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| author | Linus Walleij <linus.walleij@linaro.org> | 2021-04-10 09:31:52 +0200 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2021-04-10 09:45:51 +0200 |
| commit | c61ac36fd52cb3015acd93af5da01f8f8350051f (patch) | |
| tree | 99713ac8904d3a45ebf3d4778cf23e5c24107c25 /drivers/input | |
| parent | Input: cyttsp - error message on boot mode exit error (diff) | |
| download | linux-c61ac36fd52cb3015acd93af5da01f8f8350051f.tar.xz linux-c61ac36fd52cb3015acd93af5da01f8f8350051f.zip | |
Input: cyttsp - reduce reset pulse timings
The data sheet for CY8CTMA340 specifies that the reset pulse shall be at
least 1 ms. Specify 1-2 ms with usleep_range() to cut some slack for the
scheduler.
Curiously the datasheet does not specify how long we have to wait after a
hard reset until the chip is up, but I have found a vendor tree (Samsung
GT-S7710) that has code for this touch screen and there this is set to 5
ms so I use this with the same 1 ms fuzz.
Reviewed-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210408131153.3446138-6-linus.walleij@linaro.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers/input')
| -rw-r--r-- | drivers/input/touchscreen/cyttsp_core.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/input/touchscreen/cyttsp_core.c b/drivers/input/touchscreen/cyttsp_core.c index 4dc387659e2a..42e353f11976 100644 --- a/drivers/input/touchscreen/cyttsp_core.c +++ b/drivers/input/touchscreen/cyttsp_core.c @@ -229,10 +229,16 @@ static int cyttsp_set_sysinfo_regs(struct cyttsp *ts) static void cyttsp_hard_reset(struct cyttsp *ts) { if (ts->reset_gpio) { + /* + * According to the CY8CTMA340 datasheet page 21, the external + * reset pulse width should be >= 1 ms. The datasheet does not + * specify how long we have to wait after reset but a vendor + * tree specifies 5 ms here. + */ gpiod_set_value_cansleep(ts->reset_gpio, 1); - msleep(CY_DELAY_DFLT); + usleep_range(1000, 2000); gpiod_set_value_cansleep(ts->reset_gpio, 0); - msleep(CY_DELAY_DFLT); + usleep_range(5000, 6000); } } |