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| author | Linus Walleij <linus.walleij@linaro.org> | 2016-11-01 10:22:53 +0100 |
|---|---|---|
| committer | Lee Jones <lee.jones@linaro.org> | 2016-11-16 09:50:33 +0000 |
| commit | f40584200bc4af7aa4399635b9ac213c62a13ae7 (patch) | |
| tree | b165c82493622e97536f4bd5cae953a6b050ab1e | |
| parent | 9600702082b29fd3f8a6d744df74ad4c48d4a432 (diff) | |
| download | linux-f40584200bc4af7aa4399635b9ac213c62a13ae7.tar.gz linux-f40584200bc4af7aa4399635b9ac213c62a13ae7.tar.bz2 linux-f40584200bc4af7aa4399635b9ac213c62a13ae7.zip | |
mfd: stmpe: Fix RESET regression on STMPE2401
Since commit c4dd1ba355aae2bc3d1213da6c66c53e3c31e028
("mfd: stmpe: Add reset support for all STMPE variant")
we're resetting the STMPE expanders before use.
This caused a regression on the STMP2401 on the Nomadik
NHK8815:
stmpe-i2c 0-0043: stmpe2401 detected, chip id: 0x101
nmk-i2c 101f8000.i2c0: write to slave 0x43 timed out
nmk-i2c 101f8000.i2c0: no ack received after address transmission
stmpe-i2c 0-0044: stmpe2401 detected, chip id: 0x101
nmk-i2c 101f8000.i2c0: write to slave 0x44 timed out
nmk-i2c 101f8000.i2c0: no ack received after address transmission
It turns out that we start to poll for the reset bit to
go low again too quickly: the STMPE2401 is not yet online and
ready to be asked for the status of the RESET bit.
By introducing a 10ms delay before starting to hammer
the register for information, we get back to normal:
stmpe-i2c 0-0043: stmpe2401 detected, chip id: 0x101
stmpe-i2c 0-0044: stmpe2401 detected, chip id: 0x101
Cc: stable@vger.kernel.org
Cc: Amelie Delaunay <amelie.delaunay@st.com>
Fixes: c4dd1ba355aa ("mfd: stmpe: Add reset support for all STMPE variant")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
| -rw-r--r-- | drivers/mfd/stmpe.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/mfd/stmpe.c b/drivers/mfd/stmpe.c index cfdae8a3d779..b0c7bcdaf5df 100644 --- a/drivers/mfd/stmpe.c +++ b/drivers/mfd/stmpe.c @@ -851,6 +851,8 @@ static int stmpe_reset(struct stmpe *stmpe) if (ret < 0) return ret; + msleep(10); + timeout = jiffies + msecs_to_jiffies(100); while (time_before(jiffies, timeout)) { ret = __stmpe_reg_read(stmpe, stmpe->regs[STMPE_IDX_SYS_CTRL]); |