This is a note to let you know that I've just added the patch titled

iio: ltr501: mark register holding upper 8 bits of ALS_DATA{0,1} and

to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the staging-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From 2ac0b029a04b673ce83b5089368f467c5dca720c Mon Sep 17 00:00:00 2001

From: Marc Kleine-Budde mkl@pengutronix.de Date: Thu, 10 Jun 2021 15:46:16 +0200 Subject: iio: ltr501: mark register holding upper 8 bits of ALS_DATA{0,1} and PS_DATA as volatile, too

The regmap is configured for 8 bit registers, uses a RB-Tree cache and marks several registers as volatile (i.e. do not cache).

The ALS and PS data registers in the chip are 16 bit wide and spans two regmap registers. In the current driver only the base register is marked as volatile, resulting in the upper register only read once.

Further the data sheet notes:

| When the I2C read operation starts, all four ALS data registers are | locked until the I2C read operation of register 0x8B is completed.

Which results in the registers never update after the 2nd read.

This patch fixes the problem by marking the upper 8 bits of the ALS and PS registers as volatile, too.

Fixes: 2f2c96338afc ("iio: ltr501: Add regmap support.") Reported-by: Oliver Lang Oliver.Lang@gossenmetrawatt.com Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Tested-by: Nikita Travkin nikita@trvn.ru # ltr559 Link: https://lore.kernel.org/r/20210610134619.2101372-2-mkl@pengutronix.de Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com --- drivers/iio/light/ltr501.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c index b4323d2db0b1..0ed3392a33cf 100644 --- a/drivers/iio/light/ltr501.c +++ b/drivers/iio/light/ltr501.c @@ -32,9 +32,12 @@ #define LTR501_PART_ID 0x86 #define LTR501_MANUFAC_ID 0x87 #define LTR501_ALS_DATA1 0x88 /* 16-bit, little endian */ +#define LTR501_ALS_DATA1_UPPER 0x89 /* upper 8 bits of LTR501_ALS_DATA1 */ #define LTR501_ALS_DATA0 0x8a /* 16-bit, little endian */ +#define LTR501_ALS_DATA0_UPPER 0x8b /* upper 8 bits of LTR501_ALS_DATA0 */ #define LTR501_ALS_PS_STATUS 0x8c #define LTR501_PS_DATA 0x8d /* 16-bit, little endian */ +#define LTR501_PS_DATA_UPPER 0x8e /* upper 8 bits of LTR501_PS_DATA */ #define LTR501_INTR 0x8f /* output mode, polarity, mode */ #define LTR501_PS_THRESH_UP 0x90 /* 11 bit, ps upper threshold */ #define LTR501_PS_THRESH_LOW 0x92 /* 11 bit, ps lower threshold */ @@ -1354,9 +1357,12 @@ static bool ltr501_is_volatile_reg(struct device *dev, unsigned int reg) { switch (reg) { case LTR501_ALS_DATA1: + case LTR501_ALS_DATA1_UPPER: case LTR501_ALS_DATA0: + case LTR501_ALS_DATA0_UPPER: case LTR501_ALS_PS_STATUS: case LTR501_PS_DATA: + case LTR501_PS_DATA_UPPER: return true; default: return false;