Hello,
this is a follow-up to the comments I got from Guenter on v1 of my patch
from [0] titled:
"hwmon: (jc42) Restore the min/max/critical temperatures on resume"
There Guenter suggested: "The best solution would probably be to convert
the driver to use regmap and let regmap handle the caching". That's the
goal of this series - in addition to fixing the original resume issue
(see patch #3 - which was the reason for v1 of this series).
Changes since v1 at [0]:
- marked as RFC
- added patches for regmap (patch #1) and regcache (patch #2) conversion
- patch #3 has been updated to use regcache for restoring the register
values during system resume (this was originally patch 1/1)
- added another patch to remove caching of the temperature register
[0] https://lore.kernel.org/linux-hwmon/[email protected]/
Martin Blumenstingl (4):
hwmon: (jc42) Convert register access to use an I2C regmap
hwmon: (jc42) Convert to regmap's built-in caching
hwmon: (jc42) Restore the min/max/critical temperatures on resume
hwmon: (jc42) Don't cache the temperature register
drivers/hwmon/Kconfig | 1 +
drivers/hwmon/jc42.c | 224 +++++++++++++++++++++++-------------------
2 files changed, 125 insertions(+), 100 deletions(-)
--
2.38.1
Move over to regmap's built-in caching instead of adding a custom
caching implementation. This works for JC42_REG_TEMP_UPPER,
JC42_REG_TEMP_LOWER and JC42_REG_TEMP_CRITICAL as these values never
change except when explicitly written. For JC42_REG_TEMP a cache
variable is still kept as regmap cannot cache this register (because
it's volatile, meaning it can change at any time).
Signed-off-by: Martin Blumenstingl <[email protected]>
---
drivers/hwmon/jc42.c | 97 ++++++++++++++++++++++++--------------------
1 file changed, 54 insertions(+), 43 deletions(-)
diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c
index 329a80264556..3f524ab5451c 100644
--- a/drivers/hwmon/jc42.c
+++ b/drivers/hwmon/jc42.c
@@ -200,21 +200,6 @@ static struct jc42_chips jc42_chips[] = {
{ STM_MANID, STTS3000_DEVID, STTS3000_DEVID_MASK },
};
-enum temp_index {
- t_input = 0,
- t_crit,
- t_min,
- t_max,
- t_num_temp
-};
-
-static const u8 temp_regs[t_num_temp] = {
- [t_input] = JC42_REG_TEMP,
- [t_crit] = JC42_REG_TEMP_CRITICAL,
- [t_min] = JC42_REG_TEMP_LOWER,
- [t_max] = JC42_REG_TEMP_UPPER,
-};
-
/* Each client has this additional data */
struct jc42_data {
struct regmap *regmap;
@@ -224,7 +209,7 @@ struct jc42_data {
unsigned long last_updated; /* In jiffies */
u16 orig_config; /* original configuration */
u16 config; /* current configuration */
- u16 temp[t_num_temp];/* Temperatures */
+ u16 temp; /* Cached temperature register value */
};
#define JC42_TEMP_MIN_EXTENDED (-40000)
@@ -252,18 +237,17 @@ static int jc42_temp_from_reg(s16 reg)
static struct jc42_data *jc42_update_device(struct device *dev)
{
struct jc42_data *data = dev_get_drvdata(dev);
- unsigned int i, val;
+ unsigned int val;
int ret;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
- for (i = 0; i < t_num_temp; i++) {
- ret = regmap_read(data->regmap, temp_regs[i], &val);
- if (ret)
- goto abort;
- data->temp[i] = val;
- }
+ ret = regmap_read(data->regmap, JC42_REG_TEMP, &val);
+ if (ret)
+ goto abort;
+
+ data->temp = val;
data->last_updated = jiffies;
data->valid = true;
}
@@ -276,44 +260,67 @@ static int jc42_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct jc42_data *data = jc42_update_device(dev);
