target/linux/generic/backport-4.9/081-0001-thermal-bcm2835-add-thermal-driver-for-bcm2835-SoC.patch

   1 From bcb7dd9ef206f7d646ed8dac6fe7772083714253 Mon Sep 17 00:00:00 2001
   2 From: Stefan Wahren <stefan.wahren@i2se.com>
   3 Date: Fri, 31 Mar 2017 20:03:06 +0000
   4 Subject: [PATCH] thermal: bcm2835: add thermal driver for bcm2835 SoC
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Add basic thermal driver for bcm2835 SoC.
  10
  11 This driver currently make sure that tsense HW block is set up
  12 correctly.
  13
  14 Tested-by: Rafał Miłecki <rafal@milecki.pl>
  15 Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
  16 Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
  17 Acked-by: Eric Anholt <eric@anholt.net>
  18 Acked-by: Eduardo Valentin <edubezval@gmail.com>
  19 Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
  20 ---
  21  drivers/thermal/Kconfig           |   8 +
  22  drivers/thermal/Makefile          |   1 +
  23  drivers/thermal/bcm2835_thermal.c | 314 ++++++++++++++++++++++++++++++++++++++
  24  3 files changed, 323 insertions(+)
  25  create mode 100644 drivers/thermal/bcm2835_thermal.c
  26
  27 --- a/drivers/thermal/Kconfig
  28 +++ b/drivers/thermal/Kconfig
  29 @@ -434,4 +434,12 @@ depends on (ARCH_QCOM && OF) || COMPILE_
  30  source "drivers/thermal/qcom/Kconfig"
  31  endmenu
  32
  33 +config BCM2835_THERMAL
  34 +       tristate "Thermal sensors on bcm2835 SoC"
  35 +       depends on ARCH_BCM2835 || COMPILE_TEST
  36 +       depends on HAS_IOMEM
  37 +       depends on THERMAL_OF
  38 +       help
  39 +         Support for thermal sensors on Broadcom bcm2835 SoCs.
  40 +
  41  endif
  42 --- a/drivers/thermal/Makefile
  43 +++ b/drivers/thermal/Makefile
  44 @@ -55,3 +55,4 @@ obj-$(CONFIG_TEGRA_SOCTHERM)  += tegra/
  45  obj-$(CONFIG_HISI_THERMAL)     += hisi_thermal.o
  46  obj-$(CONFIG_MTK_THERMAL)      += mtk_thermal.o
  47  obj-$(CONFIG_GENERIC_ADC_THERMAL)      += thermal-generic-adc.o
  48 +obj-$(CONFIG_BCM2835_THERMAL) += bcm2835_thermal.o
  49 --- /dev/null
  50 +++ b/drivers/thermal/bcm2835_thermal.c
  51 @@ -0,0 +1,314 @@
  52 +/*
  53 + * Driver for Broadcom BCM2835 SoC temperature sensor
  54 + *
  55 + * Copyright (C) 2016 Martin Sperl
  56 + *
  57 + * This program is free software; you can redistribute it and/or modify
  58 + * it under the terms of the GNU General Public License as published by
  59 + * the Free Software Foundation; either version 2 of the License, or
  60 + * (at your option) any later version.
  61 + *
  62 + * This program is distributed in the hope that it will be useful,
  63 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
  64 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  65 + * GNU General Public License for more details.
