Patch "phy: zynqmp: Enable reference clock correctly" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    phy: zynqmp: Enable reference clock correctly

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     phy-zynqmp-enable-reference-clock-correctly.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit e5a343101afe6415959ca40866ac8944d24ae90a
Author: Sean Anderson <sean.anderson@xxxxxxxxx>
Date:   Fri Jun 28 16:55:36 2024 -0400

    phy: zynqmp: Enable reference clock correctly
    
    [ Upstream commit 687d6bccb28238fcfa65f7c1badfdfeac498c428 ]
    
    Lanes can use other lanes' reference clocks, as determined by refclk.
    Use refclk to determine the clock to enable/disable instead of always
    using the lane's own reference clock. This ensures the clock selected in
    xpsgtr_configure_pll is the one enabled.
    
    For the other half of the equation, always program REF_CLK_SEL even when
    we are selecting the lane's own clock. This ensures that Linux's idea of
    the reference clock matches the hardware. We use the "local" clock mux
    for this instead of going through the ref clock network.
    
    Fixes: 25d700833513 ("phy: xilinx: phy-zynqmp: dynamic clock support for power-save")
    Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxxx>
    Link: https://lore.kernel.org/r/20240628205540.3098010-2-sean.anderson@xxxxxxxxx
    Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/phy/xilinx/phy-zynqmp.c b/drivers/phy/xilinx/phy-zynqmp.c
index 2559c6594cea2..0cb5088e460b5 100644
--- a/drivers/phy/xilinx/phy-zynqmp.c
+++ b/drivers/phy/xilinx/phy-zynqmp.c
@@ -80,7 +80,8 @@
 
 /* Reference clock selection parameters */
 #define L0_Ln_REF_CLK_SEL(n)		(0x2860 + (n) * 4)
-#define L0_REF_CLK_SEL_MASK		0x8f
+#define L0_REF_CLK_LCL_SEL		BIT(7)
+#define L0_REF_CLK_SEL_MASK		0x9f
 
 /* Calibration digital logic parameters */
 #define L3_TM_CALIB_DIG19		0xec4c
@@ -349,11 +350,12 @@ static void xpsgtr_configure_pll(struct xpsgtr_phy *gtr_phy)
 		       PLL_FREQ_MASK, ssc->pll_ref_clk);
 
 	/* Enable lane clock sharing, if required */
-	if (gtr_phy->refclk != gtr_phy->lane) {
-		/* Lane3 Ref Clock Selection Register */
+	if (gtr_phy->refclk == gtr_phy->lane)
+		xpsgtr_clr_set(gtr_phy->dev, L0_Ln_REF_CLK_SEL(gtr_phy->lane),
+			       L0_REF_CLK_SEL_MASK, L0_REF_CLK_LCL_SEL);
+	else
 		xpsgtr_clr_set(gtr_phy->dev, L0_Ln_REF_CLK_SEL(gtr_phy->lane),
 			       L0_REF_CLK_SEL_MASK, 1 << gtr_phy->refclk);
-	}
 
 	/* SSC step size [7:0] */
 	xpsgtr_clr_set_phy(gtr_phy, L0_PLL_SS_STEP_SIZE_0_LSB,
@@ -573,7 +575,7 @@ static int xpsgtr_phy_init(struct phy *phy)
 	mutex_lock(&gtr_dev->gtr_mutex);
 
 	/* Configure and enable the clock when peripheral phy_init call */
-	if (clk_prepare_enable(gtr_dev->clk[gtr_phy->lane]))
+	if (clk_prepare_enable(gtr_dev->clk[gtr_phy->refclk]))
 		goto out;
 
 	/* Skip initialization if not required. */
@@ -625,7 +627,7 @@ static int xpsgtr_phy_exit(struct phy *phy)
 	gtr_phy->skip_phy_init = false;
 
 	/* Ensure that disable clock only, which configure for lane */
-	clk_disable_unprepare(gtr_dev->clk[gtr_phy->lane]);
+	clk_disable_unprepare(gtr_dev->clk[gtr_phy->refclk]);
 
 	return 0;
 }