[PATCH 4.19 33/41] Input: matrix_keypad - check for errors from of_get_named_gpio()

Greg Kroah-Hartman
2018-12-06T14:59:47Z

From: Christian Hoff <christian_hoff@gmx.net>

commit d55bda1b3e7c5a87f10da54fdda866a9a9cef30b upstream.

"of_get_named_gpio()" returns a negative error value if it fails
and drivers should check for this. This missing check was now
added to the matrix_keypad driver.

In my case "of_get_named_gpio()" returned -EPROBE_DEFER because
the referenced GPIOs belong to an I/O expander, which was not yet
probed at the point in time when the matrix_keypad driver was
loading. Because the driver did not check for errors from the
"of_get_named_gpio()" routine, it was assuming that "-EPROBE_DEFER"
is actually a GPIO number and continued as usual, which led to further
errors like this later on:

WARNING: CPU: 3 PID: 167 at drivers/gpio/gpiolib.c:114
gpio_to_desc+0xc8/0xd0
invalid GPIO -517

Note that the "GPIO number" -517 in the error message above is
actually "-EPROBE_DEFER".

As part of the patch a misleading error message "no platform data defined"
was also removed. This does not lead to information loss because the other
error paths in matrix_keypad_parse_dt() already print an error.

Signed-off-by: Christian Hoff <christian_hoff@gmx.net>
Suggested-by: Sebastian Reichel <sre@kernel.org>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
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/keyboard/matrix_keypad.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

--- a/drivers/input/keyboard/matrix_keypad.c
+++ b/drivers/input/keyboard/matrix_keypad.c
@@ -407,7 +407,7 @@ matrix_keypad_parse_dt(struct device *de
struct matrix_keypad_platform_data *pdata;
struct device_node *np = dev->of_node;
unsigned int *gpios;
- int i, nrow, ncol;
+ int ret, i, nrow, ncol;

if (!np) {
dev_err(dev, "device lacks DT data\n");
@@ -452,12 +452,19 @@ matrix_keypad_parse_dt(struct device *de
return ERR_PTR(-ENOMEM);
}

- for (i = 0; i < pdata->num_row_gpios; i++)
- gpios[i] = of_get_named_gpio(np, "row-gpios", i);
+ for (i = 0; i < nrow; i++) {
+ ret = of_get_named_gpio(np, "row-gpios", i);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ gpios[i] = ret;
+ }

- for (i = 0; i < pdata->num_col_gpios; i++)
- gpios[pdata->num_row_gpios + i] =
- of_get_named_gpio(np, "col-gpios", i);
+ for (i = 0; i < ncol; i++) {
+ ret = of_get_named_gpio(np, "col-gpios", i);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ gpios[nrow + i] = ret;
+ }

pdata->row_gpios = gpios;
pdata->col_gpios = &gpios[pdata->num_row_gpios];
@@ -484,10 +491,8 @@ static int matrix_keypad_probe(struct pl
pdata = dev_get_platdata(&pdev->dev);
if (!pdata) {
pdata = matrix_keypad_parse_dt(&pdev->dev);
- if (IS_ERR(pdata)) {
- dev_err(&pdev->dev, "no platform data defined\n");
+ if (IS_ERR(pdata))
return PTR_ERR(pdata);
- }
} else if (!pdata->keymap_data) {
dev_err(&pdev->dev, "no keymap data defined\n");
return -EINVAL;