- int temp, hyst;
+ unsigned int regval;
+ int ret, temp, hyst;
if (IS_ERR(data))
return PTR_ERR(data);
switch (attr) {
case hwmon_temp_input:
- *val = jc42_temp_from_reg(data->temp[t_input]);
+ *val = jc42_temp_from_reg(data->temp);
return 0;
case hwmon_temp_min:
- *val = jc42_temp_from_reg(data->temp[t_min]);
+ ret = regmap_read(data->regmap, JC42_REG_TEMP_LOWER, ®val);
+ if (ret)
+ return ret;
+
+ *val = jc42_temp_from_reg(regval);
return 0;
case hwmon_temp_max:
- *val = jc42_temp_from_reg(data->temp[t_max]);
+ ret = regmap_read(data->regmap, JC42_REG_TEMP_UPPER, ®val);
+ if (ret)
+ return ret;
+
+ *val = jc42_temp_from_reg(regval);
return 0;
case hwmon_temp_crit:
- *val = jc42_temp_from_reg(data->temp[t_crit]);
+ ret = regmap_read(data->regmap, JC42_REG_TEMP_CRITICAL,
+ ®val);
+ if (ret)
+ return ret;
+
+ *val = jc42_temp_from_reg(regval);
return 0;
case hwmon_temp_max_hyst:
- temp = jc42_temp_from_reg(data->temp[t_max]);
+ ret = regmap_read(data->regmap, JC42_REG_TEMP_UPPER, ®val);
+ if (ret)
+ return ret;
+
+ temp = jc42_temp_from_reg(regval);
hyst = jc42_hysteresis[(data->config & JC42_CFG_HYST_MASK)
>> JC42_CFG_HYST_SHIFT];
*val = temp - hyst;
return 0;
case hwmon_temp_crit_hyst:
- temp = jc42_temp_from_reg(data->temp[t_crit]);
+ ret = regmap_read(data->regmap, JC42_REG_TEMP_CRITICAL,
+ ®val);
+ if (ret)
+ return ret;
+
+ temp = jc42_temp_from_reg(regval);
hyst = jc42_hysteresis[(data->config & JC42_CFG_HYST_MASK)
>> JC42_CFG_HYST_SHIFT];
*val = temp - hyst;
return 0;
case hwmon_temp_min_alarm:
- *val = (data->temp[t_input] >> JC42_ALARM_MIN_BIT) & 1;
+ *val = (data->temp >> JC42_ALARM_MIN_BIT) & 1;
return 0;
case hwmon_temp_max_alarm:
- *val = (data->temp[t_input] >> JC42_ALARM_MAX_BIT) & 1;
+ *val = (data->temp >> JC42_ALARM_MAX_BIT) & 1;
return 0;
case hwmon_temp_crit_alarm:
- *val = (data->temp[t_input] >> JC42_ALARM_CRIT_BIT) & 1;
+ *val = (data->temp >> JC42_ALARM_CRIT_BIT) & 1;
return 0;
default:
return -EOPNOTSUPP;
@@ -324,6 +331,7 @@ static int jc42_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long val)
{
struct jc42_data *data = dev_get_drvdata(dev);
+ unsigned int regval;
int diff, hyst;
int ret;
@@ -331,21 +339,23 @@ static int jc42_write(struct device *dev, enum hwmon_sensor_types type,
switch (attr) {
case hwmon_temp_min:
- data->temp[t_min] = jc42_temp_to_reg(val, data->extended);
- ret = regmap_write(data->regmap, temp_regs[t_min],
- data->temp[t_min]);
+ ret = regmap_write(data->regmap, JC42_REG_TEMP_LOWER,
+ jc42_temp_to_reg(val, data->extended));
break;
case hwmon_temp_max:
- data->temp[t_max] = jc42_temp_to_reg(val, data->extended);
- ret = regmap_write(data->regmap, temp_regs[t_max],
- data->temp[t_max]);
+ ret = regmap_write(data->regmap, JC42_REG_TEMP_UPPER,
+ jc42_temp_to_reg(val, data->extended));
break;
case hwmon_temp_crit:
- data->temp[t_crit] = jc42_temp_to_reg(val, data->extended);
- ret = regmap_write(data->regmap, temp_regs[t_crit],
- data->temp[t_crit]);
+ ret = regmap_write(data->regmap, JC42_REG_TEMP_CRITICAL,
+ jc42_temp_to_reg(val, data->extended));
break;
case hwmon_temp_crit_hyst:
+ ret = regmap_read(data->regmap, JC42_REG_TEMP_CRITICAL,
+ ®val);
+ if (ret)
+ return ret;
+
/*
* JC42.4 compliant chips only support four hysteresis values.
* Pick best choice and go from there.
