Subject: [PATCH 4/8] video: atmel_lcdfb: add device tree suport

From: [email-masked] (Nicolas Ferre)
Date: Tue, 16 Apr 2013 15:42:36 +0200

On 04/11/2013 05:00 PM, Jean-Christophe PLAGNIOL-VILLARD :
> get display timings from device tree
> Use videomode helpers to get display timings and configurations from
> device tree

2 sentences? Simply elaborate the 2nd one and it will be good.

> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <[email-masked]>
> Cc: linux-fbdev at vger.kernel.org
> Cc: Nicolas Ferre <[email-masked]>
> Cc: Andrew Morton <[email-masked]>
> ---
>  .../devicetree/bindings/video/atmel,lcdc.txt       |   75 ++++++
>  drivers/video/Kconfig                              |    2 +
>  drivers/video/atmel_lcdfb.c                        |  244 +++++++++++++++++---
>  3 files changed, 289 insertions(+), 32 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/video/atmel,lcdc.txt
> 
> diff --git a/Documentation/devicetree/bindings/video/atmel,lcdc.txt b/Documentation/devicetree/bindings/video/atmel,lcdc.txt
> new file mode 100644
> index 0000000..1ec175e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/video/atmel,lcdc.txt

Why lcdc? I would have preferred atmel,lcdfb, like the driver's name: it
is even more self-explanatory...

> @@ -0,0 +1,75 @@
> +Atmel LCDC Framebuffer
> +-----------------------------------------------------
> +
> +Required properties:
> +- compatible :
> +	"atmel,at91sam9261-lcdc" , 
> +	"atmel,at91sam9263-lcdc" ,
> +	"atmel,at91sam9g10-lcdc" ,
> +	"atmel,at91sam9g45-lcdc" ,
> +	"atmel,at91sam9g45es-lcdc" ,
> +	"atmel,at91sam9rl-lcdc" ,
> +	"atmel,at32ap-lcdc"
> +- reg : Should contain 1 register ranges(address and length)
> +- interrupts : framebuffer controller interrupt
> +- display: a phandle pointing to the display node
> +
> +Required nodes:
> +- display: a display node is required to initialize the lcd panel
> +	This should be in the board dts.
> +- default-mode: a videomode within the display with timing parameters
> +	as specified below.
> +
> +Example:
> +
> +	fb0: fb at 0x00500000 {
> +		compatible = "atmel,at91sam9g45-lcdc";
> +		reg = <0x00500000 0x1000>;
> +		interrupts = <23 3 0>;
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&pinctrl_fb>;
> +		display = <&display0>;
> +		status = "okay";
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +
> +	};
> +
> +Atmel LCDC Display
> +-----------------------------------------------------
> +Required properties (as per of_videomode_helper):

Can you please point somewhere to the documentation:
Documentation/devicetree/bindings/video/display-timing.txt

> + - atmel,dmacon: dma controler configuration

Typo: controller.

> + - atmel,lcdcon2: lcd controler configuration

Ditto

> + - atmel,guard-time: lcd guard time (Delay in frame periods)

periods -> period, no?

> + - bits-per-pixel: lcd panel bit-depth.
> +
> +Optional properties (as per of_videomode_helper):
> + - atmel,lcdcon-backlight: enable backlight
> + - atmel,lcd-wiring-mode: lcd wiring mode "RGB" or "BRG"

Is it a sting, or a number (as seen below)? If it is a number, please
tell how to choose the index.

> + - atmel,power-control-gpio: gpio to power on or off the LCD (as many as needed)
> +
> +Example:
> +	display0: display {
> +		bits-per-pixel = <32>;
> +		atmel,lcdcon-backlight;
> +		atmel,dmacon = <0x1>;
> +		atmel,lcdcon2 = <0x80008002>;
> +		atmel,guard-time = <9>;
> +		atmel,lcd-wiring-mode = <1>;
> +
> +		display-timings {
> +			native-mode = <&timing0>;
> +			timing0: timing0 {
> +				clock-frequency = <9000000>;
> +				hactive = <480>;
> +				vactive = <272>;
> +				hback-porch = <1>;
> +				hfront-porch = <1>;
> +				vback-porch = <40>;
> +				vfront-porch = <1>;
> +				hsync-len = <45>;
> +				vsync-len = <1>;
> +			};
> +		};
> +	};
> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> index 4c1546f..0687482 100644
> --- a/drivers/video/Kconfig
> +++ b/drivers/video/Kconfig
> @@ -1018,6 +1018,8 @@ config FB_ATMEL
>  	select FB_CFB_FILLRECT
>  	select FB_CFB_COPYAREA
>  	select FB_CFB_IMAGEBLIT
> +	select FB_MODE_HELPERS
> +	select OF_VIDEOMODE
>  	help
>  	  This enables support for the AT91/AT32 LCD Controller.
>  
> diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c
> index f67e226..4a31570 100644
> --- a/drivers/video/atmel_lcdfb.c
> +++ b/drivers/video/atmel_lcdfb.c
> @@ -20,7 +20,11 @@
>  #include <linux/gfp.h>
>  #include <linux/module.h>
>  #include <linux/platform_data/atmel.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_gpio.h>
>  #include <video/of_display_timing.h>

