Re: [PATCH v5] video: mxsfb: Introduce regulator support

[Shawn Guo <shawn.guo@linaro.org>]

On Fri, Apr 05, 2013 at 11:19:47AM -0300, Fabio Estevam wrote:
> Instead of using a custom binding for retrieving the GPIO that activates the 
> LCD from devicetree, use a standard regulator.
> 
> This approach has the advantage to be more generic. 
> 
> For example: in the case of a board that has a PMIC supplying the LCD voltage, 
> the current approach would not work, as it only searches for a GPIO pin.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
> Chages since v4:
> - Merged the 2 previous patches into one in order not to break keep mxsfb functionality
> - Remove unneeded change in mxsfb.txt
> - Use regulator_disable to pair with regulator_enable
> Changes since v3:
> - None
> Changes since v2:
> - Use devm_regulator_get()
> Changes since v1:
> - No changes
>  Documentation/devicetree/bindings/fb/mxsfb.txt |    2 --
>  arch/arm/boot/dts/imx23-evk.dts                |   11 ++++++-
>  arch/arm/boot/dts/imx28-evk.dts                |   11 ++++++-
>  drivers/video/mxsfb.c                          |   41 +++++++++++++-----------
>  4 files changed, 43 insertions(+), 22 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/fb/mxsfb.txt b/Documentation/devicetree/bindings/fb/mxsfb.txt
> index 7ba3b76..5d810eb 100644
> --- a/Documentation/devicetree/bindings/fb/mxsfb.txt
> +++ b/Documentation/devicetree/bindings/fb/mxsfb.txt
> @@ -8,7 +8,6 @@ Required properties:
>  - display : phandle to display node (see below for details)
>  
>  Optional properties:

So this line should be removed together?

> -- panel-enable-gpios : Should specify the gpio for panel enable
>  
>  * display node
>  
> @@ -25,7 +24,6 @@ lcdif@80030000 {
>  	compatible = "fsl,imx28-lcdif";
>  	reg = <0x80030000 2000>;
>  	interrupts = <38 86>;
> -	panel-enable-gpios = <&gpio3 30 0>;
>  
>  	display: display {
>  		bits-per-pixel = <32>;
> diff --git a/arch/arm/boot/dts/imx23-evk.dts b/arch/arm/boot/dts/imx23-evk.dts
> index 7880e17..da0588a 100644
> --- a/arch/arm/boot/dts/imx23-evk.dts
> +++ b/arch/arm/boot/dts/imx23-evk.dts
> @@ -59,7 +59,7 @@
>  			lcdif@80030000 {
>  				pinctrl-names = "default";
>  				pinctrl-0 = <&lcdif_24bit_pins_a>;
> -				panel-enable-gpios = <&gpio1 18 0>;
> +				lcd-supply = <&reg_lcd_3v3>;
>  				display = <&display>;
>  				status = "okay";
>  
> @@ -120,6 +120,15 @@
>  			regulator-max-microvolt = <3300000>;
>  			gpio = <&gpio1 29 0>;
>  		};
> +
> +		reg_lcd_3v3: lcd-3v3 {
> +			compatible = "regulator-fixed";
> +			regulator-name = "lcd-3v3";
> +			regulator-min-microvolt = <3300000>;
> +			regulator-max-microvolt = <3300000>;
> +			gpio = <&gpio1 18 0>;
> +			enable-active-high;
> +		};
>  	};
>  
>  	backlight {
> diff --git a/arch/arm/boot/dts/imx28-evk.dts b/arch/arm/boot/dts/imx28-evk.dts
> index 2d4ea3b..3637bf3 100644
> --- a/arch/arm/boot/dts/imx28-evk.dts
> +++ b/arch/arm/boot/dts/imx28-evk.dts
> @@ -123,7 +123,7 @@
>  				pinctrl-names = "default";
>  				pinctrl-0 = <&lcdif_24bit_pins_a
>  					     &lcdif_pins_evk>;
> -				panel-enable-gpios = <&gpio3 30 0>;
> +				lcd-supply = <&reg_lcd_3v3>;
>  				display = <&display>;
>  				status = "okay";
>  
> @@ -310,6 +310,15 @@
>  			gpio = <&gpio3 8 0>;
>  			enable-active-high;
>  		};
> +
> +		reg_lcd_3v3: lcd-3v3 {
> +			compatible = "regulator-fixed";
> +			regulator-name = "lcd-3v3";
> +			regulator-min-microvolt = <3300000>;
> +			regulator-max-microvolt = <3300000>;
> +			gpio = <&gpio3 30 0>;
> +			enable-active-high;
> +		};
>  	};
>  
>  	sound {
> diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
> index eac7c1a..74fbfd1 100644
> --- a/drivers/video/mxsfb.c
> +++ b/drivers/video/mxsfb.c
> @@ -42,7 +42,6 @@
>  #include <linux/module.h>
>  #include <linux/kernel.h>
>  #include <linux/of_device.h>
> -#include <linux/of_gpio.h>
>  #include <video/of_display_timing.h>
>  #include <linux/platform_device.h>
>  #include <linux/clk.h>
> @@ -50,6 +49,7 @@
>  #include <linux/io.h>
>  #include <linux/pinctrl/consumer.h>
>  #include <linux/fb.h>
> +#include <linux/regulator/consumer.h>
>  #include <video/videomode.h>
>  
>  #define REG_SET	4
> @@ -179,6 +179,7 @@ struct mxsfb_info {
>  	unsigned dotclk_delay;
>  	const struct mxsfb_devdata *devdata;
>  	u32 sync;
> +	struct regulator *reg_lcd;
>  };
>  
>  #define mxsfb_is_v3(host) (host->devdata->ipversion = 3)
> @@ -338,9 +339,19 @@ static void mxsfb_enable_controller(struct fb_info *fb_info)
>  {
>  	struct mxsfb_info *host = to_imxfb_host(fb_info);
>  	u32 reg;
> +	int ret;
>  
>  	dev_dbg(&host->pdev->dev, "%s\n", __func__);
>  
> +	if (!IS_ERR(host->reg_lcd)) {
> +		ret = regulator_enable(host->reg_lcd);
> +		if (ret) {
> +			dev_err(&host->pdev->dev,
> +				"lcd regulator enable failed:	%d\n", ret);
> +			return;
> +		}
> +	}
> +
>  	clk_prepare_enable(host->clk);
>  	clk_set_rate(host->clk, PICOS2KHZ(fb_info->var.pixclock) * 1000U);
>  
> @@ -362,9 +373,19 @@ static void mxsfb_disable_controller(struct fb_info *fb_info)
>  	struct mxsfb_info *host = to_imxfb_host(fb_info);
>  	unsigned loop;
>  	u32 reg;
> +	int ret;
>  
>  	dev_dbg(&host->pdev->dev, "%s\n", __func__);
>  
> +	if (!IS_ERR(host->reg_lcd)) {
> +		ret = regulator_disable(host->reg_lcd);
> +		if (ret) {
> +			dev_err(&host->pdev->dev,
> +				"lcd regulator disable failed: %d\n", ret);
> +			return;
> +		}
> +	}
> +
Shouldn't this be done as the last step of disabling?

