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82 lines
2.0 KiB
82 lines
2.0 KiB
// 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 <[email protected]> |
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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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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 <[email protected]>"); |
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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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