linux-kernel - [PATCHv3 1/3] pwm: make the PWM

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Date:	Fri, 28 Mar 2014 09:48:58 +0100
From:	Lothar Waßmann <LW@...O-electronics.de>
To:	Thierry Reding <thierry.reding@...il.com>,
	linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org,
	Lothar Waßmann <LW@...O-electronics.de>,
	Shawn Guo <shawn.guo@...aro.org>,
	Sascha Hauer <kernel@...gutronix.de>,
	Arnd Bergmann <arnd@...db.de>
Subject: [PATCHv3 1/3] pwm: make the PWM_POLARITY flag in DTB optional

Change the pwm chip driver registration, so that a chip driver that
supports polarity inversion can still be used with DTBs that don't
provide the 'PWM_POLARITY' flag.

This is done to provide polarity inversion support for the pwm-imx
driver without having to modify all existing DTS files.

Signed-off-by: Lothar Waßmann <LW@...O-electronics.de>
---
 drivers/pwm/core.c |   46 ++++++++++++++++------------------------------
 1 file changed, 16 insertions(+), 30 deletions(-)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index a804713..dc15543 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -131,12 +131,12 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
 	return 0;
 }
 
-struct pwm_device *
-of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
+struct pwm_device *of_pwm_xlate(struct pwm_chip *pc,
+				const struct of_phandle_args *args)
 {
 	struct pwm_device *pwm;
 
-	if (pc->of_pwm_n_cells < 3)
+	if (pc->of_pwm_n_cells < 2)
 		return ERR_PTR(-EINVAL);
 
 	if (args->args[0] >= pc->npwm)
@@ -148,6 +148,9 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
 
 	pwm_set_period(pwm, args->args[1]);
 
+	if (pc->of_pwm_n_cells < 3)
+		return pwm;
+
 	if (args->args[2] & PWM_POLARITY_INVERTED)
 		pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
 	else
@@ -155,27 +158,14 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
 
 	return pwm;
 }
-EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
 
-static struct pwm_device *
-of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
+struct pwm_device *
+of_pwm_xlate_with_flags(struct pwm_chip *pc,
+			const struct of_phandle_args *args)
 {
-	struct pwm_device *pwm;
-
-	if (pc->of_pwm_n_cells < 2)
-		return ERR_PTR(-EINVAL);
-
-	if (args->args[0] >= pc->npwm)
-		return ERR_PTR(-EINVAL);
-
-	pwm = pwm_request_from_chip(pc, args->args[0], NULL);
-	if (IS_ERR(pwm))
-		return pwm;
-
-	pwm_set_period(pwm, args->args[1]);
-
-	return pwm;
+	return of_pwm_xlate(pc, args);
 }
+EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
 
 static void of_pwmchip_add(struct pwm_chip *chip)
 {
@@ -183,8 +173,11 @@ static void of_pwmchip_add(struct pwm_chip *chip)
 		return;
 
 	if (!chip->of_xlate) {
-		chip->of_xlate = of_pwm_simple_xlate;
-		chip->of_pwm_n_cells = 2;
+		chip->of_xlate = of_pwm_xlate;
+		if (chip->ops->set_polarity)
+			chip->of_pwm_n_cells = 3;
+		else
+			chip->of_pwm_n_cells = 2;
 	}
 
 	of_node_get(chip->dev->of_node);
@@ -536,13 +529,6 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 		goto put;
 	}
 
-	if (args.args_count != pc->of_pwm_n_cells) {
-		pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
-			 args.np->full_name);
-		pwm = ERR_PTR(-EINVAL);
-		goto put;
-	}
-
 	pwm = pc->of_xlate(pc, &args);
 	if (IS_ERR(pwm))
 		goto put;
-- 
1.7.10.4

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