561 lines
14 KiB
C
561 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Voltage regulators coupler for NVIDIA Tegra20
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* Copyright (C) 2019 GRATE-DRIVER project
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*
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* Voltage constraints borrowed from downstream kernel sources
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* Copyright (C) 2010-2011 NVIDIA Corporation
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*/
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#define pr_fmt(fmt) "tegra voltage-coupler: " fmt
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/of.h>
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#include <linux/reboot.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/machine.h>
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#include <linux/suspend.h>
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#include <soc/tegra/fuse.h>
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#include <soc/tegra/pmc.h>
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struct tegra_regulator_coupler {
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struct regulator_coupler coupler;
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struct regulator_dev *core_rdev;
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struct regulator_dev *cpu_rdev;
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struct regulator_dev *rtc_rdev;
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struct notifier_block reboot_notifier;
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struct notifier_block suspend_notifier;
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int core_min_uV, cpu_min_uV;
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bool sys_reboot_mode_req;
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bool sys_reboot_mode;
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bool sys_suspend_mode_req;
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bool sys_suspend_mode;
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};
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static inline struct tegra_regulator_coupler *
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to_tegra_coupler(struct regulator_coupler *coupler)
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{
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return container_of(coupler, struct tegra_regulator_coupler, coupler);
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}
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static int tegra20_core_limit(struct tegra_regulator_coupler *tegra,
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struct regulator_dev *core_rdev)
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{
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int core_min_uV = 0;
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int core_max_uV;
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int core_cur_uV;
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int err;
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/*
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* Tegra20 SoC has critical DVFS-capable devices that are
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* permanently-active or active at a boot time, like EMC
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* (DRAM controller) or Display controller for example.
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*
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* The voltage of a CORE SoC power domain shall not be dropped below
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* a minimum level, which is determined by device's clock rate.
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* This means that we can't fully allow CORE voltage scaling until
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* the state of all DVFS-critical CORE devices is synced.
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*/
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if (tegra_pmc_core_domain_state_synced() && !tegra->sys_reboot_mode) {
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pr_info_once("voltage state synced\n");
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return 0;
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}
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if (tegra->core_min_uV > 0)
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return tegra->core_min_uV;
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core_cur_uV = regulator_get_voltage_rdev(core_rdev);
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if (core_cur_uV < 0)
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return core_cur_uV;
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core_max_uV = max(core_cur_uV, 1200000);
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err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
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if (err)
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return err;
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/*
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* Limit minimum CORE voltage to a value left from bootloader or,
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* if it's unreasonably low value, to the most common 1.2v or to
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* whatever maximum value defined via board's device-tree.
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*/
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tegra->core_min_uV = core_max_uV;
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pr_info("core voltage initialized to %duV\n", tegra->core_min_uV);
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return tegra->core_min_uV;
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}
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static int tegra20_core_rtc_max_spread(struct regulator_dev *core_rdev,
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struct regulator_dev *rtc_rdev)
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{
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struct coupling_desc *c_desc = &core_rdev->coupling_desc;
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struct regulator_dev *rdev;
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int max_spread;
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unsigned int i;
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for (i = 1; i < c_desc->n_coupled; i++) {
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max_spread = core_rdev->constraints->max_spread[i - 1];
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rdev = c_desc->coupled_rdevs[i];
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if (rdev == rtc_rdev && max_spread)
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return max_spread;
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}
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pr_err_once("rtc-core max-spread is undefined in device-tree\n");
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return 150000;
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}
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static int tegra20_cpu_nominal_uV(void)
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{
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switch (tegra_sku_info.soc_speedo_id) {
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case 0:
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return 1100000;
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case 1:
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return 1025000;
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default:
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return 1125000;
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}
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}
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static int tegra20_core_nominal_uV(void)
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{
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switch (tegra_sku_info.soc_speedo_id) {
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default:
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return 1225000;
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case 2:
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return 1300000;
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}
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}
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static int tegra20_core_rtc_update(struct tegra_regulator_coupler *tegra,
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struct regulator_dev *core_rdev,
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struct regulator_dev *rtc_rdev,
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int cpu_uV, int cpu_min_uV)
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{
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int core_min_uV, core_max_uV = INT_MAX;
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int rtc_min_uV, rtc_max_uV = INT_MAX;
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int core_target_uV;
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int rtc_target_uV;
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int max_spread;
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int core_uV;
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int rtc_uV;
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int err;
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/*
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* RTC and CORE voltages should be no more than 170mV from each other,
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* CPU should be below RTC and CORE by at least 120mV. This applies
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* to all Tegra20 SoC's.
