From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nicolas Ferre <nicolas.ferre@atmel.com>
Date: Tue, 16 Apr 2013 13:42:36 +0000
Subject: Re: [PATCH 4/8] video: atmel_lcdfb: add device tree suport
Message-Id: <516D554C.1090909@atmel.com>
List-Id: <linux-fbdev.vger.kernel.org>
References: <20130411145741.GB25242@game.jcrosoft.org>
 <1365692422-9565-1-git-send-email-plagnioj@jcrosoft.com>
 <1365692422-9565-4-git-send-email-plagnioj@jcrosoft.com>
In-Reply-To: <1365692422-9565-4-git-send-email-plagnioj@jcrosoft.com>
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To: linux-arm-kernel@lists.infradead.org

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 <plagnioj@jcrosoft.com>
> Cc: linux-fbdev@vger.kernel.org
> Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> ---
>  .../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
>=20
> diff --git a/Documentation/devicetree/bindings/video/atmel,lcdc.txt b/Doc=
umentation/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" ,=20
> +	"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@0x00500000 {
> +		compatible =3D "atmel,at91sam9g45-lcdc";
> +		reg =3D <0x00500000 0x1000>;
> +		interrupts =3D <23 3 0>;
> +		pinctrl-names =3D "default";
> +		pinctrl-0 =3D <&pinctrl_fb>;
> +		display =3D <&display0>;
> +		status =3D "okay";
> +		#address-cells =3D <1>;
> +		#size-cells =3D <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 =3D <32>;
> +		atmel,lcdcon-backlight;
> +		atmel,dmacon =3D <0x1>;
> +		atmel,lcdcon2 =3D <0x80008002>;
> +		atmel,guard-time =3D <9>;
> +		atmel,lcd-wiring-mode =3D <1>;
> +
> +		display-timings {
> +			native-mode =3D <&timing0>;
> +			timing0: timing0 {
> +				clock-frequency =3D <9000000>;
> +				hactive =3D <480>;
> +				vactive =3D <272>;
> +				hback-porch =3D <1>;
> +				hfront-porch =3D <1>;
> +				vback-porch =3D <40>;
> +				vfront-porch =3D <1>;
> +				hsync-len =3D <45>;
> +				vsync-len =3D <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.
> =20
> 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>
> =20
>  #include <mach/cpu.h>
>  #include <asm/gpio.h>
> @@ -59,6 +63,13 @@ struct atmel_lcdfb_info {
>  	struct atmel_lcdfb_config *config;
>  };
> =20
> +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))
> =20
> @@ -945,16 +956,187 @@ static void atmel_lcdfb_stop_clock(struct atmel_lc=
dfb_info *sinfo)
>  	clk_disable(sinfo->lcdc_clk);
>  }
> =20
> +#ifdef CONFIG_OF
> +static const struct of_device_id atmel_lcdfb_dt_ids[] =3D {
> +	{ .compatible =3D "atmel,at91sam9261-lcdc" , .data =3D &at91sam9261_con=
fig, },
> +	{ .compatible =3D "atmel,at91sam9263-lcdc" , .data =3D &at91sam9263_con=
fig, },
> +	{ .compatible =3D "atmel,at91sam9g10-lcdc" , .data =3D &at91sam9g10_con=
fig, },
> +	{ .compatible =3D "atmel,at91sam9g45-lcdc" , .data =3D &at91sam9g45_con=
fig, },
> +	{ .compatible =3D "atmel,at91sam9g45es-lcdc" , .data =3D &at91sam9g45es=
_config, },
> +	{ .compatible =3D "atmel,at91sam9rl-lcdc" , .data =3D &at91sam9rl_confi=
g, },
> +	{ .compatible =3D "atmel,at32ap-lcdc" , .data =3D &at32ap_config, },
> +	{ /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, atmel_lcdfb_dt_ids);
> +
> +static const char *atmel_lcdfb_wiring_modes[] =3D {
> +	[ATMEL_LCDC_WIRING_BGR]	=3D "BRG",
> +	[ATMEL_LCDC_WIRING_RGB]	=3D "RGB",
> +};
> +
> +const int atmel_lcdfb_get_of_wiring_modes(struct device_node *np)
> +{
> +	const char *mode;
> +	int err, i;
> +
> +	err =3D of_property_read_string(np, "atmel,lcd-wiring-mode", &mode);
> +	if (err < 0)
> +		return ATMEL_LCDC_WIRING_BGR;
> +
> +	for (i =3D 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 *pda=
ta, 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 =3D sinfo->info;
> +	struct atmel_lcdfb_pdata *pdata =3D &sinfo->pdata;
> +	struct fb_var_screeninfo *var =3D &info->var;
> +	struct device *dev =3D &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 =3D false;
> +	int ret =3D -ENOENT;
> +	int i, gpio;
> +
> +	sinfo->config =3D (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 =3D of_parse_phandle(np, "display", 0);
> +	if (!display_np) {
> +		dev_err(dev, "failed to find display phandle\n");
> +		return -ENOENT;
> +	}
> +
> +	ret =3D of_property_read_u32(display_np, "bits-per-pixel", &var->bits_p=
er_pixel);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get property bits-per-pixel\n");
> +		goto put_display_node;
> +	}
> +
> +	ret =3D of_property_read_u32(display_np, "atmel,guard-time", &pdata->gu=
ard_time);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get property atmel,guard-time\n");
> +		goto put_display_node;
> +	}
> +
> +	ret =3D of_property_read_u32(display_np, "atmel,lcdcon2", &pdata->defau=
lt_lcdcon2);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get property atmel,lcdcon2\n");
> +		goto put_display_node;
> +	}
> +
> +	ret =3D of_property_read_u32(display_np, "atmel,dmacon", &pdata->defaul=
t_dmacon);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get property bits-per-pixel\n");

No, wrong error message.

