1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. 4 */ 5 6 #include <linux/module.h> 7 #include <linux/of_address.h> 8 #include <linux/platform_device.h> 9 #include <linux/thermal.h> 10 11 struct thermal_mmio { 12 void __iomem *mmio_base; 13 u32 (*read_mmio)(void __iomem *mmio_base); 14 u32 mask; 15 int factor; 16 }; 17 18 static u32 thermal_mmio_readb(void __iomem *mmio_base) 19 { 20 return readb(mmio_base); 21 } 22 23 static int thermal_mmio_get_temperature(void *private, int *temp) 24 { 25 int t; 26 struct thermal_mmio *sensor = 27 (struct thermal_mmio *)private; 28 29 t = sensor->read_mmio(sensor->mmio_base) & sensor->mask; 30 t *= sensor->factor; 31 32 *temp = t; 33 34 return 0; 35 } 36 37 static const struct thermal_zone_of_device_ops thermal_mmio_ops = { 38 .get_temp = thermal_mmio_get_temperature, 39 }; 40 41 static int thermal_mmio_probe(struct platform_device *pdev) 42 { 43 struct resource *resource; 44 struct thermal_mmio *sensor; 45 int (*sensor_init_func)(struct platform_device *pdev, 46 struct thermal_mmio *sensor); 47 struct thermal_zone_device *thermal_zone; 48 int ret; 49 int temperature; 50 51 sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL); 52 if (!sensor) 53 return -ENOMEM; 54 55 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0); 56 sensor->mmio_base = devm_ioremap_resource(&pdev->dev, resource); 57 if (IS_ERR(sensor->mmio_base)) 58 return PTR_ERR(sensor->mmio_base); 59 60 sensor_init_func = device_get_match_data(&pdev->dev); 61 if (sensor_init_func) { 62 ret = sensor_init_func(pdev, sensor); 63 if (ret) { 64 dev_err(&pdev->dev, 65 "failed to initialize sensor (%d)\n", 66 ret); 67 return ret; 68 } 69 } 70 71 thermal_zone = devm_thermal_zone_of_sensor_register(&pdev->dev, 72 0, 73 sensor, 74 &thermal_mmio_ops); 75 if (IS_ERR(thermal_zone)) { 76 dev_err(&pdev->dev, 77 "failed to register sensor (%ld)\n", 78 PTR_ERR(thermal_zone)); 79 return PTR_ERR(thermal_zone); 80 } 81 82 thermal_mmio_get_temperature(sensor, &temperature); 83 dev_info(&pdev->dev, 84 "thermal mmio sensor %s registered, current temperature: %d\n", 85 pdev->name, temperature); 86 87 return 0; 88 } 89 90 static int al_thermal_init(struct platform_device *pdev, 91 struct thermal_mmio *sensor) 92 { 93 sensor->read_mmio = thermal_mmio_readb; 94 sensor->mask = 0xff; 95 sensor->factor = 1000; 96 97 return 0; 98 } 99 100 static const struct of_device_id thermal_mmio_id_table[] = { 101 { .compatible = "amazon,al-thermal", .data = al_thermal_init}, 102 {} 103 }; 104 MODULE_DEVICE_TABLE(of, thermal_mmio_id_table); 105 106 static struct platform_driver thermal_mmio_driver = { 107 .probe = thermal_mmio_probe, 108 .driver = { 109 .name = "thermal-mmio", 110 .of_match_table = of_match_ptr(thermal_mmio_id_table), 111 }, 112 }; 113 114 module_platform_driver(thermal_mmio_driver); 115 116 MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>"); 117 MODULE_DESCRIPTION("Thermal MMIO Driver"); 118 MODULE_LICENSE("GPL v2"); 119