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557 lines
13 KiB
557 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Driver for voltage controller regulators |
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* |
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* Copyright (C) 2017 Google, Inc. |
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*/ |
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#include <linux/delay.h> |
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#include <linux/err.h> |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/of_device.h> |
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#include <linux/regulator/coupler.h> |
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#include <linux/regulator/driver.h> |
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#include <linux/regulator/of_regulator.h> |
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#include <linux/sort.h> |
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#include "internal.h" |
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struct vctrl_voltage_range { |
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int min_uV; |
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int max_uV; |
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}; |
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struct vctrl_voltage_ranges { |
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struct vctrl_voltage_range ctrl; |
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struct vctrl_voltage_range out; |
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}; |
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struct vctrl_voltage_table { |
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int ctrl; |
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int out; |
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int ovp_min_sel; |
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}; |
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struct vctrl_data { |
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struct regulator_dev *rdev; |
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struct regulator_desc desc; |
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bool enabled; |
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unsigned int min_slew_down_rate; |
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unsigned int ovp_threshold; |
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struct vctrl_voltage_ranges vrange; |
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struct vctrl_voltage_table *vtable; |
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unsigned int sel; |
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}; |
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static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV) |
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{ |
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struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl; |
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struct vctrl_voltage_range *out = &vctrl->vrange.out; |
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return ctrl->min_uV + |
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DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) * |
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(ctrl->max_uV - ctrl->min_uV), |
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out->max_uV - out->min_uV); |
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} |
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static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV) |
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{ |
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struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl; |
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struct vctrl_voltage_range *out = &vctrl->vrange.out; |
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if (ctrl_uV < 0) { |
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pr_err("vctrl: failed to get control voltage\n"); |
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return ctrl_uV; |
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} |
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if (ctrl_uV < ctrl->min_uV) |
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return out->min_uV; |
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if (ctrl_uV > ctrl->max_uV) |
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return out->max_uV; |
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return out->min_uV + |
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DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) * |
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(out->max_uV - out->min_uV), |
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ctrl->max_uV - ctrl->min_uV); |
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} |
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static int vctrl_get_voltage(struct regulator_dev *rdev) |
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{ |
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
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int ctrl_uV; |
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if (!rdev->supply) |
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return -EPROBE_DEFER; |
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ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev); |
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return vctrl_calc_output_voltage(vctrl, ctrl_uV); |
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} |
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static int vctrl_set_voltage(struct regulator_dev *rdev, |
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int req_min_uV, int req_max_uV, |
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unsigned int *selector) |
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{ |
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
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int orig_ctrl_uV; |
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int uV; |
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int ret; |
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if (!rdev->supply) |
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return -EPROBE_DEFER; |
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orig_ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev); |
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uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV); |
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if (req_min_uV >= uV || !vctrl->ovp_threshold) |
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/* voltage rising or no OVP */ |
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return regulator_set_voltage_rdev(rdev->supply->rdev, |
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vctrl_calc_ctrl_voltage(vctrl, req_min_uV), |
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vctrl_calc_ctrl_voltage(vctrl, req_max_uV), |
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PM_SUSPEND_ON); |
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while (uV > req_min_uV) { |
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int max_drop_uV = (uV * vctrl->ovp_threshold) / 100; |
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int next_uV; |
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int next_ctrl_uV; |
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int delay; |
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/* Make sure no infinite loop even in crazy cases */ |
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if (max_drop_uV == 0) |
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max_drop_uV = 1; |
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next_uV = max_t(int, req_min_uV, uV - max_drop_uV); |
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next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV); |
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ret = regulator_set_voltage_rdev(rdev->supply->rdev, |
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next_ctrl_uV, |
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next_ctrl_uV, |
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PM_SUSPEND_ON); |
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if (ret) |
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goto err; |
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delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate); |
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usleep_range(delay, delay + DIV_ROUND_UP(delay, 10)); |
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uV = next_uV; |
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} |
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return 0; |
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err: |
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/* Try to go back to original voltage */ |
