drivers/pwm/pwm-lpss-platform.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Intel Low Power Subsystem PWM controller driver
   4  *
   5  * Copyright (C) 2014, Intel Corporation
   6  *
   7  * Derived from the original pwm-lpss.c
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/mod_devicetable.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/pm_runtime.h>
  15 #include <linux/property.h>
  16
  17 #include "pwm-lpss.h"
  18
  19
  20 static int pwm_lpss_probe_platform(struct platform_device *pdev)
  21 {
  22         const struct pwm_lpss_boardinfo *info;
  23         struct pwm_chip *chip;
  24         void __iomem *base;
  25
  26         info = device_get_match_data(&pdev->dev);
  27         if (!info)
  28                 return -ENODEV;
  29
  30         base = devm_platform_ioremap_resource(pdev, 0);
  31         if (IS_ERR(base))
  32                 return PTR_ERR(base);
  33
  34         chip = devm_pwm_lpss_probe(&pdev->dev, base, info);
  35         if (IS_ERR(chip))
  36                 return PTR_ERR(chip);
  37
  38         /*
  39          * On Cherry Trail devices the GFX0._PS0 AML checks if the controller
  40          * is on and if it is not on it turns it on and restores what it
  41          * believes is the correct state to the PWM controller.
  42          * Because of this we must disallow direct-complete, which keeps the
  43          * controller (runtime)suspended on resume, to avoid 2 issues:
  44          * 1. The controller getting turned on without the linux-pm code
  45          *    knowing about this. On devices where the controller is unused
  46          *    this causes it to stay on during the next suspend causing high
  47          *    battery drain (because S0i3 is not reached)
  48          * 2. The state restoring code unexpectedly messing with the controller
  49          *
  50          * Leaving the controller runtime-suspended (skipping runtime-resume +
  51          * normal-suspend) during suspend is fine.
  52          */
  53         if (info->other_devices_aml_touches_pwm_regs)
  54                 dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE|
  55                                                     DPM_FLAG_SMART_SUSPEND);
  56
  57         pm_runtime_set_active(&pdev->dev);
  58         pm_runtime_enable(&pdev->dev);
  59
  60         return 0;
  61 }
  62
  63 static void pwm_lpss_remove_platform(struct platform_device *pdev)
  64 {
  65         pm_runtime_disable(&pdev->dev);
  66 }
  67
  68 static const struct acpi_device_id pwm_lpss_acpi_match[] = {
  69         { "80860F09", (unsigned long)&pwm_lpss_byt_info },
  70         { "80862288", (unsigned long)&pwm_lpss_bsw_info },
  71         { "80862289", (unsigned long)&pwm_lpss_bsw_info },
  72         { "80865AC8", (unsigned long)&pwm_lpss_bxt_info },
  73         { },
  74 };
  75 MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
  76
  77 static struct platform_driver pwm_lpss_driver_platform = {
  78         .driver = {
  79                 .name = "pwm-lpss",
  80                 .acpi_match_table = pwm_lpss_acpi_match,
  81         },
  82         .probe = pwm_lpss_probe_platform,
  83         .remove_new = pwm_lpss_remove_platform,
  84 };
  85 module_platform_driver(pwm_lpss_driver_platform);
  86
  87 MODULE_DESCRIPTION("PWM platform driver for Intel LPSS");
  88 MODULE_LICENSE("GPL v2");
  89 MODULE_IMPORT_NS(PWM_LPSS);
  90 MODULE_ALIAS("platform:pwm-lpss");