As said in patch 1/8, this one belongs to this 4/8 patch.

> +#include <video/videomode.h>
>  
>  #include <mach/cpu.h>
>  #include <asm/gpio.h>
> @@ -59,6 +63,13 @@ struct atmel_lcdfb_info {
>  	struct atmel_lcdfb_config *config;
>  };
>  
> +struct atmel_lcdfb_power_ctrl_gpio {
> +	int gpio;
> +	int active_low;
> +
> +	struct list_head list;
> +};
> +
>  #define lcdc_readl(sinfo, reg)		__raw_readl((sinfo)->mmio+(reg))
>  #define lcdc_writel(sinfo, reg, val)	__raw_writel((val), (sinfo)->mmio+(reg))
>  
> @@ -945,16 +956,187 @@ static void atmel_lcdfb_stop_clock(struct atmel_lcdfb_info *sinfo)
>  	clk_disable(sinfo->lcdc_clk);
>  }
>  
> +#ifdef CONFIG_OF
> +static const struct of_device_id atmel_lcdfb_dt_ids[] = {
> +	{ .compatible = "atmel,at91sam9261-lcdc" , .data = &at91sam9261_config, },
> +	{ .compatible = "atmel,at91sam9263-lcdc" , .data = &at91sam9263_config, },
> +	{ .compatible = "atmel,at91sam9g10-lcdc" , .data = &at91sam9g10_config, },
> +	{ .compatible = "atmel,at91sam9g45-lcdc" , .data = &at91sam9g45_config, },
> +	{ .compatible = "atmel,at91sam9g45es-lcdc" , .data = &at91sam9g45es_config, },
> +	{ .compatible = "atmel,at91sam9rl-lcdc" , .data = &at91sam9rl_config, },
> +	{ .compatible = "atmel,at32ap-lcdc" , .data = &at32ap_config, },
> +	{ /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, atmel_lcdfb_dt_ids);
> +
> +static const char *atmel_lcdfb_wiring_modes[] = {
> +	[ATMEL_LCDC_WIRING_BGR]	= "BRG",
> +	[ATMEL_LCDC_WIRING_RGB]	= "RGB",
> +};
> +
> +const int atmel_lcdfb_get_of_wiring_modes(struct device_node *np)
> +{
> +	const char *mode;
> +	int err, i;
> +
> +	err = of_property_read_string(np, "atmel,lcd-wiring-mode", &mode);
> +	if (err < 0)
> +		return ATMEL_LCDC_WIRING_BGR;
> +
> +	for (i = 0; i < ARRAY_SIZE(atmel_lcdfb_wiring_modes); i++)
> +		if (!strcasecmp(mode, atmel_lcdfb_wiring_modes[i]))
> +			return i;
> +
> +	return -ENODEV;
> +}
> +
> +static void atmel_lcdfb_power_control_gpio(struct atmel_lcdfb_pdata *pdata, int on)
> +{
> +	struct atmel_lcdfb_power_ctrl_gpio *og;
> +
> +	list_for_each_entry(og, &pdata->pwr_gpios, list)
> +		gpio_set_value(og->gpio, on);
> +}
> +
> +static int atmel_lcdfb_of_init(struct atmel_lcdfb_info *sinfo)
> +{
> +	struct fb_info *info = sinfo->info;
> +	struct atmel_lcdfb_pdata *pdata = &sinfo->pdata;
> +	struct fb_var_screeninfo *var = &info->var;
> +	struct device *dev = &sinfo->pdev->dev;
> +	struct device_node *np =dev->of_node;
> +	struct device_node *display_np;
> +	struct device_node *timings_np;
> +	struct display_timings *timings;
> +	enum of_gpio_flags flags;
> +	struct atmel_lcdfb_power_ctrl_gpio *og;
> +	bool is_gpio_power = false;
> +	int ret = -ENOENT;
> +	int i, gpio;
> +
> +	sinfo->config = (struct atmel_lcdfb_config*)
> +		of_match_device(atmel_lcdfb_dt_ids, dev)->data;

Please split it in 2 steps, otherwise the day that the drivers doesn't
find the device in dt_ids table, it hangs here with an Oops.

