mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
e3aa45f2f8
As the comment above the code setting the DPM_FLAG_NO_DIRECT_COMPLETE
flag explains:
/*
* On Cherry Trail devices the GFX0._PS0 AML checks if the controller
* is on and if it is not on it turns it on and restores what it
* believes is the correct state to the PWM controller.
* Because of this we must disallow direct-complete, which keeps the
* controller (runtime)suspended, on resume to avoid 2 issues:
* 1. The controller getting turned on without the linux-pm code
* knowing about this. On devices where the controller is unused
* this causes it to stay on during the next suspend causing high
* battery drain (because S0i3 is not reached)
* 2. The state restoring code unexpectedly messing with the controller
*/
The pm-core must not skip resume to avoid the GFX0._PS0 AML code messing
with the PWM controller behind our back. But leaving the controller
runtime-suspended (skipping runtime-resume + normal-suspend) during
suspend is fine. Set the DPM_FLAG_SMART_SUSPEND flag to allow this.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
115 lines
3.2 KiB
C
115 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Intel Low Power Subsystem PWM controller driver
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*
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* Copyright (C) 2014, Intel Corporation
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*
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* Derived from the original pwm-lpss.c
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*/
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#include <linux/acpi.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/pm_runtime.h>
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#include "pwm-lpss.h"
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/* BayTrail */
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static const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
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.clk_rate = 25000000,
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.npwm = 1,
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.base_unit_bits = 16,
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};
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/* Braswell */
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static const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
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.clk_rate = 19200000,
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.npwm = 1,
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.base_unit_bits = 16,
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.other_devices_aml_touches_pwm_regs = true,
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};
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/* Broxton */
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static const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
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.clk_rate = 19200000,
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.npwm = 4,
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.base_unit_bits = 22,
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.bypass = true,
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};
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static int pwm_lpss_probe_platform(struct platform_device *pdev)
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{
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const struct pwm_lpss_boardinfo *info;
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const struct acpi_device_id *id;
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struct pwm_lpss_chip *lpwm;
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struct resource *r;
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id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
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if (!id)
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return -ENODEV;
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info = (const struct pwm_lpss_boardinfo *)id->driver_data;
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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lpwm = pwm_lpss_probe(&pdev->dev, r, info);
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if (IS_ERR(lpwm))
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return PTR_ERR(lpwm);
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platform_set_drvdata(pdev, lpwm);
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/*
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* On Cherry Trail devices the GFX0._PS0 AML checks if the controller
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* is on and if it is not on it turns it on and restores what it
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* believes is the correct state to the PWM controller.
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* Because of this we must disallow direct-complete, which keeps the
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* controller (runtime)suspended on resume, to avoid 2 issues:
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* 1. The controller getting turned on without the linux-pm code
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* knowing about this. On devices where the controller is unused
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* this causes it to stay on during the next suspend causing high
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* battery drain (because S0i3 is not reached)
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* 2. The state restoring code unexpectedly messing with the controller
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*
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* Leaving the controller runtime-suspended (skipping runtime-resume +
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* normal-suspend) during suspend is fine.
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*/
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if (info->other_devices_aml_touches_pwm_regs)
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dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE|
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DPM_FLAG_SMART_SUSPEND);
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pm_runtime_set_active(&pdev->dev);
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pm_runtime_enable(&pdev->dev);
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return 0;
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}
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static int pwm_lpss_remove_platform(struct platform_device *pdev)
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{
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struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev);
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pm_runtime_disable(&pdev->dev);
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return pwm_lpss_remove(lpwm);
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}
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static const struct acpi_device_id pwm_lpss_acpi_match[] = {
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{ "80860F09", (unsigned long)&pwm_lpss_byt_info },
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{ "80862288", (unsigned long)&pwm_lpss_bsw_info },
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{ "80862289", (unsigned long)&pwm_lpss_bsw_info },
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{ "80865AC8", (unsigned long)&pwm_lpss_bxt_info },
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{ },
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};
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MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
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static struct platform_driver pwm_lpss_driver_platform = {
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.driver = {
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.name = "pwm-lpss",
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.acpi_match_table = pwm_lpss_acpi_match,
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},
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.probe = pwm_lpss_probe_platform,
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.remove = pwm_lpss_remove_platform,
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};
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module_platform_driver(pwm_lpss_driver_platform);
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MODULE_DESCRIPTION("PWM platform driver for Intel LPSS");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:pwm-lpss");
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