Merge remote-tracking branch 'regulator/topic/vctrl' into regulator-next
authorMark Brown <broonie@kernel.org>
Sun, 30 Apr 2017 13:17:44 +0000 (22:17 +0900)
committerMark Brown <broonie@kernel.org>
Sun, 30 Apr 2017 13:17:44 +0000 (22:17 +0900)
Documentation/devicetree/bindings/regulator/vctrl.txt [new file with mode: 0644]
drivers/regulator/Kconfig
drivers/regulator/Makefile
drivers/regulator/vctrl-regulator.c [new file with mode: 0644]

diff --git a/Documentation/devicetree/bindings/regulator/vctrl.txt b/Documentation/devicetree/bindings/regulator/vctrl.txt
new file mode 100644 (file)
index 0000000..601328d
--- /dev/null
@@ -0,0 +1,49 @@
+Bindings for Voltage controlled regulators
+==========================================
+
+Required properties:
+--------------------
+- compatible             : must be "vctrl-regulator".
+- regulator-min-microvolt : smallest voltage consumers may set
+- regulator-max-microvolt : largest voltage consumers may set
+- ctrl-supply            : The regulator supplying the control voltage.
+- ctrl-voltage-range     : an array of two integer values describing the range
+                           (min/max) of the control voltage. The values specify
+                           the control voltage needed to generate the corresponding
+                           regulator-min/max-microvolt output voltage.
+
+Optional properties:
+--------------------
+- ovp-threshold-percent        : overvoltage protection (OVP) threshold of the
+                         regulator in percent. Some regulators have an OVP
+                         circuitry which shuts down the regulator when the
+                         actual output voltage deviates beyond a certain
+                         margin from the expected value for a given control
+                         voltage. On larger voltage decreases this can occur
+                         undesiredly since the output voltage does not adjust
+                         inmediately to changes in the control voltage. To
+                         avoid this situation the vctrl driver breaks down
+                         larger voltage decreases into multiple steps, where
+                         each step is within the OVP threshold.
+- min-slew-down-rate   : Describes how slowly the regulator voltage will decay
+                         down in the worst case (lightest expected load).
+                         Specified in uV / us (like main regulator ramp rate).
+                         This value is required when ovp-threshold-percent is
+                         specified.
+
+Example:
+
+       vctrl-reg {
+               compatible = "vctrl-regulator";
+               regulator-name = "vctrl_reg";
+
+               ctrl-supply = <&ctrl_reg>;
+
+               regulator-min-microvolt = <800000>;
+               regulator-max-microvolt = <1500000>;
+
+               ctrl-voltage-range = <200000 500000>;
+
+               min-slew-down-rate = <225>;
+               ovp-threshold-percent = <16>;
+       };
index d54044c03a6cfbe91a968798d0c2e95d2e10a56e..48db87d6dfef4d0bc6f2037feeab7cf88c7949c5 100644 (file)
@@ -877,6 +877,13 @@ config REGULATOR_TWL4030
          This driver supports the voltage regulators provided by
          this family of companion chips.
 
+config REGULATOR_VCTRL
+       tristate "Voltage controlled regulators"
+       depends on OF
+       help
+         This driver provides support for voltage regulators whose output
+         voltage is controlled by the voltage of another regulator.
