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Subject[PATCH 3/6] hwmon: (lm90) Simplify read functions
Date
Return both error code and register value as return code from
read functions, and always check for errors.

This reduces code size on x86_64 by more than 1k while at
the same time improving error resiliency.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
drivers/hwmon/lm90.c | 308 ++++++++++++++++++++++++++++++++-------------------
1 file changed, 193 insertions(+), 115 deletions(-)

diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index 9d733cb0504c..2a330bdbf1bc 100644
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -171,7 +171,6 @@ enum chips { lm90, adm1032, lm99, lm86, max6657, max6659, adt7461, max6680,

#define SA56004_REG_R_LOCAL_TEMPL 0x22

-#define LM90_DEF_CONVRATE_RVAL 6 /* Def conversion rate register value */
#define LM90_MAX_CONVRATE_MS 16000 /* Maximum conversion rate in ms */

/* TMP451 registers */
@@ -410,7 +409,7 @@ static inline s32 adm1032_write_byte(struct i2c_client *client, u8 value)
* because we don't want the address pointer to change between the write
* byte and the read byte transactions.
*/
-static int lm90_read_reg(struct i2c_client *client, u8 reg, u8 *value)
+static int lm90_read_reg(struct i2c_client *client, u8 reg)
{
int err;

@@ -421,20 +420,12 @@ static int lm90_read_reg(struct i2c_client *client, u8 reg, u8 *value)
} else
err = i2c_smbus_read_byte_data(client, reg);

- if (err < 0) {
- dev_warn(&client->dev, "Register %#02x read failed (%d)\n",
- reg, err);
- return err;
- }
- *value = err;
-
- return 0;
+ return err;
}

-static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
+static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl)
{
- int err;
- u8 oldh, newh, l;
+ int oldh, newh, l;

/*
* There is a trick here. We have to read two registers to have the
@@ -449,18 +440,21 @@ static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
* we have to read the low byte again, and now we believe we have a
* correct reading.
*/
- if ((err = lm90_read_reg(client, regh, &oldh))
- || (err = lm90_read_reg(client, regl, &l))
- || (err = lm90_read_reg(client, regh, &newh)))
- return err;
+ oldh = lm90_read_reg(client, regh);
+ if (oldh < 0)
+ return oldh;
+ l = lm90_read_reg(client, regl);
+ if (l < 0)
+ return l;
+ newh = lm90_read_reg(client, regh);
+ if (newh < 0)
+ return newh;
if (oldh != newh) {
- err = lm90_read_reg(client, regl, &l);
- if (err)
- return err;
+ l = lm90_read_reg(client, regl);
+ if (l < 0)
+ return l;
}
- *value = (newh << 8) | l;
-
- return 0;
+ return (newh << 8) | l;
}

/*
@@ -471,20 +465,23 @@ static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
* various registers have different meanings as a result of selecting a
* non-default remote channel.
*/
-static inline void lm90_select_remote_channel(struct i2c_client *client,
- struct lm90_data *data,
- int channel)
+static inline int lm90_select_remote_channel(struct i2c_client *client,
+ struct lm90_data *data,
+ int channel)
{
- u8 config;
+ int config;

if (data->kind == max6696) {
- lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
+ config = lm90_read_reg(client, LM90_REG_R_CONFIG1);
+ if (config < 0)
+ return config;
config &= ~0x08;
if (channel)
config |= 0x08;
i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
config);
}
+ return 0;
}

/*
@@ -516,104 +513,153 @@ static struct lm90_data *lm90_update_device(struct device *dev)
struct lm90_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
unsigned long next_update;
+ int val = 0;

mutex_lock(&data->update_lock);

