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_lpss_chip *lpwm;
  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         lpwm = devm_pwm_lpss_probe(&pdev->dev, base, info);
  35         if (IS_ERR(lpwm))
  36                 return PTR_ERR(lpwm);
  37
  38         platform_set_drvdata(pdev, lpwm);
  39
  40         /*
  41          * On Cherry Trail devices the GFX0._PS0 AML checks if the controller
  42          * is on and if it is not on it turns it on and restores what it
  43          * believes is the correct state to the PWM controller.
  44          * Because of this we must disallow direct-complete, which keeps the
  45          * controller (runtime)suspended on resume, to avoid 2 issues:
  46          * 1. The controller getting turned on without the linux-pm code
  47          *    knowing about this. On devices where the controller is unused
  48          *    this causes it to stay on during the next suspend causing high
  49          *    battery drain (because S0i3 is not reached)
  50          * 2. The state restoring code unexpectedly messing with the controller
  51          *
  52          * Leaving the controller runtime-suspended (skipping runtime-resume +
  53          * normal-suspend) during suspend is fine.
  54          */
  55         if (info->other_devices_aml_touches_pwm_regs)
  56                 dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE|
  57                                                     DPM_FLAG_SMART_SUSPEND);
  58
  59         pm_runtime_set_active(&pdev->dev);
  60         pm_runtime_enable(&pdev->dev);
  61
  62         return 0;
  63 }
  64
  65 static void pwm_lpss_remove_platform(struct platform_device *pdev)
  66 {
  67         pm_runtime_disable(&pdev->dev);
  68 }
  69
  70 static const struct acpi_device_id pwm_lpss_acpi_match[] = {
  71         { "80860F09", (unsigned long)&pwm_lpss_byt_info },
  72         { "80862288", (unsigned long)&pwm_lpss_bsw_info },
  73         { "80862289", (unsigned long)&pwm_lpss_bsw_info },
  74         { "80865AC8", (unsigned long)&pwm_lpss_bxt_info },
  75         { },
  76 };
  77 MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
  78
  79 static struct platform_driver pwm_lpss_driver_platform = {
  80         .driver = {
  81                 .name = "pwm-lpss",
  82                 .acpi_match_table = pwm_lpss_acpi_match,
  83         },
  84         .probe = pwm_lpss_probe_platform,
  85         .remove_new = pwm_lpss_remove_platform,
  86 };
  87 module_platform_driver(pwm_lpss_driver_platform);
  88
  89 MODULE_DESCRIPTION("PWM platform driver for Intel LPSS");
  90 MODULE_LICENSE("GPL v2");
  91 MODULE_IMPORT_NS(PWM_LPSS);
  92 MODULE_ALIAS("platform:pwm-lpss");