drivers/thermal/zx2967_thermal.c

   1 /*
   2  * ZTE's zx2967 family thermal sensor driver
   3  *
   4  * Copyright (C) 2017 ZTE Ltd.
   5  *
   6  * Author: Baoyou Xie <baoyou.xie@linaro.org>
   7  *
   8  * License terms: GNU General Public License (GPL) version 2
   9  */
  10
  11 #include <linux/clk.h>
  12 #include <linux/device.h>
  13 #include <linux/err.h>
  14 #include <linux/iopoll.h>
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/thermal.h>
  18
  19 /* Power Mode: 0->low 1->high */
  20 #define ZX2967_THERMAL_POWER_MODE       0
  21 #define ZX2967_POWER_MODE_LOW           0
  22 #define ZX2967_POWER_MODE_HIGH          1
  23
  24 /* DCF Control Register */
  25 #define ZX2967_THERMAL_DCF              0x4
  26 #define ZX2967_DCF_EN                   BIT(1)
  27 #define ZX2967_DCF_FREEZE               BIT(0)
  28
  29 /* Selection Register */
  30 #define ZX2967_THERMAL_SEL              0x8
  31
  32 /* Control Register */
  33 #define ZX2967_THERMAL_CTRL             0x10
  34
  35 #define ZX2967_THERMAL_READY            BIT(12)
  36 #define ZX2967_THERMAL_TEMP_MASK        GENMASK(11, 0)
  37 #define ZX2967_THERMAL_ID_MASK          0x18
  38 #define ZX2967_THERMAL_ID               0x10
  39
  40 #define ZX2967_GET_TEMP_TIMEOUT_US      (100 * 1024)
  41
  42 /**
  43  * struct zx2967_thermal_priv - zx2967 thermal sensor private structure
  44  * @tzd: struct thermal_zone_device where the sensor is registered
  45  * @lock: prevents read sensor in parallel
  46  * @clk_topcrm: topcrm clk structure
  47  * @clk_apb: apb clk structure
  48  * @regs: pointer to base address of the thermal sensor
  49  */
  50
  51 struct zx2967_thermal_priv {
  52         struct thermal_zone_device      *tzd;
  53         struct mutex                    lock;
  54         struct clk                      *clk_topcrm;
  55         struct clk                      *clk_apb;
  56         void __iomem                    *regs;
  57         struct device                   *dev;
  58 };
  59
  60 static int zx2967_thermal_get_temp(void *data, int *temp)
  61 {
  62         void __iomem *regs;
  63         struct zx2967_thermal_priv *priv = data;
  64         u32 val;
  65         int ret;
  66
  67         if (!priv->tzd)
  68                 return -EAGAIN;
  69
  70         regs = priv->regs;
  71         mutex_lock(&priv->lock);
  72         writel_relaxed(ZX2967_POWER_MODE_LOW,
  73                        regs + ZX2967_THERMAL_POWER_MODE);
  74         writel_relaxed(ZX2967_DCF_EN, regs + ZX2967_THERMAL_DCF);
  75
  76         val = readl_relaxed(regs + ZX2967_THERMAL_SEL);
  77         val &= ~ZX2967_THERMAL_ID_MASK;
  78         val |= ZX2967_THERMAL_ID;
  79         writel_relaxed(val, regs + ZX2967_THERMAL_SEL);
  80
  81         /*
  82          * Must wait for a while, surely it's a bit odd.
  83          * otherwise temperature value we got has a few deviation, even if
  84          * the THERMAL_READY bit is set.
  85          */
  86         usleep_range(100, 300);
  87         ret = readx_poll_timeout(readl, regs + ZX2967_THERMAL_CTRL,
  88                                  val, val & ZX2967_THERMAL_READY, 300,
  89                                  ZX2967_GET_TEMP_TIMEOUT_US);
  90         if (ret) {
  91                 dev_err(priv->dev, "Thermal sensor data timeout\n");
  92                 goto unlock;
  93         }
  94
  95         writel_relaxed(ZX2967_DCF_FREEZE | ZX2967_DCF_EN,
  96                        regs + ZX2967_THERMAL_DCF);
  97         val = readl_relaxed(regs + ZX2967_THERMAL_CTRL)
  98                          & ZX2967_THERMAL_TEMP_MASK;
  99         writel_relaxed(ZX2967_POWER_MODE_HIGH,
 100                        regs + ZX2967_THERMAL_POWER_MODE);
 101
 102         /*
 103          * Calculate temperature
 104          * In dts, slope is multiplied by 1000.
