1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Driver for Broadcom BCM2835 SoC temperature sensor 4 * 5 * Copyright (C) 2016 Martin Sperl 6 */ 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 0x00 24 #define BCM2835_TS_TSENSSTAT 0x04 25 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 increments 31 * 000b = 1178 mV, 001b = 1184 mV, ... 111b = 1220 mV 32 */ 33 #define BCM2835_TS_TSENSCTL_CTRL_BITS 3 34 #define BCM2835_TS_TSENSCTL_CTRL_SHIFT 2 35 #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 1 40 #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 8 44 #define BCM2835_TS_TSENSCTL_THOLD_BITS 10 45 #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 reset 51 * which based on a clock counter (TSENS clock assumed) 52 */ 53 #define BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT 18 54 #define BCM2835_TS_TSENSCTL_RSTDELAY_BITS 8 55 #define BCM2835_TS_TSENSCTL_REGULEN BIT(26) 56 57 #define BCM2835_TS_TSENSSTAT_DATA_BITS 10 58 #define BCM2835_TS_TSENSSTAT_DATA_SHIFT 0 59 #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 66 struct bcm2835_thermal_data { 67 struct thermal_zone_device *tz; 68 void __iomem *regs; 69 struct clk *clk; 70 struct dentry *debugfsdir; 71 }; 72 73 static int bcm2835_thermal_adc2temp(u32 adc, int offset, int slope) 74 { 75 return offset + slope * adc; 76 } 77 78 static 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 91 static int bcm2835_thermal_get_temp(void *d, int *temp) 92 { 93 struct bcm2835_thermal_data *data = d; 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 } 108 109 static const struct debugfs_reg32 bcm2835_thermal_regs[] = { 110 { 111 .name = "ctl", 112 .offset = 0 113 }, 114 { 115 .name = "stat", 116 .offset = 4 117 } 118 }; 119 120 static void bcm2835_thermal_debugfs(struct platform_device *pdev) 121 { 122 struct thermal_zone_device *tz = platform_get_drvdata(pdev); 123 struct bcm2835_thermal_data *data = tz->devdata; 124 struct debugfs_regset32 *regset; 125 126 data->debugfsdir = debugfs_create_dir("bcm2835_thermal", NULL); 127 if (!data->debugfsdir) 128 return; 129 130 regset = devm_kzalloc(&pdev->dev, sizeof(*regset), GFP_KERNEL); 131 if (!regset) 132 return; 133 134 regset->regs = bcm2835_thermal_regs; 135 regset->nregs = ARRAY_SIZE(bcm2835_thermal_regs); 136 regset->base = data->regs; 137 138 debugfs_create_regset32("regset", 0444, data->debugfsdir, regset); 139 } 140 141 static const struct thermal_zone_of_device_ops bcm2835_thermal_ops = { 142 .get_temp = bcm2835_thermal_get_temp, 143 }; 144 145 /* 146 * Note: as per Raspberry Foundation FAQ 147 * (https://www.raspberrypi.org/help/faqs/#performanceOperatingTemperature) 148 * the recommended temperature range for the SoC -40C to +85C 149 * so the trip limit is set to 80C. 150 * this applies to all the BCM283X SoC 151 */ 152 153 static const struct of_device_id bcm2835_thermal_of_match_table[] = { 154 { 155 .compatible = "brcm,bcm2835-thermal", 156 }, 157 { 158 .compatible = "brcm,bcm2836-thermal", 159 }, 160 { 161 .compatible = "brcm,bcm2837-thermal", 162 }, 163 {}, 164 }; 165 MODULE_DEVICE_TABLE(of, bcm2835_thermal_of_match_table); 166 167 static int bcm2835_thermal_probe(struct platform_device *pdev) 168 { 169 const struct of_device_id *match; 170 struct thermal_zone_device *tz; 171 struct bcm2835_thermal_data *data; 172 struct resource *res; 173 int err = 0; 174 u32 val; 175 unsigned long rate; 176 177 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 178 if (!data) 179 return -ENOMEM; 180 181 match = of_match_device(bcm2835_thermal_of_match_table, 182 &pdev->dev); 183 if (!match) 184 return -EINVAL; 185 186 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 