Re: [PATCH] eeprom: at24: Add support for 24c1025 EEPROM

[Wolfram Sang <wsa@kernel.org>]

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On Tue, Oct 19, 2021 at 12:00:39AM +0300, Maxim Kochetkov wrote:
> Microchip EEPROM 24xx1025 is like a 24c1024. The only difference
> between them is that the I2C address bit used to select between the
> two banks is bit 2 for the 1025 and not bit 0 as in the 1024.
> 
> Signed-off-by: Maxim Kochetkov <fido_max@inbox.ru>

Adding Bartosz' new email to CC...

> ---
>  drivers/misc/eeprom/at24.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 305ffad131a2..6543ff6536aa 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -96,6 +96,7 @@ struct at24_data {
>  	 * Some chips tie up multiple I2C addresses; dummy devices reserve
>  	 * them for us, and we'll use them with SMBus calls.
>  	 */
> +	u8 bank_addr_shift;
>  	struct at24_client client[];
>  };
>  
> @@ -123,6 +124,7 @@ MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");
>  struct at24_chip_data {
>  	u32 byte_len;
>  	u8 flags;
> +	u8 bank_addr_shift;
>  	void (*read_post)(unsigned int off, char *buf, size_t count);
>  };
>  
> @@ -137,6 +139,12 @@ struct at24_chip_data {
>  		.read_post = _read_post,				\
>  	}
>  
> +#define AT24_CHIP_DATA_BS(_name, _len, _flags, _bank_addr_shift)	\
> +	static const struct at24_chip_data _name = {			\
> +		.byte_len = _len, .flags = _flags,			\
> +		.bank_addr_shift = _bank_addr_shift			\
> +	}
> +
>  static void at24_read_post_vaio(unsigned int off, char *buf, size_t count)
>  {
>  	int i;
> @@ -197,6 +205,7 @@ AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16);
>  AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16);
>  AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16);
>  AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16);
> +AT24_CHIP_DATA_BS(at24_data_24c1025, 1048576 / 8, AT24_FLAG_ADDR16, 2);
>  AT24_CHIP_DATA(at24_data_24c2048, 2097152 / 8, AT24_FLAG_ADDR16);
>  /* identical to 24c08 ? */
>  AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0);
> @@ -225,6 +234,7 @@ static const struct i2c_device_id at24_ids[] = {
>  	{ "24c256",	(kernel_ulong_t)&at24_data_24c256 },
>  	{ "24c512",	(kernel_ulong_t)&at24_data_24c512 },
>  	{ "24c1024",	(kernel_ulong_t)&at24_data_24c1024 },
> +	{ "24c1025",	(kernel_ulong_t)&at24_data_24c1025 },
>  	{ "24c2048",    (kernel_ulong_t)&at24_data_24c2048 },
>  	{ "at24",	0 },
>  	{ /* END OF LIST */ }
> @@ -254,6 +264,7 @@ static const struct of_device_id at24_of_match[] = {
>  	{ .compatible = "atmel,24c256",		.data = &at24_data_24c256 },
>  	{ .compatible = "atmel,24c512",		.data = &at24_data_24c512 },
>  	{ .compatible = "atmel,24c1024",	.data = &at24_data_24c1024 },
> +	{ .compatible = "atmel,24c1025",	.data = &at24_data_24c1025 },
>  	{ .compatible = "atmel,24c2048",	.data = &at24_data_24c2048 },
>  	{ /* END OF LIST */ },
>  };
> @@ -548,7 +559,8 @@ static int at24_make_dummy_client(struct at24_data *at24, unsigned int index,
>  	dev = &base_client->dev;
>  
>  	dummy_client = devm_i2c_new_dummy_device(dev, base_client->adapter,
> -						 base_client->addr + index);
> +						 base_client->addr +
> +						 (index << at24->bank_addr_shift));
>  	if (IS_ERR(dummy_client))
>  		return PTR_ERR(dummy_client);
>  
> @@ -689,6 +701,7 @@ static int at24_probe(struct i2c_client *client)
>  	at24->page_size = page_size;
>  	at24->flags = flags;
>  	at24->read_post = cdata->read_post;
> +	at24->bank_addr_shift = cdata->bank_addr_shift;
>  	at24->num_addresses = num_addresses;
>  	at24->offset_adj = at24_get_offset_adj(flags, byte_len);
>  	at24->client[0].client = client;
> -- 
> 2.32.0
> 

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