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