[PATCH v2 0/2] bus: ts-nbus: Two improvements

[PATCH v2 0/2] bus: ts-nbus: Two improvements

[Uwe Kleine-König]

Hello Arnd,

the last changes for drivers/bus/ts-nbus.c went in via arm-soc. Would
you pick up these two, too? Tell me if a PR would simplify things for
you. I'd base it on top of fc540426f7baa0c7d4b477e80435d075659092a2
then.

Changes since (implicit) v1 of this series
(https://lore.kernel.org/linux-kernel/cover.1702160838.git.u.kleine-koenig@pengutronix.de):

 - Add a closing parenthesis to the commit log of patch 1 (xkcd#859)
 - Fix return value in one error path of patch 2, noticed by Christophe
   JAILLET)
 - (trivially) rebased to current next

Uwe Kleine-König (2):
  bus: ts-nbus: Convert to atomic pwm API
  bus: ts-nbus: Improve error reporting

 drivers/bus/ts-nbus.c | 81 ++++++++++++++++++-------------------------
 1 file changed, 34 insertions(+), 47 deletions(-)

base-commit: 39676dfe52331dba909c617f213fdb21015c8d10
-- 
2.43.0

[PATCH v2 1/2] bus: ts-nbus: Convert to atomic pwm API

[Uwe Kleine-König]

With this change the PWM hardware is only configured once (instead of
three times).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/bus/ts-nbus.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/bus/ts-nbus.c b/drivers/bus/ts-nbus.c
index 4fa932cb0915..19c5d1f4e4d7 100644
--- a/drivers/bus/ts-nbus.c
+++ b/drivers/bus/ts-nbus.c
@@ -273,7 +273,7 @@ EXPORT_SYMBOL_GPL(ts_nbus_write);
 static int ts_nbus_probe(struct platform_device *pdev)
 {
 	struct pwm_device *pwm;
-	struct pwm_args pargs;
+	struct pwm_state state;
 	struct device *dev = &pdev->dev;
 	struct ts_nbus *ts_nbus;
 	int ret;
@@ -296,25 +296,22 @@ static int ts_nbus_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	pwm_get_args(pwm, &pargs);
-	if (!pargs.period) {
+	pwm_init_state(pwm, &state);
+	if (!state.period) {
 		dev_err(&pdev->dev, "invalid PWM period\n");
 		return -EINVAL;
 	}
 
-	/*
-	 * FIXME: pwm_apply_args() should be removed when switching to
-	 * the atomic PWM API.
-	 */
-	pwm_apply_args(pwm);
-	ret = pwm_config(pwm, pargs.period, pargs.period);
+	state.duty_cycle = state.period;
+	state.enabled = true;
+
+	ret = pwm_apply_state(pwm, &state);
 	if (ret < 0)
 		return ret;
 
 	/*
 	 * we can now start the FPGA and populate the peripherals.
 	 */
-	pwm_enable(pwm);
 	ts_nbus->pwm = pwm;
 
 	/*
-- 
2.43.0

[PATCH v2 2/2] bus: ts-nbus: Improve error reporting

[Uwe Kleine-König]

Using dev_err_probe() brings several improvements:

 - emits the symbolic error code
 - properly handles EPROBE_DEFER
 - combines error message generation and return value handling

While at it add error messages to two error paths that were silent
before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/bus/ts-nbus.c | 66 ++++++++++++++++++-------------------------
 1 file changed, 28 insertions(+), 38 deletions(-)

diff --git a/drivers/bus/ts-nbus.c b/drivers/bus/ts-nbus.c
index 19c5d1f4e4d7..baf22a82c47a 100644
--- a/drivers/bus/ts-nbus.c
+++ b/drivers/bus/ts-nbus.c
@@ -39,45 +39,39 @@ struct ts_nbus {
 /*
  * request all gpios required by the bus.
  */
-static int ts_nbus_init_pdata(struct platform_device *pdev, struct ts_nbus
-		*ts_nbus)
+static int ts_nbus_init_pdata(struct platform_device *pdev,
+			      struct ts_nbus *ts_nbus)
 {
 	ts_nbus->data = devm_gpiod_get_array(&pdev->dev, "ts,data",
 			GPIOD_OUT_HIGH);
-	if (IS_ERR(ts_nbus->data)) {
-		dev_err(&pdev->dev, "failed to retrieve ts,data-gpio from dts\n");
-		return PTR_ERR(ts_nbus->data);
-	}
+	if (IS_ERR(ts_nbus->data))
+		return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->data),
+				     "failed to retrieve ts,data-gpio from dts\n");
 
 	ts_nbus->csn = devm_gpiod_get(&pdev->dev, "ts,csn", GPIOD_OUT_HIGH);
-	if (IS_ERR(ts_nbus->csn)) {
-		dev_err(&pdev->dev, "failed to retrieve ts,csn-gpio from dts\n");
-		return PTR_ERR(ts_nbus->csn);
-	}
+	if (IS_ERR(ts_nbus->csn))
+		return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->csn),
+			      "failed to retrieve ts,csn-gpio from dts\n");
 