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regulator_set_voltage_rdev(rdev->supply->rdev, orig_ctrl_uV, orig_ctrl_uV, |
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PM_SUSPEND_ON); |
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return ret; |
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} |
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static int vctrl_get_voltage_sel(struct regulator_dev *rdev) |
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{ |
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
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return vctrl->sel; |
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} |
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static int vctrl_set_voltage_sel(struct regulator_dev *rdev, |
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unsigned int selector) |
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{ |
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
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unsigned int orig_sel = vctrl->sel; |
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int ret; |
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if (!rdev->supply) |
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return -EPROBE_DEFER; |
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if (selector >= rdev->desc->n_voltages) |
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return -EINVAL; |
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if (selector >= vctrl->sel || !vctrl->ovp_threshold) { |
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/* voltage rising or no OVP */ |
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ret = regulator_set_voltage_rdev(rdev->supply->rdev, |
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vctrl->vtable[selector].ctrl, |
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vctrl->vtable[selector].ctrl, |
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PM_SUSPEND_ON); |
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if (!ret) |
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vctrl->sel = selector; |
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return ret; |
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} |
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while (vctrl->sel != selector) { |
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unsigned int next_sel; |
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int delay; |
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if (selector >= vctrl->vtable[vctrl->sel].ovp_min_sel) |
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next_sel = selector; |
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else |
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next_sel = vctrl->vtable[vctrl->sel].ovp_min_sel; |
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ret = regulator_set_voltage_rdev(rdev->supply->rdev, |
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vctrl->vtable[next_sel].ctrl, |
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vctrl->vtable[next_sel].ctrl, |
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PM_SUSPEND_ON); |
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if (ret) { |
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dev_err(&rdev->dev, |
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"failed to set control voltage to %duV\n", |
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vctrl->vtable[next_sel].ctrl); |
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goto err; |
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} |
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vctrl->sel = next_sel; |
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delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out - |
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vctrl->vtable[next_sel].out, |
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vctrl->min_slew_down_rate); |
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usleep_range(delay, delay + DIV_ROUND_UP(delay, 10)); |
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} |
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return 0; |
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err: |
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if (vctrl->sel != orig_sel) { |
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/* Try to go back to original voltage */ |
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if (!regulator_set_voltage_rdev(rdev->supply->rdev, |
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vctrl->vtable[orig_sel].ctrl, |
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vctrl->vtable[orig_sel].ctrl, |
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PM_SUSPEND_ON)) |
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vctrl->sel = orig_sel; |
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else |
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dev_warn(&rdev->dev, |
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"failed to restore original voltage\n"); |
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} |
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return ret; |
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} |
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static int vctrl_list_voltage(struct regulator_dev *rdev, |
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unsigned int selector) |
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{ |
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
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if (selector >= rdev->desc->n_voltages) |
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return -EINVAL; |
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return vctrl->vtable[selector].out; |
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} |
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static int vctrl_parse_dt(struct platform_device *pdev, |
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struct vctrl_data *vctrl) |
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{ |
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int ret; |
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struct device_node *np = pdev->dev.of_node; |
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u32 pval; |
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u32 vrange_ctrl[2]; |
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ret = of_property_read_u32(np, "ovp-threshold-percent", &pval); |
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if (!ret) { |
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vctrl->ovp_threshold = pval; |
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if (vctrl->ovp_threshold > 100) { |
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dev_err(&pdev->dev, |
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"ovp-threshold-percent (%u) > 100\n", |
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vctrl->ovp_threshold); |
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return -EINVAL; |
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} |
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} |
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ret = of_property_read_u32(np, "min-slew-down-rate", &pval); |
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if (!ret) { |
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vctrl->min_slew_down_rate = pval; |
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/* We use the value as int and as divider; sanity check */ |
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if (vctrl->min_slew_down_rate == 0) { |
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dev_err(&pdev->dev, |
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"min-slew-down-rate must not be 0\n"); |
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return -EINVAL; |
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} else if (vctrl->min_slew_down_rate > INT_MAX) { |
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dev_err(&pdev->dev, "min-slew-down-rate (%u) too big\n", |
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vctrl->min_slew_down_rate); |
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return -EINVAL; |
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} |
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} |
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if (vctrl->ovp_threshold && !vctrl->min_slew_down_rate) { |
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dev_err(&pdev->dev, |
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"ovp-threshold-percent requires min-slew-down-rate\n"); |
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return -EINVAL; |
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} |
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ret = of_property_read_u32(np, "regulator-min-microvolt", &pval); |
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if (ret) { |