  66 + */
  67 +
  68 +#include <linux/clk.h>
  69 +#include <linux/debugfs.h>
  70 +#include <linux/device.h>
  71 +#include <linux/err.h>
  72 +#include <linux/io.h>
  73 +#include <linux/kernel.h>
  74 +#include <linux/module.h>
  75 +#include <linux/of.h>
  76 +#include <linux/of_address.h>
  77 +#include <linux/of_device.h>
  78 +#include <linux/platform_device.h>
  79 +#include <linux/thermal.h>
  80 +
  81 +#define BCM2835_TS_TSENSCTL                    0x00
  82 +#define BCM2835_TS_TSENSSTAT                   0x04
  83 +
  84 +#define BCM2835_TS_TSENSCTL_PRWDW              BIT(0)
  85 +#define BCM2835_TS_TSENSCTL_RSTB               BIT(1)
  86 +
  87 +/*
  88 + * bandgap reference voltage in 6 mV increments
  89 + * 000b = 1178 mV, 001b = 1184 mV, ... 111b = 1220 mV
  90 + */
  91 +#define BCM2835_TS_TSENSCTL_CTRL_BITS          3
  92 +#define BCM2835_TS_TSENSCTL_CTRL_SHIFT         2
  93 +#define BCM2835_TS_TSENSCTL_CTRL_MASK              \
  94 +       GENMASK(BCM2835_TS_TSENSCTL_CTRL_BITS +     \
  95 +               BCM2835_TS_TSENSCTL_CTRL_SHIFT - 1, \
  96 +               BCM2835_TS_TSENSCTL_CTRL_SHIFT)
  97 +#define BCM2835_TS_TSENSCTL_CTRL_DEFAULT       1
  98 +#define BCM2835_TS_TSENSCTL_EN_INT             BIT(5)
  99 +#define BCM2835_TS_TSENSCTL_DIRECT             BIT(6)
 100 +#define BCM2835_TS_TSENSCTL_CLR_INT            BIT(7)
 101 +#define BCM2835_TS_TSENSCTL_THOLD_SHIFT                8
 102 +#define BCM2835_TS_TSENSCTL_THOLD_BITS         10
 103 +#define BCM2835_TS_TSENSCTL_THOLD_MASK              \
 104 +       GENMASK(BCM2835_TS_TSENSCTL_THOLD_BITS +     \
 105 +               BCM2835_TS_TSENSCTL_THOLD_SHIFT - 1, \
 106 +               BCM2835_TS_TSENSCTL_THOLD_SHIFT)
 107 +/*
 108 + * time how long the block to be asserted in reset
 109 + * which based on a clock counter (TSENS clock assumed)
 110 + */
 111 +#define BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT     18
 112 +#define BCM2835_TS_TSENSCTL_RSTDELAY_BITS      8
 113 +#define BCM2835_TS_TSENSCTL_REGULEN            BIT(26)
 114 +
 115 +#define BCM2835_TS_TSENSSTAT_DATA_BITS         10
 116 +#define BCM2835_TS_TSENSSTAT_DATA_SHIFT                0
 117 +#define BCM2835_TS_TSENSSTAT_DATA_MASK              \
 118 +       GENMASK(BCM2835_TS_TSENSSTAT_DATA_BITS +     \
 119 +               BCM2835_TS_TSENSSTAT_DATA_SHIFT - 1, \
 120 +               BCM2835_TS_TSENSSTAT_DATA_SHIFT)
 121 +#define BCM2835_TS_TSENSSTAT_VALID             BIT(10)
 122 +#define BCM2835_TS_TSENSSTAT_INTERRUPT         BIT(11)
 123 +
 124 +struct bcm2835_thermal_data {
 125 +       struct thermal_zone_device *tz;
 126 +       void __iomem *regs;
 127 +       struct clk *clk;
 128 +       struct dentry *debugfsdir;
 129 +};
 130 +
 131 +static int bcm2835_thermal_adc2temp(u32 adc, int offset, int slope)
 132 +{
 133 +       return offset + slope * adc;
 134 +}
 135 +
 136 +static int bcm2835_thermal_temp2adc(int temp, int offset, int slope)
 137 +{
 138 +       temp -= offset;
 139 +       temp /= slope;
 140 +
 141 +       if (temp < 0)
 142 +               temp = 0;
 143 +       if (temp >= BIT(BCM2835_TS_TSENSSTAT_DATA_BITS))
 144 +               temp = BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1;
 145 +
 146 +       return temp;
 147 +}
 148 +
 149 +static int bcm2835_thermal_get_temp(void *d, int *temp)
 150 +{
 151 +       struct bcm2835_thermal_data *data = d;
 152 +       u32 val = readl(data->regs + BCM2835_TS_TSENSSTAT);
 153 +
 154 +       if (!(val & BCM2835_TS_TSENSSTAT_VALID))
 155 +               return -EIO;
 156 +
 157 +       val &= BCM2835_TS_TSENSSTAT_DATA_MASK;
 158 +
 159 +       *temp = bcm2835_thermal_adc2temp(
 160 +               val,
 161 +               thermal_zone_get_offset(data->tz),
 162 +               thermal_zone_get_slope(data->tz));
 163 +
 164 +       return 0;
 165 +}
 166 +
 167 +static const struct debugfs_reg32 bcm2835_thermal_regs[] = {
 168 +       {
 169 +               .name = "ctl",
 170 +               .offset = 0
 171 +       },
 172 +       {
 173 +               .name = "stat",
 174 +               .offset = 4
 175 +       }