 	ts_nbus->txrx = devm_gpiod_get(&pdev->dev, "ts,txrx", GPIOD_OUT_HIGH);
-	if (IS_ERR(ts_nbus->txrx)) {
-		dev_err(&pdev->dev, "failed to retrieve ts,txrx-gpio from dts\n");
-		return PTR_ERR(ts_nbus->txrx);
-	}
+	if (IS_ERR(ts_nbus->txrx))
+		return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->txrx),
+				     "failed to retrieve ts,txrx-gpio from dts\n");
 
 	ts_nbus->strobe = devm_gpiod_get(&pdev->dev, "ts,strobe", GPIOD_OUT_HIGH);
-	if (IS_ERR(ts_nbus->strobe)) {
-		dev_err(&pdev->dev, "failed to retrieve ts,strobe-gpio from dts\n");
-		return PTR_ERR(ts_nbus->strobe);
-	}
+	if (IS_ERR(ts_nbus->strobe))
+		return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->strobe),
+				     "failed to retrieve ts,strobe-gpio from dts\n");
 
 	ts_nbus->ale = devm_gpiod_get(&pdev->dev, "ts,ale", GPIOD_OUT_HIGH);
-	if (IS_ERR(ts_nbus->ale)) {
-		dev_err(&pdev->dev, "failed to retrieve ts,ale-gpio from dts\n");
-		return PTR_ERR(ts_nbus->ale);
-	}
+	if (IS_ERR(ts_nbus->ale))
+		return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->ale),
+				     "failed to retrieve ts,ale-gpio from dts\n");
 
 	ts_nbus->rdy = devm_gpiod_get(&pdev->dev, "ts,rdy", GPIOD_IN);
-	if (IS_ERR(ts_nbus->rdy)) {
-		dev_err(&pdev->dev, "failed to retrieve ts,rdy-gpio from dts\n");
-		return PTR_ERR(ts_nbus->rdy);
-	}
+	if (IS_ERR(ts_nbus->rdy))
+		return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->rdy),
+				     "failed to retrieve ts,rdy-gpio from dts\n");
 
 	return 0;
 }
@@ -289,25 +283,20 @@ static int ts_nbus_probe(struct platform_device *pdev)
 		return ret;
 
 	pwm = devm_pwm_get(dev, NULL);
-	if (IS_ERR(pwm)) {
-		ret = PTR_ERR(pwm);
-		if (ret != -EPROBE_DEFER)
-			dev_err(dev, "unable to request PWM\n");
-		return ret;
-	}
+	if (IS_ERR(pwm))
+		return dev_err_probe(dev, PTR_ERR(pwm),
+				     "unable to request PWM\n");
 
 	pwm_init_state(pwm, &state);
-	if (!state.period) {
-		dev_err(&pdev->dev, "invalid PWM period\n");
-		return -EINVAL;
-	}
+	if (!state.period)
+		return dev_err_probe(dev, -EINVAL, "invalid PWM period\n");
 
 	state.duty_cycle = state.period;
 	state.enabled = true;
 
 	ret = pwm_apply_state(pwm, &state);
 	if (ret < 0)
-		return ret;
+		return dev_err_probe(dev, ret, "failed to configure PWM\n");
 
 	/*
 	 * we can now start the FPGA and populate the peripherals.
@@ -321,7 +310,8 @@ static int ts_nbus_probe(struct platform_device *pdev)
 
 	ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
 	if (ret < 0)
-		return ret;
+		return dev_err_probe(dev, ret,
+				     "failed to populate platform devices on bus\n");
 
 	dev_info(dev, "initialized\n");
 
-- 
2.43.0

Re: [PATCH v2 0/2] bus: ts-nbus: Two improvements

[Arnd Bergmann]

On Mon, Dec 25, 2023, at 19:12, Uwe Kleine-König wrote:
> Hello Arnd,
>
> the last changes for drivers/bus/ts-nbus.c went in via arm-soc. Would
> you pick up these two, too? Tell me if a PR would simplify things for
> you. I'd base it on top of fc540426f7baa0c7d4b477e80435d075659092a2
> then.
>
> Changes since (implicit) v1 of this series
> (https://lore.kernel.org/linux-kernel/cover.1702160838.git.u.kleine-koenig@pengutronix.de):

Hi Uwe,

I can take these, but it's a little late for the 6.8 merge
window now. I've added Sebastien to Cc in case he as any
comments as the original author, I think you had a stale
email address from him in v1 and hopefully this one is still
active.

If there are no other comments, please send a pull request
or the two patches to soc@kernel.org after the merge window.

    Arnd