| From 968491709e5b1aaf429428814fff3d932fa90b60 Mon Sep 17 00:00:00 2001 |
| From: Bernhard Bender <bernhard.bender@bytecmed.com> |
| Date: Thu, 23 Jul 2015 13:58:08 -0700 |
| Subject: Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen |
| |
| commit 968491709e5b1aaf429428814fff3d932fa90b60 upstream. |
| |
| This patch fixes a problem in the usbtouchscreen driver for DMC TSC-30 |
| touch screen. Due to a missing delay between the RESET and SET_RATE |
| commands, the touch screen may become unresponsive during system startup or |
| driver loading. |
| |
| According to the DMC documentation, a delay is needed after the RESET |
| command to allow the chip to complete its internal initialization. As this |
| delay is not guaranteed, we had a system where the touch screen |
| occasionally did not send any touch data. There was no other indication of |
| the problem. |
| |
| The patch fixes the problem by adding a 150ms delay between the RESET and |
| SET_RATE commands. |
| |
| Suggested-by: Jakob Mustafa <jakob.mustafa@bytecmed.com> |
| Signed-off-by: Bernhard Bender <bernhard.bender@bytecmed.com> |
| Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> |
| Signed-off-by: Zefan Li <lizefan@huawei.com> |
| --- |
| drivers/input/touchscreen/usbtouchscreen.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- a/drivers/input/touchscreen/usbtouchscreen.c |
| +++ b/drivers/input/touchscreen/usbtouchscreen.c |
| @@ -586,6 +586,9 @@ static int dmc_tsc10_init(struct usbtouc |
| goto err_out; |
| } |
| |
| + /* TSC-25 data sheet specifies a delay after the RESET command */ |
| + msleep(150); |
| + |
| /* set coordinate output rate */ |
| buf[0] = buf[1] = 0xFF; |
| ret = usb_control_msg(dev, usb_rcvctrlpipe (dev, 0), |
