152 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/* Sparx5 SoC temperature sensor driver3 *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 017#define TEMP_CFG 418#define TEMP_CFG_CYCLES GENMASK(24, 15)19#define TEMP_CFG_ENA BIT(0)20#define TEMP_STAT 821#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_enable(struct s5_hwmon *hwmon)30{31 u32 val = readl(hwmon->base + TEMP_CFG);32 u32 clk = clk_get_rate(hwmon->clk) / USEC_PER_SEC;33 34 val &= ~TEMP_CFG_CYCLES;35 val |= FIELD_PREP(TEMP_CFG_CYCLES, clk);36 val |= TEMP_CFG_ENA;37 38 writel(val, hwmon->base + TEMP_CFG);39}40 41static int s5_read(struct device *dev, enum hwmon_sensor_types type,42 u32 attr, int channel, long *temp)43{44 struct s5_hwmon *hwmon = dev_get_drvdata(dev);45 int rc = 0, value;46 u32 stat;47 48 switch (attr) {49 case hwmon_temp_input:50 stat = readl_relaxed(hwmon->base + TEMP_STAT);51 if (!(stat & TEMP_STAT_VALID))52 return -EAGAIN;53 value = stat & TEMP_STAT_TEMP;54 /*55 * From register documentation:56 * Temp(C) = TEMP_SENSOR_STAT.TEMP / 4096 * 352.2 - 109.457 */58 value = DIV_ROUND_CLOSEST(value * 3522, 4096) - 1094;59 /*60 * Scale down by 10 from above and multiply by 1000 to61 * have millidegrees as specified by the hwmon sysfs62 * interface.63 */64 value *= 100;65 *temp = value;66 break;67 default:68 rc = -EOPNOTSUPP;69 break;70 }71 72 return rc;73}74 75static umode_t s5_is_visible(const void *_data, enum hwmon_sensor_types type,76 u32 attr, int channel)77{78 if (type != hwmon_temp)79 return 0;80 81 switch (attr) {82 case hwmon_temp_input:83 return 0444;84 default:85 return 0;86 }87}88 89static const struct hwmon_channel_info * const s5_info[] = {90 HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),91 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),92 NULL93};94 95static const struct hwmon_ops s5_hwmon_ops = {96 .is_visible = s5_is_visible,97 .read = s5_read,98};99 100static const struct hwmon_chip_info s5_chip_info = {101 .ops = &s5_hwmon_ops,102 .info = s5_info,103};104 105static int s5_temp_probe(struct platform_device *pdev)106{107 struct device *hwmon_dev;108 struct s5_hwmon *hwmon;109 110 hwmon = devm_kzalloc(&pdev->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 hwmon->clk = devm_clk_get_enabled(&pdev->dev, NULL);119 if (IS_ERR(hwmon->clk))120 return PTR_ERR(hwmon->clk);121 122 s5_temp_enable(hwmon);123 124 hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,125 "s5_temp",126 hwmon,127 &s5_chip_info,128 NULL);129 130 return PTR_ERR_OR_ZERO(hwmon_dev);131}132 133static const struct of_device_id s5_temp_match[] = {134 { .compatible = "microchip,sparx5-temp" },135 {},136};137MODULE_DEVICE_TABLE(of, s5_temp_match);138 139static struct platform_driver s5_temp_driver = {140 .probe = s5_temp_probe,141 .driver = {142 .name = "sparx5-temp",143 .of_match_table = s5_temp_match,144 },145};146 147module_platform_driver(s5_temp_driver);148 149MODULE_AUTHOR("Lars Povlsen <lars.povlsen@microchip.com>");150MODULE_DESCRIPTION("Sparx5 SoC temperature sensor driver");151MODULE_LICENSE("GPL");152