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Our driver configures the device to read at 2Hz, but then only allows the user to read cached temp values at up to 0.5Hz. Let's allow users to read as quickly as we do. Signed-off-by: Kyle Roeschley <kyle.roeschley@ni.com> Link: https://lore.kernel.org/r/20191014140310.7438-1-kyle.roeschley@ni.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
341 lines
7.6 KiB
C
341 lines
7.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* tmp421.c
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*
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* Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
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* Preliminary support by:
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* Melvin Rook, Raymond Ng
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*/
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/*
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* Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
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* Supported models: TMP421, TMP422, TMP423, TMP441, TMP442
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/jiffies.h>
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#include <linux/i2c.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include <linux/of_device.h>
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#include <linux/sysfs.h>
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/* Addresses to scan */
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static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
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I2C_CLIENT_END };
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enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 };
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/* The TMP421 registers */
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#define TMP421_STATUS_REG 0x08
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#define TMP421_CONFIG_REG_1 0x09
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#define TMP421_CONVERSION_RATE_REG 0x0B
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#define TMP421_MANUFACTURER_ID_REG 0xFE
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#define TMP421_DEVICE_ID_REG 0xFF
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static const u8 TMP421_TEMP_MSB[4] = { 0x00, 0x01, 0x02, 0x03 };
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static const u8 TMP421_TEMP_LSB[4] = { 0x10, 0x11, 0x12, 0x13 };
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/* Flags */
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#define TMP421_CONFIG_SHUTDOWN 0x40
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#define TMP421_CONFIG_RANGE 0x04
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/* Manufacturer / Device ID's */
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#define TMP421_MANUFACTURER_ID 0x55
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#define TMP421_DEVICE_ID 0x21
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#define TMP422_DEVICE_ID 0x22
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#define TMP423_DEVICE_ID 0x23
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#define TMP441_DEVICE_ID 0x41
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#define TMP442_DEVICE_ID 0x42
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static const struct i2c_device_id tmp421_id[] = {
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{ "tmp421", 2 },
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{ "tmp422", 3 },
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{ "tmp423", 4 },
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{ "tmp441", 2 },
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{ "tmp442", 3 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, tmp421_id);
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static const struct of_device_id __maybe_unused tmp421_of_match[] = {
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{
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.compatible = "ti,tmp421",
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.data = (void *)2
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},
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{
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.compatible = "ti,tmp422",
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.data = (void *)3
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},
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{
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.compatible = "ti,tmp423",
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.data = (void *)4
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},
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{
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.compatible = "ti,tmp441",
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.data = (void *)2
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},
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{
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.compatible = "ti,tmp442",
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.data = (void *)3
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},
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{ },
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};
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MODULE_DEVICE_TABLE(of, tmp421_of_match);
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struct tmp421_data {
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struct i2c_client *client;
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struct mutex update_lock;
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u32 temp_config[5];
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struct hwmon_channel_info temp_info;
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const struct hwmon_channel_info *info[2];
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struct hwmon_chip_info chip;
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char valid;
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unsigned long last_updated;
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unsigned long channels;
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u8 config;
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s16 temp[4];
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};
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static int temp_from_s16(s16 reg)
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{
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/* Mask out status bits */
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int temp = reg & ~0xf;
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return (temp * 1000 + 128) / 256;
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}
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static int temp_from_u16(u16 reg)
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{
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/* Mask out status bits */
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int temp = reg & ~0xf;
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/* Add offset for extended temperature range. */
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temp -= 64 * 256;
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return (temp * 1000 + 128) / 256;
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}
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static struct tmp421_data *tmp421_update_device(struct device *dev)
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{
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struct tmp421_data *data = dev_get_drvdata(dev);
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struct i2c_client *client = data->client;
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int i;
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mutex_lock(&data->update_lock);
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if (time_after(jiffies, data->last_updated + (HZ / 2)) ||
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!data->valid) {
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data->config = i2c_smbus_read_byte_data(client,
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TMP421_CONFIG_REG_1);
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for (i = 0; i < data->channels; i++) {
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data->temp[i] = i2c_smbus_read_byte_data(client,
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TMP421_TEMP_MSB[i]) << 8;
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data->temp[i] |= i2c_smbus_read_byte_data(client,
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TMP421_TEMP_LSB[i]);
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}
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data->last_updated = jiffies;
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data->valid = 1;
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}
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mutex_unlock(&data->update_lock);
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return data;
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}
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static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
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u32 attr, int channel, long *val)
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{
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struct tmp421_data *tmp421 = tmp421_update_device(dev);
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switch (attr) {
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case hwmon_temp_input:
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if (tmp421->config & TMP421_CONFIG_RANGE)
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*val = temp_from_u16(tmp421->temp[channel]);
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else
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*val = temp_from_s16(tmp421->temp[channel]);
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return 0;
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case hwmon_temp_fault:
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/*
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* The OPEN bit signals a fault. This is bit 0 of the temperature
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* register (low byte).
