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28a340db90
By converting the driver to regmap, we can use regmap to cache non-volatile registers. Stop caching the temperature register; while potentially reading it more often can result in reading it more often than necessary, this is offset by the gain due to not re-reading the limit registers. A positive side effect of this change is that limit registers can now be read and updated before the first temperature conversion is complete. Acked-by: Nishanth Menon <nm@ti.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
310 lines
8.0 KiB
C
310 lines
8.0 KiB
C
/* Texas Instruments TMP102 SMBus temperature sensor driver
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*
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* Copyright (C) 2010 Steven King <sfking@fdwdc.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/delay.h>
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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/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/device.h>
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#include <linux/jiffies.h>
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#include <linux/regmap.h>
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#include <linux/thermal.h>
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#include <linux/of.h>
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#define DRIVER_NAME "tmp102"
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#define TMP102_TEMP_REG 0x00
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#define TMP102_CONF_REG 0x01
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/* note: these bit definitions are byte swapped */
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#define TMP102_CONF_SD 0x0100
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#define TMP102_CONF_TM 0x0200
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#define TMP102_CONF_POL 0x0400
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#define TMP102_CONF_F0 0x0800
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#define TMP102_CONF_F1 0x1000
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#define TMP102_CONF_R0 0x2000
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#define TMP102_CONF_R1 0x4000
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#define TMP102_CONF_OS 0x8000
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#define TMP102_CONF_EM 0x0010
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#define TMP102_CONF_AL 0x0020
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#define TMP102_CONF_CR0 0x0040
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#define TMP102_CONF_CR1 0x0080
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#define TMP102_TLOW_REG 0x02
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#define TMP102_THIGH_REG 0x03
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#define TMP102_CONFREG_MASK (TMP102_CONF_SD | TMP102_CONF_TM | \
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TMP102_CONF_POL | TMP102_CONF_F0 | \
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TMP102_CONF_F1 | TMP102_CONF_OS | \
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TMP102_CONF_EM | TMP102_CONF_AL | \
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TMP102_CONF_CR0 | TMP102_CONF_CR1)
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#define TMP102_CONFIG_CLEAR (TMP102_CONF_SD | TMP102_CONF_OS | \
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TMP102_CONF_CR0)
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#define TMP102_CONFIG_SET (TMP102_CONF_TM | TMP102_CONF_EM | \
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TMP102_CONF_CR1)
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#define CONVERSION_TIME_MS 35 /* in milli-seconds */
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struct tmp102 {
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struct regmap *regmap;
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u16 config_orig;
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unsigned long ready_time;
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};
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/* convert left adjusted 13-bit TMP102 register value to milliCelsius */
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static inline int tmp102_reg_to_mC(s16 val)
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{
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return ((val & ~0x01) * 1000) / 128;
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}
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/* convert milliCelsius to left adjusted 13-bit TMP102 register value */
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static inline u16 tmp102_mC_to_reg(int val)
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{
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return (val * 128) / 1000;
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}
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static int tmp102_read_temp(void *dev, int *temp)
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{
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struct tmp102 *tmp102 = dev_get_drvdata(dev);
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unsigned int reg;
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int ret;
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if (time_before(jiffies, tmp102->ready_time)) {
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dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
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return -EAGAIN;
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}
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ret = regmap_read(tmp102->regmap, TMP102_TEMP_REG, ®);
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if (ret < 0)
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return ret;
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*temp = tmp102_reg_to_mC(reg);
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return 0;
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}
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static ssize_t tmp102_show_temp(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
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struct tmp102 *tmp102 = dev_get_drvdata(dev);
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int regaddr = sda->index;
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unsigned int reg;
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int err;
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if (regaddr == TMP102_TEMP_REG &&
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time_before(jiffies, tmp102->ready_time))
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return -EAGAIN;
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err = regmap_read(tmp102->regmap, regaddr, ®);
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if (err < 0)
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return err;
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return sprintf(buf, "%d\n", tmp102_reg_to_mC(reg));
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}
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static ssize_t tmp102_set_temp(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
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struct tmp102 *tmp102 = dev_get_drvdata(dev);
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int reg = sda->index;
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long val;
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int err;
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if (kstrtol(buf, 10, &val) < 0)
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return -EINVAL;
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val = clamp_val(val, -256000, 255000);
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err = regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(val));
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return err ? : count;
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}
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static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL,
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TMP102_TEMP_REG);
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static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
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tmp102_set_temp, TMP102_TLOW_REG);
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static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
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tmp102_set_temp, TMP102_THIGH_REG);
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static struct attribute *tmp102_attrs[] = {
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&sensor_dev_attr_temp1_input.dev_attr.attr,
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&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