> +
> +	display_np = of_parse_phandle(np, "display", 0);
> +	if (!display_np) {
> +		dev_err(dev, "failed to find display phandle\n");
> +		return -ENOENT;
> +	}
> +
> +	ret = of_property_read_u32(display_np, "bits-per-pixel", &var->bits_per_pixel);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get property bits-per-pixel\n");
> +		goto put_display_node;
> +	}
> +
> +	ret = of_property_read_u32(display_np, "atmel,guard-time", &pdata->guard_time);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get property atmel,guard-time\n");
> +		goto put_display_node;
> +	}
> +
> +	ret = of_property_read_u32(display_np, "atmel,lcdcon2", &pdata->default_lcdcon2);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get property atmel,lcdcon2\n");
> +		goto put_display_node;
> +	}
> +
> +	ret = of_property_read_u32(display_np, "atmel,dmacon", &pdata->default_dmacon);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get property bits-per-pixel\n");

No, wrong error message.

> +		goto put_display_node;
> +	}
> +
> +	ret = -ENOMEM;
> +	for (i = 0; i < of_gpio_named_count(display_np, "atmel,power-control-gpio"); i++) {
> +		gpio = of_get_named_gpio_flags(display_np, "atmel,power-control-gpio",
> +					       i, &flags);
> +		if (gpio < 0)
> +			continue;
> +
> +		og = devm_kzalloc(dev, sizeof(*og), GFP_KERNEL);
> +		if (!og)
> +			goto put_display_node;
> +
> +		og->gpio = gpio;
> +		og->active_low = flags & OF_GPIO_ACTIVE_LOW;
> +		is_gpio_power = true;
> +		ret = devm_gpio_request(dev, gpio, "lcd-power-control-gpio");
> +		if (ret) {
> +			dev_err(dev, "request gpio %d failed\n", gpio);
> +			goto put_display_node;
> +		}
> +
> +		ret = gpio_direction_output(gpio, og->active_low);
> +		if (ret) {
> +			dev_err(dev, "set direction output gpio %d failed\n", gpio);
> +			goto put_display_node;
> +		}
> +	}
> +
> +	if (is_gpio_power)
> +		pdata->atmel_lcdfb_power_control = atmel_lcdfb_power_control_gpio;
> +
> +	ret = atmel_lcdfb_get_of_wiring_modes(display_np);
> +	if (ret < 0) {
> +		dev_err(dev, "invalid atmel,lcd-wiring-mode\n");
> +		goto put_display_node;
> +	}
> +	pdata->lcd_wiring_mode = ret;
> +
> +	pdata->lcdcon_is_backlight = of_property_read_bool(display_np, "atmel,lcdcon-backlight");
> +
> +	timings = of_get_display_timings(display_np);
> +	if (!timings) {
> +		dev_err(dev, "failed to get display timings\n");
> +		goto put_display_node;
> +	}
> +
> +	timings_np = of_find_node_by_name(display_np, "display-timings");
> +	if (!timings_np) {
> +		dev_err(dev, "failed to find display-timings node\n");
> +		goto put_display_node;
> +	}
> +
> +	for (i = 0; i < of_get_child_count(timings_np); i++) {
> +		struct videomode vm;
> +		struct fb_videomode fb_vm;
> +
> +		ret = videomode_from_timing(timings, &vm, i);
> +		if (ret < 0)
> +			goto put_timings_node;
> +		ret = fb_videomode_from_videomode(&vm, &fb_vm);
> +		if (ret < 0)
> +			goto put_timings_node;
> +
> +		fb_add_videomode(&fb_vm, &info->modelist);
> +	}
> +
> +	return 0;
> +
> +put_timings_node:
> +	of_node_put(timings_np);
> +put_display_node:
> +	of_node_put(display_np);
> +	return ret;
> +}
> +#else
> +static int atmel_lcdfb_of_init(struct atmel_lcdfb_info *sinfo)
> +{
> +	return 0;
> +}
> +#endif
>  
>  static int __init atmel_lcdfb_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct fb_info *info;
>  	struct atmel_lcdfb_info *sinfo;
> -	struct atmel_lcdfb_pdata *pdata;
> -	struct fb_videomode fbmode;
> +	struct atmel_lcdfb_pdata *pdata = NULL;
>  	struct resource *regs = NULL;
