Re: [PATCH v2 17/27] drm/tegra: Add Tegra114 HDMI support

[Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>]

On 10/07/2013 02:34 AM, Thierry Reding wrote:
> From: Mikko Perttunen <mperttunen-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> Tegra114 TMDS configuration requires a new peak_current field and the
> driver current override bit has changed position.

> diff --git a/drivers/gpu/drm/tegra/hdmi.c b/drivers/gpu/drm/tegra/hdmi.c

>  static const struct tmds_config tegra2_tmds_config[] = {
> @@ -223,6 +224,85 @@ static const struct tmds_config tegra3_tmds_config[] = {

Not related to this patch, but those should have been named
tegra20_tmds_config[] and tegra30_tmds_config[].

>  static void tegra_hdmi_setup_tmds(struct tegra_hdmi *hdmi,

> -	value = tmds->drive_current | DRIVE_CURRENT_FUSE_OVERRIDE;
> -	tegra_hdmi_writel(hdmi, value, HDMI_NV_PDISP_SOR_LANE_DRIVE_CURRENT);
> +	if (of_device_is_compatible(np, "nvidia,tegra114-hdmi")) {

Let's not check this at run-time. Instead, host1x_drm_subdevs[]'s .data
field should be used to contain either flags or a pointer to a
configuration structure, either of which can be directly consulted to
determine the properties of the HW in a feature-oriented/semantic way.

drivers/gpio/gpio-tegra.c's
tegra20_gpio_config/tegra30_gpio_config/tegra_gpio_of_match provide a
good example of this.

This means that if Tegra124 is identical to Tegra114, yet a hypothetical
Tegra999 is different, you don't have to keep adjusting these if
conditions throughout the code; they can simply refer to the same
feature bit forever.