+
 config REGULATOR_VEXPRESS
        tristate "Versatile Express regulators"
        depends on VEXPRESS_CONFIG
index f30cb0e2d6fb4f236faf1699415e8cd3f179744a..dc3503fb3e30c0980acc4fe850302d0e91fd20a8 100644 (file)
@@ -109,6 +109,7 @@ obj-$(CONFIG_REGULATOR_TPS65912) += tps65912-regulator.o
 obj-$(CONFIG_REGULATOR_TPS80031) += tps80031-regulator.o
 obj-$(CONFIG_REGULATOR_TPS65132) += tps65132-regulator.o
 obj-$(CONFIG_REGULATOR_TWL4030) += twl-regulator.o twl6030-regulator.o
+obj-$(CONFIG_REGULATOR_VCTRL) += vctrl-regulator.o
 obj-$(CONFIG_REGULATOR_VEXPRESS) += vexpress-regulator.o
 obj-$(CONFIG_REGULATOR_WM831X) += wm831x-dcdc.o
 obj-$(CONFIG_REGULATOR_WM831X) += wm831x-isink.o
diff --git a/drivers/regulator/vctrl-regulator.c b/drivers/regulator/vctrl-regulator.c
new file mode 100644 (file)
index 0000000..78de002
--- /dev/null
@@ -0,0 +1,546 @@
+/*
+ * Driver for voltage controller regulators
+ *
+ * Copyright (C) 2017 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/sort.h>
+
+struct vctrl_voltage_range {
+       int min_uV;
+       int max_uV;
+};
+
+struct vctrl_voltage_ranges {
+       struct vctrl_voltage_range ctrl;
+       struct vctrl_voltage_range out;
+};
+
+struct vctrl_voltage_table {
+       int ctrl;
+       int out;
+       int ovp_min_sel;
+};
+
+struct vctrl_data {
+       struct regulator_dev *rdev;
+       struct regulator_desc desc;
+       struct regulator *ctrl_reg;
+       bool enabled;
+       unsigned int min_slew_down_rate;
+       unsigned int ovp_threshold;
+       struct vctrl_voltage_ranges vrange;
+       struct vctrl_voltage_table *vtable;
+       unsigned int sel;
+};
+
+static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV)
+{
+       struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
+       struct vctrl_voltage_range *out = &vctrl->vrange.out;
+
+       return ctrl->min_uV +
+               DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) *
+                                     (ctrl->max_uV - ctrl->min_uV),
+                                     out->max_uV - out->min_uV);
+}
+
+static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV)
+{
+       struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
+       struct vctrl_voltage_range *out = &vctrl->vrange.out;
+
+       if (ctrl_uV < 0) {
+               pr_err("vctrl: failed to get control voltage\n");
+               return ctrl_uV;
+       }
+
+       if (ctrl_uV < ctrl->min_uV)
+               return out->min_uV;
+
+       if (ctrl_uV > ctrl->max_uV)
+               return out->max_uV;
+
+       return out->min_uV +
+               DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) *
+                                     (out->max_uV - out->min_uV),
+                                     ctrl->max_uV - ctrl->min_uV);
+}
+
+static int vctrl_get_voltage(struct regulator_dev *rdev)
+{
+       struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+       int ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg);
+
+       return vctrl_calc_output_voltage(vctrl, ctrl_uV);
+}
+
+static int vctrl_set_voltage(struct regulator_dev *rdev,
+                            int req_min_uV, int req_max_uV,
+                            unsigned int *selector)
+{
+       struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+       struct regulator *ctrl_reg = vctrl->ctrl_reg;
+       int orig_ctrl_uV = regulator_get_voltage(ctrl_reg);
+       int uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV);
+       int ret;
+
+       if (req_min_uV >= uV || !vctrl->ovp_threshold)
+               /* voltage rising or no OVP */
+               return regulator_set_voltage(
+                       ctrl_reg,
+                       vctrl_calc_ctrl_voltage(vctrl, req_min_uV),
+                       vctrl_calc_ctrl_voltage(vctrl, req_max_uV));
+
+       while (uV > req_min_uV) {
+               int max_drop_uV = (uV * vctrl->ovp_threshold) / 100;
+               int next_uV;
+               int next_ctrl_uV;
+               int delay;
+
+               /* Make sure no infinite loop even in crazy cases */
+               if (max_drop_uV == 0)
+                       max_drop_uV = 1;
+
+               next_uV = max_t(int, req_min_uV, uV - max_drop_uV);
+               next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV);
+
+               ret = regulator_set_voltage(ctrl_reg,
+                                           next_ctrl_uV,
+                                           next_ctrl_uV);
+               if (ret)
+                       goto err;
+
+               delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate);