next_update = data->last_updated +
msecs_to_jiffies(data->update_interval);
if (time_after(jiffies, next_update) || !data->valid) {
- u8 h, l;
- u8 alarms;
-
dev_dbg(&client->dev, "Updating lm90 data.\n");
- lm90_read_reg(client, LM90_REG_R_LOCAL_LOW,
- &data->temp8[LOCAL_LOW]);
- lm90_read_reg(client, LM90_REG_R_LOCAL_HIGH,
- &data->temp8[LOCAL_HIGH]);
- lm90_read_reg(client, LM90_REG_R_LOCAL_CRIT,
- &data->temp8[LOCAL_CRIT]);
- lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT,
- &data->temp8[REMOTE_CRIT]);
- lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);
+ val = lm90_read_reg(client, LM90_REG_R_LOCAL_LOW);
+ if (val < 0)
+ goto error;
+ data->temp8[LOCAL_LOW] = val;
+
+ val = lm90_read_reg(client, LM90_REG_R_LOCAL_HIGH);
+ if (val < 0)
+ goto error;
+ data->temp8[LOCAL_HIGH] = val;
+
+ val = lm90_read_reg(client, LM90_REG_R_LOCAL_CRIT);
+ if (val < 0)
+ goto error;
+ data->temp8[LOCAL_CRIT] = val;
+
+ val = lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT);
+ if (val < 0)
+ goto error;
+ data->temp8[REMOTE_CRIT] = val;
+ val = lm90_read_reg(client, LM90_REG_R_TCRIT_HYST);
+ if (val < 0)
+ goto error;
+ data->temp_hyst = val;

if (data->reg_local_ext) {
- lm90_read16(client, LM90_REG_R_LOCAL_TEMP,
- data->reg_local_ext,
- &data->temp11[LOCAL_TEMP]);
+ val = lm90_read16(client, LM90_REG_R_LOCAL_TEMP,
+ data->reg_local_ext);
+ if (val < 0)
+ goto error;
+ data->temp11[LOCAL_TEMP] = val;
} else {
- if (lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP,
- &h) == 0)
- data->temp11[LOCAL_TEMP] = h << 8;
+ val = lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP);
+ if (val < 0)
+ goto error;
+ data->temp11[LOCAL_TEMP] = val << 8;
}
- lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
- LM90_REG_R_REMOTE_TEMPL,
- &data->temp11[REMOTE_TEMP]);
-
- if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &h) == 0) {
- data->temp11[REMOTE_LOW] = h << 8;
- if ((data->flags & LM90_HAVE_REM_LIMIT_EXT)
- && lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL,
- &l) == 0)
- data->temp11[REMOTE_LOW] |= l;
+ val = lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
+ LM90_REG_R_REMOTE_TEMPL);
+ if (val < 0)
+ goto error;
+ data->temp11[REMOTE_TEMP] = val;
+
+ lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH);
+ if (val < 0)
+ goto error;
+ data->temp11[REMOTE_LOW] = val << 8;
+ if (data->flags & LM90_HAVE_REM_LIMIT_EXT) {
+ val = lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL);
+ if (val < 0)
+ goto error;
+ data->temp11[REMOTE_LOW] |= val;
}
- if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &h) == 0) {
- data->temp11[REMOTE_HIGH] = h << 8;
- if ((data->flags & LM90_HAVE_REM_LIMIT_EXT)
- && lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL,
- &l) == 0)
- data->temp11[REMOTE_HIGH] |= l;
+ val = lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH);
+ if (val < 0)
+ goto error;
+ data->temp11[REMOTE_HIGH] = val << 8;
+ if (data->flags & LM90_HAVE_REM_LIMIT_EXT) {
+ val = lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL);
+ if (val < 0)
+ goto error;
+ data->temp11[REMOTE_HIGH] |= val;
}

if (data->flags & LM90_HAVE_OFFSET) {
- if (lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSH,
- &h) == 0
- && lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSL,
- &l) == 0)
- data->temp11[REMOTE_OFFSET] = (h << 8) | l;
+ val = lm90_read16(client, LM90_REG_R_REMOTE_OFFSH,
+ LM90_REG_R_REMOTE_OFFSL);
+ if (val < 0)
+ goto error;
+ data->temp11[REMOTE_OFFSET] = val;
}
if (data->flags & LM90_HAVE_EMERGENCY) {
- lm90_read_reg(client, MAX6659_REG_R_LOCAL_EMERG,
- &data->temp8[LOCAL_EMERG]);
- lm90_read_reg(client, MAX6659_REG_R_REMOTE_EMERG,
- &data->temp8[REMOTE_EMERG]);
+ val = lm90_read_reg(client, MAX6659_REG_R_LOCAL_EMERG);
+ if (val < 0)
+ goto error;
+ data->temp8[LOCAL_EMERG] = val;
+ val = lm90_read_reg(client, MAX6659_REG_R_REMOTE_EMERG);
+ if (val < 0)
+ goto error;
+ data->temp8[REMOTE_EMERG] = val;
}
- lm90_read_reg(client, LM90_REG_R_STATUS, &alarms);
- data->alarms = alarms; /* save as 16 bit value */
+ val = lm90_read_reg(client, LM90_REG_R_STATUS);
+ if (val < 0)
+ goto error;
+ data->alarms = val; /* lower 8 bit of alarms */

