84 lines
2.0 KiB
C
84 lines
2.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Force-disables a regulator to power down a device
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*
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* Michael Klein <michael@fossekall.de>
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*
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* Copyright (C) 2020 Michael Klein
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*
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* Based on the gpio-poweroff driver.
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*/
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/pm.h>
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#include <linux/regulator/consumer.h>
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#define TIMEOUT_MS 3000
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/*
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* Hold configuration here, cannot be more than one instance of the driver
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* since pm_power_off itself is global.
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*/
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static struct regulator *cpu_regulator;
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static void regulator_poweroff_do_poweroff(void)
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{
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if (cpu_regulator && regulator_is_enabled(cpu_regulator))
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regulator_force_disable(cpu_regulator);
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/* give it some time */
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mdelay(TIMEOUT_MS);
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WARN_ON(1);
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}
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static int regulator_poweroff_probe(struct platform_device *pdev)
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{
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/* If a pm_power_off function has already been added, leave it alone */
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if (pm_power_off != NULL) {
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dev_err(&pdev->dev,
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"%s: pm_power_off function already registered\n",
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__func__);
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return -EBUSY;
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}
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cpu_regulator = devm_regulator_get(&pdev->dev, "cpu");
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if (IS_ERR(cpu_regulator))
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return PTR_ERR(cpu_regulator);
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pm_power_off = ®ulator_poweroff_do_poweroff;
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return 0;
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}
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static int regulator_poweroff_remove(__maybe_unused struct platform_device *pdev)
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{
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if (pm_power_off == ®ulator_poweroff_do_poweroff)
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pm_power_off = NULL;
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return 0;
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}
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static const struct of_device_id of_regulator_poweroff_match[] = {
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{ .compatible = "regulator-poweroff", },
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{},
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};
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MODULE_DEVICE_TABLE(of, of_regulator_poweroff_match);
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static struct platform_driver regulator_poweroff_driver = {
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.probe = regulator_poweroff_probe,
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.remove = regulator_poweroff_remove,
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.driver = {
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.name = "poweroff-regulator",
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.of_match_table = of_regulator_poweroff_match,
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},
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};
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module_platform_driver(regulator_poweroff_driver);
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MODULE_AUTHOR("Michael Klein <michael@fossekall.de>");
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MODULE_DESCRIPTION("Regulator poweroff driver");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:poweroff-regulator");
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