1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* Sparx5 SoC temperature sensor driver
  3 *
  4 * Copyright (C) 2020 Lars Povlsen <lars.povlsen@microchip.com>
  5 */
  6
  7#include <linux/bitfield.h>
  8#include <linux/clk.h>
  9#include <linux/hwmon.h>
 10#include <linux/init.h>
 11#include <linux/io.h>
 12#include <linux/mod_devicetable.h>
 13#include <linux/module.h>
 14#include <linux/platform_device.h>
 15
 16#define TEMP_CTRL		0
 17#define TEMP_CFG		4
 18#define  TEMP_CFG_CYCLES	GENMASK(24, 15)
 19#define  TEMP_CFG_ENA		BIT(0)
 20#define TEMP_STAT		8
 21#define  TEMP_STAT_VALID	BIT(12)
 22#define  TEMP_STAT_TEMP		GENMASK(11, 0)
 23
 24struct s5_hwmon {
 25	void __iomem *base;
 26	struct clk *clk;
 27};
 28
 29static void s5_temp_clk_disable(void *data)
 30{
 31	struct clk *clk = data;
 32
 33	clk_disable_unprepare(clk);
 34}
 35
 36static void s5_temp_enable(struct s5_hwmon *hwmon)
 37{
 38	u32 val = readl(hwmon->base + TEMP_CFG);
 39	u32 clk = clk_get_rate(hwmon->clk) / USEC_PER_SEC;
 40
 41	val &= ~TEMP_CFG_CYCLES;
 42	val |= FIELD_PREP(TEMP_CFG_CYCLES, clk);
 43	val |= TEMP_CFG_ENA;
 44
 45	writel(val, hwmon->base + TEMP_CFG);
 46}
 47
 48static int s5_read(struct device *dev, enum hwmon_sensor_types type,
 49		   u32 attr, int channel, long *temp)
 50{
 51	struct s5_hwmon *hwmon = dev_get_drvdata(dev);
 52	int rc = 0, value;
 53	u32 stat;
 54
 55	switch (attr) {
 56	case hwmon_temp_input:
 57		stat = readl_relaxed(hwmon->base + TEMP_STAT);
 58		if (!(stat & TEMP_STAT_VALID))
 59			return -EIO;
 60		value = stat & TEMP_STAT_TEMP;
 61		/*
 62		 * From register documentation:
 63		 * Temp(C) = TEMP_SENSOR_STAT.TEMP / 4096 * 352.2 - 109.4
 64		 */
 65		value = DIV_ROUND_CLOSEST(value * 3522, 4096) - 1094;
 66		/*
 67		 * Scale down by 10 from above and multiply by 1000 to
 68		 * have millidegrees as specified by the hwmon sysfs
 69		 * interface.
 70		 */
 71		value *= 100;
 72		*temp = value;
 73		break;
 74	default:
 75		rc = -EOPNOTSUPP;
 76		break;
 77	}
 78
 79	return rc;
 80}
 81
 82static umode_t s5_is_visible(const void *_data, enum hwmon_sensor_types type,
 83			     u32 attr, int channel)
 84{
 85	if (type != hwmon_temp)
 86		return 0;
 87
 88	switch (attr) {
 89	case hwmon_temp_input:
 90		return 0444;
 91	default:
 92		return 0;
 93	}
 94}
 95
 96static const struct hwmon_channel_info *s5_info[] = {
 97	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
 98	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
 99	NULL
100};
101
102static const struct hwmon_ops s5_hwmon_ops = {
103	.is_visible = s5_is_visible,
104	.read = s5_read,
105};
106
107static const struct hwmon_chip_info s5_chip_info = {
108	.ops = &s5_hwmon_ops,
109	.info = s5_info,
110};
111
112static int s5_temp_probe(struct platform_device *pdev)
113{
114	struct device *hwmon_dev;
115	struct s5_hwmon *hwmon;
116	int ret;
117
118	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
119	if (!hwmon)
120		return -ENOMEM;
121
122	hwmon->base = devm_platform_ioremap_resource(pdev, 0);
123	if (IS_ERR(hwmon->base))
124		return PTR_ERR(hwmon->base);
125
126	hwmon->clk = devm_clk_get(&pdev->dev, NULL);
127	if (IS_ERR(hwmon->clk))
128		return PTR_ERR(hwmon->clk);
129
130	ret = clk_prepare_enable(hwmon->clk);
131	if (ret)
132		return ret;
133
134	ret = devm_add_action_or_reset(&pdev->dev, s5_temp_clk_disable,
135				       hwmon->clk);
136	if (ret)
137		return ret;
138
139	s5_temp_enable(hwmon);
140
141	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
142							 "s5_temp",
143							 hwmon,
144							 &s5_chip_info,
145							 NULL);
146
147	return PTR_ERR_OR_ZERO(hwmon_dev);
148}
149
150static const struct of_device_id s5_temp_match[] = {
151	{ .compatible = "microchip,sparx5-temp" },
152	{},
153};
154MODULE_DEVICE_TABLE(of, s5_temp_match);
155
156static struct platform_driver s5_temp_driver = {
157	.probe = s5_temp_probe,
158	.driver = {
159		.name = "sparx5-temp",
160		.of_match_table = s5_temp_match,
161	},
162};
163
164module_platform_driver(s5_temp_driver);
165
166MODULE_AUTHOR("Lars Povlsen <lars.povlsen@microchip.com>");
167MODULE_DESCRIPTION("Sparx5 SoC temperature sensor driver");
168MODULE_LICENSE("GPL");