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

Richard Genoud richard.genoud at gmail.com
Thu May 30 01:01:58 EST 2013


2013/4/11 Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>:
> get display timings from device tree
> Use videomode helpers to get display timings and configurations from
> device tree
>
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> Cc: linux-fbdev at vger.kernel.org
> Cc: Nicolas Ferre <nicolas.ferre at atmel.com>
> Cc: Andrew Morton <akpm at 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
>
> 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
> @@ -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):
> +
> + - atmel,dmacon: dma controler configuration
> + - atmel,lcdcon2: lcd controler configuration
> + - atmel,guard-time: lcd guard time (Delay in frame periods)
> + - 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"
> + - atmel,power-control-gpio: gpio to power on or off the LCD (as many as needed)
still on lcdcon_pol_negative, we can add something like that:
 - atmel,lcdcon-pwm-pulse-low: Output PWM pulses are low level (high
level if not set)

> +
> +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>
> +#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;
> +
> +       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");
> +               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");

and here, something like:
pdata->lcdcon_pol_negative = of_property_read_bool(display_np,
"atmel,lcdcon-pwm-pulse-low");
would be nice


Regards,
Richard.


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