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"); 114