Re: [alsa-devel] [RFC PATCH 38/40] soundwire: cadence_master: make clock stop exit configurable on init

Guennadi Liakhovetski
2019-07-26T16:03:04Z

On Thu, Jul 25, 2019 at 06:40:30PM -0500, Pierre-Louis Bossart wrote:
> The use of clock stop is not a requirement, the IP can e.g. be
> completely power gated and not detect any wakes while in s2idle/deep
> sleep.
>
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> ---
> drivers/soundwire/cadence_master.c | 15 ++++++++-------
> drivers/soundwire/cadence_master.h | 2 +-
> drivers/soundwire/intel.c | 2 +-
> 3 files changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
> index 53278aa2436f..4ab6f70d7705 100644
> --- a/drivers/soundwire/cadence_master.c
> +++ b/drivers/soundwire/cadence_master.c
> @@ -1010,7 +1010,7 @@ static u32 cdns_set_default_frame_shape(int n_rows, int n_cols)
> * sdw_cdns_init() - Cadence initialization
> * @cdns: Cadence instance
> */
> -int sdw_cdns_init(struct sdw_cdns *cdns)
> +int sdw_cdns_init(struct sdw_cdns *cdns, bool clock_stop_exit)
> {
> struct sdw_bus *bus = &cdns->bus;
> struct sdw_master_prop *prop = &bus->prop;
> @@ -1018,12 +1018,13 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
> int divider;
> int ret;
>
> - /* Exit clock stop */
> - ret = cdns_clear_bit(cdns, CDNS_MCP_CONTROL,
> - CDNS_MCP_CONTROL_CLK_STOP_CLR);
> - if (ret < 0) {
> - dev_err(cdns->dev, "Couldn't exit from clock stop\n");
> - return ret;
> + if (clock_stop_exit) {
> + ret = cdns_clear_bit(cdns, CDNS_MCP_CONTROL,
> + CDNS_MCP_CONTROL_CLK_STOP_CLR);
> + if (ret < 0) {
> + dev_err(cdns->dev, "Couldn't exit from clock stop\n");
> + return ret;
> + }
> }
>
> /* Set clock divider */
> diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h
> index 1a0ba36dd78f..091b771b570d 100644
> --- a/drivers/soundwire/cadence_master.h
> +++ b/drivers/soundwire/cadence_master.h
> @@ -158,7 +158,7 @@ extern struct sdw_master_ops sdw_cdns_master_ops;
> irqreturn_t sdw_cdns_irq(int irq, void *dev_id);
> irqreturn_t sdw_cdns_thread(int irq, void *dev_id);
>
> -int sdw_cdns_init(struct sdw_cdns *cdns);
> +int sdw_cdns_init(struct sdw_cdns *cdns, bool clock_stop_exit);
> int sdw_cdns_pdi_init(struct sdw_cdns *cdns,
> struct sdw_cdns_stream_config config);
> int sdw_cdns_exit_reset(struct sdw_cdns *cdns);
> diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
> index 1192d5775484..db7bf2912767 100644
> --- a/drivers/soundwire/intel.c
> +++ b/drivers/soundwire/intel.c
> @@ -1043,7 +1043,7 @@ static int intel_init(struct sdw_intel *sdw)
> intel_link_power_up(sdw);
> intel_shim_init(sdw);
>
> - return sdw_cdns_init(&sdw->cdns);
> + return sdw_cdns_init(&sdw->cdns, false);

This is the only caller of this function so far, so, it looks like
the second argument ATM is always "false." I assume you foresee other
uses with "true" in the future, otherwise maybe just fix it to false
in the function?

Thanks
Guennadi

> }
>
> /*
> --
> 2.20.1
>
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