 105          */
 106         *temp = DIV_ROUND_CLOSEST(((s32)val + priv->tzd->tzp->offset) * 1000,
 107                                   priv->tzd->tzp->slope);
 108
 109 unlock:
 110         mutex_unlock(&priv->lock);
 111         return ret;
 112 }
 113
 114 static const struct thermal_zone_of_device_ops zx2967_of_thermal_ops = {
 115         .get_temp = zx2967_thermal_get_temp,
 116 };
 117
 118 static int zx2967_thermal_probe(struct platform_device *pdev)
 119 {
 120         struct zx2967_thermal_priv *priv;
 121         struct resource *res;
 122         int ret;
 123
 124         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 125         if (!priv)
 126                 return -ENOMEM;
 127
 128         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 129         priv->regs = devm_ioremap_resource(&pdev->dev, res);
 130         if (IS_ERR(priv->regs))
 131                 return PTR_ERR(priv->regs);
 132
 133         priv->clk_topcrm = devm_clk_get(&pdev->dev, "topcrm");
 134         if (IS_ERR(priv->clk_topcrm)) {
 135                 ret = PTR_ERR(priv->clk_topcrm);
 136                 dev_err(&pdev->dev, "failed to get topcrm clock: %d\n", ret);
 137                 return ret;
 138         }
 139
 140         ret = clk_prepare_enable(priv->clk_topcrm);
 141         if (ret) {
 142                 dev_err(&pdev->dev, "failed to enable topcrm clock: %d\n",
 143                         ret);
 144                 return ret;
 145         }
 146
 147         priv->clk_apb = devm_clk_get(&pdev->dev, "apb");
 148         if (IS_ERR(priv->clk_apb)) {
 149                 ret = PTR_ERR(priv->clk_apb);
 150                 dev_err(&pdev->dev, "failed to get apb clock: %d\n", ret);
 151                 goto disable_clk_topcrm;
 152         }
 153
 154         ret = clk_prepare_enable(priv->clk_apb);
 155         if (ret) {
 156                 dev_err(&pdev->dev, "failed to enable apb clock: %d\n",
 157                         ret);
 158                 goto disable_clk_topcrm;
 159         }
 160
 161         mutex_init(&priv->lock);
 162         priv->tzd = thermal_zone_of_sensor_register(&pdev->dev,
 163                                         0, priv, &zx2967_of_thermal_ops);
 164
 165         if (IS_ERR(priv->tzd)) {
 166                 ret = PTR_ERR(priv->tzd);
 167                 dev_err(&pdev->dev, "failed to register sensor: %d\n", ret);
 168                 goto disable_clk_all;
 169         }
 170
 171         if (priv->tzd->tzp->slope == 0) {
 172                 thermal_zone_of_sensor_unregister(&pdev->dev, priv->tzd);
 173                 dev_err(&pdev->dev, "coefficients of sensor is invalid\n");
 174                 ret = -EINVAL;
 175                 goto disable_clk_all;
 176         }
 177
 178         priv->dev = &pdev->dev;
 179         platform_set_drvdata(pdev, priv);
 180
 181         return 0;
 182
 183 disable_clk_all:
 184         clk_disable_unprepare(priv->clk_apb);
 185 disable_clk_topcrm:
 186         clk_disable_unprepare(priv->clk_topcrm);
 187         return ret;
 188 }
 189
 190 static int zx2967_thermal_exit(struct platform_device *pdev)
 191 {
 192         struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
 193
 194         thermal_zone_of_sensor_unregister(&pdev->dev, priv->tzd);
 195         clk_disable_unprepare(priv->clk_topcrm);
 196         clk_disable_unprepare(priv->clk_apb);
 197
 198         return 0;
 199 }
 200
 201 static const struct of_device_id zx2967_thermal_id_table[] = {
 202         { .compatible = "zte,zx296718-thermal" },
 203         {}
 204 };
 205 MODULE_DEVICE_TABLE(of, zx2967_thermal_id_table);
 206
 207 #ifdef CONFIG_PM_SLEEP
 208 static int zx2967_thermal_suspend(struct device *dev)
 209 {
 210         struct zx2967_thermal_priv *priv = dev_get_drvdata(dev);
 211
 212         if (priv && priv->clk_topcrm)
 213                 clk_disable_unprepare(priv->clk_topcrm);
 214
 215         if (priv && priv->clk_apb)
 216                 clk_disable_unprepare(priv->clk_apb);
 217
 218         return 0;
 219 }
 220
 221 static int zx2967_thermal_resume(struct device *dev)
 222 {
 223         struct zx2967_thermal_priv *priv = dev_get_drvdata(dev);
 224         int error;
 225
 226         error = clk_prepare_enable(priv->clk_topcrm);
 227         if (error)
 228                 return error;
 229
 230         error = clk_prepare_enable(priv->clk_apb);
 231         if (error) {
 232                 clk_disable_unprepare(priv->clk_topcrm);
 233                 return error;
 234         }
 235
 236         return 0;
 237 }
 238 #endif
 239
 240 static SIMPLE_DEV_PM_OPS(zx2967_thermal_pm_ops,
 241                          zx2967_thermal_suspend, zx2967_thermal_resume);
 242
 243 static struct platform_driver zx2967_thermal_driver = {
 244         .probe = zx2967_thermal_probe,
 245         .remove = zx2967_thermal_exit,
 246         .driver = {
 247                 .name = "zx2967_thermal",
 248                 .of_match_table = zx2967_thermal_id_table,
 249                 .pm = &zx2967_thermal_pm_ops,
 250         },
 251 };
 252 module_platform_driver(zx2967_thermal_driver);
 253
 254 MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
 255 MODULE_DESCRIPTION("ZTE zx2967 thermal driver");
 256 MODULE_LICENSE("GPL v2");