linux-kernel - [PATCH 4/8] Input: st1232 - do not reset the chip too early

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Date:   Tue, 22 Oct 2019 12:56:18 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Martin Kepplinger <martink@...teo.de>
Cc:     Dixit Parmar <dixitparmar19@...il.com>,
        Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
        Matthias Fend <matthias.fend@...fvision.net>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 4/8] Input: st1232 - do not reset the chip too early

We should not be putting the chip into reset while interrupts are enabled
and ISR may be running. Fix this by installing a custom devm action and
powering off the device/resetting GPIO line from there. This ensures proper
ordering.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
---

 drivers/input/touchscreen/st1232.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
index bb116f41f1c0..bfea02202ded 100644
--- a/drivers/input/touchscreen/st1232.c
+++ b/drivers/input/touchscreen/st1232.c
@@ -149,6 +149,11 @@ static void st1232_ts_power(struct st1232_ts_data *ts, bool poweron)
 		gpiod_set_value_cansleep(ts->reset_gpio, !poweron);
 }
 
+static void st1232_ts_power_off(void *data)
+{
+	st1232_ts_power(data, false);
+}
+
 static const struct st_chip_info st1232_chip_info = {
 	.have_z		= true,
 	.max_x		= 0x31f, /* 800 - 1 */
@@ -229,6 +234,13 @@ static int st1232_ts_probe(struct i2c_client *client,
 
 	st1232_ts_power(ts, true);
 
+	error = devm_add_action_or_reset(&client->dev, st1232_ts_power_off, ts);
+	if (error) {
+		dev_err(&client->dev,
+			"Failed to install power off action: %d\n", error);
+		return error;
+	}
+
 	input_dev->name = "st1232-touchscreen";
 	input_dev->id.bustype = BUS_I2C;
 	input_dev->dev.parent = &client->dev;
@@ -270,15 +282,6 @@ static int st1232_ts_probe(struct i2c_client *client,
 	return 0;
 }
 
-static int st1232_ts_remove(struct i2c_client *client)
-{
-	struct st1232_ts_data *ts = i2c_get_clientdata(client);
-
-	st1232_ts_power(ts, false);
-
-	return 0;
-}
-
 static int __maybe_unused st1232_ts_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
@@ -324,7 +327,6 @@ MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
 
 static struct i2c_driver st1232_ts_driver = {
 	.probe		= st1232_ts_probe,
-	.remove		= st1232_ts_remove,
 	.id_table	= st1232_ts_id,
 	.driver = {
 		.name	= ST1232_TS_NAME,
-- 
2.23.0.866.gb869b98d4c-goog