linux-kernel - [PATCH 4.19 056/106] soundwire: intel: fix channel number reported by hardware

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Message-Id: <20191006171147.789863879@linuxfoundation.org>
Date:   Sun,  6 Oct 2019 19:21:02 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Vinod Koul <vkoul@...nel.org>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 056/106] soundwire: intel: fix channel number reported by hardware

From: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>

[ Upstream commit 18046335643de6d21327f5ae034c8fb8463f6715 ]

On all released Intel controllers (CNL/CML/ICL), PDI2 reports an
invalid count, force the correct hardware-supported value

This may have to be revisited with platform-specific values if the
hardware changes, but for now this is good enough.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Link: https://lore.kernel.org/r/20190806005522.22642-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/soundwire/intel.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index a6e2581ada703..29bc99c4a7b66 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -282,6 +282,16 @@ intel_pdi_get_ch_cap(struct sdw_intel *sdw, unsigned int pdi_num, bool pcm)
 
 	if (pcm) {
 		count = intel_readw(shim, SDW_SHIM_PCMSYCHC(link_id, pdi_num));
+
+		/*
+		 * WORKAROUND: on all existing Intel controllers, pdi
+		 * number 2 reports channel count as 1 even though it
+		 * supports 8 channels. Performing hardcoding for pdi
+		 * number 2.
+		 */
+		if (pdi_num == 2)
+			count = 7;
+
 	} else {
 		count = intel_readw(shim, SDW_SHIM_PDMSCAP(link_id));
 		count = ((count & SDW_SHIM_PDMSCAP_CPSS) >>
-- 
2.20.1