1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Functions to access SY3686A power management chip temperature
4 *
5 * Copyright (C) 2021 reMarkable AS - http://www.remarkable.com/
6 *
7 * Authors: Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>
8 * Alistair Francis <alistair@alistair23.me>
9 */
10
11 #include <linux/err.h>
12 #include <linux/hwmon.h>
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17 #include <linux/regulator/machine.h>
18
19 #include <linux/mfd/sy7636a.h>
20
sy7636a_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * temp)21 static int sy7636a_read(struct device *dev, enum hwmon_sensor_types type,
22 u32 attr, int channel, long *temp)
23 {
24 struct regmap *regmap = dev_get_drvdata(dev);
25 int ret, reg_val;
26
27 ret = regmap_read(regmap,
28 SY7636A_REG_TERMISTOR_READOUT, ®_val);
29 if (ret)
30 return ret;
31
32 *temp = reg_val * 1000;
33
34 return 0;
35 }
36
sy7636a_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)37 static umode_t sy7636a_is_visible(const void *data,
38 enum hwmon_sensor_types type,
39 u32 attr, int channel)
40 {
41 if (type != hwmon_temp)
42 return 0;
43
44 if (attr != hwmon_temp_input)
45 return 0;
46
47 return 0444;
48 }
49
50 static const struct hwmon_ops sy7636a_hwmon_ops = {
51 .is_visible = sy7636a_is_visible,
52 .read = sy7636a_read,
53 };
54
55 static const struct hwmon_channel_info *sy7636a_info[] = {
56 HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
57 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
58 NULL
59 };
60
61 static const struct hwmon_chip_info sy7636a_chip_info = {
62 .ops = &sy7636a_hwmon_ops,
63 .info = sy7636a_info,
64 };
65
sy7636a_sensor_probe(struct platform_device * pdev)66 static int sy7636a_sensor_probe(struct platform_device *pdev)
67 {
68 struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
69 struct regulator *regulator;
70 struct device *hwmon_dev;
71 int err;
72
73 if (!regmap)
74 return -EPROBE_DEFER;
75
76 regulator = devm_regulator_get(&pdev->dev, "vcom");
77 if (IS_ERR(regulator))
78 return PTR_ERR(regulator);
79
80 err = regulator_enable(regulator);
81 if (err)
82 return err;
83
84 hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
85 "sy7636a_temperature", regmap,
86 &sy7636a_chip_info, NULL);
87
88 if (IS_ERR(hwmon_dev)) {
89 err = PTR_ERR(hwmon_dev);
90 dev_err(&pdev->dev, "Unable to register hwmon device, returned %d\n", err);
91 return err;
92 }
93
94 return 0;
95 }
96
97 static struct platform_driver sy7636a_sensor_driver = {
98 .probe = sy7636a_sensor_probe,
99 .driver = {
100 .name = "sy7636a-temperature",
101 },
102 };
103 module_platform_driver(sy7636a_sensor_driver);
104
105 MODULE_DESCRIPTION("SY7636A sensor driver");
106 MODULE_LICENSE("GPL");
107