On 04/07/2017 04:19 PM, Romain Perier wrote:
> Currently, the audio sampler clock is enabled from dw_hdmi_setup() at
> step E. and is kept enabled for later use. This clock should be enabled
> and disabled along with the actual audio stream and not always on (that
> is bad for PM). Futhermore, as described by the datasheet, the I2S
> variant need to gate/ungate the clock when the stream is
> enabled/disabled.
>
> This commit adds a parameter to hdmi_audio_enable_clk() that controls
> when the audio sample clock must be enabled or disabled. Then, it adds
> the call to this function from dw_hdmi_i2s_audio_enable() and
> dw_hdmi_i2s_audio_disable().
>
> Signed-off-by: Romain Perier <romain.perier@xxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/bridge/dw-hdmi.c | 16 +++++++++-------
> 1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
> index d34e0a5..3bd0807 100644
> --- a/drivers/gpu/drm/bridge/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/dw-hdmi.c
> @@ -559,6 +559,12 @@ void dw_hdmi_set_sample_rate(struct dw_hdmi *hdmi, unsigned int rate)
> }
> EXPORT_SYMBOL_GPL(dw_hdmi_set_sample_rate);
>
> +static void hdmi_enable_audio_clk(struct dw_hdmi *hdmi, bool enable)
> +{
> + hdmi_modb(hdmi, enable ? 0 : HDMI_MC_CLKDIS_AUDCLK_DISABLE,
> + HDMI_MC_CLKDIS_AUDCLK_DISABLE, HDMI_MC_CLKDIS);
> +}
> +
> void dw_hdmi_ahb_audio_enable(struct dw_hdmi *hdmi)
> {
> hdmi_set_cts_n(hdmi, hdmi->audio_cts, hdmi->audio_n);
> @@ -572,12 +578,13 @@ void dw_hdmi_ahb_audio_disable(struct dw_hdmi *hdmi)
> void dw_hdmi_i2s_audio_enable(struct dw_hdmi *hdmi)
> {
> hdmi_set_cts_n(hdmi, hdmi->audio_cts, hdmi->audio_n);
> + hdmi_enable_audio_clk(hdmi, true);
> }
>
>
> void dw_hdmi_i2s_audio_disable(struct dw_hdmi *hdmi)
> {
> -
> + hdmi_enable_audio_clk(hdmi, false);
> }
I think the NULL check is still valid if you fill this function, because the IP also
support other modes (SPDIF and GPA).
>
> void dw_hdmi_audio_enable(struct dw_hdmi *hdmi)
> @@ -1365,11 +1372,6 @@ static void dw_hdmi_enable_video_path(struct dw_hdmi *hdmi)
> }
> }
>
> -static void hdmi_enable_audio_clk(struct dw_hdmi *hdmi)
> -{
> - hdmi_modb(hdmi, 0, HDMI_MC_CLKDIS_AUDCLK_DISABLE, HDMI_MC_CLKDIS);
> -}
> -
> /* Workaround to clear the overflow condition */
> static void dw_hdmi_clear_overflow(struct dw_hdmi *hdmi)
> {
> @@ -1471,7 +1473,7 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode)
>
> /* HDMI Initialization Step E - Configure audio */
> hdmi_clk_regenerator_update_pixel_clock(hdmi);
> - hdmi_enable_audio_clk(hdmi);
> + hdmi_enable_audio_clk(hdmi, true);
> }
>
> /* not for DVI mode */
>
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