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Commit ff7ec0d1 authored by David Collins's avatar David Collins
Browse files

regulator: cpr3-regulator: ensure monotonicity of CPR floor voltages 



Modify the cpr3-regulator driver so that it guarantees that CPR
floor voltages increase monotonically from lower to higher
corners.  This is necessary to ensure stable operation when the
vdd-supply voltage drops to the floor voltage of a corner after
all CPR sensors of a given CPR hardware thread are bypassed
during HMSS cluster power collapse.

Change-Id: Ib24836552cef95418b8fa3468e92b8a5bb18d592
Signed-off-by: default avatarDavid Collins <collinsd@codeaurora.org>
parent 50e0173f

drivers/regulator/cpr3-util.c

+29 −3
Original line number Diff line number Diff line
@@ -823,7 +823,8 @@ void cpr3_open_loop_voltage_as_ceiling(struct cpr3_regulator *vreg) 
 * @combo_offset:	The array offset for the selected fuse combo

 *

 * This function also ensures that the open-loop voltage for each corner falls

 * within the final floor to ceiling voltage range.

 * within the final floor to ceiling voltage range and that floor voltages

 * increase monotonically.

 *

 * Return: 0 on success, errno on failure

 */
@@ -831,11 +832,12 @@ int cpr3_limit_floor_voltages(struct cpr3_regulator *vreg, int corner_sum, 
				int combo_offset)

{

	char *prop = "qcom,cpr-floor-to-ceiling-max-range";

	int i, rc, floor_new;

	int i, floor_new;

	u32 *floor_range;

	int rc = 0;



	if (!of_find_property(vreg->of_node, prop, NULL))

		return 0;

		goto enforce_monotonicity;



	floor_range = kcalloc(vreg->corner_count, sizeof(*floor_range),

				GFP_KERNEL);
@@ -864,6 +866,30 @@ int cpr3_limit_floor_voltages(struct cpr3_regulator *vreg, int corner_sum, 


free_floor_adjust:

	kfree(floor_range);



enforce_monotonicity:

	/* Ensure that floor voltages increase monotonically. */

	for (i = 1; i < vreg->corner_count; i++) {

		if (vreg->corner[i].floor_volt

		    < vreg->corner[i - 1].floor_volt) {

			cpr3_debug(vreg, "corner %d floor voltage=%d uV < corner %d voltage=%d uV; overriding: corner %d voltage=%d\n",

				i, vreg->corner[i].floor_volt,

				i - 1, vreg->corner[i - 1].floor_volt,

				i, vreg->corner[i - 1].floor_volt);

			vreg->corner[i].floor_volt

				= vreg->corner[i - 1].floor_volt;



			if (vreg->corner[i].open_loop_volt

			    < vreg->corner[i].floor_volt)

				vreg->corner[i].open_loop_volt

					= vreg->corner[i].floor_volt;

			if (vreg->corner[i].ceiling_volt

			    < vreg->corner[i].floor_volt)

				vreg->corner[i].ceiling_volt

					= vreg->corner[i].floor_volt;

		}

	}



	return rc;

}