1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Kirkwood thermal sensor driver 4 * 5 * Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org> 6 */ 7 #include <linux/device.h> 8 #include <linux/err.h> 9 #include <linux/io.h> 10 #include <linux/kernel.h> 11 #include <linux/of.h> 12 #include <linux/module.h> 13 #include <linux/platform_device.h> 14 #include <linux/thermal.h> 15 16 #define KIRKWOOD_THERMAL_VALID_OFFSET 9 17 #define KIRKWOOD_THERMAL_VALID_MASK 0x1 18 #define KIRKWOOD_THERMAL_TEMP_OFFSET 10 19 #define KIRKWOOD_THERMAL_TEMP_MASK 0x1FF 20 21 /* Kirkwood Thermal Sensor Dev Structure */ 22 struct kirkwood_thermal_priv { 23 void __iomem *sensor; 24 }; 25 26 static int kirkwood_get_temp(struct thermal_zone_device *thermal, 27 int *temp) 28 { 29 unsigned long reg; 30 struct kirkwood_thermal_priv *priv = thermal_zone_device_priv(thermal); 31 32 reg = readl_relaxed(priv->sensor); 33 34 /* Valid check */ 35 if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) & 36 KIRKWOOD_THERMAL_VALID_MASK)) 37 return -EIO; 38 39 /* 40 * Calculate temperature. According to Marvell internal 41 * documentation the formula for this is: 42 * Celsius = (322-reg)/1.3625 43 */ 44 reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) & 45 KIRKWOOD_THERMAL_TEMP_MASK; 46 *temp = ((3220000000UL - (10000000UL * reg)) / 13625); 47 48 return 0; 49 } 50 51 static struct thermal_zone_device_ops ops = { 52 .get_temp = kirkwood_get_temp, 53 }; 54 55 static const struct of_device_id kirkwood_thermal_id_table[] = { 56 { .compatible = "marvell,kirkwood-thermal" }, 57 {} 58 }; 59 60 static int kirkwood_thermal_probe(struct platform_device *pdev) 61 { 62 struct thermal_zone_device *thermal = NULL; 63 struct kirkwood_thermal_priv *priv; 64 int ret; 65 66 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 67 if (!priv) 68 return -ENOMEM; 69 70 priv->sensor = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); 71 if (IS_ERR(priv->sensor)) 72 return PTR_ERR(priv->sensor); 73 74 thermal = thermal_tripless_zone_device_register("kirkwood_thermal", 75 priv, &ops, NULL); 76 if (IS_ERR(thermal)) { 77 dev_err(&pdev->dev, 78 "Failed to register thermal zone device\n"); 79 return PTR_ERR(thermal); 80 } 81 ret = thermal_zone_device_enable(thermal); 82 if (ret) { 83 thermal_zone_device_unregister(thermal); 84 dev_err(&pdev->dev, "Failed to enable thermal zone device\n"); 85 return ret; 86 } 87 88 platform_set_drvdata(pdev, thermal); 89 90 return 0; 91 } 92 93 static int kirkwood_thermal_exit(struct platform_device *pdev) 94 { 95 struct thermal_zone_device *kirkwood_thermal = 96 platform_get_drvdata(pdev); 97 98 thermal_zone_device_unregister(kirkwood_thermal); 99 100 return 0; 101 } 102 103 MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table); 104 105 static struct platform_driver kirkwood_thermal_driver = { 106 .probe = kirkwood_thermal_probe, 107 .remove = kirkwood_thermal_exit, 108 .driver = { 109 .name = "kirkwood_thermal", 110 .of_match_table = kirkwood_thermal_id_table, 111 }, 112 }; 113 114 module_platform_driver(kirkwood_thermal_driver); 115 116 MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>"); 117 MODULE_DESCRIPTION("kirkwood thermal driver"); 118 MODULE_LICENSE("GPL"); 119