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dev_err(&pdev->dev, |
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"failed to read regulator-min-microvolt: %d\n", ret); |
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return ret; |
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} |
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vctrl->vrange.out.min_uV = pval; |
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ret = of_property_read_u32(np, "regulator-max-microvolt", &pval); |
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if (ret) { |
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dev_err(&pdev->dev, |
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"failed to read regulator-max-microvolt: %d\n", ret); |
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return ret; |
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} |
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vctrl->vrange.out.max_uV = pval; |
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ret = of_property_read_u32_array(np, "ctrl-voltage-range", vrange_ctrl, |
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2); |
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if (ret) { |
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dev_err(&pdev->dev, "failed to read ctrl-voltage-range: %d\n", |
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ret); |
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return ret; |
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} |
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if (vrange_ctrl[0] >= vrange_ctrl[1]) { |
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dev_err(&pdev->dev, "ctrl-voltage-range is invalid: %d-%d\n", |
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vrange_ctrl[0], vrange_ctrl[1]); |
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return -EINVAL; |
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} |
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vctrl->vrange.ctrl.min_uV = vrange_ctrl[0]; |
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vctrl->vrange.ctrl.max_uV = vrange_ctrl[1]; |
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return 0; |
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} |
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static int vctrl_cmp_ctrl_uV(const void *a, const void *b) |
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{ |
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const struct vctrl_voltage_table *at = a; |
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const struct vctrl_voltage_table *bt = b; |
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return at->ctrl - bt->ctrl; |
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} |
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static int vctrl_init_vtable(struct platform_device *pdev, |
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struct regulator *ctrl_reg) |
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{ |
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struct vctrl_data *vctrl = platform_get_drvdata(pdev); |
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struct regulator_desc *rdesc = &vctrl->desc; |
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struct vctrl_voltage_range *vrange_ctrl = &vctrl->vrange.ctrl; |
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int n_voltages; |
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int ctrl_uV; |
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int i, idx_vt; |
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n_voltages = regulator_count_voltages(ctrl_reg); |
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rdesc->n_voltages = n_voltages; |
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/* determine number of steps within the range of the vctrl regulator */ |
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for (i = 0; i < n_voltages; i++) { |
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ctrl_uV = regulator_list_voltage(ctrl_reg, i); |
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if (ctrl_uV < vrange_ctrl->min_uV || |
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ctrl_uV > vrange_ctrl->max_uV) |
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rdesc->n_voltages--; |
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} |
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if (rdesc->n_voltages == 0) { |
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dev_err(&pdev->dev, "invalid configuration\n"); |
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return -EINVAL; |
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} |
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vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages, |
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sizeof(struct vctrl_voltage_table), |
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GFP_KERNEL); |
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if (!vctrl->vtable) |
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return -ENOMEM; |
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/* create mapping control <=> output voltage */ |
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for (i = 0, idx_vt = 0; i < n_voltages; i++) { |
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ctrl_uV = regulator_list_voltage(ctrl_reg, i); |
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if (ctrl_uV < vrange_ctrl->min_uV || |
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ctrl_uV > vrange_ctrl->max_uV) |
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continue; |
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vctrl->vtable[idx_vt].ctrl = ctrl_uV; |
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vctrl->vtable[idx_vt].out = |
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vctrl_calc_output_voltage(vctrl, ctrl_uV); |
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idx_vt++; |
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} |
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/* we rely on the table to be ordered by ascending voltage */ |
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sort(vctrl->vtable, rdesc->n_voltages, |
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sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV, |
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NULL); |
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/* pre-calculate OVP-safe downward transitions */ |
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for (i = rdesc->n_voltages - 1; i > 0; i--) { |
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int j; |
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int ovp_min_uV = (vctrl->vtable[i].out * |
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(100 - vctrl->ovp_threshold)) / 100; |
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for (j = 0; j < i; j++) { |
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if (vctrl->vtable[j].out >= ovp_min_uV) { |
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vctrl->vtable[i].ovp_min_sel = j; |
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break; |
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} |
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} |
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if (j == i) { |
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dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n", |
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vctrl->vtable[i].out); |
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/* use next lowest voltage */ |
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vctrl->vtable[i].ovp_min_sel = i - 1; |
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} |
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} |
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return 0; |
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} |
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static int vctrl_enable(struct regulator_dev *rdev) |
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{ |
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
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vctrl->enabled = true; |
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return 0; |
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} |
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static int vctrl_disable(struct regulator_dev *rdev) |
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{ |
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
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vctrl->enabled = false; |
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return 0; |
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} |
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static int vctrl_is_enabled(struct regulator_dev *rdev) |
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{ |
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
