[PATCH 4.18 01/34] eeprom: at24: Add support for address-width property

Greg Kroah-Hartman
2018-11-08T21:52:30Z

[ 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>
---
drivers/misc/eeprom/at24.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index f5cc517d1131..7e50e1d6f58c 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -478,6 +478,23 @@ static void at24_properties_to_pdata(struct device *dev,
if (device_property_present(dev, "no-read-rollover"))
chip->flags |= AT24_FLAG_NO_RDROL;

+ 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, "size", &val);
if (!err)
chip->byte_len = val;
--
2.17.1