>  	struct resource *map = NULL;
> +	struct fb_modelist *modelist;
>  	int ret;
>  
>  	dev_dbg(dev, "%s BEGIN\n", __func__);
> @@ -967,17 +1149,35 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
>  	}
>  
>  	sinfo = info->par;
> +	sinfo->pdev = pdev;
> +	sinfo->info = info;
> +
> +	INIT_LIST_HEAD(&info->modelist);
>  
> -	if (dev->platform_data) {
> -		pdata = (struct atmel_lcdfb_pdata *)dev->platform_data;
> +	if (pdev->dev.of_node) {
> +		ret = atmel_lcdfb_of_init(sinfo);
> +		if (ret)
> +			goto free_info;
> +	} else if (dev->platform_data) {
> +		struct fb_monspecs *monspecs;
> +		int i;
> +
> +		pdata = dev->platform_data;
> +		monspecs = pdata->default_monspecs;
>  		sinfo->pdata = *pdata;
> +
> +		for (i = 0; i < monspecs->modedb_len; i++)
> +			fb_add_videomode(&monspecs->modedb[i], &info->modelist);
> +
> +		sinfo->config = atmel_lcdfb_get_config(pdev);
> +
> +		info->var.bits_per_pixel = pdata->default_bpp ? pdata->default_bpp : 16;
> +		memcpy(&info->monspecs, pdata->default_monspecs, sizeof(info->monspecs));
>  	} else {
>  		dev_err(dev, "cannot get default configuration\n");
>  		goto free_info;
>  	}
> -	sinfo->info = info;
> -	sinfo->pdev = pdev;
> -	sinfo->config = atmel_lcdfb_get_config(pdev);
> +
>  	if (!sinfo->config)
>  		goto free_info;
>  
> @@ -986,7 +1186,6 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
>  	info->pseudo_palette = sinfo->pseudo_palette;
>  	info->fbops = &atmel_lcdfb_ops;
>  
> -	memcpy(&info->monspecs, pdata->default_monspecs, sizeof(info->monspecs));
>  	info->fix = atmel_lcdfb_fix;
>  
>  	/* Enable LCDC Clocks */
> @@ -1002,14 +1201,11 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
>  	}
>  	atmel_lcdfb_start_clock(sinfo);
>  
> -	ret = fb_find_mode(&info->var, info, NULL, info->monspecs.modedb,
> -			info->monspecs.modedb_len, info->monspecs.modedb,
> -			pdata->default_bpp);
> -	if (!ret) {
> -		dev_err(dev, "no suitable video mode found\n");
> -		goto stop_clk;
> -	}
> +	modelist = list_first_entry(&info->modelist,
> +			struct fb_modelist, list);
> +	fb_videomode_to_var(&info->var, &modelist->mode);
>  
> +	atmel_lcdfb_check_var(&info->var, info);
>  
>  	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	if (!regs) {
> @@ -1093,18 +1289,6 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
>  		goto unregister_irqs;
>  	}
>  
> -	/*
> -	 * This makes sure that our colour bitfield
> -	 * descriptors are correctly initialised.
> -	 */
> -	atmel_lcdfb_check_var(&info->var, info);
> -
> -	ret = fb_set_var(info, &info->var);
> -	if (ret) {
> -		dev_warn(dev, "unable to set display parameters\n");
> -		goto free_cmap;
> -	}
> -
>  	dev_set_drvdata(dev, info);
>  
>  	/*
> @@ -1116,10 +1300,6 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
>  		goto reset_drvdata;
>  	}
>  
> -	/* add selected videomode to modelist */
> -	fb_var_to_videomode(&fbmode, &info->var);
> -	fb_add_videomode(&fbmode, &info->modelist);
> -
>  	/* Power up the LCDC screen */
>  	atmel_lcdfb_power_control(sinfo, 1);
>  
> @@ -1130,7 +1310,6 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
>  
>  reset_drvdata:
>  	dev_set_drvdata(dev, NULL);
> -free_cmap:
>  	fb_dealloc_cmap(&info->cmap);
>  unregister_irqs:
>  	cancel_work_sync(&sinfo->task);
> @@ -1249,6 +1428,7 @@ static struct platform_driver atmel_lcdfb_driver = {
>  	.driver		= {
>  		.name	= "atmel_lcdfb",
>  		.owner	= THIS_MODULE,
> +		.of_match_table	= of_match_ptr(atmel_lcdfb_dt_ids),
>  	},
>  };
>  
> 

-- 
Nicolas Ferre