[PATCH 03/16] soundwire: cadence: add interface to check clock status

[Pierre-Louis Bossart]

From: Rander Wang <rander.wang@xxxxxxxxx>

If master is in clock stop state, driver can't modify registers
in master except the registers for clock stop setting.

Signed-off-by: Rander Wang <rander.wang@xxxxxxxxx>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
 drivers/soundwire/cadence_master.c | 19 +++++++++++++++++++
 drivers/soundwire/cadence_master.h |  2 ++
 2 files changed, 21 insertions(+)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 941809ea00a8..71cba2585151 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1207,6 +1207,25 @@ static const struct sdw_master_port_ops cdns_port_ops = {
 	.dpn_port_enable_ch = cdns_port_enable,
 };
 
+/**
+ * sdw_cdns_is_clock_stop: Check clock status
+ *
+ * @cdns: Cadence instance
+ */
+bool sdw_cdns_is_clock_stop(struct sdw_cdns *cdns)
+{
+	u32 status;
+
+	status = cdns_readl(cdns, CDNS_MCP_STAT) & CDNS_MCP_STAT_CLK_STOP;
+	if (status) {
+		dev_dbg(cdns->dev, "Clock is stopped\n");
+		return true;
+	}
+
+	return false;
+}
+EXPORT_SYMBOL(sdw_cdns_is_clock_stop);
+
 /**
  * sdw_cdns_probe() - Cadence probe routine
  * @cdns: Cadence instance
diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h
index 44e802bba702..691faa386889 100644
--- a/drivers/soundwire/cadence_master.h
+++ b/drivers/soundwire/cadence_master.h
@@ -144,6 +144,8 @@ int sdw_cdns_pdi_init(struct sdw_cdns *cdns,
 int sdw_cdns_exit_reset(struct sdw_cdns *cdns);
 int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns, bool state);
 
+bool sdw_cdns_is_clock_stop(struct sdw_cdns *cdns);
+
 #ifdef CONFIG_DEBUG_FS
 void sdw_cdns_debugfs_init(struct sdw_cdns *cdns, struct dentry *root);
 #endif
-- 
2.20.1