[PATCH 5/5] hwmon: (tmp102) Convert to use regmap, and drop local cache

Guenter Roeck
2016-06-24T00:29:07Z

By concerting 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.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
drivers/hwmon/tmp102.c | 158 +++++++++++++++++++++++++------------------------
1 file changed, 81 insertions(+), 77 deletions(-)

diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c
index 487b4ef5992c..0c6eee7b7b80 100644
--- a/drivers/hwmon/tmp102.c
+++ b/drivers/hwmon/tmp102.c
@@ -24,6 +24,7 @@
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/jiffies.h>
+#include <linux/regmap.h>
#include <linux/thermal.h>
#include <linux/of.h>

@@ -47,6 +48,8 @@
#define TMP102_TLOW_REG 0x02
#define TMP102_THIGH_REG 0x03

+#define TMP102_NUM_REG 0x04
+
#define TMP102_CONFREG_MASK (TMP102_CONF_SD | TMP102_CONF_TM | \
TMP102_CONF_POL | TMP102_CONF_F0 | \
TMP102_CONF_F1 | TMP102_CONF_OS | \
@@ -61,13 +64,9 @@
#define CONVERSION_TIME_MS 35 /* in milli-seconds */

struct tmp102 {
- struct i2c_client *client;
- struct mutex lock;
+ struct regmap *regmap;
u16 config_orig;
- unsigned long last_update;
unsigned long ready_time;
- bool valid;
- int temp[3];
};

/* convert left adjusted 13-bit TMP102 register value to milliCelsius */
@@ -82,16 +81,11 @@ static inline u16 tmp102_mC_to_reg(int val)
return (val * 128) / 1000;
}

-static const u8 tmp102_reg[] = {
- TMP102_TEMP_REG,
- TMP102_TLOW_REG,
- TMP102_THIGH_REG,
-};
-
-static struct tmp102 *tmp102_update_device(struct device *dev)
+static int tmp102_read_temp(void *dev, int *temp)
{
struct tmp102 *tmp102 = dev_get_drvdata(dev);
- struct i2c_client *client = tmp102->client;
+ unsigned int reg;
+ int ret;

/* Is it too early to return a conversion ? */
if (time_before(jiffies, tmp102->ready_time)) {
@@ -100,28 +94,11 @@ static struct tmp102 *tmp102_update_device(struct device *dev)
msleep(jiffies_to_msecs(sleeptime));
}

- mutex_lock(&tmp102->lock);
- if (!tmp102->valid ||
- time_after(jiffies, tmp102->last_update + HZ / 3)) {
- int i;
- for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
- int status = i2c_smbus_read_word_swapped(client,
- tmp102_reg[i]);
- if (status > -1)
- tmp102->temp[i] = tmp102_reg_to_mC(status);
- }
- tmp102->last_update = jiffies;
- tmp102->valid = true;
- }
- mutex_unlock(&tmp102->lock);
- return tmp102;
-}
+ ret = regmap_read(tmp102->regmap, TMP102_TEMP_REG, &reg);
+ if (ret < 0)
+ return ret;

-static int tmp102_read_temp(void *dev, int *temp)
-{
- struct tmp102 *tmp102 = tmp102_update_device(dev);
-
- *temp = tmp102->temp[0];
+ *temp = tmp102_reg_to_mC(reg);

return 0;
}
@@ -131,9 +108,24 @@ static ssize_t tmp102_show_temp(struct device *dev,
char *buf)
{
struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
- struct tmp102 *tmp102 = tmp102_update_device(dev);
+ struct tmp102 *tmp102 = dev_get_drvdata(dev);
+ int regaddr = sda->index;
+ unsigned int reg;
+ int err;

- return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
+ /* Is it too early to return a conversion ? */
+ if (regaddr == TMP102_TEMP_REG &&
+ time_before(jiffies, tmp102->ready_time)) {
+ unsigned long sleeptime = tmp102->ready_time - jiffies;
+
+ msleep(jiffies_to_msecs(sleeptime));
+ }
+
+ err = regmap_read(tmp102->regmap, regaddr, &reg);
+ if (err < 0)
+ return err;
+
+ return sprintf(buf, "%d\n", tmp102_reg_to_mC(reg));
}

static ssize_t tmp102_set_temp(struct device *dev,
@@ -142,29 +134,26 @@ static ssize_t tmp102_set_temp(struct device *dev,
{
struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
struct tmp102 *tmp102 = dev_get_drvdata(dev);
- struct i2c_client *client = tmp102->client;
+ int reg = sda->index;
long val;
- int status;
+ int err;

if (kstrtol(buf, 10, &val) < 0)
return -EINVAL;
val = clamp_val(val, -256000, 255000);