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*/
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max_spread = tegra20_core_rtc_max_spread(core_rdev, rtc_rdev);
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/*
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* The core voltage scaling is currently not hooked up in drivers,
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* hence we will limit the minimum core voltage to a reasonable value.
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* This should be good enough for the time being.
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*/
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core_min_uV = tegra20_core_limit(tegra, core_rdev);
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if (core_min_uV < 0)
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return core_min_uV;
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err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
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if (err)
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return err;
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err = regulator_check_consumers(core_rdev, &core_min_uV, &core_max_uV,
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PM_SUSPEND_ON);
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if (err)
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return err;
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/* prepare voltage level for suspend */
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if (tegra->sys_suspend_mode)
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core_min_uV = clamp(tegra20_core_nominal_uV(),
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core_min_uV, core_max_uV);
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core_uV = regulator_get_voltage_rdev(core_rdev);
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if (core_uV < 0)
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return core_uV;
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core_min_uV = max(cpu_min_uV + 125000, core_min_uV);
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if (core_min_uV > core_max_uV)
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return -EINVAL;
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if (cpu_uV + 120000 > core_uV)
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pr_err("core-cpu voltage constraint violated: %d %d\n",
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core_uV, cpu_uV + 120000);
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rtc_uV = regulator_get_voltage_rdev(rtc_rdev);
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if (rtc_uV < 0)
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return rtc_uV;
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if (cpu_uV + 120000 > rtc_uV)
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pr_err("rtc-cpu voltage constraint violated: %d %d\n",
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rtc_uV, cpu_uV + 120000);
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if (abs(core_uV - rtc_uV) > 170000)
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pr_err("core-rtc voltage constraint violated: %d %d\n",
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core_uV, rtc_uV);
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rtc_min_uV = max(cpu_min_uV + 125000, core_min_uV - max_spread);
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err = regulator_check_voltage(rtc_rdev, &rtc_min_uV, &rtc_max_uV);
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if (err)
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return err;
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while (core_uV != core_min_uV || rtc_uV != rtc_min_uV) {
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if (core_uV < core_min_uV) {
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core_target_uV = min(core_uV + max_spread, core_min_uV);
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core_target_uV = min(rtc_uV + max_spread, core_target_uV);
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} else {
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core_target_uV = max(core_uV - max_spread, core_min_uV);
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core_target_uV = max(rtc_uV - max_spread, core_target_uV);
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}
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if (core_uV == core_target_uV)
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goto update_rtc;
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err = regulator_set_voltage_rdev(core_rdev,
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core_target_uV,
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core_max_uV,
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PM_SUSPEND_ON);
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if (err)
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return err;
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core_uV = core_target_uV;
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update_rtc:
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if (rtc_uV < rtc_min_uV) {
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rtc_target_uV = min(rtc_uV + max_spread, rtc_min_uV);
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rtc_target_uV = min(core_uV + max_spread, rtc_target_uV);
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} else {
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rtc_target_uV = max(rtc_uV - max_spread, rtc_min_uV);
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rtc_target_uV = max(core_uV - max_spread, rtc_target_uV);
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}
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if (rtc_uV == rtc_target_uV)
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continue;
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err = regulator_set_voltage_rdev(rtc_rdev,
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rtc_target_uV,
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rtc_max_uV,
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PM_SUSPEND_ON);
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if (err)
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return err;
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rtc_uV = rtc_target_uV;
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}
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return 0;
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}
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static int tegra20_core_voltage_update(struct tegra_regulator_coupler *tegra,
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struct regulator_dev *cpu_rdev,
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struct regulator_dev *core_rdev,
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struct regulator_dev *rtc_rdev)
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{
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int cpu_uV;
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cpu_uV = regulator_get_voltage_rdev(cpu_rdev);
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if (cpu_uV < 0)
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return cpu_uV;
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return tegra20_core_rtc_update(tegra, core_rdev, rtc_rdev,
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cpu_uV, cpu_uV);
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}
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static int tegra20_cpu_voltage_update(struct tegra_regulator_coupler *tegra,
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struct regulator_dev *cpu_rdev,
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struct regulator_dev *core_rdev,
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struct regulator_dev *rtc_rdev)
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{
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int cpu_min_uV_consumers = 0;
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int cpu_max_uV = INT_MAX;
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int cpu_min_uV = 0;
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int cpu_uV;
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int err;
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err = regulator_check_voltage(cpu_rdev, &cpu_min_uV, &cpu_max_uV);
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if (err)
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return err;
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err = regulator_check_consumers(cpu_rdev, &cpu_min_uV, &cpu_max_uV,
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PM_SUSPEND_ON);
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if (err)
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return err;
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err = regulator_check_consumers(cpu_rdev, &cpu_min_uV_consumers,
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&cpu_max_uV, PM_SUSPEND_ON);
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if (err)
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return err;
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cpu_uV = regulator_get_voltage_rdev(cpu_rdev);
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if (cpu_uV < 0)
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return cpu_uV;
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/* store boot voltage level */
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if (!tegra->cpu_min_uV)
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tegra->cpu_min_uV = cpu_uV;
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/*
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* CPU's regulator may not have any consumers, hence the voltage
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* must not be changed in that case because CPU simply won't
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* survive the voltage drop if it's running on a higher frequency.
