i2c: slave-eeprom: Make it possible to pre-load eeprom data

If the slave eeprom has a "firmware-name" in devicetree, then pre-load
the data in the eeprom with this file. Otherwise we init the eeprom with
0xFF.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Signed-off-by: Björn Ardö <bjorn.ardo@axis.com>
[wsa: some cosmetic changes]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/i2c-slave-eeprom.c b/drivers/i2c/i2c-slave-eeprom.c
index cb415b1..f868dfc 100644 (file)
--- a/drivers/i2c/i2c-slave-eeprom.c
+++ b/drivers/i2c/i2c-slave-eeprom.c
@@ -18,6 +18,7 @@
  */
 
 #include <linux/bitfield.h>
+#include <linux/firmware.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/module.h>
@@ -120,6 +121,26 @@ static ssize_t i2c_slave_eeprom_bin_write(struct file *filp, struct kobject *kob
        return count;
 }
 
+static int i2c_slave_init_eeprom_data(struct eeprom_data *eeprom, struct i2c_client *client,
+                                     unsigned int size)
+{
+       const struct firmware *fw;
+       const char *eeprom_data;
+       int ret = device_property_read_string(&client->dev, "firmware-name", &eeprom_data);
+
+       if (!ret) {
+               ret = request_firmware_into_buf(&fw, eeprom_data, &client->dev,
+                                               eeprom->buffer, size);
+               if (ret)
+                       return ret;
+               release_firmware(fw);
+       } else {
+               /* An empty eeprom typically has all bits set to 1 */
+               memset(eeprom->buffer, 0xff, size);
+       }
+       return 0;
+}
+
 static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
        struct eeprom_data *eeprom;
@@ -138,6 +159,10 @@ static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_de
        spin_lock_init(&eeprom->buffer_lock);
        i2c_set_clientdata(client, eeprom);
 
+       ret = i2c_slave_init_eeprom_data(eeprom, client, size);
+       if (ret)
+               return ret;
+
        sysfs_bin_attr_init(&eeprom->bin);
        eeprom->bin.attr.name = "slave-eeprom";
        eeprom->bin.attr.mode = S_IRUSR | S_IWUSR;