eeprom: at24: Add support for address-width property

[ Upstream commit a2b3bf4846e5eed62ea6abb096af2c950961033c ]

Provide a flexible way to determine the addressing bits of eeprom.
Pass the addressing bits to driver through address-width property.

Signed-off-by: Alan Chiang <alanx.chiang@intel.com>
Signed-off-by: Andy Yeh <andy.yeh@intel.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 4cc0b42..ded48a0 100644 (file)
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -577,6 +577,23 @@ static void at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
        if (device_property_present(dev, "read-only"))
                chip->flags |= AT24_FLAG_READONLY;
 
+       err = device_property_read_u32(dev, "address-width", &val);
+       if (!err) {
+               switch (val) {
+               case 8:
+                       if (chip->flags & AT24_FLAG_ADDR16)
+                               dev_warn(dev, "Override address width to be 8, while default is 16\n");
+                       chip->flags &= ~AT24_FLAG_ADDR16;
+                       break;
+               case 16:
+                       chip->flags |= AT24_FLAG_ADDR16;
+                       break;
+               default:
+                       dev_warn(dev, "Bad \"address-width\" property: %u\n",
+                                val);
+               }
+       }
+
        err = device_property_read_u32(dev, "pagesize", &val);
        if (!err) {
                chip->page_size = val;