1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Synaptics AS370 SoC Hardware Monitoring Driver
  4 *
  5 * Copyright (C) 2018 Synaptics Incorporated
  6 * Author: Jisheng Zhang <jszhang@kernel.org>
  7 */
  8
  9#include <linux/bitops.h>
 10#include <linux/hwmon.h>
 11#include <linux/init.h>
 12#include <linux/io.h>
 13#include <linux/module.h>
 14#include <linux/of_device.h>
 15
 16#define CTRL		0x0
 17#define  PD		BIT(0)
 18#define  EN		BIT(1)
 19#define  T_SEL		BIT(2)
 20#define  V_SEL		BIT(3)
 21#define  NMOS_SEL	BIT(8)
 22#define  PMOS_SEL	BIT(9)
 23#define STS		0x4
 24#define  BN_MASK	GENMASK(11, 0)
 25#define  EOC		BIT(12)
 26
 27struct as370_hwmon {
 28	void __iomem *base;
 29};
 30
 31static void init_pvt(struct as370_hwmon *hwmon)
 32{
 33	u32 val;
 34	void __iomem *addr = hwmon->base + CTRL;
 35
 36	val = PD;
 37	writel_relaxed(val, addr);
 38	val |= T_SEL;
 39	writel_relaxed(val, addr);
 40	val |= EN;
 41	writel_relaxed(val, addr);
 42	val &= ~PD;
 43	writel_relaxed(val, addr);
 44}
 45
 46static int as370_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
 47			    u32 attr, int channel, long *temp)
 48{
 49	int val;
 50	struct as370_hwmon *hwmon = dev_get_drvdata(dev);
 51
 52	switch (attr) {
 53	case hwmon_temp_input:
 54		val = readl_relaxed(hwmon->base + STS) & BN_MASK;
 55		*temp = DIV_ROUND_CLOSEST(val * 251802, 4096) - 85525;
 56		break;
 57	default:
 58		return -EOPNOTSUPP;
 59	}
 60
 61	return 0;
 62}
 63
 64static umode_t
 65as370_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
 66		       u32 attr, int channel)
 67{
 68	if (type != hwmon_temp)
 69		return 0;
 70
 71	switch (attr) {
 72	case hwmon_temp_input:
 73		return 0444;
 74	default:
 75		return 0;
 76	}
 77}
 78
 79static const u32 as370_hwmon_temp_config[] = {
 80	HWMON_T_INPUT,
 81	0
 82};
 83
 84static const struct hwmon_channel_info as370_hwmon_temp = {
 85	.type = hwmon_temp,
 86	.config = as370_hwmon_temp_config,
 87};
 88
 89static const struct hwmon_channel_info *as370_hwmon_info[] = {
 90	&as370_hwmon_temp,
 91	NULL
 92};
 93
 94static const struct hwmon_ops as370_hwmon_ops = {
 95	.is_visible = as370_hwmon_is_visible,
 96	.read = as370_hwmon_read,
 97};
 98
 99static const struct hwmon_chip_info as370_chip_info = {
100	.ops = &as370_hwmon_ops,
101	.info = as370_hwmon_info,
102};
103
104static int as370_hwmon_probe(struct platform_device *pdev)
105{
106	struct device *hwmon_dev;
107	struct as370_hwmon *hwmon;
108	struct device *dev = &pdev->dev;
109
110	hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
111	if (!hwmon)
112		return -ENOMEM;
113
114	hwmon->base = devm_platform_ioremap_resource(pdev, 0);
115	if (IS_ERR(hwmon->base))
116		return PTR_ERR(hwmon->base);
117
118	init_pvt(hwmon);
119
120	hwmon_dev = devm_hwmon_device_register_with_info(dev,
121							 "as370",
122							 hwmon,
123							 &as370_chip_info,
124							 NULL);
125	return PTR_ERR_OR_ZERO(hwmon_dev);
126}
127
128static const struct of_device_id as370_hwmon_match[] = {
129	{ .compatible = "syna,as370-hwmon" },
130	{},
131};
132MODULE_DEVICE_TABLE(of, as370_hwmon_match);
133
134static struct platform_driver as370_hwmon_driver = {
135	.probe = as370_hwmon_probe,
136	.driver = {
137		.name = "as370-hwmon",
138		.of_match_table = as370_hwmon_match,
139	},
140};
141module_platform_driver(as370_hwmon_driver);
142
143MODULE_AUTHOR("Jisheng Zhang<jszhang@kernel.org>");
144MODULE_DESCRIPTION("Synaptics AS370 SoC hardware monitor");
145MODULE_LICENSE("GPL v2");