From 5c694f8094e44f227937540f6a5e93e747c34098 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Mon, 23 Mar 2020 22:16:26 +0100 Subject: [PATCH] video: fbdev: imxfb: ensure balanced regulator usage MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Sascha Hauer Cc: Pengutronix Kernel Team Cc: Shawn Guo Cc: Fabio Estevam Cc: NXP Linux Team Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/20200323211626.24812-1-u.kleine-koenig@pengutronix.de --- drivers/video/fbdev/imxfb.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/drivers/video/fbdev/imxfb.c b/drivers/video/fbdev/imxfb.c index 370bf2553d43..884b16efa7e8 100644 --- a/drivers/video/fbdev/imxfb.c +++ b/drivers/video/fbdev/imxfb.c @@ -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; }