drivers/thermal/khadas_mcu_fan.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Khadas MCU Controlled FAN driver
   4  *
   5  * Copyright (C) 2020 BayLibre SAS
   6  * Author(s): Neil Armstrong <narmstrong@baylibre.com>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/of.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/mfd/khadas-mcu.h>
  13 #include <linux/regmap.h>
  14 #include <linux/sysfs.h>
  15 #include <linux/thermal.h>
  16
  17 #define MAX_LEVEL 3
  18
  19 struct khadas_mcu_fan_ctx {
  20         struct khadas_mcu *mcu;
  21         unsigned int level;
  22         struct thermal_cooling_device *cdev;
  23 };
  24
  25 static int khadas_mcu_fan_set_level(struct khadas_mcu_fan_ctx *ctx,
  26                                     unsigned int level)
  27 {
  28         int ret;
  29
  30         ret = regmap_write(ctx->mcu->regmap, KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG,
  31                            level);
  32         if (ret)
  33                 return ret;
  34
  35         ctx->level = level;
  36
  37         return 0;
  38 }
  39
  40 static int khadas_mcu_fan_get_max_state(struct thermal_cooling_device *cdev,
  41                                         unsigned long *state)
  42 {
  43         *state = MAX_LEVEL;
  44
  45         return 0;
  46 }
  47
  48 static int khadas_mcu_fan_get_cur_state(struct thermal_cooling_device *cdev,
  49                                         unsigned long *state)
  50 {
  51         struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
  52
  53         *state = ctx->level;
  54
  55         return 0;
  56 }
  57
  58 static int
  59 khadas_mcu_fan_set_cur_state(struct thermal_cooling_device *cdev,
  60                              unsigned long state)
  61 {
  62         struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
  63
  64         if (state > MAX_LEVEL)
  65                 return -EINVAL;
  66
  67         if (state == ctx->level)
  68                 return 0;
  69
  70         return khadas_mcu_fan_set_level(ctx, state);
  71 }
  72
  73 static const struct thermal_cooling_device_ops khadas_mcu_fan_cooling_ops = {
  74         .get_max_state = khadas_mcu_fan_get_max_state,
  75         .get_cur_state = khadas_mcu_fan_get_cur_state,
  76         .set_cur_state = khadas_mcu_fan_set_cur_state,
  77 };
  78
  79 static int khadas_mcu_fan_probe(struct platform_device *pdev)
  80 {
  81         struct khadas_mcu *mcu = dev_get_drvdata(pdev->dev.parent);
  82         struct thermal_cooling_device *cdev;
  83         struct device *dev = &pdev->dev;
  84         struct khadas_mcu_fan_ctx *ctx;
  85         int ret;
  86
  87         ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
  88         if (!ctx)
  89                 return -ENOMEM;
  90         ctx->mcu = mcu;
  91         platform_set_drvdata(pdev, ctx);
  92
  93         cdev = devm_thermal_of_cooling_device_register(dev->parent,
  94                         dev->parent->of_node, "khadas-mcu-fan", ctx,
  95                         &khadas_mcu_fan_cooling_ops);
  96         if (IS_ERR(cdev)) {
  97                 ret = PTR_ERR(cdev);
  98                 dev_err(dev, "Failed to register khadas-mcu-fan as cooling device: %d\n",
  99                         ret);
 100                 return ret;
 101         }
 102         ctx->cdev = cdev;
 103
 104         return 0;
 105 }
 106
 107 static void khadas_mcu_fan_shutdown(struct platform_device *pdev)
 108 {
 109         struct khadas_mcu_fan_ctx *ctx = platform_get_drvdata(pdev);
 110
 111         khadas_mcu_fan_set_level(ctx, 0);
 112 }
 113
 114 #ifdef CONFIG_PM_SLEEP
 115 static int khadas_mcu_fan_suspend(struct device *dev)
 116 {
 117         struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
 118         unsigned int level_save = ctx->level;
 119         int ret;
 120
 121         ret = khadas_mcu_fan_set_level(ctx, 0);
 122         if (ret)
 123                 return ret;
 124
 125         ctx->level = level_save;
 126
 127         return 0;
 128 }
 129
 130 static int khadas_mcu_fan_resume(struct device *dev)
 131 {
 132         struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
 133
 134         return khadas_mcu_fan_set_level(ctx, ctx->level);
 135 }
 136 #endif
 137
 138 static SIMPLE_DEV_PM_OPS(khadas_mcu_fan_pm, khadas_mcu_fan_suspend,
 139                          khadas_mcu_fan_resume);
 140
 141 static const struct platform_device_id khadas_mcu_fan_id_table[] = {
 142         { .name = "khadas-mcu-fan-ctrl", },
 143         {},
 144 };
 145 MODULE_DEVICE_TABLE(platform, khadas_mcu_fan_id_table);
 146
 147 static struct platform_driver khadas_mcu_fan_driver = {
 148         .probe          = khadas_mcu_fan_probe,
 149         .shutdown       = khadas_mcu_fan_shutdown,
 150         .driver = {
 151                 .name           = "khadas-mcu-fan-ctrl",
 152                 .pm             = &khadas_mcu_fan_pm,
 153         },
 154         .id_table       = khadas_mcu_fan_id_table,
 155 };
 156
 157 module_platform_driver(khadas_mcu_fan_driver);
 158
 159 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
 160 MODULE_DESCRIPTION("Khadas MCU FAN driver");
 161 MODULE_LICENSE("GPL");