From e32213fbc5432c28268dced0dc8735dcf8532d36 Mon Sep 17 00:00:00 2001 From: Sven Van Asbroeck Date: Fri, 8 Dec 2017 11:28:30 -0500 Subject: eeprom: at24: support eeproms that do not auto-rollover reads Some multi-address eeproms in the at24 family may not automatically roll-over reads to the next slave address. On those eeproms, reads that straddle slave boundaries will not work correctly. Solution: Mark such eeproms with a flag that prevents reads straddling slave boundaries. Add the AT24_FLAG_NO_RDROL flag to the eeprom entry in the device_id table, or add 'no-read-rollover' to the eeprom devicetree entry. Note that I have not personally enountered an at24 chip that does not support read rollovers. They may or may not exist. However, my hardware requires this functionality because of a quirk. Signed-off-by: Sven Van Asbroeck Signed-off-by: Bartosz Golaszewski --- include/linux/platform_data/at24.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/platform_data/at24.h b/include/linux/platform_data/at24.h index 271a4e25af67..841bb2815a41 100644 --- a/include/linux/platform_data/at24.h +++ b/include/linux/platform_data/at24.h @@ -50,6 +50,8 @@ struct at24_platform_data { #define AT24_FLAG_TAKE8ADDR BIT(4) /* take always 8 addresses (24c00) */ #define AT24_FLAG_SERIAL BIT(3) /* factory-programmed serial number */ #define AT24_FLAG_MAC BIT(2) /* factory-programmed mac address */ +#define AT24_FLAG_NO_RDROL BIT(1) /* does not auto-rollover reads to */ + /* the next slave address */ void (*setup)(struct nvmem_device *nvmem, void *context); void *context; -- cgit v1.2.3