[PATCH v2] misc: i2c_eeprom: implement different probe test eeprom offset

[Heiko Schocher]

Hello Eugen,

Am 07.05.2020 um 10:53 schrieb Eugen Hristev:
> Because of this commit :
> 5ae84860b0 ("misc: i2c_eeprom: verify that the chip is functional at probe()")
> at probe time, each eeprom is tested for read at offset 0.
> 
> The Atmel AT24MAC402 eeprom has different mapping. One i2c slave address is
> used for the lower 0x80 bytes and another i2c slave address is used for the
> upper 0x80 bytes. Because of this basically the i2c master sees 2 different
> slaves. We need the upper bytes because we read the unique MAC address from
> this EEPROM area.
> 
> However this implies that our slave address will return error on reads
> from address 0x0 to 0x80.
> 
> To solve this, implemented an offset field inside platform data that is by
> default 0 (as it is used now), but can be changed in the compatible table.
> 
> The probe function will now read at this offset and use it, instead of blindly
> checking offset 0.
> 
> This will fix the regression noticed on these EEPROMs since the commit
> abovementioned that introduces the probe failed issue.
> 
> Signed-off-by: Eugen Hristev <eugen.hristev at microchip.com>
> ---
> 
> Please disregard patch
> [PATCH] misc: i2c_eeprom: implement different probe test eeprom offset
> 
> as that patch was mistakenly done on an older u-boot version.
> This v2 patch applies correctly on u-boot/master
> 
> Changes in v2:
> - adapt to latest changes in driver. v1 was done on u-boot 2020.01 accidentaly.
> 
>   drivers/misc/i2c_eeprom.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)

Thanks for rebasing!

I prefer to fix the issue instead reverting commit:

5ae84860b0 ("misc: i2c_eeprom: verify that the chip is functional at probe()")

Reviewed-by: Heiko Schocher <hs at denx.de>

@Baruch, is this Ok for you?

bye,
Heiko
> 
> diff --git a/drivers/misc/i2c_eeprom.c b/drivers/misc/i2c_eeprom.c
> index ef5f103c98..32a1b20856 100644
> --- a/drivers/misc/i2c_eeprom.c
> +++ b/drivers/misc/i2c_eeprom.c
> @@ -17,6 +17,7 @@ struct i2c_eeprom_drv_data {
>   	u32 pagesize; /* page size in bytes */
>   	u32 addr_offset_mask; /* bits in addr used for offset overflow */
>   	u32 offset_len; /* size in bytes of offset */
> +	u32 start_offset; /* valid start offset inside memory, by default 0 */
>   };
>   
>   int i2c_eeprom_read(struct udevice *dev, int offset, uint8_t *buf, int size)
> @@ -147,7 +148,11 @@ static int i2c_eeprom_std_probe(struct udevice *dev)
>   	i2c_set_chip_addr_offset_mask(dev, data->addr_offset_mask);
>   
>   	/* Verify that the chip is functional */
> -	ret = i2c_eeprom_read(dev, 0, &test_byte, 1);
> +	/*
> +	 * Not all eeproms start from offset 0. Valid offset is available
> +	 * in the platform data struct.
> +	 */
> +	ret = i2c_eeprom_read(dev, data->start_offset, &test_byte, 1);
>   	if (ret)
>   		return -ENODEV;
>   
> @@ -215,6 +220,7 @@ static const struct i2c_eeprom_drv_data atmel24mac402_data = {
>   	.pagesize = 16,
>   	.addr_offset_mask = 0,
>   	.offset_len = 1,
> +	.start_offset = 0x80,
>   };
>   
>   static const struct i2c_eeprom_drv_data atmel24c32_data = {
> 

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