linux-kernel - [PATCH 2/3] pwm: cros-ec: Simplify device tree xlation

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Date: Fri,  7 Jun 2024 10:44:16 +0200
From: "Uwe Kleine-König" <ukleinek@...libre.com>
To: Benson Leung <bleung@...omium.org>
Cc: Guenter Roeck <groeck@...omium.org>,
	linux-pwm@...r.kernel.org,
	chrome-platform@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] pwm: cros-ec: Simplify device tree xlation

The cros-ec device tree binding only uses #pwm-cells = <1>, and so there
is no period provided in the device tree. Up to now this was handled by
hardcoding the period to the only supported value in the custom xlate
callback. Apart from that, the default xlate callback (i.e.
of_pwm_xlate_with_flags()) handles this just fine (and better, e.g. by
checking args->args_count >= 1 before accessing args->args[0]).

To simplify make use of of_pwm_xlate_with_flags(), drop the custom
callback and provide the default period in .probe() already.

Apart from simplifying the driver this also drops the last non-core user
of pwm_request_from_chip() and so makes further simplifications
possible.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...libre.com>
---
 drivers/pwm/pwm-cros-ec.c | 32 ++++++++++++--------------------
 1 file changed, 12 insertions(+), 20 deletions(-)

diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c
index ba4ee0b507b7..fcc33a2cb878 100644
--- a/drivers/pwm/pwm-cros-ec.c
+++ b/drivers/pwm/pwm-cros-ec.c
@@ -169,24 +169,6 @@ static int cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }
 
-static struct pwm_device *
-cros_ec_pwm_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
-{
-	struct pwm_device *pwm;
-
-	if (args->args[0] >= chip->npwm)
-		return ERR_PTR(-EINVAL);
-
-	pwm = pwm_request_from_chip(chip, args->args[0], NULL);
-	if (IS_ERR(pwm))
-		return pwm;
-
-	/* The EC won't let us change the period */
-	pwm->args.period = EC_PWM_MAX_DUTY;
-
-	return pwm;
-}
-
 static const struct pwm_ops cros_ec_pwm_ops = {
 	.get_state	= cros_ec_pwm_get_state,
 	.apply		= cros_ec_pwm_apply,
@@ -237,7 +219,7 @@ static int cros_ec_pwm_probe(struct platform_device *pdev)
 	struct cros_ec_pwm_device *ec_pwm;
 	struct pwm_chip *chip;
 	bool use_pwm_type = false;
-	unsigned int npwm;
+	unsigned int i, npwm;
 	int ret;
 
 	if (!ec)
@@ -263,7 +245,17 @@ static int cros_ec_pwm_probe(struct platform_device *pdev)
 
 	/* PWM chip */
 	chip->ops = &cros_ec_pwm_ops;
-	chip->of_xlate = cros_ec_pwm_xlate;
+
+	/*
+	 * The device tree binding for this device is special as it only uses a
+	 * single cell (for the hwid) and so doesn't provide a default period.
+	 * This isn't a big problem though as the hardware only supports a
+	 * single period length, it's just a bit ugly to make this fit into the
+	 * pwm core abstractions. So initialize the period here, as
+	 * of_pwm_xlate_with_flags() won't do that for us.
+	 */
+	for (i = 0; i < npwm; ++i)
+		chip->pwms[i].args.period = EC_PWM_MAX_DUTY;
 
 	dev_dbg(dev, "Probed %u PWMs\n", chip->npwm);
 
-- 
2.43.0