+               usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
+
+               uV = next_uV;
+       }
+
+       return 0;
+
+err:
+       /* Try to go back to original voltage */
+       regulator_set_voltage(ctrl_reg, orig_ctrl_uV, orig_ctrl_uV);
+
+       return ret;
+}
+
+static int vctrl_get_voltage_sel(struct regulator_dev *rdev)
+{
+       struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+
+       return vctrl->sel;
+}
+
+static int vctrl_set_voltage_sel(struct regulator_dev *rdev,
+                                unsigned int selector)
+{
+       struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+       struct regulator *ctrl_reg = vctrl->ctrl_reg;
+       unsigned int orig_sel = vctrl->sel;
+       int ret;
+
+       if (selector >= rdev->desc->n_voltages)
+               return -EINVAL;
+
+       if (selector >= vctrl->sel || !vctrl->ovp_threshold) {
+               /* voltage rising or no OVP */
+               ret = regulator_set_voltage(ctrl_reg,
+                                           vctrl->vtable[selector].ctrl,
+                                           vctrl->vtable[selector].ctrl);
+               if (!ret)
+                       vctrl->sel = selector;
+
+               return ret;
+       }
+
+       while (vctrl->sel != selector) {
+               unsigned int next_sel;
+               int delay;
+
+               if (selector >= vctrl->vtable[vctrl->sel].ovp_min_sel)
+                       next_sel = selector;
+               else
+                       next_sel = vctrl->vtable[vctrl->sel].ovp_min_sel;
+
+               ret = regulator_set_voltage(ctrl_reg,
+                                           vctrl->vtable[next_sel].ctrl,
+                                           vctrl->vtable[next_sel].ctrl);
+               if (ret) {
+                       dev_err(&rdev->dev,
+                               "failed to set control voltage to %duV\n",
+                               vctrl->vtable[next_sel].ctrl);
+                       goto err;
+               }
+               vctrl->sel = next_sel;
+
+               delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out -
+                                    vctrl->vtable[next_sel].out,
+                                    vctrl->min_slew_down_rate);
+               usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
+       }
+
+       return 0;
+
+err:
+       if (vctrl->sel != orig_sel) {
+               /* Try to go back to original voltage */
+               if (!regulator_set_voltage(ctrl_reg,
+                                          vctrl->vtable[orig_sel].ctrl,
+                                          vctrl->vtable[orig_sel].ctrl))
+                       vctrl->sel = orig_sel;
+               else
+                       dev_warn(&rdev->dev,
+                                "failed to restore original voltage\n");
+       }
+
+       return ret;
+}
+
+static int vctrl_list_voltage(struct regulator_dev *rdev,
+                             unsigned int selector)
+{
+       struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+
+       if (selector >= rdev->desc->n_voltages)
+               return -EINVAL;
+
+       return vctrl->vtable[selector].out;
+}
+
+static int vctrl_parse_dt(struct platform_device *pdev,
+                         struct vctrl_data *vctrl)
+{
+       int ret;
+       struct device_node *np = pdev->dev.of_node;
+       u32 pval;
+       u32 vrange_ctrl[2];
+
+       vctrl->ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl");
+       if (IS_ERR(vctrl->ctrl_reg))
+               return PTR_ERR(vctrl->ctrl_reg);
+
+       ret = of_property_read_u32(np, "ovp-threshold-percent", &pval);
+       if (!ret) {
+               vctrl->ovp_threshold = pval;
+               if (vctrl->ovp_threshold > 100) {
+                       dev_err(&pdev->dev,
+                               "ovp-threshold-percent (%u) > 100\n",
+                               vctrl->ovp_threshold);
+                       return -EINVAL;
+               }
+       }
+
+       ret = of_property_read_u32(np, "min-slew-down-rate", &pval);
+       if (!ret) {
+               vctrl->min_slew_down_rate = pval;
+
+               /* We use the value as int and as divider; sanity check */
+               if (vctrl->min_slew_down_rate == 0) {
+                       dev_err(&pdev->dev,
+                               "min-slew-down-rate must not be 0\n");
+                       return -EINVAL;
+               } else if (vctrl->min_slew_down_rate > INT_MAX) {
+                       dev_err(&pdev->dev, "min-slew-down-rate (%u) too big\n",
+                               vctrl->min_slew_down_rate);