@@ -353,7 +363,7 @@ static int jc42_write(struct device *dev, enum hwmon_sensor_types type,
val = clamp_val(val, (data->extended ? JC42_TEMP_MIN_EXTENDED
: JC42_TEMP_MIN) - 6000,
JC42_TEMP_MAX);
- diff = jc42_temp_from_reg(data->temp[t_crit]) - val;
+ diff = jc42_temp_from_reg(regval) - val;
hyst = 0;
if (diff > 0) {
if (diff < 2250)
@@ -491,6 +501,7 @@ static const struct regmap_config jc42_regmap_config = {
.writeable_reg = jc42_writable_reg,
.readable_reg = jc42_readable_reg,
.volatile_reg = jc42_volatile_reg,
+ .cache_type = REGCACHE_RBTREE,
};
static int jc42_probe(struct i2c_client *client)
--
2.38.1
Switch the jc42 driver to use an I2C regmap to access the registers.
This is done in preparation for improving the caching of registers and
to restore the cached limits during system resume.
Signed-off-by: Martin Blumenstingl <[email protected]>
---
drivers/hwmon/Kconfig | 1 +
drivers/hwmon/jc42.c | 102 +++++++++++++++++++++++++-----------------
2 files changed, 63 insertions(+), 40 deletions(-)
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 7ac3daaf59ce..d3bccc8176c5 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -799,6 +799,7 @@ config SENSORS_IT87
config SENSORS_JC42
tristate "JEDEC JC42.4 compliant memory module temperature sensors"
depends on I2C
+ select REGMAP_I2C
help
If you say yes here, you get support for JEDEC JC42.4 compliant
temperature sensors, which are used on many DDR3 memory modules for
diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c
index 30888feaf589..329a80264556 100644
--- a/drivers/hwmon/jc42.c
+++ b/drivers/hwmon/jc42.c
@@ -19,6 +19,7 @@
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/of.h>
+#include <linux/regmap.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = {
@@ -216,7 +217,7 @@ static const u8 temp_regs[t_num_temp] = {
/* Each client has this additional data */
struct jc42_data {
- struct i2c_client *client;
+ struct regmap *regmap;
struct mutex update_lock; /* protect register access */
bool extended; /* true if extended range supported */
bool valid;
@@ -251,19 +252,16 @@ static int jc42_temp_from_reg(s16 reg)
static struct jc42_data *jc42_update_device(struct device *dev)
{
struct jc42_data *data = dev_get_drvdata(dev);
- struct i2c_client *client = data->client;
- struct jc42_data *ret = data;
- int i, val;
+ unsigned int i, val;
+ int ret;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
for (i = 0; i < t_num_temp; i++) {
- val = i2c_smbus_read_word_swapped(client, temp_regs[i]);
- if (val < 0) {
- ret = ERR_PTR(val);
+ ret = regmap_read(data->regmap, temp_regs[i], &val);
+ if (ret)
goto abort;
- }
data->temp[i] = val;
}
data->last_updated = jiffies;
@@ -271,7 +269,7 @@ static struct jc42_data *jc42_update_device(struct device *dev)
}
abort:
mutex_unlock(&data->update_lock);
- return ret;
+ return ret ? ERR_PTR(ret) : data;
}
static int jc42_read(struct device *dev, enum hwmon_sensor_types type,
@@ -326,7 +324,6 @@ static int jc42_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long val)
{
struct jc42_data *data = dev_get_drvdata(dev);
- struct i2c_client *client = data->client;
int diff, hyst;
int ret;
@@ -335,18 +332,18 @@ static int jc42_write(struct device *dev, enum hwmon_sensor_types type,
switch (attr) {
case hwmon_temp_min:
data->temp[t_min] = jc42_temp_to_reg(val, data->extended);
- ret = i2c_smbus_write_word_swapped(client, temp_regs[t_min],
- data->temp[t_min]);
+ ret = regmap_write(data->regmap, temp_regs[t_min],
+ data->temp[t_min]);
break;
case hwmon_temp_max:
data->temp[t_max] = jc42_temp_to_reg(val, data->extended);
- ret = i2c_smbus_write_word_swapped(client, temp_regs[t_max],
- data->temp[t_max]);
+ ret = regmap_write(data->regmap, temp_regs[t_max],
+ data->temp[t_max]);
break;
case hwmon_temp_crit:
data->temp[t_crit] = jc42_temp_to_reg(val, data->extended);
- ret = i2c_smbus_write_word_swapped(client, temp_regs[t_crit],
- data->temp[t_crit]);
+ ret = regmap_write(data->regmap, temp_regs[t_crit],