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*/
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if (!cpu_min_uV_consumers)
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cpu_min_uV = cpu_uV;
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/* restore boot voltage level */
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if (tegra->sys_reboot_mode)
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cpu_min_uV = max(cpu_min_uV, tegra->cpu_min_uV);
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/* prepare voltage level for suspend */
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if (tegra->sys_suspend_mode)
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cpu_min_uV = clamp(tegra20_cpu_nominal_uV(),
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cpu_min_uV, cpu_max_uV);
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if (cpu_min_uV > cpu_uV) {
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err = tegra20_core_rtc_update(tegra, core_rdev, rtc_rdev,
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cpu_uV, cpu_min_uV);
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if (err)
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return err;
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err = regulator_set_voltage_rdev(cpu_rdev, cpu_min_uV,
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cpu_max_uV, PM_SUSPEND_ON);
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if (err)
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return err;
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} else if (cpu_min_uV < cpu_uV) {
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err = regulator_set_voltage_rdev(cpu_rdev, cpu_min_uV,
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cpu_max_uV, PM_SUSPEND_ON);
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if (err)
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return err;
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err = tegra20_core_rtc_update(tegra, core_rdev, rtc_rdev,
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cpu_uV, cpu_min_uV);
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if (err)
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return err;
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}
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return 0;
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}
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static int tegra20_regulator_balance_voltage(struct regulator_coupler *coupler,
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struct regulator_dev *rdev,
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suspend_state_t state)
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{
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struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
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struct regulator_dev *core_rdev = tegra->core_rdev;
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struct regulator_dev *cpu_rdev = tegra->cpu_rdev;
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struct regulator_dev *rtc_rdev = tegra->rtc_rdev;
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if ((core_rdev != rdev && cpu_rdev != rdev && rtc_rdev != rdev) ||
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state != PM_SUSPEND_ON) {
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pr_err("regulators are not coupled properly\n");
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return -EINVAL;
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}
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tegra->sys_reboot_mode = READ_ONCE(tegra->sys_reboot_mode_req);
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tegra->sys_suspend_mode = READ_ONCE(tegra->sys_suspend_mode_req);
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if (rdev == cpu_rdev)
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return tegra20_cpu_voltage_update(tegra, cpu_rdev,
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core_rdev, rtc_rdev);
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if (rdev == core_rdev)
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return tegra20_core_voltage_update(tegra, cpu_rdev,
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core_rdev, rtc_rdev);
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pr_err("changing %s voltage not permitted\n", rdev_get_name(rtc_rdev));
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return -EPERM;
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}
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static int tegra20_regulator_prepare_suspend(struct tegra_regulator_coupler *tegra,
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bool sys_suspend_mode)
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{
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int err;
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if (!tegra->core_rdev || !tegra->rtc_rdev || !tegra->cpu_rdev)
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return 0;
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/*
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* All power domains are enabled early during resume from suspend
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* by GENPD core. Domains like VENC may require a higher voltage
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* when enabled during resume from suspend. This also prepares
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* hardware for resuming from LP0.