 176 +};
 177 +
 178 +static void bcm2835_thermal_debugfs(struct platform_device *pdev)
 179 +{
 180 +       struct thermal_zone_device *tz = platform_get_drvdata(pdev);
 181 +       struct bcm2835_thermal_data *data = tz->devdata;
 182 +       struct debugfs_regset32 *regset;
 183 +
 184 +       data->debugfsdir = debugfs_create_dir("bcm2835_thermal", NULL);
 185 +       if (!data->debugfsdir)
 186 +               return;
 187 +
 188 +       regset = devm_kzalloc(&pdev->dev, sizeof(*regset), GFP_KERNEL);
 189 +       if (!regset)
 190 +               return;
 191 +
 192 +       regset->regs = bcm2835_thermal_regs;
 193 +       regset->nregs = ARRAY_SIZE(bcm2835_thermal_regs);
 194 +       regset->base = data->regs;
 195 +
 196 +       debugfs_create_regset32("regset", 0444, data->debugfsdir, regset);
 197 +}
 198 +
 199 +static struct thermal_zone_of_device_ops bcm2835_thermal_ops = {
 200 +       .get_temp = bcm2835_thermal_get_temp,
 201 +};
 202 +
 203 +/*
 204 + * Note: as per Raspberry Foundation FAQ
 205 + * (https://www.raspberrypi.org/help/faqs/#performanceOperatingTemperature)
 206 + * the recommended temperature range for the SoC -40C to +85C
 207 + * so the trip limit is set to 80C.
 208 + * this applies to all the BCM283X SoC
 209 + */
 210 +
 211 +static const struct of_device_id bcm2835_thermal_of_match_table[] = {
 212 +       {
 213 +               .compatible = "brcm,bcm2835-thermal",
 214 +       },
 215 +       {
 216 +               .compatible = "brcm,bcm2836-thermal",
 217 +       },
 218 +       {
 219 +               .compatible = "brcm,bcm2837-thermal",
 220 +       },
 221 +       {},
 222 +};
 223 +MODULE_DEVICE_TABLE(of, bcm2835_thermal_of_match_table);
 224 +
 225 +static int bcm2835_thermal_probe(struct platform_device *pdev)
 226 +{
 227 +       const struct of_device_id *match;
 228 +       struct thermal_zone_device *tz;
 229 +       struct bcm2835_thermal_data *data;
 230 +       struct resource *res;
 231 +       int err = 0;
 232 +       u32 val;
 233 +       unsigned long rate;
 234 +
 235 +       data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 236 +       if (!data)
 237 +               return -ENOMEM;
 238 +
 239 +       match = of_match_device(bcm2835_thermal_of_match_table,
 240 +                               &pdev->dev);
 241 +       if (!match)
 242 +               return -EINVAL;
 243 +
 244 +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 245 +       data->regs = devm_ioremap_resource(&pdev->dev, res);
 246 +       if (IS_ERR(data->regs)) {
 247 +               err = PTR_ERR(data->regs);
 248 +               dev_err(&pdev->dev, "Could not get registers: %d\n", err);
 249 +               return err;
 250 +       }
 251 +
 252 +       data->clk = devm_clk_get(&pdev->dev, NULL);
 253 +       if (IS_ERR(data->clk)) {
 254 +               err = PTR_ERR(data->clk);
 255 +               if (err != -EPROBE_DEFER)
 256 +                       dev_err(&pdev->dev, "Could not get clk: %d\n", err);
 257 +               return err;
 258 +       }
 259 +
 260 +       err = clk_prepare_enable(data->clk);
 261 +       if (err)
 262 +               return err;
 263 +
 264 +       rate = clk_get_rate(data->clk);
 265 +       if ((rate < 1920000) || (rate > 5000000))
 266 +               dev_warn(&pdev->dev,
 267 +                        "Clock %pCn running at %pCr Hz is outside of the recommended range: 1.92 to 5MHz\n",
 268 +                        data->clk, data->clk);
 269 +
 270 +       /* register of thermal sensor and get info from DT */
 271 +       tz = thermal_zone_of_sensor_register(&pdev->dev, 0, data,
 272 +                                            &bcm2835_thermal_ops);
 273 +       if (IS_ERR(tz)) {
 274 +               err = PTR_ERR(tz);
 275 +               dev_err(&pdev->dev,
 276 +                       "Failed to register the thermal device: %d\n",
 277 +                       err);
 278 +               goto err_clk;
 279 +       }
 280 +
 281 +       /*
 282 +        * right now the FW does set up the HW-block, so we are not
 283 +        * touching the configuration registers.
