eeprom: at24: Add support for 24c1025 EEPROM

JIRA: https://issues.redhat.com/browse/RHEL-37020
CVE: CVE-2024-35848

commit d08aea2
Author: Maxim Kochetkov <fido_max@inbox.ru>
Date: Fri, 10 Dec 2021 21:26:03 +0300

    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>
    Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

Signed-off-by: Mark Salter <msalter@redhat.com>

Author: mosalter

drivers/misc/eeprom/at24.c

@@ -91,6 +91,7 @@ struct at24_data {
 	 * Some chips tie up multiple I2C addresses; dummy devices reserve
 	 * them for us.
 	 */
+	u8 bank_addr_shift;
 	struct regmap *client_regmaps[];
 };
 
@@ -118,6 +119,7 @@ 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);
 };
 
@@ -132,6 +134,12 @@ 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;
@@ -192,6 +200,7 @@ 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);
@@ -220,6 +229,7 @@ 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 */ }
@@ -249,6 +259,7 @@ 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 */ },
 };
@@ -533,7 +544,8 @@ static int at24_make_dummy_client(struct at24_data *at24, unsigned int index,
 
 	dummy_client = devm_i2c_new_dummy_device(&base_client->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);
 
@@ -674,6 +686,7 @@ 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_regmaps[0] = regmap;