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*/
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WRITE_ONCE(tegra->sys_suspend_mode_req, sys_suspend_mode);
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err = regulator_sync_voltage_rdev(tegra->cpu_rdev);
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if (err)
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return err;
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err = regulator_sync_voltage_rdev(tegra->core_rdev);
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if (err)
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return err;
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return 0;
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}
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static int tegra20_regulator_suspend(struct notifier_block *notifier,
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unsigned long mode, void *arg)
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{
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struct tegra_regulator_coupler *tegra;
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int ret = 0;
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tegra = container_of(notifier, struct tegra_regulator_coupler,
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suspend_notifier);
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switch (mode) {
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case PM_HIBERNATION_PREPARE:
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case PM_RESTORE_PREPARE:
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case PM_SUSPEND_PREPARE:
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ret = tegra20_regulator_prepare_suspend(tegra, true);
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break;
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case PM_POST_HIBERNATION:
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case PM_POST_RESTORE:
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case PM_POST_SUSPEND:
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ret = tegra20_regulator_prepare_suspend(tegra, false);
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break;
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}
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if (ret)
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pr_err("failed to prepare regulators: %d\n", ret);
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return notifier_from_errno(ret);
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}
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static int tegra20_regulator_prepare_reboot(struct tegra_regulator_coupler *tegra,
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bool sys_reboot_mode)
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{
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int err;
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if (!tegra->core_rdev || !tegra->rtc_rdev || !tegra->cpu_rdev)
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return 0;
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WRITE_ONCE(tegra->sys_reboot_mode_req, true);
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/*
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* Some devices use CPU soft-reboot method and in this case we
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* should ensure that voltages are sane for the reboot by restoring
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* the minimum boot levels.
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*/
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err = regulator_sync_voltage_rdev(tegra->cpu_rdev);
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if (err)
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return err;
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err = regulator_sync_voltage_rdev(tegra->core_rdev);
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if (err)
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return err;
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WRITE_ONCE(tegra->sys_reboot_mode_req, sys_reboot_mode);
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return 0;
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}
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static int tegra20_regulator_reboot(struct notifier_block *notifier,
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unsigned long event, void *cmd)
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{
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struct tegra_regulator_coupler *tegra;
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int ret;
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if (event != SYS_RESTART)
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return NOTIFY_DONE;
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tegra = container_of(notifier, struct tegra_regulator_coupler,
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reboot_notifier);
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ret = tegra20_regulator_prepare_reboot(tegra, true);
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return notifier_from_errno(ret);
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}
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static int tegra20_regulator_attach(struct regulator_coupler *coupler,
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struct regulator_dev *rdev)
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{
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struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
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struct device_node *np = rdev->dev.of_node;
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if (of_property_read_bool(np, "nvidia,tegra-core-regulator") &&
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!tegra->core_rdev) {
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tegra->core_rdev = rdev;
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return 0;
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}
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if (of_property_read_bool(np, "nvidia,tegra-rtc-regulator") &&
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!tegra->rtc_rdev) {
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tegra->rtc_rdev = rdev;
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return 0;
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}
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if (of_property_read_bool(np, "nvidia,tegra-cpu-regulator") &&
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!tegra->cpu_rdev) {
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tegra->cpu_rdev = rdev;
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return 0;
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}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int tegra20_regulator_detach(struct regulator_coupler *coupler,
|
|
struct regulator_dev *rdev)
|
|
{
|
|
struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
|
|
|
|
/*
|
|
* We don't expect regulators to be decoupled during reboot,
|
|
* this may race with the reboot handler and shouldn't ever
|
|
* happen in practice.
|
|
*/
|
|
if (WARN_ON_ONCE(system_state > SYSTEM_RUNNING))
|
|
return -EPERM;
|
|
|
|
if (tegra->core_rdev == rdev) {
|
|
tegra->core_rdev = NULL;
|
|
return 0;
|
|
}
|
|
|
|
if (tegra->rtc_rdev == rdev) {
|
|
tegra->rtc_rdev = NULL;
|
|
return 0;
|
|
}
|
|
|
|
if (tegra->cpu_rdev == rdev) {
|
|
tegra->cpu_rdev = NULL;
|
|
return 0;
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static struct tegra_regulator_coupler tegra20_coupler = {
|
|
.coupler = {
|
|
.attach_regulator = tegra20_regulator_attach,
|
|
.detach_regulator = tegra20_regulator_detach,
|
|
.balance_voltage = tegra20_regulator_balance_voltage,
|
|
},
|
|
.reboot_notifier.notifier_call = tegra20_regulator_reboot,
|
|
.suspend_notifier.notifier_call = tegra20_regulator_suspend,
|
|
};
|
|
|
|
static int __init tegra_regulator_coupler_init(void)
|
|
{
|
|
int err;
|
|
|
|
if (!of_machine_is_compatible("nvidia,tegra20"))
|
|
return 0;
|
|
|
|
err = register_reboot_notifier(&tegra20_coupler.reboot_notifier);
|
|
WARN_ON(err);
|
|
|
|
err = register_pm_notifier(&tegra20_coupler.suspend_notifier);
|
|
WARN_ON(err);
|
|
|
|
return regulator_coupler_register(&tegra20_coupler.coupler);
|
|
}
|
|
arch_initcall(tegra_regulator_coupler_init);
|