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return vctrl->enabled; |
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} |
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static const struct regulator_ops vctrl_ops_cont = { |
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.enable = vctrl_enable, |
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.disable = vctrl_disable, |
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.is_enabled = vctrl_is_enabled, |
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.get_voltage = vctrl_get_voltage, |
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.set_voltage = vctrl_set_voltage, |
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}; |
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static const struct regulator_ops vctrl_ops_non_cont = { |
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.enable = vctrl_enable, |
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.disable = vctrl_disable, |
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.is_enabled = vctrl_is_enabled, |
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.set_voltage_sel = vctrl_set_voltage_sel, |
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.get_voltage_sel = vctrl_get_voltage_sel, |
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.list_voltage = vctrl_list_voltage, |
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.map_voltage = regulator_map_voltage_iterate, |
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}; |
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static int vctrl_probe(struct platform_device *pdev) |
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{ |
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struct device_node *np = pdev->dev.of_node; |
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struct vctrl_data *vctrl; |
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const struct regulator_init_data *init_data; |
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struct regulator_desc *rdesc; |
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struct regulator_config cfg = { }; |
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struct vctrl_voltage_range *vrange_ctrl; |
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struct regulator *ctrl_reg; |
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int ctrl_uV; |
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int ret; |
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vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data), |
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GFP_KERNEL); |
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if (!vctrl) |
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return -ENOMEM; |
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platform_set_drvdata(pdev, vctrl); |
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ret = vctrl_parse_dt(pdev, vctrl); |
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if (ret) |
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return ret; |
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ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl"); |
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if (IS_ERR(ctrl_reg)) |
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return PTR_ERR(ctrl_reg); |
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vrange_ctrl = &vctrl->vrange.ctrl; |
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rdesc = &vctrl->desc; |
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rdesc->name = "vctrl"; |
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rdesc->type = REGULATOR_VOLTAGE; |
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rdesc->owner = THIS_MODULE; |
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rdesc->supply_name = "ctrl"; |
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if ((regulator_get_linear_step(ctrl_reg) == 1) || |
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(regulator_count_voltages(ctrl_reg) == -EINVAL)) { |
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rdesc->continuous_voltage_range = true; |
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rdesc->ops = &vctrl_ops_cont; |
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} else { |
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rdesc->ops = &vctrl_ops_non_cont; |
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} |
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init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc); |
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if (!init_data) |
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return -ENOMEM; |
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cfg.of_node = np; |
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cfg.dev = &pdev->dev; |
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cfg.driver_data = vctrl; |
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cfg.init_data = init_data; |
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if (!rdesc->continuous_voltage_range) { |
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ret = vctrl_init_vtable(pdev, ctrl_reg); |
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if (ret) |
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return ret; |
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/* Use locked consumer API when not in regulator framework */ |
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ctrl_uV = regulator_get_voltage(ctrl_reg); |
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if (ctrl_uV < 0) { |
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dev_err(&pdev->dev, "failed to get control voltage\n"); |
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return ctrl_uV; |
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} |
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/* determine current voltage selector from control voltage */ |
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if (ctrl_uV < vrange_ctrl->min_uV) { |
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vctrl->sel = 0; |
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} else if (ctrl_uV > vrange_ctrl->max_uV) { |
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vctrl->sel = rdesc->n_voltages - 1; |
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} else { |
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int i; |
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for (i = 0; i < rdesc->n_voltages; i++) { |
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if (ctrl_uV == vctrl->vtable[i].ctrl) { |
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vctrl->sel = i; |
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break; |
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} |
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} |
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} |
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} |
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/* Drop ctrl-supply here in favor of regulator core managed supply */ |
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devm_regulator_put(ctrl_reg); |
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vctrl->rdev = devm_regulator_register(&pdev->dev, rdesc, &cfg); |
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if (IS_ERR(vctrl->rdev)) { |
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ret = PTR_ERR(vctrl->rdev); |
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dev_err(&pdev->dev, "failed to register regulator: %d\n", ret); |
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return ret; |
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} |
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return 0; |
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} |
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static const struct of_device_id vctrl_of_match[] = { |
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{ .compatible = "vctrl-regulator", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, vctrl_of_match); |
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static struct platform_driver vctrl_driver = { |
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.probe = vctrl_probe, |
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.driver = { |
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.name = "vctrl-regulator", |
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.of_match_table = of_match_ptr(vctrl_of_match), |
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}, |
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}; |
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module_platform_driver(vctrl_driver); |
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MODULE_DESCRIPTION("Voltage Controlled Regulator Driver"); |
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MODULE_AUTHOR("Matthias Kaehlcke <[email protected]>"); |
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MODULE_LICENSE("GPL v2");
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