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Subject[PATCH] Input: egalax_ts - do not release gpio if probe successful
Date
Thus preventing anyone to later modify the interrupt GPIO direction
and/or state without the driver knowing.

Also checking if device is present before allocating the input device.

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
---
drivers/input/touchscreen/egalax_ts.c | 56 ++++++++++++++++-------------------
1 file changed, 25 insertions(+), 31 deletions(-)

diff --git a/drivers/input/touchscreen/egalax_ts.c b/drivers/input/touchscreen/egalax_ts.c
index 1afc08b08155..f6b94bb19bd8 100644
--- a/drivers/input/touchscreen/egalax_ts.c
+++ b/drivers/input/touchscreen/egalax_ts.c
@@ -62,6 +62,7 @@
struct egalax_ts {
struct i2c_client *client;
struct input_dev *input_dev;
+ struct gpio_desc *wakeup_gpio;
};

static irqreturn_t egalax_ts_interrupt(int irq, void *dev_id)
@@ -120,36 +121,21 @@ static irqreturn_t egalax_ts_interrupt(int irq, void *dev_id)
}

/* wake up controller by an falling edge of interrupt gpio. */
-static int egalax_wake_up_device(struct i2c_client *client)
+static int egalax_wake_up_device(struct gpio_desc *wakeup_gpio)
{
- struct device_node *np = client->dev.of_node;
- int gpio;
int ret;

- if (!np)
- return -ENODEV;
-
- gpio = of_get_named_gpio(np, "wakeup-gpios", 0);
- if (!gpio_is_valid(gpio))
- return -ENODEV;
-
- ret = gpio_request(gpio, "egalax_irq");
- if (ret < 0) {
- dev_err(&client->dev,
- "request gpio failed, cannot wake up controller: %d\n",
- ret);
+ /* wake up controller via an falling edge on IRQ gpio. */
+ ret = gpiod_direction_output(wakeup_gpio, 0);
+ if (ret < 0)
return ret;
- }

- /* wake up controller via an falling edge on IRQ gpio. */
- gpio_direction_output(gpio, 0);
- gpio_set_value(gpio, 1);
+ gpiod_set_value(wakeup_gpio, 1);

/* controller should be waken up, return irq. */
- gpio_direction_input(gpio);
- gpio_free(gpio);
+ ret = gpiod_direction_input(wakeup_gpio);

- return 0;
+ return ret;
}

static int egalax_firmware_version(struct i2c_client *client)
@@ -177,17 +163,15 @@ static int egalax_ts_probe(struct i2c_client *client,
return -ENOMEM;
}

- input_dev = devm_input_allocate_device(&client->dev);
- if (!input_dev) {
- dev_err(&client->dev, "Failed to allocate memory\n");
- return -ENOMEM;
+ ts->wakeup_gpio = devm_gpiod_get_index(&client->dev, "wakeup",
+ 0, GPIOD_ASIS);
+ if (IS_ERR(ts->wakeup_gpio)) {
+ dev_err(&client->dev, "Failed to get wakeup gpio");
+ return -ENODEV;
}

- ts->client = client;
- ts->input_dev = input_dev;
-
/* controller may be in sleep, wake it up. */
- error = egalax_wake_up_device(client);
+ error = egalax_wake_up_device(ts->wakeup_gpio);
if (error) {
dev_err(&client->dev, "Failed to wake up the controller\n");
return error;
@@ -199,6 +183,15 @@ static int egalax_ts_probe(struct i2c_client *client,
return error;
}

+ input_dev = devm_input_allocate_device(&client->dev);
+ if (!input_dev) {
+ dev_err(&client->dev, "Failed to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ ts->client = client;
+ ts->input_dev = input_dev;
+
input_dev->name = "EETI eGalax Touch Screen";
input_dev->id.bustype = BUS_I2C;

@@ -254,8 +247,9 @@ static int __maybe_unused egalax_ts_suspend(struct device *dev)
static int __maybe_unused egalax_ts_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
+ struct egalax_ts *ts = i2c_get_clientdata(client);

- return egalax_wake_up_device(client);
+ return egalax_wake_up_device(ts->wakeup_gpio);
}

static SIMPLE_DEV_PM_OPS(egalax_ts_pm_ops, egalax_ts_suspend, egalax_ts_resume);
--
2.11.0
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