diff options
Diffstat (limited to 'drivers/hwmon/ltq-cputemp.c')
| -rw-r--r-- | drivers/hwmon/ltq-cputemp.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/hwmon/ltq-cputemp.c b/drivers/hwmon/ltq-cputemp.c new file mode 100644 index 000000000..1d33f9459 --- /dev/null +++ b/drivers/hwmon/ltq-cputemp.c @@ -0,0 +1,163 @@ +/* Lantiq cpu temperature sensor driver + * + * Copyright (C) 2017 Florian Eckert <fe@dev.tdt.de> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version + * + * This program is distributed in the hope that it will be useful + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/> + */ + +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/of_device.h> + +#include <lantiq_soc.h> + +/* gphy1 configuration register contains cpu temperature */ +#define CGU_GPHY1_CR 0x0040 +#define CGU_TEMP_PD BIT(19) + +static void ltq_cputemp_enable(void) +{ + ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR); +} + +static void ltq_cputemp_disable(void *data) +{ + ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) & ~CGU_TEMP_PD, CGU_GPHY1_CR); +} + +static int ltq_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *temp) +{ + int value; + + switch (attr) { + case hwmon_temp_input: + /* get the temperature including one decimal place */ + value = (ltq_cgu_r32(CGU_GPHY1_CR) >> 9) & 0x01FF; + value = value * 5; + /* range -38 to +154 °C, register value zero is -38.0 °C */ + value -= 380; + /* scale temp to millidegree */ + value = value * 100; + break; + default: + return -EOPNOTSUPP; + } + + *temp = value; + return 0; +} + +static umode_t ltq_is_visible(const void *_data, enum hwmon_sensor_types type, + u32 attr, int channel) +{ + if (type != hwmon_temp) + return 0; + + switch (attr) { + case hwmon_temp_input: + return 0444; + default: + return 0; + } +} + +static const u32 ltq_chip_config[] = { + HWMON_C_REGISTER_TZ, + 0 +}; + +static const struct hwmon_channel_info ltq_chip = { + .type = hwmon_chip, + .config = ltq_chip_config, +}; + +static const u32 ltq_temp_config[] = { + HWMON_T_INPUT, + 0 +}; + +static const struct hwmon_channel_info ltq_temp = { + .type = hwmon_temp, + .config = ltq_temp_config, +}; + +static const struct hwmon_channel_info *ltq_info[] = { + <q_chip, + <q_temp, + NULL +}; + +static const struct hwmon_ops ltq_hwmon_ops = { + .is_visible = ltq_is_visible, + .read = ltq_read, +}; + +static const struct hwmon_chip_info ltq_chip_info = { + .ops = <q_hwmon_ops, + .info = ltq_info, +}; + +static int ltq_cputemp_probe(struct platform_device *pdev) +{ + struct device *hwmon_dev; + int err = 0; + + /* available on vr9 v1.2 SoCs only */ + if (ltq_soc_type() != SOC_TYPE_VR9_2) + return -ENODEV; + + err = devm_add_action(&pdev->dev, ltq_cputemp_disable, NULL); + if (err) + return err; + + ltq_cputemp_enable(); + + hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, + "ltq_cputemp", + NULL, + <q_chip_info, + NULL); + + if (IS_ERR(hwmon_dev)) { + dev_err(&pdev->dev, "Failed to register as hwmon device"); + return PTR_ERR(hwmon_dev); + } + + return 0; +} + +const struct of_device_id ltq_cputemp_match[] = { + { .compatible = "lantiq,cputemp" }, + {}, +}; +MODULE_DEVICE_TABLE(of, ltq_cputemp_match); + +static struct platform_driver ltq_cputemp_driver = { + .probe = ltq_cputemp_probe, + .driver = { + .name = "ltq-cputemp", + .of_match_table = ltq_cputemp_match, + }, +}; + +module_platform_driver(ltq_cputemp_driver); + +MODULE_AUTHOR("Florian Eckert <fe@dev.tdt.de>"); +MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver"); +MODULE_LICENSE("GPL"); |