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authorLinus Walleij <linus.walleij@linaro.org>2016-11-01 10:22:53 +0100
committerLee Jones <lee.jones@linaro.org>2016-11-16 09:50:33 +0000
commitf40584200bc4af7aa4399635b9ac213c62a13ae7 (patch)
treeb165c82493622e97536f4bd5cae953a6b050ab1e
parent9600702082b29fd3f8a6d744df74ad4c48d4a432 (diff)
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.c2
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]);