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