ice: wait before enabling TSPLL

JIRA: https://issues.redhat.com/browse/RHEL-104246

Upstream commit(s):
commit df3f3c5
Author: Karol Kolacinski <karol.kolacinski@intel.com>
Date:   Mon Jun 23 17:30:01 2025 -0700

    ice: wait before enabling TSPLL

    To ensure proper operation, wait for 10 to 20 microseconds before
    enabling TSPLL.

    Adjust wait time after enabling TSPLL from 1-5 ms to 1-2 ms.

    Those values are empirical and tested on multiple HW configurations.

    Reviewed-by: Milena Olech <milena.olech@intel.com>
    Signed-off-by: Karol Kolacinski <karol.kolacinski@intel.com>
    Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Signed-off-by: Petr Oros <poros@redhat.com>

Author: orosp

drivers/net/ethernet/intel/ice/ice_tspll.c

@@ -261,15 +261,18 @@ static int ice_tspll_cfg_e82x(struct ice_hw *hw, enum ice_tspll_freq clk_freq,
 	if (err)
 		return err;
 
+	/* Wait to ensure everything is stable */
+	usleep_range(10, 20);
+
 	/* Finally, enable the PLL */
 	r24 |= ICE_CGU_R23_R24_TSPLL_ENABLE;
 
 	err = ice_write_cgu_reg(hw, ICE_CGU_R24, r24);
 	if (err)
 		return err;
 
-	/* Wait to verify if the PLL locks */
-	usleep_range(1000, 5000);
+	/* Wait at least 1 ms to verify if the PLL locks */
+	usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
 
 	err = ice_read_cgu_reg(hw, ICE_CGU_RO_BWM_LF, &val);
 	if (err)
@@ -445,15 +448,18 @@ static int ice_tspll_cfg_e825c(struct ice_hw *hw, enum ice_tspll_freq clk_freq,
 	if (err)
 		return err;
 
+	/* Wait to ensure everything is stable */
+	usleep_range(10, 20);
+
 	/* Finally, enable the PLL */
 	r23 |= ICE_CGU_R23_R24_TSPLL_ENABLE;
 
 	err = ice_write_cgu_reg(hw, ICE_CGU_R23, r23);
 	if (err)
 		return err;
 
-	/* Wait to verify if the PLL locks */
-	usleep_range(1000, 5000);
+	/* Wait at least 1 ms to verify if the PLL locks */
+	usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
 
 	err = ice_read_cgu_reg(hw, ICE_CGU_RO_LOCK, &val);
 	if (err)