[PATCH] eeprom: at24: add ST M24256E Additional Write lockable page support

[Marek Vasut]

The ST M24256E behaves as a regular M24C256, except for the E variant
which uses up another I2C address for Additional Write lockable page.
This page is 64 Bytes long and can contain additional data. Add entry
for it, so users can describe that page in DT. Note that users still
have to describe the main M24C256 area separately as that is on separate
I2C address from this page.

Unlike M24C32-D and M24C64-D, this part is specifically ST and does not
have any comparable M24* counterparts from other vendors, hence the st,
vendor prefix. Furthermore, the part name is M24256E without C between
the 24 and 256, this is not a typo. Finally, there is M24C256-D part,
which does contain 32 Bytes long Additional Write lockable page, which
is a different part and not supported by this patch.

Datasheet: https://www.st.com/resource/en/datasheet/m24256e-f.pdf

>From Linux kernel commit:
339cb28b9ee6 ("eeprom: at24: add ST M24256E Additional Write lockable page support")

Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: Christoph Niedermaier <cniedermaier at dh-electronics.com>
Cc: Tom Rini <trini at konsulko.com>
Cc: u-boot at dh-electronics.com
Cc: u-boot at lists.denx.de
---
 drivers/misc/i2c_eeprom.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/misc/i2c_eeprom.c b/drivers/misc/i2c_eeprom.c
index 10f0173d805..3cb38aa28ad 100644
--- a/drivers/misc/i2c_eeprom.c
+++ b/drivers/misc/i2c_eeprom.c
@@ -264,6 +264,13 @@ static const struct i2c_eeprom_drv_data atmel24c256_data = {
 	.offset_len = 2,
 };
 
+static const struct i2c_eeprom_drv_data st24256e_wlp_data = {
+	.size = 64,
+	.pagesize = 64,
+	.addr_offset_mask = 0,
+	.offset_len = 2,
+};
+
 static const struct i2c_eeprom_drv_data atmel24c512_data = {
 	.size = 65536,
 	.pagesize = 64,
@@ -287,6 +294,7 @@ static const struct udevice_id i2c_eeprom_std_ids[] = {
 	{ .compatible = "atmel,24c128", (ulong)&atmel24c128_data },
 	{ .compatible = "atmel,24c256", (ulong)&atmel24c256_data },
 	{ .compatible = "atmel,24c512", (ulong)&atmel24c512_data },
+	{ .compatible = "st,24256e-wl", (ulong)&st24256e_wlp_data },
 	{ }
 };
 
-- 
2.45.2