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->devdata; 31 32 reg = readl_relaxed(priv->sensor); 33 34 /* Valid check */ 35 if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) & 36 KIRKWOOD_THERMAL_VALID_MASK)) { 37 dev_err(&thermal->device, 38 "Temperature sensor reading not valid\n"); 39 return -EIO; 40 } 41 42 /* 43 * Calculate temperature. According to Marvell internal 44 * documentation the formula for this is: 45 * Celsius = (322-reg)/1.3625 46 */ 47 reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) & 48 KIRKWOOD_THERMAL_TEMP_MASK; 49 *temp = ((3220000000UL - (10000000UL * reg)) / 13625); 50 51 return 0; 52 } 53 54 static struct thermal_zone_device_ops ops = { 55 .get_temp = kirkwood_get_temp, 56 }; 57 58 static const struct of_device_id kirkwood_thermal_id_table[] = { 59 { .compatible = "marvell,kirkwood-thermal" }, 60 {} 61 }; 62 63 static int kirkwood_thermal_probe(struct platform_device *pdev) 64 { 65 struct thermal_zone_device *thermal = NULL; 66 struct kirkwood_thermal_priv *priv; 67 struct resource *res; 68 69 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 70 if (!priv) 71 return -ENOMEM; 72 73 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 74 priv->sensor = devm_ioremap_resource(&pdev->dev, res); 75 if (IS_ERR(priv->sensor)) 76 return PTR_ERR(priv->sensor); 77 78 thermal = thermal_zone_device_register("kirkwood_thermal", 0, 0, 79 priv, &ops, NULL, 0, 0); 80 if (IS_ERR(thermal)) { 81 dev_err(&pdev->dev, 82 "Failed to register thermal zone device\n"); 83 return PTR_ERR(thermal); 84 } 85 86 platform_set_drvdata(pdev, thermal); 87 88 return 0; 89 } 90 91 static int kirkwood_thermal_exit(struct platform_device *pdev) 92 { 93 struct thermal_zone_device *kirkwood_thermal = 94 platform_get_drvdata(pdev); 95 96 thermal_zone_device_unregister(kirkwood_thermal); 97 98 return 0; 99 } 100 101 MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table); 102 103 static struct platform_driver kirkwood_thermal_driver = { 104 .probe = kirkwood_thermal_probe, 105 .remove = kirkwood_thermal_exit, 106 .driver = { 107 .name = "kirkwood_thermal", 108 .of_match_table = kirkwood_thermal_id_table, 109 }, 110 }; 111 112 module_platform_driver(kirkwood_thermal_driver); 113 114 MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>"); 115 MODULE_DESCRIPTION("kirkwood thermal driver"); 116 MODULE_LICENSE("GPL"); 117