+                       return -EINVAL;
+               }
+       }
+
+       if (vctrl->ovp_threshold && !vctrl->min_slew_down_rate) {
+               dev_err(&pdev->dev,
+                       "ovp-threshold-percent requires min-slew-down-rate\n");
+               return -EINVAL;
+       }
+
+       ret = of_property_read_u32(np, "regulator-min-microvolt", &pval);
+       if (ret) {
+               dev_err(&pdev->dev,
+                       "failed to read regulator-min-microvolt: %d\n", ret);
+               return ret;
+       }
+       vctrl->vrange.out.min_uV = pval;
+
+       ret = of_property_read_u32(np, "regulator-max-microvolt", &pval);
+       if (ret) {
+               dev_err(&pdev->dev,
+                       "failed to read regulator-max-microvolt: %d\n", ret);
+               return ret;
+       }
+       vctrl->vrange.out.max_uV = pval;
+
+       ret = of_property_read_u32_array(np, "ctrl-voltage-range", vrange_ctrl,
+                                        2);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to read ctrl-voltage-range: %d\n",
+                       ret);
+               return ret;
+       }
+
+       if (vrange_ctrl[0] >= vrange_ctrl[1]) {
+               dev_err(&pdev->dev, "ctrl-voltage-range is invalid: %d-%d\n",
+                       vrange_ctrl[0], vrange_ctrl[1]);
+               return -EINVAL;
+       }
+
+       vctrl->vrange.ctrl.min_uV = vrange_ctrl[0];
+       vctrl->vrange.ctrl.max_uV = vrange_ctrl[1];
+
+       return 0;
+}
+
+static int vctrl_cmp_ctrl_uV(const void *a, const void *b)
+{
+       const struct vctrl_voltage_table *at = a;
+       const struct vctrl_voltage_table *bt = b;
+
+       return at->ctrl - bt->ctrl;
+}
+
+static int vctrl_init_vtable(struct platform_device *pdev)
+{
+       struct vctrl_data *vctrl = platform_get_drvdata(pdev);
+       struct regulator_desc *rdesc = &vctrl->desc;
+       struct regulator *ctrl_reg = vctrl->ctrl_reg;
+       struct vctrl_voltage_range *vrange_ctrl = &vctrl->vrange.ctrl;
+       int n_voltages;
+       int ctrl_uV;
+       int i, idx_vt;
+
+       n_voltages = regulator_count_voltages(ctrl_reg);
+
+       rdesc->n_voltages = n_voltages;
+
+       /* determine number of steps within the range of the vctrl regulator */
+       for (i = 0; i < n_voltages; i++) {
+               ctrl_uV = regulator_list_voltage(ctrl_reg, i);
+
+               if (ctrl_uV < vrange_ctrl->min_uV ||
+                   ctrl_uV > vrange_ctrl->max_uV) {
+                       rdesc->n_voltages--;
+                       continue;
+               }
+       }
+
+       if (rdesc->n_voltages == 0) {
+               dev_err(&pdev->dev, "invalid configuration\n");
+               return -EINVAL;
+       }
+
+       vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages,
+                                    sizeof(struct vctrl_voltage_table),
+                                    GFP_KERNEL);
+       if (!vctrl->vtable)
+               return -ENOMEM;
+
+       /* create mapping control <=> output voltage */
+       for (i = 0, idx_vt = 0; i < n_voltages; i++) {
+               ctrl_uV = regulator_list_voltage(ctrl_reg, i);
+
+               if (ctrl_uV < vrange_ctrl->min_uV ||
+                   ctrl_uV > vrange_ctrl->max_uV)
+                       continue;
+
+               vctrl->vtable[idx_vt].ctrl = ctrl_uV;
+               vctrl->vtable[idx_vt].out =
+                       vctrl_calc_output_voltage(vctrl, ctrl_uV);
+               idx_vt++;
+       }
+
+       /* we rely on the table to be ordered by ascending voltage */
+       sort(vctrl->vtable, rdesc->n_voltages,
+            sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV,
+            NULL);
+
+       /* pre-calculate OVP-safe downward transitions */
+       for (i = rdesc->n_voltages - 1; i > 0; i--) {
+               int j;
+               int ovp_min_uV = (vctrl->vtable[i].out *
+                                 (100 - vctrl->ovp_threshold)) / 100;
+
+               for (j = 0; j < i; j++) {
+                       if (vctrl->vtable[j].out >= ovp_min_uV) {
+                               vctrl->vtable[i].ovp_min_sel = j;
+                               break;
+                       }
+               }
+
+               if (j == i) {
+                       dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n",
+                               vctrl->vtable[i].out);
+                       /* use next lowest voltage */
+                       vctrl->vtable[i].ovp_min_sel = i - 1;
+               }
+       }
+
+       return 0;
+}
+
+static int vctrl_enable(struct regulator_dev *rdev)
+{
