282 lines · c
1// SPDX-License-Identifier: GPL-2.0+2/*3 * Driver for Broadcom BCM2835 SoC temperature sensor4 *5 * Copyright (C) 2016 Martin Sperl6 */7 8#include <linux/clk.h>9#include <linux/debugfs.h>10#include <linux/device.h>11#include <linux/err.h>12#include <linux/io.h>13#include <linux/kernel.h>14#include <linux/module.h>15#include <linux/of.h>16#include <linux/of_address.h>17#include <linux/of_device.h>18#include <linux/platform_device.h>19#include <linux/thermal.h>20 21#include "../thermal_hwmon.h"22 23#define BCM2835_TS_TSENSCTL 0x0024#define BCM2835_TS_TSENSSTAT 0x0425 26#define BCM2835_TS_TSENSCTL_PRWDW BIT(0)27#define BCM2835_TS_TSENSCTL_RSTB BIT(1)28 29/*30 * bandgap reference voltage in 6 mV increments31 * 000b = 1178 mV, 001b = 1184 mV, ... 111b = 1220 mV32 */33#define BCM2835_TS_TSENSCTL_CTRL_BITS 334#define BCM2835_TS_TSENSCTL_CTRL_SHIFT 235#define BCM2835_TS_TSENSCTL_CTRL_MASK \36 GENMASK(BCM2835_TS_TSENSCTL_CTRL_BITS + \37 BCM2835_TS_TSENSCTL_CTRL_SHIFT - 1, \38 BCM2835_TS_TSENSCTL_CTRL_SHIFT)39#define BCM2835_TS_TSENSCTL_CTRL_DEFAULT 140#define BCM2835_TS_TSENSCTL_EN_INT BIT(5)41#define BCM2835_TS_TSENSCTL_DIRECT BIT(6)42#define BCM2835_TS_TSENSCTL_CLR_INT BIT(7)43#define BCM2835_TS_TSENSCTL_THOLD_SHIFT 844#define BCM2835_TS_TSENSCTL_THOLD_BITS 1045#define BCM2835_TS_TSENSCTL_THOLD_MASK \46 GENMASK(BCM2835_TS_TSENSCTL_THOLD_BITS + \47 BCM2835_TS_TSENSCTL_THOLD_SHIFT - 1, \48 BCM2835_TS_TSENSCTL_THOLD_SHIFT)49/*50 * time how long the block to be asserted in reset51 * which based on a clock counter (TSENS clock assumed)52 */53#define BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT 1854#define BCM2835_TS_TSENSCTL_RSTDELAY_BITS 855#define BCM2835_TS_TSENSCTL_REGULEN BIT(26)56 57#define BCM2835_TS_TSENSSTAT_DATA_BITS 1058#define BCM2835_TS_TSENSSTAT_DATA_SHIFT 059#define BCM2835_TS_TSENSSTAT_DATA_MASK \60 GENMASK(BCM2835_TS_TSENSSTAT_DATA_BITS + \61 BCM2835_TS_TSENSSTAT_DATA_SHIFT - 1, \62 BCM2835_TS_TSENSSTAT_DATA_SHIFT)63#define BCM2835_TS_TSENSSTAT_VALID BIT(10)64#define BCM2835_TS_TSENSSTAT_INTERRUPT BIT(11)65 66struct bcm2835_thermal_data {67 struct thermal_zone_device *tz;68 void __iomem *regs;69 struct clk *clk;70 struct dentry *debugfsdir;71};72 73static int bcm2835_thermal_adc2temp(u32 adc, int offset, int slope)74{75 return offset + slope * adc;76}77 78static int bcm2835_thermal_temp2adc(int temp, int offset, int slope)79{80 temp -= offset;81 temp /= slope;82 83 if (temp < 0)84 temp = 0;85 if (temp >= BIT(BCM2835_TS_TSENSSTAT_DATA_BITS))86 temp = BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1;87 88 return temp;89}90 91static int bcm2835_thermal_get_temp(struct thermal_zone_device *tz, int *temp)92{93 struct bcm2835_thermal_data *data = thermal_zone_device_priv(tz);94 u32 val = readl(data->regs + BCM2835_TS_TSENSSTAT);95 96 if (!(val & BCM2835_TS_TSENSSTAT_VALID))97 return -EIO;98 99 val &= BCM2835_TS_TSENSSTAT_DATA_MASK;100 101 *temp = bcm2835_thermal_adc2temp(102 val,103 thermal_zone_get_offset(data->tz),104 thermal_zone_get_slope(data->tz));105 106 return 0;107}108 109static const struct debugfs_reg32 bcm2835_thermal_regs[] = {110 {111 .name = "ctl",112 .offset = 0113 },114 {115 .name = "stat",116 .offset = 4117 }118};119 120static void bcm2835_thermal_debugfs(struct platform_device *pdev)121{122 struct bcm2835_thermal_data *data = platform_get_drvdata(pdev);123 struct debugfs_regset32 *regset;124 125 data->debugfsdir = debugfs_create_dir("bcm2835_thermal", NULL);126 127 regset = devm_kzalloc(&pdev->dev, sizeof(*regset), GFP_KERNEL);128 if (!regset)129 return;130 131 regset->regs = bcm2835_thermal_regs;132 regset->nregs = ARRAY_SIZE(bcm2835_thermal_regs);133 regset->base = data->regs;134 135 debugfs_create_regset32("regset", 0444, data->debugfsdir, regset);136}137 138static const struct thermal_zone_device_ops bcm2835_thermal_ops = {139 .get_temp = bcm2835_thermal_get_temp,140};141 142/*143 * Note: as per Raspberry Foundation FAQ144 * (https://www.raspberrypi.org/help/faqs/#performanceOperatingTemperature)145 * the recommended temperature range for the SoC -40C to +85C146 * so the trip limit is set to 80C.147 * this applies to all the BCM283X SoC148 */149 150static const struct of_device_id bcm2835_thermal_of_match_table[] = {151 {152 .compatible = "brcm,bcm2835-thermal",153 },154 {155 .compatible = "brcm,bcm2836-thermal",156 },157 {158 .compatible = "brcm,bcm2837-thermal",159 },160 {},161};162MODULE_DEVICE_TABLE(of, bcm2835_thermal_of_match_table);163 164static int bcm2835_thermal_probe(struct platform_device *pdev)165{166 struct device *dev = &pdev->dev;167 const struct of_device_id *match;168 struct thermal_zone_device *tz;169 struct bcm2835_thermal_data *data;170 int err = 0;171 u32 val;172 unsigned long rate;173 174 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);175 if (!data)176 return -ENOMEM;177 178 match = of_match_device(bcm2835_thermal_of_match_table, dev);179 if (!match)180 return -EINVAL;181 182 data->regs = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);183 if (IS_ERR(data->regs)) {184 err = PTR_ERR(data->regs);185 return err;186 }187 188 data->clk = devm_clk_get_enabled(dev, NULL);189 if (IS_ERR(data->clk))190 return dev_err_probe(dev, PTR_ERR(data->clk), "Could not get clk\n");191 192 rate = clk_get_rate(data->clk);193 if ((rate < 1920000) || (rate > 5000000))194 dev_warn(dev,195 "Clock %pCn running at %lu Hz is outside of the recommended range: 1.92 to 5MHz\n",196 data->clk, rate);197 198 /* register of thermal sensor and get info from DT */199 tz = devm_thermal_of_zone_register(dev, 0, data, &bcm2835_thermal_ops);200 if (IS_ERR(tz))201 return dev_err_probe(dev, PTR_ERR(tz), "Failed to register the thermal device\n");202 203 /*204 * right now the FW does set up the HW-block, so we are not205 * touching the configuration registers.206 * But if the HW is not enabled, then set it up207 * using "sane" values used by the firmware right now.208 */209 val = readl(data->regs + BCM2835_TS_TSENSCTL);210 if (!(val & BCM2835_TS_TSENSCTL_RSTB)) {211 int offset, slope, crit_temp;212 213 slope = thermal_zone_get_slope(tz);214 offset = thermal_zone_get_offset(tz);215 /*216 * For now we deal only with critical, otherwise217 * would need to iterate218 */219 err = thermal_zone_get_crit_temp(tz, &crit_temp);220 if (err < 0) {221 dev_err(dev, "Not able to read trip_temp: %d\n", err);222 return err;223 }224 225 /* set bandgap reference voltage and enable voltage regulator */226 val = (BCM2835_TS_TSENSCTL_CTRL_DEFAULT <<227 BCM2835_TS_TSENSCTL_CTRL_SHIFT) |228 BCM2835_TS_TSENSCTL_REGULEN;229 230 /* use the recommended reset duration */231 val |= (0xFE << BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT);232 233 /* trip_adc value from info */234 val |= bcm2835_thermal_temp2adc(crit_temp,235 offset,236 slope)237 << BCM2835_TS_TSENSCTL_THOLD_SHIFT;238 239 /* write the value back to the register as 2 steps */240 writel(val, data->regs + BCM2835_TS_TSENSCTL);241 val |= BCM2835_TS_TSENSCTL_RSTB;242 writel(val, data->regs + BCM2835_TS_TSENSCTL);243 }244 245 data->tz = tz;246 247 platform_set_drvdata(pdev, data);248 249 /*250 * Thermal_zone doesn't enable hwmon as default,251 * enable it here252 */253 err = thermal_add_hwmon_sysfs(tz);254 if (err)255 return err;256 257 bcm2835_thermal_debugfs(pdev);258 259 return 0;260}261 262static void bcm2835_thermal_remove(struct platform_device *pdev)263{264 struct bcm2835_thermal_data *data = platform_get_drvdata(pdev);265 266 debugfs_remove_recursive(data->debugfsdir);267}268 269static struct platform_driver bcm2835_thermal_driver = {270 .probe = bcm2835_thermal_probe,271 .remove_new = bcm2835_thermal_remove,272 .driver = {273 .name = "bcm2835_thermal",274 .of_match_table = bcm2835_thermal_of_match_table,275 },276};277module_platform_driver(bcm2835_thermal_driver);278 279MODULE_AUTHOR("Martin Sperl");280MODULE_DESCRIPTION("Thermal driver for bcm2835 chip");281MODULE_LICENSE("GPL");282