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video: fbdev: imxfb: ensure balanced regulator usage 

The fbdev framework doesn't care to call the .set_power callback only on
changes. So the driver has to care for itself that the regulator doesn't
get disabled more often than enabled.

This fixes the regulator warning

	unbalanced disables for lcd supply

which can be triggered by doing

	echo 4 > /sys/class/lcd/imxfb-lcd/lcd_power

twice.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323211626.24812-1-u.kleine-koenig@pengutronix.de
This commit is contained in:
Uwe Kleine-König 2020-03-23 22:16:26 +01:00 committed by Bartlomiej Zolnierkiewicz
parent 04dff10ffb
commit 5c694f8094
1 changed files with 21 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
drivers/video/fbdev/imxfb.c
View File

@ -172,6 +172,7 @@ struct imxfb_info {
int num_modes;
struct regulator *lcd_pwr;
int lcd_pwr_enabled;
};
static const struct platform_device_id imxfb_devtype[] = {
@ -801,16 +802,30 @@ static int imxfb_lcd_get_power(struct lcd_device *lcddev)
return FB_BLANK_UNBLANK;
}
static int imxfb_regulator_set(struct imxfb_info *fbi, int enable)
{
int ret;
if (enable == fbi->lcd_pwr_enabled)
return 0;
if (enable)
ret = regulator_enable(fbi->lcd_pwr);
else
ret = regulator_disable(fbi->lcd_pwr);
if (ret == 0)
fbi->lcd_pwr_enabled = enable;
return ret;
}
static int imxfb_lcd_set_power(struct lcd_device *lcddev, int power)
{
struct imxfb_info *fbi = dev_get_drvdata(&lcddev->dev);
if (!IS_ERR(fbi->lcd_pwr)) {
if (power == FB_BLANK_UNBLANK)
return regulator_enable(fbi->lcd_pwr);
else
return regulator_disable(fbi->lcd_pwr);
}
if (!IS_ERR(fbi->lcd_pwr))
return imxfb_regulator_set(fbi, power == FB_BLANK_UNBLANK);
return 0;
}