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