[PATCH] drm/aspeed: Add sysfs for output settings

[Andrew Jeffery]

On Wed, 16 Sep 2020, at 18:04, Joel Stanley wrote:
> These settings are used by an ASPEED BMC to determine when the host is
> trying to drive the display over PCIe (vga_pw) and to switch the
> output between PCIe and the internal graphics device (dac_mux).
> 
> The valid values for the dac mux are:
> 
>  00: VGA mode (default, aka PCIe)
>  01: Graphics CRT (aka BMC internal graphics, this driver)
>  10: Pass through mode from video input port A
>  11: Pass through mode from video input port B
> 
> Values for the read-only vga password register are:
> 
>  1: Host driving the display
>  0: Host not driving the display
> 
> Signed-off-by: Joel Stanley <joel at jms.id.au>
> ---
>  drivers/gpu/drm/aspeed/aspeed_gfx_drv.c | 71 +++++++++++++++++++++++++
>  1 file changed, 71 insertions(+)
> 
> diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c 
> b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> index 903f4f304647..9e06a3683f8a 100644
> --- a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> @@ -205,6 +205,69 @@ static const struct of_device_id 
> aspeed_gfx_match[] = {
>  	{ }
>  };
>  
> +#define ASPEED_SCU_VGA0		0x50
> +#define ASPEED_SCU_MISC_CTRL	0x2c
> +
> +static ssize_t dac_mux_store(struct device *dev, struct 
> device_attribute *attr,
> +			     const char *buf, size_t count)
> +{
> +	struct aspeed_gfx *priv = dev_get_drvdata(dev);
> +	u32 val;
> +	int rc;
> +
> +	rc = kstrtou32(buf, 0, &val);
> +	if (rc)
> +		return rc;
> +
> +	if (val < 0 || val > 3)

val is unsigned so can't be less than zero.

Otherwise,

Reviewed-by: Andrew Jeffery <andrew at aj.id.au>

> +		return -EINVAL;
> +
> +	rc = regmap_update_bits(priv->scu, ASPEED_SCU_MISC_CTRL, 0x30000, val 
> << 16);
> +	if (rc < 0)
> +		return 0;
> +
> +	return count;
> +}
> +
> +static ssize_t dac_mux_show(struct device *dev, struct 
> device_attribute *attr, char *buf)
> +{
> +	struct aspeed_gfx *priv = dev_get_drvdata(dev);
> +	u32 reg;
> +	int rc;
> +
> +	rc = regmap_read(priv->scu, ASPEED_SCU_MISC_CTRL, &reg);
> +	if (rc)
> +		return rc;
> +
> +	return sprintf(buf, "%u\n", (reg >> 16) & 0x3);
> +}
> +static DEVICE_ATTR_RW(dac_mux);
> +
> +static ssize_t
> +vga_pw_show(struct device *dev, struct device_attribute *attr, char 
> *buf)
> +{
> +	struct aspeed_gfx *priv = dev_get_drvdata(dev);
> +	u32 reg;
> +	int rc;
> +
> +	rc = regmap_read(priv->scu, ASPEED_SCU_VGA0, &reg);
> +	if (rc)
> +		return rc;
> +
> +	return sprintf(buf, "%u\n", reg & 1);
> +}
> +static DEVICE_ATTR_RO(vga_pw);
> +
> +static struct attribute *aspeed_sysfs_entries[] = {
> +	&dev_attr_vga_pw.attr,
> +	&dev_attr_dac_mux.attr,
> +	NULL,
> +};
> +
> +static struct attribute_group aspeed_sysfs_attr_group = {
> +	.attrs = aspeed_sysfs_entries,
> +};
> +
>  static int aspeed_gfx_probe(struct platform_device *pdev)
>  {
>  	struct aspeed_gfx *priv;
> @@ -219,6 +282,12 @@ static int aspeed_gfx_probe(struct platform_device 
> *pdev)
>  	if (ret)
>  		return ret;
>  
> +	dev_set_drvdata(&pdev->dev, priv);
> +
> +	ret = sysfs_create_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
> +	if (ret)
> +		return ret;
> +
>  	ret = drm_dev_register(&priv->drm, 0);
>  	if (ret)
>  		goto err_unload;
> @@ -227,6 +296,7 @@ static int aspeed_gfx_probe(struct platform_device *pdev)
>  	return 0;
>  
>  err_unload:
> +	sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
>  	aspeed_gfx_unload(&priv->drm);
>  
>  	return ret;
> @@ -236,6 +306,7 @@ static int aspeed_gfx_remove(struct platform_device *pdev)
>  {
>  	struct drm_device *drm = platform_get_drvdata(pdev);
>  
> +	sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
>  	drm_dev_unregister(drm);
>  	aspeed_gfx_unload(drm);
>  
> -- 
> 2.28.0
> 
>