> +		goto put_display_node;
> +	}
> +
> +	ret =3D -ENOMEM;
> +	for (i =3D 0; i < of_gpio_named_count(display_np, "atmel,power-control-=
gpio"); i++) {
> +		gpio =3D of_get_named_gpio_flags(display_np, "atmel,power-control-gpio=
",
> +					       i, &flags);
> +		if (gpio < 0)
> +			continue;
> +
> +		og =3D devm_kzalloc(dev, sizeof(*og), GFP_KERNEL);
> +		if (!og)
> +			goto put_display_node;
> +
> +		og->gpio =3D gpio;
> +		og->active_low =3D flags & OF_GPIO_ACTIVE_LOW;
> +		is_gpio_power =3D true;
> +		ret =3D 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 =3D 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 =3D atmel_lcdfb_power_control_gpio;
> +
> +	ret =3D 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 =3D ret;
> +
> +	pdata->lcdcon_is_backlight =3D of_property_read_bool(display_np, "atmel=
,lcdcon-backlight");
> +
> +	timings =3D of_get_display_timings(display_np);
> +	if (!timings) {
> +		dev_err(dev, "failed to get display timings\n");
> +		goto put_display_node;
> +	}
> +
> +	timings_np =3D 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 =3D 0; i < of_get_child_count(timings_np); i++) {
> +		struct videomode vm;
> +		struct fb_videomode fb_vm;
> +
> +		ret =3D videomode_from_timing(timings, &vm, i);
> +		if (ret < 0)
> +			goto put_timings_node;
> +		ret =3D 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
> =20
>  static int __init atmel_lcdfb_probe(struct platform_device *pdev)
>  {
>  	struct device *dev =3D &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 =3D NULL;
>  	struct resource *regs =3D NULL;
>  	struct resource *map =3D NULL;
> +	struct fb_modelist *modelist;
>  	int ret;
> =20
>  	dev_dbg(dev, "%s BEGIN\n", __func__);
> @@ -967,17 +1149,35 @@ static int __init atmel_lcdfb_probe(struct platfor=
m_device *pdev)
>  	}
> =20
>  	sinfo =3D info->par;
> +	sinfo->pdev =3D pdev;
> +	sinfo->info =3D info;
> +
> +	INIT_LIST_HEAD(&info->modelist);
> =20
> -	if (dev->platform_data) {
> -		pdata =3D (struct atmel_lcdfb_pdata *)dev->platform_data;
> +	if (pdev->dev.of_node) {
> +		ret =3D atmel_lcdfb_of_init(sinfo);
> +		if (ret)
> +			goto free_info;
> +	} else if (dev->platform_data) {
> +		struct fb_monspecs *monspecs;
> +		int i;
> +
> +		pdata =3D dev->platform_data;
> +		monspecs =3D pdata->default_monspecs;
>  		sinfo->pdata =3D *pdata;
> +
> +		for (i =3D 0; i < monspecs->modedb_len; i++)
> +			fb_add_videomode(&monspecs->modedb[i], &info->modelist);
> +
> +		sinfo->config =3D atmel_lcdfb_get_config(pdev);
> +
> +		info->var.bits_per_pixel =3D 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 =3D info;
> -	sinfo->pdev =3D pdev;
> -	sinfo->config =3D atmel_lcdfb_get_config(pdev);
> +
>  	if (!sinfo->config)
>  		goto free_info;
> =20
> @@ -986,7 +1186,6 @@ static int __init atmel_lcdfb_probe(struct platform_=
device *pdev)
>  	info->pseudo_palette =3D sinfo->pseudo_palette;
>  	info->fbops =3D &atmel_lcdfb_ops;
> =20
> -	memcpy(&info->monspecs, pdata->default_monspecs, sizeof(info->monspecs)=
);
>  	info->fix =3D atmel_lcdfb_fix;
> =20
>  	/* Enable LCDC Clocks */
> @@ -1002,14 +1201,11 @@ static int __init atmel_lcdfb_probe(struct platfo=
rm_device *pdev)
>  	}
>  	atmel_lcdfb_start_clock(sinfo);
> =20
> -	ret =3D 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 =3D list_first_entry(&info->modelist,
> +			struct fb_modelist, list);
> +	fb_videomode_to_var(&info->var, &modelist->mode);
> =20
> +	atmel_lcdfb_check_var(&info->var, info);
> =20
>  	regs =3D platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	if (!regs) {
> @@ -1093,18 +1289,6 @@ static int __init atmel_lcdfb_probe(struct platfor=
m_device *pdev)
>  		goto unregister_irqs;
>  	}
> =20
> -	/*
> -	 * This makes sure that our colour bitfield
> -	 * descriptors are correctly initialised.
> -	 */
> -	atmel_lcdfb_check_var(&info->var, info);
> -
> -	ret =3D 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);
> =20
>  	/*
> @@ -1116,10 +1300,6 @@ static int __init atmel_lcdfb_probe(struct platfor=
m_device *pdev)
>  		goto reset_drvdata;
>  	}
> =20
> -	/* 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);
> =20
> @@ -1130,7 +1310,6 @@ static int __init atmel_lcdfb_probe(struct platform=
_device *pdev)
> =20
>  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 =
=3D {
>  	.driver		=3D {
>  		.name	=3D "atmel_lcdfb",
>  		.owner	=3D THIS_MODULE,
> +		.of_match_table	=3D of_match_ptr(atmel_lcdfb_dt_ids),
>  	},
>  };
> =20
>=20


--=20
Nicolas Ferre