Input: matrix_keypad - check for errors from of_get_named_gpio()

BugLink: https://bugs.launchpad.net/bugs/1837161
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>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/input/keyboard/matrix_keypad.c b/drivers/input/keyboard/matrix_keypad.c
index 41614c185918259d54546a50125601270f3852d7..782dda68d93ae7d327bc8cf20ee013afdacf032b 100644 (file)
--- a/drivers/input/keyboard/matrix_keypad.c
+++ b/drivers/input/keyboard/matrix_keypad.c
@@ -407,7 +407,7 @@ matrix_keypad_parse_dt(struct device *dev)
        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 *dev)
                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 platform_device *pdev)
        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;