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&sensor_dev_attr_temp1_max.dev_attr.attr,
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NULL
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};
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ATTRIBUTE_GROUPS(tmp102);
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static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
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.get_temp = tmp102_read_temp,
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};
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static void tmp102_restore_config(void *data)
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{
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struct tmp102 *tmp102 = data;
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regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
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}
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static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
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{
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return reg != TMP102_TEMP_REG;
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}
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static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
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{
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return reg == TMP102_TEMP_REG;
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}
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static const struct regmap_config tmp102_regmap_config = {
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.reg_bits = 8,
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.val_bits = 16,
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.max_register = TMP102_THIGH_REG,
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.writeable_reg = tmp102_is_writeable_reg,
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.volatile_reg = tmp102_is_volatile_reg,
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.val_format_endian = REGMAP_ENDIAN_BIG,
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.cache_type = REGCACHE_RBTREE,
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.use_single_rw = true,
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};
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static int tmp102_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 tmp102 *tmp102;
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unsigned int regval;
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int err;
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if (!i2c_check_functionality(client->adapter,
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I2C_FUNC_SMBUS_WORD_DATA)) {
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dev_err(dev,
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"adapter doesn't support SMBus word transactions\n");
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return -ENODEV;
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}
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tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
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if (!tmp102)
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return -ENOMEM;
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i2c_set_clientdata(client, tmp102);
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tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
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if (IS_ERR(tmp102->regmap))
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return PTR_ERR(tmp102->regmap);
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err = regmap_read(tmp102->regmap, TMP102_CONF_REG, ®val);
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if (err < 0) {
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dev_err(dev, "error reading config register\n");
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return err;
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}
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if ((regval & ~TMP102_CONFREG_MASK) !=
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(TMP102_CONF_R0 | TMP102_CONF_R1)) {
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dev_err(dev, "unexpected config register value\n");
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return -ENODEV;
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}
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tmp102->config_orig = regval;
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devm_add_action(dev, tmp102_restore_config, tmp102);
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regval &= ~TMP102_CONFIG_CLEAR;
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regval |= TMP102_CONFIG_SET;
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err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
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if (err < 0) {
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dev_err(dev, "error writing config register\n");
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return err;
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}
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tmp102->ready_time = jiffies;
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if (tmp102->config_orig & TMP102_CONF_SD) {
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/*
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* Mark that we are not ready with data until the first
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* conversion is complete
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*/
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tmp102->ready_time += msecs_to_jiffies(CONVERSION_TIME_MS);
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}
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
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tmp102,
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tmp102_groups);
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if (IS_ERR(hwmon_dev)) {
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dev_dbg(dev, "unable to register hwmon device\n");
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return PTR_ERR(hwmon_dev);
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}
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devm_thermal_zone_of_sensor_register(hwmon_dev, 0, hwmon_dev,
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&tmp102_of_thermal_ops);
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dev_info(dev, "initialized\n");
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int tmp102_suspend(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct tmp102 *tmp102 = i2c_get_clientdata(client);
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return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
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TMP102_CONF_SD, TMP102_CONF_SD);
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}
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static int tmp102_resume(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct tmp102 *tmp102 = i2c_get_clientdata(client);
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int err;
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err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
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TMP102_CONF_SD, 0);
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tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
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return err;
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}
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#endif /* CONFIG_PM */
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static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
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static const struct i2c_device_id tmp102_id[] = {
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{ "tmp102", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, tmp102_id);
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static struct i2c_driver tmp102_driver = {
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.driver.name = DRIVER_NAME,
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.driver.pm = &tmp102_dev_pm_ops,
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.probe = tmp102_probe,
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.id_table = tmp102_id,
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};
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module_i2c_driver(tmp102_driver);
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MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
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MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
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MODULE_LICENSE("GPL");
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