On 3/23/20 10:16 PM, Uwe Kleine-König wrote:
> 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-koe...@pengutronix.de>
Patch queued for v5.8, thanks.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
> ---
> 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;
> }
>
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