[alsa-devel] [PATCH 12/17] soundwire: cadence_master: make use of mclk_freq property

[Pierre-Louis Bossart]

Now that the prototype and Intel implementation are enabled, use this
property to avoid hard-coded values.

For example for ICL the mclk_freq value is 38.4 MHz while on CNL/CML
it's 24 MHz. The mclk_freq should not be confused with the
max_clk_freq, which si the maximum bus clock. The mclk_freq is
typically tied to the oscillator frequency and does not change between
platforms. The max_clk_freq value is linked to the maximum bandwidth
needed and topology/trace length.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 89c55e4bb72c..049ecfad2c00 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -175,8 +175,6 @@
 #define CDNS_PDI_CONFIG_PORT			GENMASK(4, 0)
 
 /* Driver defaults */
-
-#define CDNS_DEFAULT_CLK_DIVIDER		0
 #define CDNS_DEFAULT_SSP_INTERVAL		0x18
 #define CDNS_TX_TIMEOUT				2000
 
@@ -922,7 +920,10 @@ static u32 cdns_set_initial_frame_shape(int n_rows, int n_cols)
  */
 int sdw_cdns_init(struct sdw_cdns *cdns)
 {
+	struct sdw_bus *bus = &cdns->bus;
+	struct sdw_master_prop *prop = &bus->prop;
 	u32 val;
+	int divider;
 	int ret;
 
 	/* Exit clock stop */
@@ -934,9 +935,11 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
 	}
 
 	/* Set clock divider */
+	divider	= (prop->mclk_freq / prop->max_clk_freq) - 1;
 	val = cdns_readl(cdns, CDNS_MCP_CLK_CTRL0);
-	val |= CDNS_DEFAULT_CLK_DIVIDER;
+	val |= divider;
 	cdns_writel(cdns, CDNS_MCP_CLK_CTRL0, val);
+	cdns_writel(cdns, CDNS_MCP_CLK_CTRL1, val);
 
 	/*
 	 * Frame shape changes after initialization have to be done
@@ -984,6 +987,7 @@ EXPORT_SYMBOL(sdw_cdns_init);
 
 int cdns_bus_conf(struct sdw_bus *bus, struct sdw_bus_params *params)
 {
+	struct sdw_master_prop *prop = &bus->prop;
 	struct sdw_cdns *cdns = bus_to_cdns(bus);
 	int mcp_clkctrl_off, mcp_clkctrl;
 	int divider;
@@ -993,7 +997,9 @@ int cdns_bus_conf(struct sdw_bus *bus, struct sdw_bus_params *params)
 		return -EINVAL;
 	}
 
-	divider	= (params->max_dr_freq / params->curr_dr_freq) - 1;
+	divider	= prop->mclk_freq * SDW_DOUBLE_RATE_FACTOR /
+		params->curr_dr_freq;
+	divider--; /* divider is 1/(N+1) */
 
 	if (params->next_bank)
 		mcp_clkctrl_off = CDNS_MCP_CLK_CTRL1;
-- 
2.20.1