+ /* constrain machine-level voltage specs to fit
+ * the actual range supported by this regulator.
+ */
+ if (ops->list_voltage && rdev->desc->n_voltages) {
+ int count = rdev->desc->n_voltages;
+ int i;
+ int min_uV = INT_MAX;
+ int max_uV = INT_MIN;
+ int cmin = constraints->min_uV;
+ int cmax = constraints->max_uV;
+
+ /* it's safe to autoconfigure fixed-voltage supplies */
+ if (count == 1 && !cmin) {
+ cmin = INT_MIN;
+ cmax = INT_MAX;
+ }
+
+ /* else require explicit machine-level constraints */
+ else if (cmin <= 0 || cmax <= 0 || cmax < cmin) {
+ pr_err("%s: %s '%s' voltage constraints\n",
+ __func__, "invalid", name);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* initial: [cmin..cmax] valid, [min_uV..max_uV] not */
+ for (i = 0; i < count; i++) {
+ int value;
+
+ value = ops->list_voltage(rdev, i);
+ if (value <= 0)
+ continue;
+
+ /* maybe adjust [min_uV..max_uV] */
+ if (value >= cmin && value < min_uV)
+ min_uV = value;
+ if (value <= cmax && value > max_uV)
+ max_uV = value;
+ }
+
+ /* final: [min_uV..max_uV] valid iff constraints valid */
+ if (max_uV < min_uV) {
+ pr_err("%s: %s '%s' voltage constraints\n",
+ __func__, "unsupportable", name);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* use regulator's subset of machine constraints */
+ if (constraints->min_uV < min_uV) {
+ pr_debug("%s: override '%s' %s, %d -> %d\n",
+ __func__, name, "min_uV",
+ constraints->min_uV, min_uV);
+ constraints->min_uV = min_uV;
+ }
+ if (constraints->max_uV > max_uV) {
+ pr_debug("%s: override '%s' %s, %d -> %d\n",
+ __func__, name, "max_uV",
+ constraints->max_uV, max_uV);
+ constraints->max_uV = max_uV;
+ }
+ }
+