linux-kernel - [PATCH] soundwire: intel: fix factor of two in MCLK handling

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Date:   Mon, 13 Jan 2020 17:11:29 -0600
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     alsa-devel@...a-project.org
Cc:     linux-kernel@...r.kernel.org, tiwai@...e.de, broonie@...nel.org,
        vkoul@...nel.org, gregkh@...uxfoundation.org, jank@...ence.com,
        srinivas.kandagatla@...aro.org, slawomir.blauciak@...el.com,
        Bard liao <yung-chuan.liao@...ux.intel.com>,
        Rander Wang <rander.wang@...ux.intel.com>,
        Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Sanyog Kale <sanyog.r.kale@...el.com>
Subject: [PATCH] soundwire: intel: fix factor of two in MCLK handling

From: Bard Liao <yung-chuan.liao@...ux.intel.com>

Somehow Intel folks were confused, the property is 2x what the mclk
frequency actually is (checked the actual bus frequency with a scope)

Signed-off-by: Bard Liao <yung-chuan.liao@...ux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
---
 drivers/soundwire/intel.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 0371d3d5501a..06ef3a3ac080 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -880,6 +880,9 @@ 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;
+
 	fwnode_property_read_u32(link,
 				 "intel-quirk-mask",
 				 &quirk_mask);
-- 
2.20.1