[PATCH v5 1/4] pps: clients: gpio: propagate probe error codes

[Eliav Farber <farbere@amazon.com>]

On the two probe error paths that map and request the interrupt, probe
overwrote the error from gpiod_to_irq() and request_threaded_irq() with a
hardcoded -EINVAL, hiding meaningful codes such as -EBUSY, -ENOMEM or
-EPROBE_DEFER from the caller. The request_threaded_irq() failure message
also logged the IRQ number but not the errno.

Switch both paths to dev_err_probe() so the actual error code is returned
and logged symbolically, and so a repeated -EPROBE_DEFER during boot is
logged at debug level rather than spamming the console. This also matches
pps_gpio_setup() in the same file, which already uses dev_err_probe().

Fixes: 161520451dfa ("pps: new client driver using GPIO")
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
Changes in v5:
- Use dev_err_probe() on both error paths instead of dev_err() + return,
  so a propagated -EPROBE_DEFER is logged at debug level (no console spam
  on repeated deferral) and the code is emitted symbolically. This also
  matches pps_gpio_setup() in the same file. Drop Bartosz Golaszewski's
  Reviewed-by as the patch changed materially

Changes in v4:
- Add Fixes: 161520451dfa ("pps: new client driver using GPIO") and
  Bartosz Golaszewski's Reviewed-by. The hardcoded -EINVAL on both error
  paths predates 4461d65176b4 (which only switched gpio_to_irq() to
  gpiod_to_irq() and left those returns as context), so the tag points at
  the original driver rather than the descriptor conversion

Changes in v3:
- New patch, split out of the pinctrl change: while converting the probe
  error paths to a goto, Takashi Sakamoto noted that the hardcoded -EINVAL
  discards the real gpiod_to_irq()/request_threaded_irq() error, so fix
  that separately first

 drivers/pps/clients/pps-gpio.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
index 73ec2c7335e5..ccc2fb470b7e 100644
--- a/drivers/pps/clients/pps-gpio.c
+++ b/drivers/pps/clients/pps-gpio.c
@@ -163,10 +163,8 @@ static int pps_gpio_probe(struct platform_device *pdev)
 
 	/* IRQ setup */
 	ret = gpiod_to_irq(data->gpio_pin);
-	if (ret < 0) {
-		dev_err(dev, "failed to map GPIO to IRQ: %d\n", ret);
-		return -EINVAL;
-	}
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to map GPIO to IRQ\n");
 	data->irq = ret;
 
 	/* initialize PPS specific parts of the bookkeeping data structure. */
@@ -197,8 +195,8 @@ static int pps_gpio_probe(struct platform_device *pdev)
 			  data->info.name, data);
 	if (ret) {
 		pps_unregister_source(data->pps);
-		dev_err(dev, "failed to acquire IRQ %d\n", data->irq);
-		return -EINVAL;
+		return dev_err_probe(dev, ret, "failed to acquire IRQ %d\n",
+				     data->irq);
 	}
 
 	dev_dbg(&data->pps->dev, "Registered IRQ %d as PPS source\n",
-- 
2.47.3