187 data->regs = devm_ioremap_resource(&pdev->dev, res); 188 if (IS_ERR(data->regs)) { 189 err = PTR_ERR(data->regs); 190 dev_err(&pdev->dev, "Could not get registers: %d\n", err); 191 return err; 192 } 193 194 data->clk = devm_clk_get(&pdev->dev, NULL); 195 if (IS_ERR(data->clk)) { 196 err = PTR_ERR(data->clk); 197 if (err != -EPROBE_DEFER) 198 dev_err(&pdev->dev, "Could not get clk: %d\n", err); 199 return err; 200 } 201 202 err = clk_prepare_enable(data->clk); 203 if (err) 204 return err; 205 206 rate = clk_get_rate(data->clk); 207 if ((rate < 1920000) || (rate > 5000000)) 208 dev_warn(&pdev->dev, 209 "Clock %pCn running at %lu Hz is outside of the recommended range: 1.92 to 5MHz\n", 210 data->clk, rate); 211 212 /* register of thermal sensor and get info from DT */ 213 tz = thermal_zone_of_sensor_register(&pdev->dev, 0, data, 214 &bcm2835_thermal_ops); 215 if (IS_ERR(tz)) { 216 err = PTR_ERR(tz); 217 dev_err(&pdev->dev, 218 "Failed to register the thermal device: %d\n", 219 err); 220 goto err_clk; 221 } 222 223 /* 224 * right now the FW does set up the HW-block, so we are not 225 * touching the configuration registers. 226 * But if the HW is not enabled, then set it up 227 * using "sane" values used by the firmware right now. 228 */ 229 val = readl(data->regs + BCM2835_TS_TSENSCTL); 230 if (!(val & BCM2835_TS_TSENSCTL_RSTB)) { 231 int trip_temp, offset, slope; 232 233 slope = thermal_zone_get_slope(tz); 234 offset = thermal_zone_get_offset(tz); 235 /* 236 * For now we deal only with critical, otherwise 237 * would need to iterate 238 */ 239 err = tz->ops->get_trip_temp(tz, 0, &trip_temp); 240 if (err < 0) { 241 dev_err(&pdev->dev, 242 "Not able to read trip_temp: %d\n", 243 err); 244 goto err_tz; 245 } 246 247 /* set bandgap reference voltage and enable voltage regulator */ 248 val = (BCM2835_TS_TSENSCTL_CTRL_DEFAULT << 249 BCM2835_TS_TSENSCTL_CTRL_SHIFT) | 250 BCM2835_TS_TSENSCTL_REGULEN; 251 252 /* use the recommended reset duration */ 253 val |= (0xFE << BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT); 254 255 /* trip_adc value from info */ 256 val |= bcm2835_thermal_temp2adc(trip_temp, 257 offset, 258 slope) 259 << BCM2835_TS_TSENSCTL_THOLD_SHIFT; 260 261 /* write the value back to the register as 2 steps */ 262 writel(val, data->regs + BCM2835_TS_TSENSCTL); 263 val |= BCM2835_TS_TSENSCTL_RSTB; 264 writel(val, data->regs + BCM2835_TS_TSENSCTL); 265 } 266 267 data->tz = tz; 268 269 platform_set_drvdata(pdev, tz); 270 271 /* 272 * Thermal_zone doesn't enable hwmon as default, 273 * enable it here 274 */ 275 tz->tzp->no_hwmon = false; 276 err = thermal_add_hwmon_sysfs(tz); 277 if (err) 278 goto err_tz; 279 280 bcm2835_thermal_debugfs(pdev); 281 282 return 0; 283 err_tz: 284 thermal_zone_of_sensor_unregister(&pdev->dev, tz); 285 err_clk: 286 clk_disable_unprepare(data->clk); 287 288 return err; 289 } 290 291 static int bcm2835_thermal_remove(struct platform_device *pdev) 292 { 293 struct thermal_zone_device *tz = platform_get_drvdata(pdev); 294 struct bcm2835_thermal_data *data = tz->devdata; 295 296 debugfs_remove_recursive(data->debugfsdir); 297 thermal_zone_of_sensor_unregister(&pdev->dev, tz); 298 clk_disable_unprepare(data->clk); 299 300 return 0; 301 } 302 303 static struct platform_driver bcm2835_thermal_driver = { 304 .probe = bcm2835_thermal_probe, 305 .remove = bcm2835_thermal_remove, 306 .driver = { 307 .name = "bcm2835_thermal", 308 .of_match_table = bcm2835_thermal_of_match_table, 309 }, 310 }; 311 module_platform_driver(bcm2835_thermal_driver); 312 313 MODULE_AUTHOR("Martin Sperl"); 314 MODULE_DESCRIPTION("Thermal driver for bcm2835 chip"); 315 MODULE_LICENSE("GPL"); 316