+       struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+       int ret = regulator_enable(vctrl->ctrl_reg);
+
+       if (!ret)
+               vctrl->enabled = true;
+
+       return ret;
+}
+
+static int vctrl_disable(struct regulator_dev *rdev)
+{
+       struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+       int ret = regulator_disable(vctrl->ctrl_reg);
+
+       if (!ret)
+               vctrl->enabled = false;
+
+       return ret;
+}
+
+static int vctrl_is_enabled(struct regulator_dev *rdev)
+{
+       struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+
+       return vctrl->enabled;
+}
+
+static const struct regulator_ops vctrl_ops_cont = {
+       .enable           = vctrl_enable,
+       .disable          = vctrl_disable,
+       .is_enabled       = vctrl_is_enabled,
+       .get_voltage      = vctrl_get_voltage,
+       .set_voltage      = vctrl_set_voltage,
+};
+
+static const struct regulator_ops vctrl_ops_non_cont = {
+       .enable           = vctrl_enable,
+       .disable          = vctrl_disable,
+       .is_enabled       = vctrl_is_enabled,
+       .set_voltage_sel = vctrl_set_voltage_sel,
+       .get_voltage_sel = vctrl_get_voltage_sel,
+       .list_voltage    = vctrl_list_voltage,
+       .map_voltage     = regulator_map_voltage_iterate,
+};
+
+static int vctrl_probe(struct platform_device *pdev)
+{
+       struct device_node *np = pdev->dev.of_node;
+       struct vctrl_data *vctrl;
+       const struct regulator_init_data *init_data;
+       struct regulator_desc *rdesc;
+       struct regulator_config cfg = { };
+       struct vctrl_voltage_range *vrange_ctrl;
+       int ctrl_uV;
+       int ret;
+
+       vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data),
+                            GFP_KERNEL);
+       if (!vctrl)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, vctrl);
+
+       ret = vctrl_parse_dt(pdev, vctrl);
+       if (ret)
+               return ret;
+
+       vrange_ctrl = &vctrl->vrange.ctrl;
+
+       rdesc = &vctrl->desc;
+       rdesc->name = "vctrl";
+       rdesc->type = REGULATOR_VOLTAGE;
+       rdesc->owner = THIS_MODULE;
+
+       if ((regulator_get_linear_step(vctrl->ctrl_reg) == 1) ||
+           (regulator_count_voltages(vctrl->ctrl_reg) == -EINVAL)) {
+               rdesc->continuous_voltage_range = true;
+               rdesc->ops = &vctrl_ops_cont;
+       } else {
+               rdesc->ops = &vctrl_ops_non_cont;
+       }
+
+       init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc);
+       if (!init_data)
+               return -ENOMEM;
+
+       cfg.of_node = np;
+       cfg.dev = &pdev->dev;
+       cfg.driver_data = vctrl;
+       cfg.init_data = init_data;
+
+       if (!rdesc->continuous_voltage_range) {
+               ret = vctrl_init_vtable(pdev);
+               if (ret)
+                       return ret;
+
+               ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg);
+               if (ctrl_uV < 0) {
+                       dev_err(&pdev->dev, "failed to get control voltage\n");
+                       return ctrl_uV;
+               }
+
+               /* determine current voltage selector from control voltage */
+               if (ctrl_uV < vrange_ctrl->min_uV) {
+                       vctrl->sel = 0;
+               } else if (ctrl_uV > vrange_ctrl->max_uV) {
+                       vctrl->sel = rdesc->n_voltages - 1;
+               } else {
+                       int i;
+
+                       for (i = 0; i < rdesc->n_voltages; i++) {
+                               if (ctrl_uV == vctrl->vtable[i].ctrl) {
+                                       vctrl->sel = i;
+                                       break;
+                               }
+                       }
+               }
+       }
+
+       vctrl->rdev = devm_regulator_register(&pdev->dev, rdesc, &cfg);
+       if (IS_ERR(vctrl->rdev)) {
+               ret = PTR_ERR(vctrl->rdev);
+               dev_err(&pdev->dev, "failed to register regulator: %d\n", ret);
+               return ret;
+       }
+
+       return 0;
+}
+
+static const struct of_device_id vctrl_of_match[] = {
+       { .compatible = "vctrl-regulator", },
+       {},
+};
+MODULE_DEVICE_TABLE(of, vctrl_of_match);
+
+static struct platform_driver vctrl_driver = {
+       .probe          = vctrl_probe,
+       .driver         = {
+               .name           = "vctrl-regulator",
+               .of_match_table = of_match_ptr(vctrl_of_match),
+       },
+};
+
+module_platform_driver(vctrl_driver);
+
+MODULE_DESCRIPTION("Voltage Controlled Regulator Driver");
+MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
+MODULE_LICENSE("GPL v2");