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Message-ID: <20240806083840.24094-1-yung-chuan.liao@linux.intel.com>
Date: Tue, 6 Aug 2024 16:38:40 +0800
From: Bard Liao <yung-chuan.liao@...ux.intel.com>
To: linux-sound@...r.kernel.org,
vkoul@...nel.org
Cc: vinod.koul@...aro.org,
linux-kernel@...r.kernel.org,
pierre-louis.bossart@...ux.intel.com,
bard.liao@...el.com
Subject: [PATCH] soundwire: intel_auxdevice: add kernel parameter for mclk divider
From: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Add a kernel parameter to work-around discrepancies between hardware
and platform firmware, it's not unusual to see e.g. 38.4MHz listed in
_DSD properties as the SoundWire clock source, but the hardware may be
based on a 19.2 MHz mclk source.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@...ux.intel.com>
---
drivers/soundwire/intel_auxdevice.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/soundwire/intel_auxdevice.c b/drivers/soundwire/intel_auxdevice.c
index dff49c5ce5b3..e372195b07b3 100644
--- a/drivers/soundwire/intel_auxdevice.c
+++ b/drivers/soundwire/intel_auxdevice.c
@@ -41,6 +41,10 @@ static int md_flags;
module_param_named(sdw_md_flags, md_flags, int, 0444);
MODULE_PARM_DESC(sdw_md_flags, "SoundWire Intel Master device flags (0x0 all off)");
+static int mclk_divider;
+module_param_named(sdw_mclk_divider, mclk_divider, int, 0444);
+MODULE_PARM_DESC(sdw_mclk_divider, "SoundWire Intel mclk divider");
+
struct wake_capable_part {
const u16 mfg_id;
const u16 part_id;
@@ -142,8 +146,12 @@ static int sdw_master_read_intel_prop(struct sdw_bus *bus)
"intel-sdw-ip-clock",
&prop->mclk_freq);
- /* the values reported by BIOS are the 2x clock, not the bus clock */
- prop->mclk_freq /= 2;
+ if (mclk_divider)
+ /* use kernel parameter for BIOS or board work-arounds */
+ prop->mclk_freq /= mclk_divider;
+ else
+ /* the values reported by BIOS are the 2x clock, not the bus clock */
+ prop->mclk_freq /= 2;
fwnode_property_read_u32(link,
"intel-quirk-mask",
--
2.43.0
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