Re: [alsa-devel] [PATCH v4 0/7] ASoC: Intel: Skylake: Add a clk driver to enable ssp clks early

[Vinod Koul <vinod.koul@intel.com>]

On Wed, Nov 22, 2017 at 05:39:45PM +0530, Sriram Periyasamy wrote:
> For certain platforms, clocks (mclk/sclk/fs) are required to be up before
> the stream start. Example: some codecs needs the mclk/sclk/fs to be
> enabled early for a successful clock synchronization. Some platforms
> require clock to be enabled at boot and be always ON.
> 
> By sending set_dma_control IPC (with the i2s blobs queried from NHLT),
> these clocks can be enabled early after the firmware is downloaded.
> 
> With this series, a virtual clock driver is created which provides
> interface to send the required IPCs from machine driver to enable the
> clocks. NHLT is parsed during probe and the clock information is populated.
> The pointer to blob is cached and sent along with the set_dma_control IPC
> structure during the clk prepare/unprepare callback. Clocks are created for
> a ssp if the nhlt table has endpoint configuration for that particular ssp.
> Skylake driver creates a platform driver with the clock information and
> register the clk ops callback.
> 
> Kabylake machine driver uses the clock interface to enable the clocks early
> as it is required by the rt5663 driver for clock synchronization.

All:

Acked-By: Vinod Koul <vinod.koul@intel.com>

-- 
~Vinod