From: Devarsh Thakkar devarsht@ti.com
[ Upstream commit 2c27aaee934a1b5229152fe33a14f1fdf50da143 ]
Do read-modify-write so that we re-use the characterized reset value as specified in TRM [1] to program calibration wait time which defines number of cycles to wait for after startup state machine is in bandgap enable state.
This fixes PLL lock timeout error faced while using RPi DSI Panel on TI's AM62L and J721E SoC since earlier calibration wait time was getting overwritten to zero value thus failing the PLL to lockup and causing timeout.
[1] AM62P TRM (Section 14.8.6.3.2.1.1 DPHY_TX_DPHYTX_CMN0_CMN_DIG_TBIT2): Link: https://www.ti.com/lit/pdf/spruj83
Cc: stable@vger.kernel.org Fixes: 7a343c8bf4b5 ("phy: Add Cadence D-PHY support") Signed-off-by: Devarsh Thakkar devarsht@ti.com Tested-by: Harikrishna Shenoy h-shenoy@ti.com Reviewed-by: Tomi Valkeinen tomi.valkeinen@ideasonboard.com Link: https://lore.kernel.org/r/20250704125915.1224738-3-devarsht@ti.com Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/phy/cadence/cdns-dphy.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c index a5d6d87003423..8d93a830ab8bf 100644 --- a/drivers/phy/cadence/cdns-dphy.c +++ b/drivers/phy/cadence/cdns-dphy.c @@ -30,6 +30,7 @@
#define DPHY_CMN_SSM DPHY_PMA_CMN(0x20) #define DPHY_CMN_SSM_EN BIT(0) +#define DPHY_CMN_SSM_CAL_WAIT_TIME GENMASK(8, 1) #define DPHY_CMN_TX_MODE_EN BIT(9)
#define DPHY_CMN_PWM DPHY_PMA_CMN(0x40) @@ -421,7 +422,8 @@ static int cdns_dphy_power_on(struct phy *phy) writel(reg, dphy->regs + DPHY_BAND_CFG);
/* Start TX state machine. */ - writel(DPHY_CMN_SSM_EN | DPHY_CMN_TX_MODE_EN, + reg = readl(dphy->regs + DPHY_CMN_SSM); + writel((reg & DPHY_CMN_SSM_CAL_WAIT_TIME) | DPHY_CMN_SSM_EN | DPHY_CMN_TX_MODE_EN, dphy->regs + DPHY_CMN_SSM);
ret = cdns_dphy_wait_for_pll_lock(dphy);