drivers/hwmon/as370-hwmon.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Synaptics AS370 SoC Hardware Monitoring Driver
   4  *
   5  * Copyright (C) 2018 Synaptics Incorporated
   6  * Author: Jisheng Zhang <jszhang@kernel.org>
   7  */
   8
   9 #include <linux/bitops.h>
  10 #include <linux/hwmon.h>
  11 #include <linux/init.h>
  12 #include <linux/io.h>
  13 #include <linux/module.h>
  14 #include <linux/of_device.h>
  15
  16 #define CTRL            0x0
  17 #define  PD             BIT(0)
  18 #define  EN             BIT(1)
  19 #define  T_SEL          BIT(2)
  20 #define  V_SEL          BIT(3)
  21 #define  NMOS_SEL       BIT(8)
  22 #define  PMOS_SEL       BIT(9)
  23 #define STS             0x4
  24 #define  BN_MASK        GENMASK(11, 0)
  25 #define  EOC            BIT(12)
  26
  27 struct as370_hwmon {
  28         void __iomem *base;
  29 };
  30
  31 static void init_pvt(struct as370_hwmon *hwmon)
  32 {
  33         u32 val;
  34         void __iomem *addr = hwmon->base + CTRL;
  35
  36         val = PD;
  37         writel_relaxed(val, addr);
  38         val |= T_SEL;
  39         writel_relaxed(val, addr);
  40         val |= EN;
  41         writel_relaxed(val, addr);
  42         val &= ~PD;
  43         writel_relaxed(val, addr);
  44 }
  45
  46 static int as370_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
  47                             u32 attr, int channel, long *temp)
  48 {
  49         int val;
  50         struct as370_hwmon *hwmon = dev_get_drvdata(dev);
  51
  52         switch (attr) {
  53         case hwmon_temp_input:
  54                 val = readl_relaxed(hwmon->base + STS) & BN_MASK;
  55                 *temp = DIV_ROUND_CLOSEST(val * 251802, 4096) - 85525;
  56                 break;
  57         default:
  58                 return -EOPNOTSUPP;
  59         }
  60
  61         return 0;
  62 }
  63
  64 static umode_t
  65 as370_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
  66                        u32 attr, int channel)
  67 {
  68         if (type != hwmon_temp)
  69                 return 0;
  70
  71         switch (attr) {
  72         case hwmon_temp_input:
  73                 return 0444;
  74         default:
  75                 return 0;
  76         }
  77 }
  78
  79 static const struct hwmon_channel_info * const as370_hwmon_info[] = {
  80         HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
  81         NULL
  82 };
  83
  84 static const struct hwmon_ops as370_hwmon_ops = {
  85         .is_visible = as370_hwmon_is_visible,
  86         .read = as370_hwmon_read,
  87 };
  88
  89 static const struct hwmon_chip_info as370_chip_info = {
  90         .ops = &as370_hwmon_ops,
  91         .info = as370_hwmon_info,
  92 };
  93
  94 static int as370_hwmon_probe(struct platform_device *pdev)
  95 {
  96         struct device *hwmon_dev;
  97         struct as370_hwmon *hwmon;
  98         struct device *dev = &pdev->dev;
  99
 100         hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
 101         if (!hwmon)
 102                 return -ENOMEM;
 103
 104         hwmon->base = devm_platform_ioremap_resource(pdev, 0);
 105         if (IS_ERR(hwmon->base))
 106                 return PTR_ERR(hwmon->base);
 107
 108         init_pvt(hwmon);
 109
 110         hwmon_dev = devm_hwmon_device_register_with_info(dev,
 111                                                          "as370",
 112                                                          hwmon,
 113                                                          &as370_chip_info,
 114                                                          NULL);
 115         return PTR_ERR_OR_ZERO(hwmon_dev);
 116 }
 117
 118 static const struct of_device_id as370_hwmon_match[] = {
 119         { .compatible = "syna,as370-hwmon" },
 120         {},
 121 };
 122 MODULE_DEVICE_TABLE(of, as370_hwmon_match);
 123
 124 static struct platform_driver as370_hwmon_driver = {
 125         .probe = as370_hwmon_probe,
 126         .driver = {
 127                 .name = "as370-hwmon",
 128                 .of_match_table = as370_hwmon_match,
 129         },
 130 };
 131 module_platform_driver(as370_hwmon_driver);
 132
 133 MODULE_AUTHOR("Jisheng Zhang<jszhang@kernel.org>");
 134 MODULE_DESCRIPTION("Synaptics AS370 SoC hardware monitor");
 135 MODULE_LICENSE("GPL v2");