The at24cs series EEPROM chips have an additional read-only memory area,
that is visible on a different i2c slave address. Tie it up with a dummy
device.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
---
drivers/misc/eeprom/at24.c | 30 ++++++++++++++++++++++++++----
1 file changed, 26 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index c6cb7f8..3a75a52 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -102,6 +102,8 @@ MODULE_PARM_DESC(write_timeout, "Time (in ms) to try writes (default 25)");
#define AT24_BITMASK(x) (BIT(x) - 1)
+#define AT24CS_SERIAL_ADDR(addr) (addr + 0x08)
+
/* create non-zero magic value for given eeprom parameters */
#define AT24_DEVICE_MAGIC(_len, _flags) \
((1 << AT24_SIZE_FLAGS | (_flags)) \
@@ -543,6 +545,8 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
if (chip.flags & AT24_FLAG_TAKE8ADDR)
num_addresses = 8;
+ else if (chip.flags & AT24_FLAG_SERIAL)
+ num_addresses = 2;
else
num_addresses = DIV_ROUND_UP(chip.byte_len,
(chip.flags & AT24_FLAG_ADDR16) ? 65536 : 256);
@@ -601,12 +605,30 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
at24->client[0] = client;
/* use dummy devices for multiple-address chips */
- for (i = 1; i < num_addresses; i++) {
- at24->client[i] = i2c_new_dummy(client->adapter,
+ if (at24->chip.flags & AT24_FLAG_TAKE8ADDR) {
+ for (i = 1; i < num_addresses; i++) {
+ at24->client[i] = i2c_new_dummy(client->adapter,
+ client->addr + i);
+ if (!at24->client[i]) {
+ dev_err(&client->dev,
+ "address 0x%02x unavailable\n",
client->addr + i);
- if (!at24->client[i]) {
+ err = -EADDRINUSE;
+ goto err_clients;
+ }
+ }
+ }
+
+ /*
+ * at24cs series tie up an additional address for the memory area
+ * contining the serial number
+ */
+ if (at24->chip.flags & AT24_FLAG_SERIAL) {
+ at24->client[1] = i2c_new_dummy(client->adapter,
+ AT24CS_SERIAL_ADDR(client->addr));
+ if (!at24->client[1]) {
dev_err(&client->dev, "address 0x%02x unavailable\n",
- client->addr + i);
+ AT24CS_SERIAL_ADDR(client->addr));
err = -EADDRINUSE;
goto err_clients;
}
--
2.1.4
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