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