if (data->kind == max6696) {
- lm90_select_remote_channel(client, data, 1);
- lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT,
- &data->temp8[REMOTE2_CRIT]);
- lm90_read_reg(client, MAX6659_REG_R_REMOTE_EMERG,
- &data->temp8[REMOTE2_EMERG]);
- lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
- LM90_REG_R_REMOTE_TEMPL,
- &data->temp11[REMOTE2_TEMP]);
- if (!lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &h))
- data->temp11[REMOTE2_LOW] = h << 8;
- if (!lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &h))
- data->temp11[REMOTE2_HIGH] = h << 8;
+ val = lm90_select_remote_channel(client, data, 1);
+ if (val < 0)
+ goto error;
+
+ val = lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT);
+ if (val < 0)
+ goto error;
+ data->temp8[REMOTE2_CRIT] = val;
+
+ val = lm90_read_reg(client, MAX6659_REG_R_REMOTE_EMERG);
+ if (val < 0)
+ goto error;
+ data->temp8[REMOTE2_EMERG] = val;
+
+ val = lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
+ LM90_REG_R_REMOTE_TEMPL);
+ if (val < 0)
+ goto error;
+ data->temp11[REMOTE2_TEMP] = val;
+
+ val = lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH);
+ if (val < 0)
+ goto error;
+ data->temp11[REMOTE2_LOW] = val << 8;
+
+ val = lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH);
+ if (val < 0)
+ goto error;
+ data->temp11[REMOTE2_HIGH] = val << 8;
+
lm90_select_remote_channel(client, data, 0);

- if (!lm90_read_reg(client, MAX6696_REG_R_STATUS2,
- &alarms))
- data->alarms |= alarms << 8;
+ val = lm90_read_reg(client, MAX6696_REG_R_STATUS2);
+ if (val < 0)
+ goto error;
+ data->alarms |= val << 8;
}

/*
* Re-enable ALERT# output if it was originally enabled and
* relevant alarms are all clear
*/
- if ((data->config_orig & 0x80) == 0
- && (data->alarms & data->alert_alarms) == 0) {
- u8 config;
+ if (!(data->config_orig & 0x80) &&
+ !(data->alarms & data->alert_alarms)) {
+ val = lm90_read_reg(client, LM90_REG_R_CONFIG1);
+ if (val < 0)
+ goto error;

- lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
- if (config & 0x80) {
+ if (val & 0x80) {
dev_dbg(&client->dev, "Re-enabling ALERT#\n");
i2c_smbus_write_byte_data(client,
LM90_REG_W_CONFIG1,
- config & ~0x80);
+ val & ~0x80);
}
}

@@ -621,8 +667,12 @@ static struct lm90_data *lm90_update_device(struct device *dev)
data->valid = 1;
}

+error:
mutex_unlock(&data->update_lock);

+ if (val < 0)
+ return ERR_PTR(val);
+
return data;
}

@@ -764,6 +814,9 @@ static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
struct lm90_data *data = lm90_update_device(dev);
int temp;

+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
if (data->kind == adt7461 || data->kind == tmp451)
temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);
else if (data->kind == max6646)
@@ -830,6 +883,9 @@ static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
struct lm90_data *data = lm90_update_device(dev);
int temp;

+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
if (data->kind == adt7461 || data->kind == tmp451)
temp = temp_from_u16_adt7461(data, data->temp11[attr->index]);
else if (data->kind == max6646)
@@ -905,6 +961,9 @@ static ssize_t show_temphyst(struct device *dev,
struct lm90_data *data = lm90_update_device(dev);
int temp;

