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authorJeff LaBundy <jeff@labundy.com>2021-01-25 07:41:38 +0300
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2021-01-25 07:49:11 +0300
commit8e6a8b0c9fe98b905a2ae4f9f91296eb4f82b9ae (patch)
treeba8a436e8955958b75cf6692d2ba3e426fcf5c82 /drivers/input/touchscreen/iqs5xx.c
parent050fac7f056b23764a69fb1fcf3b4e4e90eb61b0 (diff)
downloadlinux-8e6a8b0c9fe98b905a2ae4f9f91296eb4f82b9ae.tar.xz
Input: iqs5xx - allow more time for ATI to complete
After the device is initialized, it runs ATI (calibration) during which it cannot readily respond to I2C communication. To keep the open and close callbacks from writing to the device too soon, the driver waits 100 ms before returning from probe. The vendor reports that ATI may actually take up to 250 ms to run (including margin), so increase the delay accordingly. Update the comments to clarify the reason for the delay as well. Signed-off-by: Jeff LaBundy <jeff@labundy.com> Link: https://lore.kernel.org/r/1611002626-5889-9-git-send-email-jeff@labundy.com Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers/input/touchscreen/iqs5xx.c')
-rw-r--r--drivers/input/touchscreen/iqs5xx.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/drivers/input/touchscreen/iqs5xx.c b/drivers/input/touchscreen/iqs5xx.c
index 35da66bfd87f..b5287301a293 100644
--- a/drivers/input/touchscreen/iqs5xx.c
+++ b/drivers/input/touchscreen/iqs5xx.c
@@ -643,13 +643,12 @@ static int iqs5xx_dev_init(struct i2c_client *client)
iqs5xx->bl_status = dev_id_info->bl_status;
/*
- * Closure of the first communication window that appears following the
- * release of reset appears to kick off an initialization period during
- * which further communication is met with clock stretching. The return
- * from this function is delayed so that further communication attempts
- * avoid this period.
+ * The following delay allows ATI to complete before the open and close
+ * callbacks are free to elicit I2C communication. Any attempts to read
+ * from or write to the device during this time may face extended clock
+ * stretching and prompt the I2C controller to report an error.
*/
- msleep(100);
+ msleep(250);
return 0;
}