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133 lines
2.8 KiB
133 lines
2.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* Lantiq cpu temperature sensor driver |
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* |
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* Copyright (C) 2017 Florian Eckert <[email protected]> |
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*/ |
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#include <linux/bitops.h> |
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#include <linux/delay.h> |
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#include <linux/hwmon.h> |
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#include <linux/hwmon-sysfs.h> |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/of_device.h> |
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#include <lantiq_soc.h> |
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/* gphy1 configuration register contains cpu temperature */ |
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#define CGU_GPHY1_CR 0x0040 |
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#define CGU_TEMP_PD BIT(19) |
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static void ltq_cputemp_enable(void) |
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{ |
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ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR); |
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} |
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static void ltq_cputemp_disable(void *data) |
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{ |
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ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) & ~CGU_TEMP_PD, CGU_GPHY1_CR); |
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} |
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static int ltq_read(struct device *dev, enum hwmon_sensor_types type, |
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u32 attr, int channel, long *temp) |
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{ |
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int value; |
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switch (attr) { |
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case hwmon_temp_input: |
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/* get the temperature including one decimal place */ |
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value = (ltq_cgu_r32(CGU_GPHY1_CR) >> 9) & 0x01FF; |
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value = value * 5; |
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/* range -38 to +154 °C, register value zero is -38.0 °C */ |
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value -= 380; |
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/* scale temp to millidegree */ |
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value = value * 100; |
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break; |
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default: |
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return -EOPNOTSUPP; |
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} |
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*temp = value; |
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return 0; |
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} |
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static umode_t ltq_is_visible(const void *_data, enum hwmon_sensor_types type, |
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u32 attr, int channel) |
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{ |
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if (type != hwmon_temp) |
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return 0; |
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switch (attr) { |
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case hwmon_temp_input: |
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return 0444; |
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default: |
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return 0; |
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} |
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} |
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static const struct hwmon_channel_info *ltq_info[] = { |
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HWMON_CHANNEL_INFO(chip, |
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HWMON_C_REGISTER_TZ), |
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HWMON_CHANNEL_INFO(temp, |
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HWMON_T_INPUT), |
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NULL |
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}; |
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static const struct hwmon_ops ltq_hwmon_ops = { |
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.is_visible = ltq_is_visible, |
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.read = ltq_read, |
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}; |
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static const struct hwmon_chip_info ltq_chip_info = { |
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.ops = <q_hwmon_ops, |
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.info = ltq_info, |
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}; |
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static int ltq_cputemp_probe(struct platform_device *pdev) |
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{ |
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struct device *hwmon_dev; |
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int err = 0; |
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/* available on vr9 v1.2 SoCs only */ |
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if (ltq_soc_type() != SOC_TYPE_VR9_2) |
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return -ENODEV; |
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err = devm_add_action(&pdev->dev, ltq_cputemp_disable, NULL); |
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if (err) |
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return err; |
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ltq_cputemp_enable(); |
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hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, |
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"ltq_cputemp", |
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NULL, |
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<q_chip_info, |
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NULL); |
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if (IS_ERR(hwmon_dev)) { |
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dev_err(&pdev->dev, "Failed to register as hwmon device"); |
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return PTR_ERR(hwmon_dev); |
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} |
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return 0; |
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} |
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const struct of_device_id ltq_cputemp_match[] = { |
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{ .compatible = "lantiq,cputemp" }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, ltq_cputemp_match); |
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static struct platform_driver ltq_cputemp_driver = { |
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.probe = ltq_cputemp_probe, |
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.driver = { |
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.name = "ltq-cputemp", |
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.of_match_table = ltq_cputemp_match, |
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}, |
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}; |
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module_platform_driver(ltq_cputemp_driver); |
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MODULE_AUTHOR("Florian Eckert <[email protected]>"); |
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MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver"); |
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MODULE_LICENSE("GPL");
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