+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
if (data->kind == adt7461 || data->kind == tmp451)
temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);
else if (data->kind == max6646)
@@ -951,6 +1010,10 @@ static ssize_t show_alarms(struct device *dev, struct device_attribute *dummy,
char *buf)
{
struct lm90_data *data = lm90_update_device(dev);
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
return sprintf(buf, "%d\n", data->alarms);
}

@@ -961,6 +1024,9 @@ static ssize_t show_alarm(struct device *dev, struct device_attribute
struct lm90_data *data = lm90_update_device(dev);
int bitnr = attr->index;

+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
}

@@ -1414,24 +1480,22 @@ static void lm90_restore_conf(void *_data)
data->config_orig);
}

-static void lm90_init_client(struct i2c_client *client, struct lm90_data *data)
+static int lm90_init_client(struct i2c_client *client, struct lm90_data *data)
{
- u8 config, convrate;
+ int config, convrate;

- if (lm90_read_reg(client, LM90_REG_R_CONVRATE, &convrate) < 0) {
- dev_warn(&client->dev, "Failed to read convrate register!\n");
- convrate = LM90_DEF_CONVRATE_RVAL;
- }
+ convrate = lm90_read_reg(client, LM90_REG_R_CONVRATE);
+ if (convrate < 0)
+ return convrate;
data->convrate_orig = convrate;

/*
* Start the conversions.
*/
lm90_set_convrate(client, data, 500); /* 500ms; 2Hz conversion rate */
- if (lm90_read_reg(client, LM90_REG_R_CONFIG1, &config) < 0) {
- dev_warn(&client->dev, "Initialization failed!\n");
- return;
- }
+ config = lm90_read_reg(client, LM90_REG_R_CONFIG1);
+ if (config < 0)
+ return config;
data->config_orig = config;

/* Check Temperature Range Select */
@@ -1459,17 +1523,24 @@ static void lm90_init_client(struct i2c_client *client, struct lm90_data *data)
i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1, config);

devm_add_action(&client->dev, lm90_restore_conf, data);
+
+ return 0;
}

static bool lm90_is_tripped(struct i2c_client *client, u16 *status)
{
struct lm90_data *data = i2c_get_clientdata(client);
- u8 st, st2 = 0;
+ int st, st2 = 0;

- lm90_read_reg(client, LM90_REG_R_STATUS, &st);
+ st = lm90_read_reg(client, LM90_REG_R_STATUS);
+ if (st < 0)
+ return false;

- if (data->kind == max6696)
- lm90_read_reg(client, MAX6696_REG_R_STATUS2, &st2);
+ if (data->kind == max6696) {
+ st2 = lm90_read_reg(client, MAX6696_REG_R_STATUS2);
+ if (st2 < 0)
+ return false;
+ }

*status = st | (st2 << 8);

@@ -1571,7 +1642,11 @@ static int lm90_probe(struct i2c_client *client,
data->max_convrate = lm90_params[data->kind].max_convrate;

/* Initialize the LM90 chip */
- lm90_init_client(client, data);
+ err = lm90_init_client(client, data);
+ if (err < 0) {
+ dev_err(dev, "Failed to initialize device\n");
+ return err;
+ }

/* Register sysfs hooks */
data->groups[groups++] = &lm90_group;
@@ -1627,13 +1702,16 @@ static void lm90_alert(struct i2c_client *client, unsigned int flag)
*/
struct lm90_data *data = i2c_get_clientdata(client);

- if ((data->flags & LM90_HAVE_BROKEN_ALERT)
- && (alarms & data->alert_alarms)) {
- u8 config;
+ if ((data->flags & LM90_HAVE_BROKEN_ALERT) &&
+ (alarms & data->alert_alarms)) {
+ int config;
+
dev_dbg(&client->dev, "Disabling ALERT#\n");
- lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
- i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
- config | 0x80);
+ config = lm90_read_reg(client, LM90_REG_R_CONFIG1);
+ if (config >= 0)
+ i2c_smbus_write_byte_data(client,
+ LM90_REG_W_CONFIG1,
+ config | 0x80);
}
} else {
dev_info(&client->dev, "Everything OK\n");
--
2.5.0
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