[PATCH 2/2] drm/aspeed: Add DVO output option to GFX driver

[Benjamin Herrenschmidt]

On Thu, 2019-05-02 at 16:51 -0500, Timothy Pearson wrote:
> The AST2500 offers an alternate GFX output mode over DVO.
> Enable DVO or VGA output mode conditionally based on two new
> device tree properties, output-vga and output-dvo.

It would be better to have output-type= which contains "dvo" or "vga"

Also you need to update the bindings.

Cheers,
Ben.

> Signed-off-by: Timothy Pearson <tpearson at raptorengineering.com>
> ---
>  drivers/gpu/drm/aspeed/aspeed_gfx.h      |  6 ++++++
>  drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c | 29
> +++++++++++++++++++++++------
>  drivers/gpu/drm/aspeed/aspeed_gfx_drv.c  | 17 ++++++++++++++++-
>  3 files changed, 45 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx.h
> b/drivers/gpu/drm/aspeed/aspeed_gfx.h
> index b34c97613aaf..6f9bc01191c0 100644
> --- a/drivers/gpu/drm/aspeed/aspeed_gfx.h
> +++ b/drivers/gpu/drm/aspeed/aspeed_gfx.h
> @@ -14,6 +14,8 @@ struct aspeed_gfx {
>  	struct drm_simple_display_pipe	pipe;
>  	struct drm_connector		connector;
>  	struct drm_fbdev_cma		*fbdev;
> +
> +	u8				output_mode;
>  };
>  
>  int aspeed_gfx_create_pipe(struct drm_device *drm);
> @@ -105,3 +107,7 @@ int aspeed_gfx_create_output(struct drm_device
> *drm);
>  
>  /* Default Threshold Seting */
>  #define G5_CRT_THROD_VAL	(CRT_THROD_LOW(0x24) |
> CRT_THROD_HIGH(0x3C))
> +
> +/* Output mode */
> +#define OUTPUT_VGA	0x1
> +#define OUTPUT_DVO	0x2
> diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> index 15db9e426ec4..ee16f9011d70 100644
> --- a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0+
>  // Copyright 2018 IBM Corporation
> +// Copyright 2019 Raptor Engineering, LLC
>  
>  #include <linux/clk.h>
>  #include <linux/reset.h>
> @@ -59,11 +60,21 @@ static void aspeed_gfx_enable_controller(struct
> aspeed_gfx *priv)
>  	u32 ctrl1 = readl(priv->base + CRT_CTRL1);
>  	u32 ctrl2 = readl(priv->base + CRT_CTRL2);
>  
> -	/* SCU2C: set DAC source for display output to Graphics CRT
> (GFX) */
> -	regmap_update_bits(priv->scu, 0x2c, BIT(16), BIT(16));
> +	if (priv->output_mode & OUTPUT_VGA) {
> +		/* SCU2C: set DAC source for display output to Graphics
> CRT (GFX) */
> +		regmap_update_bits(priv->scu, 0x2c, BIT(16), BIT(16));
> +	}
> +	if (priv->output_mode & OUTPUT_DVO) {
> +		/* SCU2C: set DVO source for display output to Graphics
> CRT (GFX) */
> +		regmap_update_bits(priv->scu, 0x2c, BIT(18), BIT(18));
> +	}
>  
>  	writel(ctrl1 | CRT_CTRL_EN, priv->base + CRT_CTRL1);
> -	writel(ctrl2 | CRT_CTRL_DAC_EN, priv->base + CRT_CTRL2);
> +
> +	if (priv->output_mode & OUTPUT_VGA)
> +		writel(ctrl2 | CRT_CTRL_DAC_EN, priv->base +
> CRT_CTRL2);
> +	if (priv->output_mode & OUTPUT_DVO)
> +		writel(ctrl2 | CRT_CTRL_DVO_EN, priv->base +
> CRT_CTRL2);
>  }
>  
>  static void aspeed_gfx_disable_controller(struct aspeed_gfx *priv)
> @@ -72,9 +83,15 @@ static void aspeed_gfx_disable_controller(struct
> aspeed_gfx *priv)
>  	u32 ctrl2 = readl(priv->base + CRT_CTRL2);
>  
>  	writel(ctrl1 & ~CRT_CTRL_EN, priv->base + CRT_CTRL1);
> -	writel(ctrl2 & ~CRT_CTRL_DAC_EN, priv->base + CRT_CTRL2);
> -
> -	regmap_update_bits(priv->scu, 0x2c, BIT(16), 0);
> +	if (priv->output_mode & OUTPUT_VGA)
> +		writel(ctrl2 & ~CRT_CTRL_DAC_EN, priv->base +
> CRT_CTRL2);
> +	if (priv->output_mode & OUTPUT_DVO)
> +		writel(ctrl2 & ~CRT_CTRL_DVO_EN, priv->base +
> CRT_CTRL2);
> +
> +	if (priv->output_mode & OUTPUT_VGA)
> +		regmap_update_bits(priv->scu, 0x2c, BIT(16), 0);
> +	if (priv->output_mode & OUTPUT_DVO)
> +		regmap_update_bits(priv->scu, 0x2c, BIT(18), 0);
>  }
>  
>  static void aspeed_gfx_crtc_mode_set_nofb(struct aspeed_gfx *priv)
> diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> index 7e9072fd0ef0..17a22dd0922a 100644
> --- a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0+
>  // Copyright 2018 IBM Corporation
> +// Copyright 2019 Raptor Engineering, LLC
>  
>  #include <linux/clk.h>
>  #include <linux/dma-mapping.h>
> @@ -50,7 +51,8 @@
>   * is the ARM's internal display controller.
>   *
>   * The driver only supports a simple configuration consisting of a
> 40MHz
> - * pixel clock, fixed by hardware limitations, and the VGA output
> path.
> + * pixel clock, fixed by hardware limitations.  It supports DVO
> output
> + * mode as well based on device tree configuration.
>   *
>   * The driver was written with the 'AST2500 Software Programming
> Guide' v17,
>   * which is available under NDA from ASPEED.
> @@ -95,6 +97,7 @@ static irqreturn_t aspeed_gfx_irq_handler(int irq,
> void *data)
>  static int aspeed_gfx_load(struct drm_device *drm)
>  {
>  	struct platform_device *pdev = to_platform_device(drm->dev);
> +	struct device_node *nc = drm->dev->of_node;
>  	struct aspeed_gfx *priv;
>  	struct resource *res;
>  	int ret;
> @@ -145,6 +148,18 @@ static int aspeed_gfx_load(struct drm_device
> *drm)
>  	}
>  	clk_prepare_enable(priv->clk);
>  
> +	if (of_property_read_bool(nc, "output-vga"))
> +		priv->output_mode |= OUTPUT_VGA;
> +	else if (of_property_read_bool(nc, "output-dvo"))
> +		priv->output_mode |= OUTPUT_DVO;
> +	else
> +		priv->output_mode = OUTPUT_VGA;
> +
> +	if (priv->output_mode & OUTPUT_VGA)
> +		DRM_INFO("Enabling VGA output\n");
> +	if (priv->output_mode & OUTPUT_DVO)
> +		DRM_INFO("Enabling DVO output\n");
> +
>  	/* Sanitize control registers */
>  	writel(0, priv->base + CRT_CTRL1);
>  	/* Preserve CRT_CTRL2[7:6] (DVO configuration) */