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
104	return 0;
105}
106
107static void khadas_mcu_fan_shutdown(struct platform_device *pdev)
108{
109	struct khadas_mcu_fan_ctx *ctx = platform_get_drvdata(pdev);
110
111	khadas_mcu_fan_set_level(ctx, 0);
112}
113
114#ifdef CONFIG_PM_SLEEP
115static int khadas_mcu_fan_suspend(struct device *dev)
116{
117	struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
118	unsigned int level_save = ctx->level;
119	int ret;
120
121	ret = khadas_mcu_fan_set_level(ctx, 0);
122	if (ret)
123		return ret;
124
125	ctx->level = level_save;
126
127	return 0;
128}
129
130static int khadas_mcu_fan_resume(struct device *dev)
131{
132	struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
133
134	return khadas_mcu_fan_set_level(ctx, ctx->level);
135}
136#endif
137
138static SIMPLE_DEV_PM_OPS(khadas_mcu_fan_pm, khadas_mcu_fan_suspend,
139			 khadas_mcu_fan_resume);
140
141static const struct platform_device_id khadas_mcu_fan_id_table[] = {
142	{ .name = "khadas-mcu-fan-ctrl", },
143	{},
144};
145MODULE_DEVICE_TABLE(platform, khadas_mcu_fan_id_table);
146
147static struct platform_driver khadas_mcu_fan_driver = {
148	.probe		= khadas_mcu_fan_probe,
149	.shutdown	= khadas_mcu_fan_shutdown,
150	.driver	= {
151		.name		= "khadas-mcu-fan-ctrl",
152		.pm		= &khadas_mcu_fan_pm,
153	},
154	.id_table	= khadas_mcu_fan_id_table,
155};
156
157module_platform_driver(khadas_mcu_fan_driver);
158
159MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
160MODULE_DESCRIPTION("Khadas MCU FAN driver");
161MODULE_LICENSE("GPL");
162