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*/
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*val = tmp421->temp[channel] & 0x01;
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return 0;
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default:
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return -EOPNOTSUPP;
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}
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}
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static umode_t tmp421_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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switch (attr) {
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case hwmon_temp_fault:
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if (channel == 0)
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return 0;
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return 0444;
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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 int tmp421_init_client(struct i2c_client *client)
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{
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int config, config_orig;
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/* Set the conversion rate to 2 Hz */
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i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
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/* Start conversions (disable shutdown if necessary) */
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config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
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if (config < 0) {
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dev_err(&client->dev,
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"Could not read configuration register (%d)\n", config);
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return config;
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}
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config_orig = config;
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config &= ~TMP421_CONFIG_SHUTDOWN;
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if (config != config_orig) {
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dev_info(&client->dev, "Enable monitoring chip\n");
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i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
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}
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return 0;
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}
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static int tmp421_detect(struct i2c_client *client,
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struct i2c_board_info *info)
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{
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enum chips kind;
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struct i2c_adapter *adapter = client->adapter;
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static const char * const names[] = {
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"TMP421", "TMP422", "TMP423",
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"TMP441", "TMP442"
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};
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int addr = client->addr;
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u8 reg;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
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return -ENODEV;
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reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
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if (reg != TMP421_MANUFACTURER_ID)
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return -ENODEV;
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reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
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if (reg & 0xf8)
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return -ENODEV;
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reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
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if (reg & 0x7f)
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return -ENODEV;
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reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
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switch (reg) {
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case TMP421_DEVICE_ID:
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kind = tmp421;
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break;
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case TMP422_DEVICE_ID:
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if (addr == 0x2a)
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return -ENODEV;
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kind = tmp422;
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break;
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case TMP423_DEVICE_ID:
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if (addr != 0x4c && addr != 0x4d)
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return -ENODEV;
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kind = tmp423;
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break;
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case TMP441_DEVICE_ID:
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kind = tmp441;
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break;
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case TMP442_DEVICE_ID:
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if (addr != 0x4c && addr != 0x4d)
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return -ENODEV;
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kind = tmp442;
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break;
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default:
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return -ENODEV;
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}
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strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
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dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
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names[kind], client->addr);
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return 0;
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}
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static const struct hwmon_ops tmp421_ops = {
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.is_visible = tmp421_is_visible,
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.read = tmp421_read,
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};
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static int tmp421_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct device *dev = &client->dev;
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struct device *hwmon_dev;
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struct tmp421_data *data;
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int i, err;
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data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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mutex_init(&data->update_lock);
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if (client->dev.of_node)
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data->channels = (unsigned long)
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of_device_get_match_data(&client->dev);
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else
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data->channels = id->driver_data;
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data->client = client;
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err = tmp421_init_client(client);
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if (err)
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return err;
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for (i = 0; i < data->channels; i++)
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data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT;
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data->chip.ops = &tmp421_ops;
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data->chip.info = data->info;
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data->info[0] = &data->temp_info;
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data->temp_info.type = hwmon_temp;
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data->temp_info.config = data->temp_config;
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hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
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data,
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&data->chip,
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NULL);
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return PTR_ERR_OR_ZERO(hwmon_dev);
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}
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static struct i2c_driver tmp421_driver = {
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.class = I2C_CLASS_HWMON,
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.driver = {
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.name = "tmp421",
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.of_match_table = of_match_ptr(tmp421_of_match),
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},
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.probe = tmp421_probe,
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.id_table = tmp421_id,
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.detect = tmp421_detect,
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.address_list = normal_i2c,
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};
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module_i2c_driver(tmp421_driver);
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MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
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MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
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MODULE_LICENSE("GPL");
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