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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Marek Vasut <marex@denx.de>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>
Subject: [PATCH 5.15 128/132] Input: ili210x - fix reset timing
Date:   Mon, 23 May 2022 19:05:37 +0200
Message-Id: <20220523165844.932797954@linuxfoundation.org>
In-Reply-To: <20220523165823.492309987@linuxfoundation.org>
References: <20220523165823.492309987@linuxfoundation.org>
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From: Marek Vasut <marex@denx.de>

commit e4920d42ce0e9c8aafb7f64b6d9d4ae02161e51e upstream.

According to Ilitek "231x & ILI251x Programming Guide" Version: 2.30
"2.1. Power Sequence", "T4 Chip Reset and discharge time" is minimum
10ms and "T2 Chip initial time" is maximum 150ms. Adjust the reset
timings such that T4 is 12ms and T2 is 160ms to fit those figures.

This prevents sporadic touch controller start up failures when some
systems with at least ILI251x controller boot, without this patch
the systems sometimes fail to communicate with the touch controller.

Fixes: 201f3c803544c ("Input: ili210x - add reset GPIO support")
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20220518204901.93534-1-marex@denx.de
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/input/touchscreen/ili210x.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/input/touchscreen/ili210x.c
+++ b/drivers/input/touchscreen/ili210x.c
@@ -420,9 +420,9 @@ static int ili210x_i2c_probe(struct i2c_
 		if (error)
 			return error;
 
-		usleep_range(50, 100);
+		usleep_range(12000, 15000);
 		gpiod_set_value_cansleep(reset_gpio, 0);
-		msleep(100);
+		msleep(160);
 	}
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);