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From: LW@KARO-electronics.de (Lothar Waßmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCHv6 2/3] pwm: make the PWM_POLARITY flag in DTB optional
Date: Fri, 10 Oct 2014 16:22:28 +0200	[thread overview]
Message-ID: <1412950949-7505-3-git-send-email-LW@KARO-electronics.de> (raw)
In-Reply-To: <1412950949-7505-1-git-send-email-LW@KARO-electronics.de>

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 Wa?mann <LW@KARO-electronics.de>
---
 drivers/pwm/core.c |   27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 130bbea..0ff1bb0 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -136,9 +136,14 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
 {
 	struct pwm_device *pwm;
 
+	/* check, whether the driver supports a third cell for flags */
 	if (pc->of_pwm_n_cells < 3)
 		return ERR_PTR(-EINVAL);
 
+	/* flags in the third cell are optional */
+	if (args->args_count < 2)
+		return ERR_PTR(-EINVAL);
+
 	if (args->args[0] >= pc->npwm)
 		return ERR_PTR(-EINVAL);
 
@@ -148,10 +153,12 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
 
 	pwm_set_period(pwm, args->args[1]);
 
-	if (args->args[2] & PWM_POLARITY_INVERTED)
-		pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
-	else
-		pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
+	if (args->args_count > 2) {
+		if (args->args[2] & PWM_POLARITY_INVERTED)
+			pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
+		else
+			pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
+	}
 
 	return pwm;
 }
@@ -162,9 +169,14 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
 {
 	struct pwm_device *pwm;
 
+	/* sanity check driver support */
 	if (pc->of_pwm_n_cells < 2)
 		return ERR_PTR(-EINVAL);
 
+	/* all cells are required */
+	if (args->args_count != pc->of_pwm_n_cells)
+		return ERR_PTR(-EINVAL);
+
 	if (args->args[0] >= pc->npwm)
 		return ERR_PTR(-EINVAL);
 
@@ -536,13 +548,6 @@ 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

  parent reply	other threads:[~2014-10-10 14:22 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-07 13:55 [PATCHv4 0/3] pwm: imx: support output polarity inversion Lothar Waßmann
2014-10-07 13:55 ` [PATCHv5 1/3] pwm: print error messages with pr_err() instead of pr_debug() Lothar Waßmann
2014-10-07 13:55 ` [PATCHv5 2/3] pwm: make the PWM_POLARITY flag in DTB optional Lothar Waßmann
2014-10-09 15:16   ` Thierry Reding
2014-10-10 14:22     ` [PATCHv6 0/3] pwm: imx: support output polarity inversion Lothar Waßmann
2014-10-10 14:22       ` [PATCHv6 1/3] pwm: print error messages with pr_err() instead of pr_debug() Lothar Waßmann
2014-10-10 14:22       ` Lothar Waßmann [this message]
2014-10-10 14:22       ` [PATCH 3/3] pwm: imx: support output polarity inversion Lothar Waßmann
2016-09-08 22:15       ` [PATCHv6 0/3] " Stefan Agner
2016-09-09  7:18         ` Lothar Waßmann
2016-09-12 12:45           ` Alexandre Belloni
2016-09-12 14:04             ` Uwe Kleine-König
2016-09-12 16:51               ` Stefan Agner
2016-09-12 20:00                 ` Uwe Kleine-König
2016-09-12 21:12                   ` Clemens Gruber
2016-09-13  6:45                     ` Uwe Kleine-König
2016-09-12 13:54           ` Vladimir Zapolskiy
2014-10-07 13:55 ` [PATCHv5 3/3] " Lothar Waßmann

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