547d9e9261
PWM controller drivers should not restore the PWM state on resume. The convention is that PWM consumers do this by calling pwm_apply_state(), so that it can be done at the exact moment when the consumer needs the state to be stored, avoiding e.g. backlight flickering. The only in kernel consumers of the pwm-lpss code, the i915 driver and the pwm-class sysfs interface code both correctly restore the state on resume, so there is no need to do this in the pwm-lpss code. More-over the removed resume handler is buggy, since it blindly restores the ctrl-register contents without setting the update bit, which is necessary to get the controller to actually use/apply the restored base-unit and on-time-div values. Acked-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200903112337.4113-8-hdegoede@redhat.com
117 lines
2.9 KiB
C
117 lines
2.9 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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dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_SMART_PREPARE);
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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 int pwm_lpss_prepare(struct device *dev)
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{
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struct pwm_lpss_chip *lpwm = dev_get_drvdata(dev);
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/*
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* If other device's AML code touches the PWM regs on suspend/resume
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* force runtime-resume the PWM controller to allow this.
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*/
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if (lpwm->info->other_devices_aml_touches_pwm_regs)
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return 0; /* Force runtime-resume */
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return 1; /* If runtime-suspended leave as is */
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}
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static const struct dev_pm_ops pwm_lpss_platform_pm_ops = {
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.prepare = pwm_lpss_prepare,
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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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.pm = &pwm_lpss_platform_pm_ops,
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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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