134 lines
2.8 KiB
C
134 lines
2.8 KiB
C
// 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 <fe@dev.tdt.de>
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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 * const 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 <fe@dev.tdt.de>");
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MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver");
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MODULE_LICENSE("GPL");
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