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/acpi.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/pm_runtime.h>
  15
  16 #include "pwm-lpss.h"
  17
  18 /* BayTrail */
  19 static const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
  20         .clk_rate = 25000000,
  21         .npwm = 1,
  22         .base_unit_bits = 16,
  23 };
  24
  25 /* Braswell */
  26 static const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
  27         .clk_rate = 19200000,
  28         .npwm = 1,
  29         .base_unit_bits = 16,
  30         .other_devices_aml_touches_pwm_regs = true,
  31 };
  32
  33 /* Broxton */
  34 static const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
  35         .clk_rate = 19200000,
  36         .npwm = 4,
  37         .base_unit_bits = 22,
  38         .bypass = true,
  39 };
  40
  41 static int pwm_lpss_probe_platform(struct platform_device *pdev)
  42 {
  43         const struct pwm_lpss_boardinfo *info;
  44         const struct acpi_device_id *id;
  45         struct pwm_lpss_chip *lpwm;
  46         struct resource *r;
  47
  48         id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
  49         if (!id)
  50                 return -ENODEV;
  51
  52         info = (const struct pwm_lpss_boardinfo *)id->driver_data;
  53         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  54
  55         lpwm = pwm_lpss_probe(&pdev->dev, r, info);
  56         if (IS_ERR(lpwm))
  57                 return PTR_ERR(lpwm);
  58
  59         platform_set_drvdata(pdev, lpwm);
  60
  61         /*
  62          * On Cherry Trail devices the GFX0._PS0 AML checks if the controller
  63          * is on and if it is not on it turns it on and restores what it
  64          * believes is the correct state to the PWM controller.
  65          * Because of this we must disallow direct-complete, which keeps the
  66          * controller (runtime)suspended on resume, to avoid 2 issues:
  67          * 1. The controller getting turned on without the linux-pm code
  68          *    knowing about this. On devices where the controller is unused
  69          *    this causes it to stay on during the next suspend causing high
  70          *    battery drain (because S0i3 is not reached)
  71          * 2. The state restoring code unexpectedly messing with the controller
  72          *
  73          * Leaving the controller runtime-suspended (skipping runtime-resume +
  74          * normal-suspend) during suspend is fine.
  75          */
  76         if (info->other_devices_aml_touches_pwm_regs)
  77                 dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE|
  78                                                     DPM_FLAG_SMART_SUSPEND);
  79
  80         pm_runtime_set_active(&pdev->dev);
  81         pm_runtime_enable(&pdev->dev);
  82
  83         return 0;
  84 }
  85
  86 static int pwm_lpss_remove_platform(struct platform_device *pdev)
  87 {
  88         pm_runtime_disable(&pdev->dev);
  89         return 0;
  90 }
  91
  92 static const struct acpi_device_id pwm_lpss_acpi_match[] = {
  93         { "80860F09", (unsigned long)&pwm_lpss_byt_info },
  94         { "80862288", (unsigned long)&pwm_lpss_bsw_info },
  95         { "80862289", (unsigned long)&pwm_lpss_bsw_info },
  96         { "80865AC8", (unsigned long)&pwm_lpss_bxt_info },
  97         { },
  98 };
  99 MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
 100
 101 static struct platform_driver pwm_lpss_driver_platform = {
 102         .driver = {
 103                 .name = "pwm-lpss",
 104                 .acpi_match_table = pwm_lpss_acpi_match,
 105         },
 106         .probe = pwm_lpss_probe_platform,
 107         .remove = pwm_lpss_remove_platform,
 108 };
 109 module_platform_driver(pwm_lpss_driver_platform);
 110
 111 MODULE_DESCRIPTION("PWM platform driver for Intel LPSS");
 112 MODULE_LICENSE("GPL v2");
 113 MODULE_ALIAS("platform:pwm-lpss");