+ data->temp[t_crit]);
break;
case hwmon_temp_crit_hyst:
/*
@@ -368,9 +365,8 @@ static int jc42_write(struct device *dev, enum hwmon_sensor_types type,
}
data->config = (data->config & ~JC42_CFG_HYST_MASK) |
(hyst << JC42_CFG_HYST_SHIFT);
- ret = i2c_smbus_write_word_swapped(data->client,
- JC42_REG_CONFIG,
- data->config);
+ ret = regmap_write(data->regmap, JC42_REG_CONFIG,
+ data->config);
break;
default:
ret = -EOPNOTSUPP;
@@ -470,51 +466,79 @@ static const struct hwmon_chip_info jc42_chip_info = {
.info = jc42_info,
};
+static bool jc42_readable_reg(struct device *dev, unsigned int reg)
+{
+ return (reg >= JC42_REG_CAP && reg <= JC42_REG_DEVICEID) ||
+ reg == JC42_REG_SMBUS;
+}
+
+static bool jc42_writable_reg(struct device *dev, unsigned int reg)
+{
+ return (reg >= JC42_REG_CONFIG && reg <= JC42_REG_TEMP_CRITICAL) ||
+ reg == JC42_REG_SMBUS;
+}
+
+static bool jc42_volatile_reg(struct device *dev, unsigned int reg)
+{
+ return reg == JC42_REG_CONFIG || reg == JC42_REG_TEMP;
+}
+
+static const struct regmap_config jc42_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 16,
+ .val_format_endian = REGMAP_ENDIAN_BIG,
+ .max_register = JC42_REG_SMBUS,
+ .writeable_reg = jc42_writable_reg,
+ .readable_reg = jc42_readable_reg,
+ .volatile_reg = jc42_volatile_reg,
+};
+
static int jc42_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
+ unsigned int config, cap;
struct jc42_data *data;
- int config, cap;
+ int ret;
data = devm_kzalloc(dev, sizeof(struct jc42_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
- data->client = client;
+ data->regmap = devm_regmap_init_i2c(client, &jc42_regmap_config);
+ if (IS_ERR(data->regmap))
+ return PTR_ERR(data->regmap);
+
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
- cap = i2c_smbus_read_word_swapped(client, JC42_REG_CAP);
- if (cap < 0)
- return cap;
+ ret = regmap_read(data->regmap, JC42_REG_CAP, &cap);
+ if (ret)
+ return ret;
data->extended = !!(cap & JC42_CAP_RANGE);
if (device_property_read_bool(dev, "smbus-timeout-disable")) {
- int smbus;
-
/*
* Not all chips support this register, but from a
* quick read of various datasheets no chip appears
* incompatible with the below attempt to disable
* the timeout. And the whole thing is opt-in...
*/
- smbus = i2c_smbus_read_word_swapped(client, JC42_REG_SMBUS);
- if (smbus < 0)
- return smbus;
- i2c_smbus_write_word_swapped(client, JC42_REG_SMBUS,
- smbus | SMBUS_STMOUT);
+ ret = regmap_set_bits(data->regmap, JC42_REG_SMBUS,
+ SMBUS_STMOUT);
+ if (ret)
+ return ret;
}
- config = i2c_smbus_read_word_swapped(client, JC42_REG_CONFIG);
- if (config < 0)
- return config;
+ ret = regmap_read(data->regmap, JC42_REG_CONFIG, &config);
+ if (ret)
+ return ret;
data->orig_config = config;
if (config & JC42_CFG_SHUTDOWN) {
config &= ~JC42_CFG_SHUTDOWN;
- i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, config);
+ regmap_write(data->regmap, JC42_REG_CONFIG, config);
}
data->config = config;
@@ -535,7 +559,7 @@ static void jc42_remove(struct i2c_client *client)
config = (data->orig_config & ~JC42_CFG_HYST_MASK)
| (data->config & JC42_CFG_HYST_MASK);
- i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, config);
+ regmap_write(data->regmap, JC42_REG_CONFIG, config);
}
}
@@ -546,8 +570,7 @@ static int jc42_suspend(struct device *dev)
struct jc42_data *data = dev_get_drvdata(dev);
data->config |= JC42_CFG_SHUTDOWN;
- i2c_smbus_write_word_swapped(data->client, JC42_REG_CONFIG,
- data->config);
+ regmap_write(data->regmap, JC42_REG_CONFIG, data->config);
return 0;
}
@@ -556,8 +579,7 @@ static int jc42_resume(struct device *dev)
struct jc42_data *data = dev_get_drvdata(dev);
data->config &= ~JC42_CFG_SHUTDOWN;
- i2c_smbus_write_word_swapped(data->client, JC42_REG_CONFIG,
- data->config);
+ regmap_write(data->regmap, JC42_REG_CONFIG, data->config);
return 0;
}
--
2.38.1
On Thu, Oct 20, 2022 at 11:03:17PM +0200, Martin Blumenstingl wrote:
> Switch the jc42 driver to use an I2C regmap to access the registers.
