diff mbox series

soundwire: intel: read AC timing control register before updating it

Message ID 20230515081301.12921-1-yung-chuan.liao@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series soundwire: intel: read AC timing control register before updating it | expand

Commit Message

Bard Liao May 15, 2023, 8:13 a.m. UTC 
From: Chao Song <chao.song@linux.intel.com>

Start from ACE1.x, DOAISE is added to AC timing control
register bit 5, it combines with DOAIS to get effective
timing, and has the default value 1.

The current code fills DOAIS, DACTQE and DODS bits to a
variable initialized to zero, and updates the variable
to AC timing control register. With this operation, We
change DOAISE to 0, and force a much more aggressive
timing. The timing is even unable to form a working
waveform on SDA pin on Meteorlake.

This patch uses read-modify-write operation for the AC
timing control register access, thus makes sure those
bits not supposed and intended to change are not touched.

Signed-off-by: Chao Song <chao.song@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
---
 drivers/soundwire/intel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Vinod Koul May 27, 2023, 10:38 a.m. UTC | #1 
On 15-05-23, 16:13, Bard Liao wrote:
> From: Chao Song <chao.song@linux.intel.com>
> 
> Start from ACE1.x, DOAISE is added to AC timing control
> register bit 5, it combines with DOAIS to get effective
> timing, and has the default value 1.
> 
> The current code fills DOAIS, DACTQE and DODS bits to a
> variable initialized to zero, and updates the variable
> to AC timing control register. With this operation, We
> change DOAISE to 0, and force a much more aggressive
> timing. The timing is even unable to form a working
> waveform on SDA pin on Meteorlake.
> 
> This patch uses read-modify-write operation for the AC
> timing control register access, thus makes sure those
> bits not supposed and intended to change are not touched.

Applied, thanks
diff mbox series

Patch

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 238acf5c97a9..8cd2c73ac66f 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -260,7 +260,7 @@  static void intel_shim_init(struct sdw_intel *sdw)
 {
 	void __iomem *shim = sdw->link_res->shim;
 	unsigned int link_id = sdw->instance;
-	u16 ioctl = 0, act = 0;
+	u16 ioctl = 0, act;
 
 	/* Initialize Shim */
 	ioctl |= SDW_SHIM_IOCTL_BKE;
@@ -281,6 +281,7 @@  static void intel_shim_init(struct sdw_intel *sdw)
 
 	intel_shim_glue_to_master_ip(sdw);
 
+	act = intel_readw(shim, SDW_SHIM_CTMCTL(link_id));
 	u16p_replace_bits(&act, 0x1, SDW_SHIM_CTMCTL_DOAIS);
 	act |= SDW_SHIM_CTMCTL_DACTQE;
 	act |= SDW_SHIM_CTMCTL_DODS;