV;
> +}
> +
>  static int saa711x_probe(struct i2c_client *client,
>  			 const struct i2c_device_id *id)
>  {
>  	struct saa711x_state *state;
>  	struct v4l2_subdev *sd;
>  	struct v4l2_ctrl_handler *hdl;
> -	int i;
> +	int ident;
>  	char name[17];
> -	char chip_id;
> -	int autodetect = !id || id->driver_data == 1;
>  
>  	/* Check if the adapter supports the needed features */
>  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
>  		return -EIO;
>  
> -	for (i = 0; i < 0x0f; i++) {
> -		i2c_smbus_write_byte_data(client, 0, i);
> -		name[i] = (i2c_smbus_read_byte_data(client, 0) & 0x0f) + '0';
> -		if (name[i] > '9')
> -			name[i] += 'a' - '9' - 1;
> -	}
> -	name[i] = '\0';
> -
> -	chip_id = name[5];
> -
> -	/* Check whether this chip is part of the saa711x series */
> -	if (memcmp(name + 1, "f711", 4)) {
> -		v4l_dbg(1, debug, client, "chip found @ 0x%x (ID %s) does not match a known saa711x chip.\n",
> -			client->addr << 1, name);
> +	ident = saa711x_detect_chip(client, id, name, sizeof(name));
> +	if (ident == -EINVAL) {
> +		/* Chip exists, but doesn't match */
> +		v4l_warn(client, "found %s while %s was expected\n",
> +			 name, id->name);
>  		return -ENODEV;
>  	}
> +	if (ident < 0)
> +		return ident;
>  
> -	/* Safety check */
> -	if (!autodetect && id->name[6] != chip_id) {
> -		v4l_warn(client, "found saa711%c while %s was expected\n",
> -			 chip_id, id->name);
> -	}
> -	snprintf(client->name, sizeof(client->name), "saa711%c", chip_id);
> -	v4l_info(client, "saa711%c found (%s) @ 0x%x (%s)\n", chip_id, name,
> -		 client->addr << 1, client->adapter->name);
> +	strlcpy(client->name, name, sizeof(client->name));
>  
>  	state = kzalloc(sizeof(struct saa711x_state), GFP_KERNEL);
>  	if (state == NULL)
> @@ -1649,31 +1706,7 @@ static int saa711x_probe(struct i2c_client *client,
>  	state->output = SAA7115_IPORT_ON;
>  	state->enable = 1;
>  	state->radio = 0;
> -	switch (chip_id) {
> -	case '1':
> -		state->ident = V4L2_IDENT_SAA7111;
> -		if (saa711x_read(sd, R_00_CHIP_VERSION) & 0xf0) {
> -			v4l_info(client, "saa7111a variant found\n");
> -			state->ident = V4L2_IDENT_SAA7111A;
> -		}
> -		break;
> -	case '3':
> -		state->ident = V4L2_IDENT_SAA7113;
> -		break;
> -	case '4':
> -		state->ident = V4L2_IDENT_SAA7114;
> -		break;
> -	case '5':
> -		state->ident = V4L2_IDENT_SAA7115;
> -		break;
> -	case '8':
> -		state->ident = V4L2_IDENT_SAA7118;
> -		break;
> -	default:
> -		state->ident = V4L2_IDENT_SAA7111;
> -		v4l2_info(sd, "WARNING: Chip is not known - Falling back to saa7111\n");
> -		break;
> -	}
> +	state->ident = ident;
>  
>  	state->audclk_freq = 48000;
>  
> -- 
> 1.8.1.4
> 

-- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com