> This is done in preparation for improving the caching of registers and
> to restore the cached limits during system resume.
>
I would suggest to combine patch 1 and 2 and drop local caching entirely
in a single patch.
Thanks,
Guenter
On Thu, Oct 20, 2022 at 11:03:18PM +0200, Martin Blumenstingl wrote:
> Move over to regmap's built-in caching instead of adding a custom
> caching implementation. This works for JC42_REG_TEMP_UPPER,
> JC42_REG_TEMP_LOWER and JC42_REG_TEMP_CRITICAL as these values never
> change except when explicitly written. For JC42_REG_TEMP a cache
> variable is still kept as regmap cannot cache this register (because
> it's volatile, meaning it can change at any time).
>
Just drop that one as well, together with jc42_update_device(),
and read the temperature directly where needed. In practice
caching of 'hot' registers isn't really worth the trouble.
Thanks,
Guenter
> Signed-off-by: Martin Blumenstingl <[email protected]>
> ---
> drivers/hwmon/jc42.c | 97 ++++++++++++++++++++++++--------------------
> 1 file changed, 54 insertions(+), 43 deletions(-)
>
> diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c
> index 329a80264556..3f524ab5451c 100644
> --- a/drivers/hwmon/jc42.c
> +++ b/drivers/hwmon/jc42.c
> @@ -200,21 +200,6 @@ static struct jc42_chips jc42_chips[] = {
> { STM_MANID, STTS3000_DEVID, STTS3000_DEVID_MASK },
> };
>
> -enum temp_index {
> - t_input = 0,
> - t_crit,
> - t_min,
> - t_max,
> - t_num_temp
> -};
> -
> -static const u8 temp_regs[t_num_temp] = {
> - [t_input] = JC42_REG_TEMP,
> - [t_crit] = JC42_REG_TEMP_CRITICAL,
> - [t_min] = JC42_REG_TEMP_LOWER,
> - [t_max] = JC42_REG_TEMP_UPPER,
> -};
> -
> /* Each client has this additional data */
> struct jc42_data {
> struct regmap *regmap;
> @@ -224,7 +209,7 @@ struct jc42_data {
> unsigned long last_updated; /* In jiffies */
> u16 orig_config; /* original configuration */
> u16 config; /* current configuration */
> - u16 temp[t_num_temp];/* Temperatures */
> + u16 temp; /* Cached temperature register value */
On Thu, Oct 20, 2022 at 11:03:16PM +0200, Martin Blumenstingl wrote:
> Hello,
>
> this is a follow-up to the comments I got from Guenter on v1 of my patch
> from [0] titled:
> "hwmon: (jc42) Restore the min/max/critical temperatures on resume"
> There Guenter suggested: "The best solution would probably be to convert
> the driver to use regmap and let regmap handle the caching". That's the
> goal of this series - in addition to fixing the original resume issue
> (see patch #3 - which was the reason for v1 of this series).
>
> Changes since v1 at [0]:
> - marked as RFC
> - added patches for regmap (patch #1) and regcache (patch #2) conversion
> - patch #3 has been updated to use regcache for restoring the register
> values during system resume (this was originally patch 1/1)
> - added another patch to remove caching of the temperature register
>
Great, excellent work. As mentioned in the patches, please combine
patches 1, 2, and 4 into a single patch. Also, drop the RFC.
Thanks,
Guenter