linux-kernel - [PATCH v11 41/56] input: atmel_mxt_ts: export GPIO reset line via sysfs

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Date:   Thu, 7 May 2020 22:56:41 -0700
From:   Jiada Wang <jiada_wang@...tor.com>
To:     <nick@...anahar.org>, <dmitry.torokhov@...il.com>,
        <jikos@...nel.org>, <benjamin.tissoires@...hat.com>,
        <bsz@...ihalf.com>
CC:     <linux-input@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <erosca@...adit-jv.com>, <Andrew_Gabbasov@...tor.com>,
        <jiada_wang@...tor.com>
Subject: [PATCH v11 41/56] input: atmel_mxt_ts: export GPIO reset line via sysfs

From: "George G. Davis" <george_davis@...tor.com>

N.B. Modifying the atmel_mxt_ts GPIO reset line during operation will
cause problems with normal driver operation.  This feature is provided
as a diagnostic debug aid.  It does not take into consideration any
pending operations which may be in progress.  Modifying the atmel_mxt_ts
GPIO reset line at any time will inevitably cause the driver to fail.

Signed-off-by: George G. Davis <george_davis@...tor.com>
Signed-off-by: Rajeev Kumar <rajeev_kumar@...tor.com>
Signed-off-by: Jiada Wang <jiada_wang@...tor.com>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 75329f87927b..ceb14b4a8d4d 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -4080,6 +4080,19 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		return error;
 	}
 
+	if (data->reset_gpio) {
+		error = gpiod_export(data->reset_gpio, 0);
+		if (error)
+			return error;
+
+		error = gpiod_export_link(&client->dev, "reset",
+					  data->reset_gpio);
+		if (error) {
+			gpiod_unexport(data->reset_gpio);
+			return error;
+		}
+	}
+
 	if (data->suspend_mode == MXT_SUSPEND_REGULATOR) {
 		enable_irq(data->irq);
 
@@ -4110,6 +4123,10 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 err_free_object:
 	mxt_free_input_device(data);
 	mxt_free_object_table(data);
+	if (data->reset_gpio) {
+		sysfs_remove_link(&client->dev.kobj, "reset");
+		gpiod_unexport(data->reset_gpio);
+	}
 	return error;
 }
 
@@ -4119,6 +4136,10 @@ static int mxt_remove(struct i2c_client *client)
 
 	disable_irq(data->irq);
 	sysfs_remove_group(&client->dev.kobj, &mxt_fw_attr_group);
+	if (data->reset_gpio) {
+		sysfs_remove_link(&client->dev.kobj, "reset");
+		gpiod_unexport(data->reset_gpio);
+	}
 	mxt_debug_msg_remove(data);
 	mxt_sysfs_remove(data);
 	mxt_free_input_device(data);
-- 
2.17.1