diff options
| author | H. Nikolaus Schaller <hns@goldelico.com> | 2019-06-04 15:35:58 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-10 10:52:26 +0300 |
| commit | ebae5c66fa67cfd5cdd5c7ef8f76cdf08a4391e3 (patch) | |
| tree | 50754d9cc649ee5b343b21813743e66e89f92bd3 /drivers/gpio | |
| parent | f55e3e088fcf989411d8bceb9969e8e1daaaf0aa (diff) | |
| download | linux-ebae5c66fa67cfd5cdd5c7ef8f76cdf08a4391e3.tar.xz | |
gpio: pca953x: hack to fix 24 bit gpio expanders
[ Upstream commit 3b00691cc46a4089368a008b30655a8343411715 ]
24 bit expanders use REG_ADDR_AI in combination with register addressing. This
conflicts with regmap which takes this bit as part of the register number,
i.e. a second cache entry is defined for accessed with REG_ADDR_AI being
set although on the chip it is the same register as with REG_ADDR_AI being
cleared.
The problem was introduced by
commit b32cecb46bdc ("gpio: pca953x: Extract the register address mangling to single function")
but only became visible by
commit 8b9f9d4dc511 ("regmap: verify if register is writeable before writing operations")
because before, the regmap size was effectively ignored and
pca953x_writeable_register() did know to ignore REG_ADDR_AI. Still, there
were two separate cache entries created.
Since the use of REG_ADDR_AI seems to be static we can work around this
issue by simply increasing the size of the regmap to cover the "virtual"
registers with REG_ADDR_AI being set. This only means that half of the
regmap buffer will be unused.
Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
Suggested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/gpio-pca953x.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index 7e76830b3368..b6f10e56dfa0 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -306,7 +306,8 @@ static const struct regmap_config pca953x_i2c_regmap = { .volatile_reg = pca953x_volatile_register, .cache_type = REGCACHE_RBTREE, - .max_register = 0x7f, + /* REVISIT: should be 0x7f but some 24 bit chips use REG_ADDR_AI */ + .max_register = 0xff, }; static u8 pca953x_recalc_addr(struct pca953x_chip *chip, int reg, int off, |