linux-kernel - [PATCH 08/16] backlight: pwm_bl: set pwm polarity when using platform data

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Date:	Wed, 19 Mar 2014 14:03:21 +0100
From:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:	linux-kernel@...r.kernel.org
Cc:	linux-arm-kernel@...ts.infradead.org,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Haavard Skinnemoen <hskinnemoen@...il.com>,
	Hans-Christian Egtvedt <egtvedt@...fundet.no>,
	Bryan Wu <cooloney@...il.com>,
	Richard Purdie <rpurdie@...ys.net>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Jingoo Han <jg1.han@...sung.com>, linux-leds@...r.kernel.org,
	linux-pwm@...r.kernel.org, linux-fbdev@...r.kernel.org,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Subject: [PATCH 08/16] backlight: pwm_bl: set pwm polarity when using platform data

Set inversed polarity when .pwm_active_low is set in the platform_data. With
device tree, this is taken care of by of_pwm_xlate_with_flags(), called from
of_pwm_get().

Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
---
 drivers/video/backlight/pwm_bl.c | 8 ++++++++
 include/linux/pwm_backlight.h    | 1 +
 2 files changed, 9 insertions(+)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index b75201ff46f6..ffdd3b2b2742 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -309,6 +309,14 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	if (data->pwm_period_ns > 0)
 		pwm_set_period(pb->pwm, data->pwm_period_ns);
 
+	/*
+	 * The DT case is taking care of polarity in of_pwm_get(). For the
+	 * non-DT case, set the polarity from platform data.
+	 */
+	if (data->pwm_active_low)
+		if (pwm_set_polarity(pb->pwm, PWM_POLARITY_INVERSED))
+			dev_err(&pdev->dev, "impossible to invert polarity\n");
+
 	pb->period = pwm_get_period(pb->pwm);
 	pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale);
 
diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
index 2de2e275b2cb..b924fce5c97a 100644
--- a/include/linux/pwm_backlight.h
+++ b/include/linux/pwm_backlight.h
@@ -15,6 +15,7 @@ struct platform_pwm_backlight_data {
 	unsigned int dft_brightness;
 	unsigned int lth_brightness;
 	unsigned int pwm_period_ns;
+	bool pwm_active_low;
 	unsigned int *levels;
 	int enable_gpio;
 	unsigned long enable_gpio_flags;
-- 
1.8.3.2

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