Quelle  pwm-lpss-platform.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Intel Low Power Subsystem PWM controller driver
 *
 * Copyright (C) 2014, Intel Corporation
 *
 * Derived from the original pwm-lpss.c
 */

#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>

#include "pwm-lpss.h"


static int pwm_lpss_probe_platform(struct platform_device *pdev)
{
 const struct pwm_lpss_boardinfo *info;
 struct pwm_chip *chip;
 void __iomem *base;

 info = device_get_match_data(&pdev->dev);
 if (!info)
  return -ENODEV;

 base = devm_platform_ioremap_resource(pdev, 0);
 if (IS_ERR(base))
  return PTR_ERR(base);

 chip = devm_pwm_lpss_probe(&pdev->dev, base, info);
 if (IS_ERR(chip))
  return PTR_ERR(chip);

 /*
 * 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
 *
 * Leaving the controller runtime-suspended (skipping runtime-resume +
 * normal-suspend) during suspend is fine.
 */
 if (info->other_devices_aml_touches_pwm_regs)
  dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE|
          DPM_FLAG_SMART_SUSPEND);

 pm_runtime_set_active(&pdev->dev);
 return devm_pm_runtime_enable(&pdev->dev);
}

static const struct acpi_device_id pwm_lpss_acpi_match[] = {
 { "80860F09", (unsigned long)&pwm_lpss_byt_info },
 { "80862288", (unsigned long)&pwm_lpss_bsw_info },
 { "80862289", (unsigned long)&pwm_lpss_bsw_info },
 { "80865AC8", (unsigned long)&pwm_lpss_bxt_info },
 { },
};
MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);

static struct platform_driver pwm_lpss_driver_platform = {
 .driver = {
  .name = "pwm-lpss",
  .acpi_match_table = pwm_lpss_acpi_match,
 },
 .probe = pwm_lpss_probe_platform,
};
module_platform_driver(pwm_lpss_driver_platform);

MODULE_DESCRIPTION("PWM platform driver for Intel LPSS");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS("PWM_LPSS");
MODULE_ALIAS("platform:pwm-lpss");