soundwire: intel: add support for MeteorLake additional clocks

In the MeteorLake hardware, the SoundWire link clock can be selected
from the Xtal, audio cardinal clock (24.576 MHz) or the 96 MHz audio
PLL.

This patches add the clock selection in a backwards-compatible manner,
using the ACPI firmware as the source of information and checking its
compatibility with hardware capabilities.

Signed-off-by: Pierre-Louis Bossart <[email protected]>
Reviewed-by: Rander Wang <[email protected]>
Signed-off-by: Bard Liao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: plbossart

drivers/soundwire/intel.c

@@ -345,8 +345,10 @@ static int intel_link_power_up(struct sdw_intel *sdw)
 	u32 spa_mask, cpa_mask;
 	u32 link_control;
 	int ret = 0;
+	u32 clock_source;
 	u32 syncprd;
 	u32 sync_reg;
+	bool lcap_mlcs;
 
 	mutex_lock(sdw->link_res->shim_lock);
 
@@ -358,12 +360,35 @@ static int intel_link_power_up(struct sdw_intel *sdw)
 	 * is only dependent on the oscillator clock provided to
 	 * the IP, so adjust based on _DSD properties reported in DSDT
 	 * tables. The values reported are based on either 24MHz
-	 * (CNL/CML) or 38.4 MHz (ICL/TGL+).
+	 * (CNL/CML) or 38.4 MHz (ICL/TGL+). On MeteorLake additional
+	 * frequencies are available with the MLCS clock source selection.
 	 */
-	if (prop->mclk_freq % 6000000)
-		syncprd = SDW_SHIM_SYNC_SYNCPRD_VAL_38_4;
-	else
-		syncprd = SDW_SHIM_SYNC_SYNCPRD_VAL_24;
+	lcap_mlcs = intel_readl(shim, SDW_SHIM_LCAP) & SDW_SHIM_LCAP_MLCS_MASK;
+
+	if (prop->mclk_freq % 6000000) {
+		if (prop->mclk_freq % 2400000) {
+			if (lcap_mlcs) {
+				syncprd = SDW_SHIM_SYNC_SYNCPRD_VAL_24_576;
+				clock_source = SDW_SHIM_MLCS_CARDINAL_CLK;
+			} else {
+				dev_err(sdw->cdns.dev, "%s: invalid clock configuration, mclk %d lcap_mlcs %d\n",
+					__func__, prop->mclk_freq, lcap_mlcs);
+				ret = -EINVAL;
+				goto out;
+			}
+		} else {
+			syncprd = SDW_SHIM_SYNC_SYNCPRD_VAL_38_4;
+			clock_source = SDW_SHIM_MLCS_XTAL_CLK;
+		}
+	} else {
+		if (lcap_mlcs) {
+			syncprd = SDW_SHIM_SYNC_SYNCPRD_VAL_96;
+			clock_source = SDW_SHIM_MLCS_AUDIO_PLL_CLK;
+		} else {
+			syncprd = SDW_SHIM_SYNC_SYNCPRD_VAL_24;
+			clock_source = SDW_SHIM_MLCS_XTAL_CLK;
+		}
+	}
 
 	if (!*shim_mask) {
 		dev_dbg(sdw->cdns.dev, "powering up all links\n");
@@ -403,6 +428,13 @@ static int intel_link_power_up(struct sdw_intel *sdw)
 				"Failed to set SHIM_SYNC: %d\n", ret);
 			goto out;
 		}
+
+		/* update link clock if needed */
+		if (lcap_mlcs) {
+			link_control = intel_readl(shim, SDW_SHIM_LCTL);
+			u32p_replace_bits(&link_control, clock_source, SDW_SHIM_LCTL_MLCS_MASK);
+			intel_writel(shim, SDW_SHIM_LCTL, link_control);
+		}
 	}
 
 	*shim_mask |= BIT(link_id);
@@ -1087,4 +1119,3 @@ const struct sdw_intel_hw_ops sdw_intel_cnl_hw_ops = {
 	.sync_check_cmdsync_unlocked = intel_check_cmdsync_unlocked,
 };
 EXPORT_SYMBOL_NS(sdw_intel_cnl_hw_ops, SOUNDWIRE_INTEL);
-

include/linux/soundwire/sdw_intel.h

@@ -22,6 +22,7 @@
 /* LCAP */
 #define SDW_SHIM_LCAP			0x0
 #define SDW_SHIM_LCAP_LCOUNT_MASK	GENMASK(2, 0)
+#define SDW_SHIM_LCAP_MLCS_MASK		BIT(8)
 
 /* LCTL */
 #define SDW_SHIM_LCTL			0x4
@@ -30,6 +31,10 @@
 #define SDW_SHIM_LCTL_SPA_MASK		GENMASK(3, 0)
 #define SDW_SHIM_LCTL_CPA		BIT(8)
 #define SDW_SHIM_LCTL_CPA_MASK		GENMASK(11, 8)
+#define SDW_SHIM_LCTL_MLCS_MASK		GENMASK(29, 27)
+#define SDW_SHIM_MLCS_XTAL_CLK		0x0
+#define SDW_SHIM_MLCS_CARDINAL_CLK	0x1
+#define SDW_SHIM_MLCS_AUDIO_PLL_CLK	0x2
 
 /* SYNC */
 #define SDW_SHIM_SYNC			0xC