 284 +        * But if the HW is not enabled, then set it up
 285 +        * using "sane" values used by the firmware right now.
 286 +        */
 287 +       val = readl(data->regs + BCM2835_TS_TSENSCTL);
 288 +       if (!(val & BCM2835_TS_TSENSCTL_RSTB)) {
 289 +               int trip_temp, offset, slope;
 290 +
 291 +               slope = thermal_zone_get_slope(tz);
 292 +               offset = thermal_zone_get_offset(tz);
 293 +               /*
 294 +                * For now we deal only with critical, otherwise
 295 +                * would need to iterate
 296 +                */
 297 +               err = tz->ops->get_trip_temp(tz, 0, &trip_temp);
 298 +               if (err < 0) {
 299 +                       err = PTR_ERR(tz);
 300 +                       dev_err(&pdev->dev,
 301 +                               "Not able to read trip_temp: %d\n",
 302 +                               err);
 303 +                       goto err_tz;
 304 +               }
 305 +
 306 +               /* set bandgap reference voltage and enable voltage regulator */
 307 +               val = (BCM2835_TS_TSENSCTL_CTRL_DEFAULT <<
 308 +                      BCM2835_TS_TSENSCTL_CTRL_SHIFT) |
 309 +                     BCM2835_TS_TSENSCTL_REGULEN;
 310 +
 311 +               /* use the recommended reset duration */
 312 +               val |= (0xFE << BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT);
 313 +
 314 +               /*  trip_adc value from info */
 315 +               val |= bcm2835_thermal_temp2adc(trip_temp,
 316 +                                               offset,
 317 +                                               slope)
 318 +                       << BCM2835_TS_TSENSCTL_THOLD_SHIFT;
 319 +
 320 +               /* write the value back to the register as 2 steps */
 321 +               writel(val, data->regs + BCM2835_TS_TSENSCTL);
 322 +               val |= BCM2835_TS_TSENSCTL_RSTB;
 323 +               writel(val, data->regs + BCM2835_TS_TSENSCTL);
 324 +       }
 325 +
 326 +       data->tz = tz;
 327 +
 328 +       platform_set_drvdata(pdev, tz);
 329 +
 330 +       bcm2835_thermal_debugfs(pdev);
 331 +
 332 +       return 0;
 333 +err_tz:
 334 +       thermal_zone_of_sensor_unregister(&pdev->dev, tz);
 335 +err_clk:
 336 +       clk_disable_unprepare(data->clk);
 337 +
 338 +       return err;
 339 +}
 340 +
 341 +static int bcm2835_thermal_remove(struct platform_device *pdev)
 342 +{
 343 +       struct thermal_zone_device *tz = platform_get_drvdata(pdev);
 344 +       struct bcm2835_thermal_data *data = tz->devdata;
 345 +
 346 +       debugfs_remove_recursive(data->debugfsdir);
 347 +       thermal_zone_of_sensor_unregister(&pdev->dev, tz);
 348 +       clk_disable_unprepare(data->clk);
 349 +
 350 +       return 0;
 351 +}
 352 +
 353 +static struct platform_driver bcm2835_thermal_driver = {
 354 +       .probe = bcm2835_thermal_probe,
 355 +       .remove = bcm2835_thermal_remove,
 356 +       .driver = {
 357 +               .name = "bcm2835_thermal",
 358 +               .of_match_table = bcm2835_thermal_of_match_table,
 359 +       },
 360 +};
 361 +module_platform_driver(bcm2835_thermal_driver);
 362 +
 363 +MODULE_AUTHOR("Martin Sperl");
 364 +MODULE_DESCRIPTION("Thermal driver for bcm2835 chip");
 365 +MODULE_LICENSE("GPL");