1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Khadas MCU Controlled FAN driver
4 *
5 * Copyright (C) 2020 BayLibre SAS
6 * Author(s): Neil Armstrong <narmstrong@baylibre.com>
7 */
8
9#include <linux/module.h>
10#include <linux/of.h>
11#include <linux/platform_device.h>
12#include <linux/mfd/khadas-mcu.h>
13#include <linux/regmap.h>
14#include <linux/sysfs.h>
15#include <linux/thermal.h>
16
17#define MAX_LEVEL 3
18
19struct khadas_mcu_fan_ctx {
20	struct khadas_mcu *mcu;
21	unsigned int level;
22	struct thermal_cooling_device *cdev;
23};
24
25static int khadas_mcu_fan_set_level(struct khadas_mcu_fan_ctx *ctx,
26				    unsigned int level)
27{
28	int ret;
29
30	ret = regmap_write(ctx->mcu->regmap, KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG,
31			   level);
32	if (ret)
33		return ret;
34
35	ctx->level = level;
36
37	return 0;
38}
39
40static int khadas_mcu_fan_get_max_state(struct thermal_cooling_device *cdev,
41					unsigned long *state)
42{
43	*state = MAX_LEVEL;
44
45	return 0;
46}
47
48static int khadas_mcu_fan_get_cur_state(struct thermal_cooling_device *cdev,
49					unsigned long *state)
50{
51	struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
52
53	*state = ctx->level;
54
55	return 0;
56}
57
58static int
59khadas_mcu_fan_set_cur_state(struct thermal_cooling_device *cdev,
60			     unsigned long state)
61{
62	struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
63
64	if (state > MAX_LEVEL)
65		return -EINVAL;
66
67	if (state == ctx->level)
68		return 0;
69
70	return khadas_mcu_fan_set_level(ctx, state);
71}
72
73static const struct thermal_cooling_device_ops khadas_mcu_fan_cooling_ops = {
74	.get_max_state = khadas_mcu_fan_get_max_state,
75	.get_cur_state = khadas_mcu_fan_get_cur_state,
76	.set_cur_state = khadas_mcu_fan_set_cur_state,
77};
78
79static int khadas_mcu_fan_probe(struct platform_device *pdev)
80{
81	struct khadas_mcu *mcu = dev_get_drvdata(pdev->dev.parent);
82	struct thermal_cooling_device *cdev;
83	struct device *dev = &pdev->dev;
84	struct khadas_mcu_fan_ctx *ctx;
85	int ret;
86
87	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
88	if (!ctx)
89		return -ENOMEM;
90	ctx->mcu = mcu;
91	platform_set_drvdata(pdev, ctx);
92
93	cdev = devm_thermal_of_cooling_device_register(dev->parent,
94			dev->parent->of_node, "khadas-mcu-fan", ctx,
95			&khadas_mcu_fan_cooling_ops);
96	if (IS_ERR(cdev)) {
97		ret = PTR_ERR(cdev);
98		dev_err(dev, "Failed to register khadas-mcu-fan as cooling device: %d\n",
99			ret);
100		return ret;
101	}
102	ctx->cdev = cdev;
103	thermal_cdev_update(cdev);
104
105	return 0;
106}
107
108static void khadas_mcu_fan_shutdown(struct platform_device *pdev)
109{
110	struct khadas_mcu_fan_ctx *ctx = platform_get_drvdata(pdev);
111
112	khadas_mcu_fan_set_level(ctx, 0);
113}
114
115#ifdef CONFIG_PM_SLEEP
116static int khadas_mcu_fan_suspend(struct device *dev)
117{
118	struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
119	unsigned int level_save = ctx->level;
120	int ret;
121
122	ret = khadas_mcu_fan_set_level(ctx, 0);
123	if (ret)
124		return ret;
125
126	ctx->level = level_save;
127
128	return 0;
129}
130
131static int khadas_mcu_fan_resume(struct device *dev)
132{
133	struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
134
135	return khadas_mcu_fan_set_level(ctx, ctx->level);
136}
137#endif
138
139static SIMPLE_DEV_PM_OPS(khadas_mcu_fan_pm, khadas_mcu_fan_suspend,
140			 khadas_mcu_fan_resume);
141
142static const struct platform_device_id khadas_mcu_fan_id_table[] = {
143	{ .name = "khadas-mcu-fan-ctrl", },
144	{},
145};
146MODULE_DEVICE_TABLE(platform, khadas_mcu_fan_id_table);
147
148static struct platform_driver khadas_mcu_fan_driver = {
149	.probe		= khadas_mcu_fan_probe,
150	.shutdown	= khadas_mcu_fan_shutdown,
151	.driver	= {
152		.name		= "khadas-mcu-fan-ctrl",
153		.pm		= &khadas_mcu_fan_pm,
154	},
155	.id_table	= khadas_mcu_fan_id_table,
156};
157
158module_platform_driver(khadas_mcu_fan_driver);
159
160MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
161MODULE_DESCRIPTION("Khadas MCU FAN driver");
162MODULE_LICENSE("GPL");
163