>  	/*
>  	 * Even if we disable the controller here, it will still continue
>  	 * until its FIFOs are running out of data
> @@ -859,8 +880,6 @@ static int mxsfb_probe(struct platform_device *pdev)
>  	struct fb_info *fb_info;
>  	struct fb_modelist *modelist;
>  	struct pinctrl *pinctrl;
> -	int panel_enable;
> -	enum of_gpio_flags flags;
>  	int ret;
>  
>  	if (of_id)
> @@ -904,21 +923,7 @@ static int mxsfb_probe(struct platform_device *pdev)
>  		goto fb_release;
>  	}
>  
> -	panel_enable = of_get_named_gpio_flags(pdev->dev.of_node,
> -					       "panel-enable-gpios", 0, &flags);
> -	if (gpio_is_valid(panel_enable)) {
> -		unsigned long f = GPIOF_OUT_INIT_HIGH;
> -		if (flags = OF_GPIO_ACTIVE_LOW)
> -			f = GPIOF_OUT_INIT_LOW;
> -		ret = devm_gpio_request_one(&pdev->dev, panel_enable,
> -					    f, "panel-enable");
> -		if (ret) {
> -			dev_err(&pdev->dev,
> -				"failed to request gpio %d: %d\n",
> -				panel_enable, ret);
> -			goto fb_release;
> -		}
> -	}
> +	host->reg_lcd = devm_regulator_get(&pdev->dev, "lcd");

I prefer to check return here ...

	if (IS_ERR(host->reg_lcd))
		host->reg_lcd = NULL;

... and then use if (host->reg_lcd) in mxsfb_enable[disable]_controller().

Shawn

>  
>  	fb_info->pseudo_palette = devm_kzalloc(&pdev->dev, sizeof(u32) * 16,
>  					       GFP_KERNEL);
> -- 
> 1.7.9.5
> 
>