linux-kernel - [RFC PATCH 3/4] pinctrl: at91: improve pinconf

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Date:	Fri, 13 Sep 2013 09:49:09 +0200
From:	Boris BREZILLON <b.brezillon@...rkiz.com>
To:	Rob Herring <rob.herring@...xeda.com>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Stephen Warren <swarren@...dotorg.org>,
	Ian Campbell <ian.campbell@...rix.com>,
	Rob Landley <rob@...dley.net>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Grant Likely <grant.likely@...aro.org>,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	Richard Genoud <richard.genoud@...il.com>,
	Jiri Kosina <jkosina@...e.cz>
Cc:	devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Boris BREZILLON <b.brezillon@...rkiz.com>
Subject: [RFC PATCH 3/4] pinctrl: at91: improve pinconf_set/get function robustness

Reset caller's config variable before setting current config flags to avoid
erronous config return.

DEBOUNCE and DEGLITCH options are mutually exclusive. Return an error if they
are both defined in the config.
Do not call set_deglitch if DEBOUNCE is enabled to avoid reseting the IFSR
register (which will result in disabling the debounce filter).

Signed-off-by: Boris BREZILLON <b.brezillon@...rkiz.com>
---
 drivers/pinctrl/pinctrl-at91.c |   18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c
index 6624bce..ac9dbea 100644
--- a/drivers/pinctrl/pinctrl-at91.c
+++ b/drivers/pinctrl/pinctrl-at91.c
@@ -724,6 +724,7 @@ static int at91_pinconf_get(struct pinctrl_dev *pctldev,
 	dev_dbg(info->dev, "%s:%d, pin_id=%d, config=0x%lx", __func__, __LINE__, pin_id, *config);
 	pio = pin_to_controller(info, pin_to_bank(pin_id));
 	pin = pin_id % MAX_NB_GPIO_PER_BANK;
+	*config = 0;
 
 	if (at91_mux_get_multidrive(pio, pin))
 		*config |= MULTI_DRIVE;
@@ -757,13 +758,20 @@ static int at91_pinconf_set(struct pinctrl_dev *pctldev,
 	if (config & PULL_UP && config & PULL_DOWN)
 		return -EINVAL;
 
-	at91_mux_set_pullup(pio, mask, config & PULL_UP);
-	at91_mux_set_multidrive(pio, mask, config & MULTI_DRIVE);
-	if (info->ops->set_deglitch)
-		info->ops->set_deglitch(pio, mask, config & DEGLITCH);
-	if (info->ops->set_debounce)
+	if (config & DEBOUNCE && config & DEGLITCH)
+		return -EINVAL;
+
+	if (config & DEBOUNCE) {
+		if (!info->ops->set_debounce)
+			return -ENOTSUPP;
+
 		info->ops->set_debounce(pio, mask, config & DEBOUNCE,
 				(config & DEBOUNCE_VAL) >> DEBOUNCE_VAL_SHIFT);
+	} else if (info->ops->set_deglitch)
+		info->ops->set_deglitch(pio, mask, config & DEGLITCH);
+
+	at91_mux_set_pullup(pio, mask, config & PULL_UP);
+	at91_mux_set_multidrive(pio, mask, config & MULTI_DRIVE);
 	if (info->ops->set_pulldown)
 		info->ops->set_pulldown(pio, mask, config & PULL_DOWN);
 	if (info->ops->disable_schmitt_trig && config & DIS_SCHMIT)
-- 
1.7.9.5

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