From 1302c71a30615226838f3583028d122f6792d720 Mon Sep 17 00:00:00 2001 From: Jeff LaBundy Date: Sun, 24 Jan 2021 20:17:08 -0800 Subject: [PATCH] Input: iqs5xx - accommodate bootloader latency The bootloader NAK's all I2C communication after the first 64-byte bulk write if the bus frequency is equal to 400 kHz. This prevents the platform from pushing updated firmware to the device. The vendor's USB bootloader programming dongle appears to insert a delay between the "open" command and the first 64-byte bulk write. Adding a similar delay to the driver seems to eliminate the issue. Furthermore, the dongle does not access the bootloader immediately after powering up the device. Follow suit by adding a delay before the "open" command to avoid wasted retries at 400 kHz. Signed-off-by: Jeff LaBundy Link: https://lore.kernel.org/r/1611002626-5889-4-git-send-email-jeff@labundy.com Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/iqs5xx.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/input/touchscreen/iqs5xx.c b/drivers/input/touchscreen/iqs5xx.c index ff0a0e96aa5c..b2de8c67b541 100644 --- a/drivers/input/touchscreen/iqs5xx.c +++ b/drivers/input/touchscreen/iqs5xx.c @@ -336,11 +336,16 @@ static int iqs5xx_bl_open(struct i2c_client *client) */ for (i = 0; i < IQS5XX_BL_ATTEMPTS; i++) { iqs5xx_reset(client); + usleep_range(350, 400); for (j = 0; j < IQS5XX_NUM_RETRIES; j++) { error = iqs5xx_bl_cmd(client, IQS5XX_BL_CMD_VER, 0); - if (!error || error == -EINVAL) - return error; + if (!error) + usleep_range(10000, 10100); + else if (error != -EINVAL) + continue; + + return error; } }