Re: [PATCH 4/5] at24: add I2C eeprom for 24cl02

[Sascha Hauer <s.hauer@pengutronix.de>]

On Mon, Jul 16, 2012 at 11:04:58AM +1000, Marc Reilly wrote:
> This series adds a driver for at24 eeproms. Much of the guts of the code
> is taken from the at24 driver in the linux kernel.
> 
> Signed-off-by: Marc Reilly <marc@cpdesign.com.au>
> ---
>  drivers/eeprom/Kconfig  |    7 +++
>  drivers/eeprom/Makefile |    1 +
>  drivers/eeprom/at24.c   |  134 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 142 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/eeprom/at24.c
> 
> diff --git a/drivers/eeprom/Kconfig b/drivers/eeprom/Kconfig
> index a0b5489..56dfd1a 100644
> --- a/drivers/eeprom/Kconfig
> +++ b/drivers/eeprom/Kconfig
> @@ -8,4 +8,11 @@ config EEPROM_AT25
>  	  after you configure the board init code to know about each eeprom
>  	  on your target board.
>  
> +config EEPROM_AT24
> +	bool "at24 based eeprom"
> +	depends on I2C
> +	help
> +	  Provides read/write for the at24 family of I2C EEPROMS.
> +	  Currently only the 2K bit versions are supported.
> +	  

Trailing whitespace here.

> +{
> +	struct at24 *priv = to_at24(cdev);
> +	const u8 *buf = _buf;
> +	const int maxwrite = 8;
> +	int numtowrite;
> +	ssize_t numwritten = 0;
> +
> +	while (count) {
> +		int ret;
> +
> +		numtowrite = count;
> +		if (numtowrite > maxwrite)
> +			numtowrite = maxwrite;
> +
> +		ret = i2c_write_reg(priv->client, offset, buf, numtowrite);
> +		if (ret < 0)
> +			return (ssize_t)ret;
> +
> +		mdelay(10);

Do we need this? This makes the driver veeery slow. If we could poll
this somehow it would be much better.

> +
> +static int at24_init(void)
> +{
> +	register_driver(&at24_driver);
> +	return 0;

We can safely return the result of register_driver here. There was a
time when barebox paniced on a failed initcall, but this is not the case
anymore. Instead we have some debug output for failed initcalls which
seems more useful

Sascha


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