- mutex_lock(&tmp102->lock);
- tmp102->temp[sda->index] = val;
- status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
- tmp102_mC_to_reg(val));
- mutex_unlock(&tmp102->lock);
- return status ? : count;
+ err = regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(val));
+ return err ? : count;
}

-static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL,
+ TMP102_TEMP_REG);

static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
- tmp102_set_temp, 1);
+ tmp102_set_temp, TMP102_TLOW_REG);

static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
- tmp102_set_temp, 2);
+ tmp102_set_temp, TMP102_THIGH_REG);

static struct attribute *tmp102_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
@@ -181,19 +170,39 @@ static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
static void tmp102_restore_config(void *data)
{
struct tmp102 *tmp102 = data;
- struct i2c_client *client = tmp102->client;

- i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
- tmp102->config_orig);
+ regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
+}
+
+static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+ return reg != TMP102_TEMP_REG;
+}
+
+static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+ return reg == TMP102_TEMP_REG;
}

+static const struct regmap_config tmp102_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 16,
+ .max_register = TMP102_THIGH_REG,
+ .num_reg_defaults_raw = TMP102_NUM_REG,
+ .writeable_reg = tmp102_is_writeable_reg,
+ .volatile_reg = tmp102_is_volatile_reg,
+ .val_format_endian = REGMAP_ENDIAN_BIG,
+ .cache_type = REGCACHE_FLAT,
+};
+
static int tmp102_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct tmp102 *tmp102;
- int status;
+ unsigned int regval;
+ int err;

if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WORD_DATA)) {
@@ -207,35 +216,36 @@ static int tmp102_probe(struct i2c_client *client,
return -ENOMEM;

i2c_set_clientdata(client, tmp102);
- tmp102->client = client;

- status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
- if (status < 0) {
+ tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
+ if (IS_ERR(tmp102->regmap))
+ return PTR_ERR(tmp102->regmap);
+
+ err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
+ if (err < 0) {
dev_err(dev, "error reading config register\n");
- return status;
+ return err;
}

- if ((status & ~TMP102_CONFREG_MASK) !=
+ if ((regval & ~TMP102_CONFREG_MASK) !=
(TMP102_CONF_R0 | TMP102_CONF_R1)) {
dev_err(dev, "unexpected config register value\n");
return -ENODEV;
}

- tmp102->config_orig = status;
+ tmp102->config_orig = regval;

devm_add_action(dev, tmp102_restore_config, tmp102);

- status &= ~TMP102_CONFIG_CLEAR;
- status |= TMP102_CONFIG_SET;
+ regval &= ~TMP102_CONFIG_CLEAR;
+ regval |= TMP102_CONFIG_SET;

- status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, status);
- if (status < 0) {
+ err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
+ if (err < 0) {
dev_err(dev, "error writing config register\n");
- return status;
+ return err;
}

- mutex_init(&tmp102->lock);
-
tmp102->ready_time = jiffies;
if (tmp102->config_orig & TMP102_CONF_SD) {
/*
@@ -264,30 +274,24 @@ static int tmp102_probe(struct i2c_client *client,
static int tmp102_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
- int config;
-
- config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
- if (config < 0)
- return config;
+ struct tmp102 *tmp102 = i2c_get_clientdata(client);

- config |= TMP102_CONF_SD;
- return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
+ return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
+ TMP102_CONF_SD, TMP102_CONF_SD);
}

static int tmp102_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct tmp102 *tmp102 = i2c_get_clientdata(client);
- int config;
+ int err;

- config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
- if (config < 0)
- return config;
+ err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
+ TMP102_CONF_SD, 0);

tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);

- config &= ~TMP102_CONF_SD;
- return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
+ return err;
}
#endif /* CONFIG_PM */

--
2.5.0