linux-kernel - Re: [PATCH 2/2] video: mxsfb: manage LCD_RESET signal according to reset-active property

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Message-ID: <yw1xtwmkw58i.fsf@unicorn.mansr.com>
Date:	Mon, 11 Jan 2016 14:38:53 +0000
From:	Måns Rullgård <mans@...sr.com>
To:	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>
Cc:	Tomi Valkeinen <tomi.valkeinen@...com>,
	linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	marex@...x.de
Subject: Re: [PATCH 2/2] video: mxsfb: manage LCD_RESET signal according to reset-active property

Mans Rullgard <mans@...sr.com> writes:

> Activate/deactivate the LCD_RESET signal as specified by the
> reset-active DT property when the controller is disabled/enabled.
> If the property is missing, leave the signal unchanged.
>
> Signed-off-by: Mans Rullgard <mans@...sr.com>
> ---

Any comments on this?

>  drivers/video/fbdev/mxsfb.c | 28 +++++++++++++++++++++++++---
>  1 file changed, 25 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/video/fbdev/mxsfb.c b/drivers/video/fbdev/mxsfb.c
> index 4e6608c..0200a0f 100644
> --- a/drivers/video/fbdev/mxsfb.c
> +++ b/drivers/video/fbdev/mxsfb.c
> @@ -99,6 +99,7 @@
>  #define CTRL1_FIFO_CLEAR		(1 << 21)
>  #define CTRL1_SET_BYTE_PACKAGING(x)	(((x) & 0xf) << 16)
>  #define CTRL1_GET_BYTE_PACKAGING(x)	(((x) >> 16) & 0xf)
> +#define CTRL1_RESET			(1 << 0)
>
>  #define TRANSFER_COUNT_SET_VCOUNT(x)	(((x) & 0xffff) << 16)
>  #define TRANSFER_COUNT_GET_VCOUNT(x)	(((x) >> 16) & 0xffff)
> @@ -152,6 +153,9 @@
>  #define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT	(1 << 6)
>  #define MXSFB_SYNC_DOTCLK_FALLING_ACT	(1 << 7) /* negtive edge sampling */
>
> +#define MXSFB_RESET_LOW			1
> +#define MXSFB_RESET_HIGH		2
> +
>  enum mxsfb_devtype {
>  	MXSFB_V3,
>  	MXSFB_V4,
> @@ -181,6 +185,7 @@ struct mxsfb_info {
>  	unsigned dotclk_delay;
>  	const struct mxsfb_devdata *devdata;
>  	u32 sync;
> +	u32 reset;
>  	struct regulator *reg_lcd;
>  };
>
> @@ -362,6 +367,11 @@ static void mxsfb_enable_controller(struct fb_info *fb_info)
>
>  	writel(CTRL_RUN, host->base + LCDC_CTRL + REG_SET);
>
> +	if (host->reset == MXSFB_RESET_HIGH)
> +		writel(CTRL1_RESET, host->base + LCDC_CTRL1 + REG_CLR);
> +	else if (host->reset == MXSFB_RESET_LOW)
> +		writel(CTRL1_RESET, host->base + LCDC_CTRL1 + REG_SET);
> +
>  	host->enabled = 1;
>  }
>
> @@ -388,6 +398,11 @@ static void mxsfb_disable_controller(struct fb_info *fb_info)
>  		loop--;
>  	}
>
> +	if (host->reset == MXSFB_RESET_HIGH)
> +		writel(CTRL1_RESET, host->base + LCDC_CTRL1 + REG_SET);
> +	else if (host->reset == MXSFB_RESET_LOW)
> +		writel(CTRL1_RESET, host->base + LCDC_CTRL1 + REG_CLR);
> +
>  	reg = readl(host->base + LCDC_VDCTRL4);
>  	writel(reg & ~VDCTRL4_SYNC_SIGNALS_ON, host->base + LCDC_VDCTRL4);
>
> @@ -410,7 +425,7 @@ static void mxsfb_disable_controller(struct fb_info *fb_info)
>  static int mxsfb_set_par(struct fb_info *fb_info)
>  {
>  	struct mxsfb_info *host = to_imxfb_host(fb_info);
> -	u32 ctrl, vdctrl0, vdctrl4;
> +	u32 ctrl, ctrl1, vdctrl0, vdctrl4;
>  	int line_size, fb_size;
>  	int reenable = 0;
>
> @@ -439,12 +454,13 @@ static int mxsfb_set_par(struct fb_info *fb_info)
>
>  	ctrl = CTRL_BYPASS_COUNT | CTRL_MASTER |
>  		CTRL_SET_BUS_WIDTH(host->ld_intf_width);
> +	ctrl1 = readl(host->base + LCDC_CTRL1) & CTRL1_RESET;
>
>  	switch (fb_info->var.bits_per_pixel) {
>  	case 16:
>  		dev_dbg(&host->pdev->dev, "Setting up RGB565 mode\n");
>  		ctrl |= CTRL_SET_WORD_LENGTH(0);
> -		writel(CTRL1_SET_BYTE_PACKAGING(0xf), host->base + LCDC_CTRL1);
> +		ctrl1 |= CTRL1_SET_BYTE_PACKAGING(0xf);
>  		break;
>  	case 32:
>  		dev_dbg(&host->pdev->dev, "Setting up RGB888/666 mode\n");
> @@ -462,7 +478,7 @@ static int mxsfb_set_par(struct fb_info *fb_info)
>  			break;
>  		}
>  		/* do not use packed pixels = one pixel per word instead */
> -		writel(CTRL1_SET_BYTE_PACKAGING(0x7), host->base + LCDC_CTRL1);
> +		ctrl1 |= CTRL1_SET_BYTE_PACKAGING(0x7);
>  		break;
>  	default:
>  		mxsfb_disable_axi_clk(host);
> @@ -472,6 +488,7 @@ static int mxsfb_set_par(struct fb_info *fb_info)
>  	}
>
>  	writel(ctrl, host->base + LCDC_CTRL);
> +	writel(ctrl1, host->base + LCDC_CTRL1);
>
>  	writel(TRANSFER_COUNT_SET_VCOUNT(fb_info->var.yres) |
>  			TRANSFER_COUNT_SET_HCOUNT(fb_info->var.xres),
> @@ -736,6 +753,7 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host,
>  	struct device_node *display_np;
>  	struct videomode vm;
>  	u32 width;
> +	u32 reset;
>  	int ret;
>
>  	display_np = of_parse_phandle(np, "display", 0);
> @@ -776,6 +794,10 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host,
>  		goto put_display_node;
>  	}
>
> +	ret = of_property_read_u32(display_np, "reset-active", &reset);
> +	if (!ret)
> +		host->reset = reset ? MXSFB_RESET_HIGH : MXSFB_RESET_LOW;
> +
>  	ret = of_get_videomode(display_np, &vm, OF_USE_NATIVE_MODE);
>  	if (ret) {
>  		dev_err(dev, "failed to get videomode from DT\n");
> -- 
> 2.6.3
>

-- 
Måns Rullgård