[PATCH v2 0/3] enable eeprom "size" property and runtime pm

[PATCH v2 0/3] enable eeprom "size" property and runtime pm

[Divagar Mohandass]

This series adds support for eeprom "size" property which will be read by the
driver for eeprom size. The existing ACPI has a different default size which
can be overridden with a DSD property value provided by the platform FW.

This series also adds support for runtime PM. The eeprom driver currently
did not have support for runtime PM and the device was kept in D0 throughout.

[v1]
- Add support for eeprom "size" property.
- Add runtime PM support to the driver.

[v2]
- Improved the patch subject.


Divagar Mohandass (3):
  dt-bindings: add eeprom "size" property
  eeprom: at24: add support to fetch eeprom device property "size"
  eeprom: at24: enable runtime pm support

 .../devicetree/bindings/eeprom/eeprom.txt          |  2 ++
 drivers/misc/eeprom/at24.c                         | 38 ++++++++++++++++++++++
 2 files changed, 40 insertions(+)

-- 
1.9.1

[PATCH v2 1/3] dt-bindings: add eeprom "size" property

[Divagar Mohandass]

This adds eeprom "size" as optional property for i2c eeproms.

"size" should be mentioned in byte and it should refer
to the eeprom size. This will be read by the driver and
used to calculating the number of bytes in read/write calls.

Signed-off-by: Divagar Mohandass <divagar.mohandass@intel.com>
---
 Documentation/devicetree/bindings/eeprom/eeprom.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/eeprom/eeprom.txt b/Documentation/devicetree/bindings/eeprom/eeprom.txt
index 5696eb5..1436569 100644
--- a/Documentation/devicetree/bindings/eeprom/eeprom.txt
+++ b/Documentation/devicetree/bindings/eeprom/eeprom.txt
@@ -32,6 +32,8 @@ Optional properties:
 
   - read-only: this parameterless property disables writes to the eeprom
 
+  - size: total eeprom size in bytes
+
 Example:
 
 eeprom@52 {
-- 
1.9.1

Re: [PATCH v2 1/3] dt-bindings: add eeprom "size" property

[Rob Herring]

On Mon, Aug 14, 2017 at 1:41 PM, Divagar Mohandass
<divagar.mohandass@intel.com> wrote:
> This adds eeprom "size" as optional property for i2c eeproms.
>
> "size" should be mentioned in byte and it should refer
> to the eeprom size. This will be read by the driver and
> used to calculating the number of bytes in read/write calls.
>
> Signed-off-by: Divagar Mohandass <divagar.mohandass@intel.com>
> ---
>  Documentation/devicetree/bindings/eeprom/eeprom.txt | 2 ++
>  1 file changed, 2 insertions(+)

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v2 1/3] dt-bindings: add eeprom "size" property

[Sakari Ailus]

Hi Divagar,

On Tue, Aug 15, 2017 at 12:11:57AM +0530, Divagar Mohandass wrote:
> This adds eeprom "size" as optional property for i2c eeproms.
> 
> "size" should be mentioned in byte and it should refer
> to the eeprom size. This will be read by the driver and
> used to calculating the number of bytes in read/write calls.

Instead of the three lines above, how about:

The "size" property allows explicitly specifying the size of the EEPROM
chip in bytes.

> 
> Signed-off-by: Divagar Mohandass <divagar.mohandass@intel.com>
> ---
>  Documentation/devicetree/bindings/eeprom/eeprom.txt | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/eeprom/eeprom.txt b/Documentation/devicetree/bindings/eeprom/eeprom.txt
> index 5696eb5..1436569 100644
> --- a/Documentation/devicetree/bindings/eeprom/eeprom.txt
> +++ b/Documentation/devicetree/bindings/eeprom/eeprom.txt
> @@ -32,6 +32,8 @@ Optional properties:
>  
>    - read-only: this parameterless property disables writes to the eeprom
>  
> +  - size: total eeprom size in bytes
> +
>  Example:
>  
>  eeprom@52 {
> -- 
> 1.9.1
> 

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi

RE: [PATCH v2 1/3] dt-bindings: add eeprom "size" property

[Mohandass, Divagar]

Hi Sakari,

Thanks for your review comments. Will address it in next patch version.

---
^Divagar

>-----Original Message-----
>From: Sakari Ailus [mailto:sakari.ailus-X3B1VOXEql0@public.gmane.org]
>Sent: Tuesday, August 22, 2017 2:41 PM
>To: Mohandass, Divagar <divagar.mohandass-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>Cc: robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org; mark.rutland-5wv7dgnIgG8@public.gmane.org; wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org;
>devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-
>kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Mani, Rajmohan <rajmohan.mani-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>Subject: Re: [PATCH v2 1/3] dt-bindings: add eeprom "size" property
>
>Hi Divagar,
>
>On Tue, Aug 15, 2017 at 12:11:57AM +0530, Divagar Mohandass wrote:
>> This adds eeprom "size" as optional property for i2c eeproms.
>>
>> "size" should be mentioned in byte and it should refer to the eeprom
>> size. This will be read by the driver and used to calculating the
>> number of bytes in read/write calls.
>
>Instead of the three lines above, how about:
>
>The "size" property allows explicitly specifying the size of the EEPROM chip in
>bytes.
>
>>
>> Signed-off-by: Divagar Mohandass <divagar.mohandass-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>> ---
>>  Documentation/devicetree/bindings/eeprom/eeprom.txt | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/eeprom/eeprom.txt
>> b/Documentation/devicetree/bindings/eeprom/eeprom.txt
>> index 5696eb5..1436569 100644
>> --- a/Documentation/devicetree/bindings/eeprom/eeprom.txt
>> +++ b/Documentation/devicetree/bindings/eeprom/eeprom.txt
>> @@ -32,6 +32,8 @@ Optional properties:
>>
>>    - read-only: this parameterless property disables writes to the
>> eeprom
>>
>> +  - size: total eeprom size in bytes
>> +
>>  Example:
>>
>>  eeprom@52 {
>> --
>> 1.9.1
>>
>
>--
>Regards,
>
>Sakari Ailus
>e-mail: sakari.ailus-X3B1VOXEql0@public.gmane.org
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[PATCH v2 2/3] eeprom: at24: add support to fetch eeprom device property "size"

[Divagar Mohandass]

This adds support to fetch device property "size" from _DSD.

There is a CAT24C16/GT24C16S NVMEM chip part of the OV13858
camera module and it is connected to i2c bus on Intel KBL board.
This device will use the existing ACPI ID INT3499 and platform
fw will expose "read-only", "pagesize" and "size" props via _DSD.

Signed-off-by: Divagar Mohandass <divagar.mohandass@intel.com>
---
 drivers/misc/eeprom/at24.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 764ff5df..2199c42 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -570,6 +570,10 @@ static void at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
 	if (device_property_present(dev, "read-only"))
 		chip->flags |= AT24_FLAG_READONLY;
 
+	err = device_property_read_u32(dev, "size", &val);
+	if (!err)
+		chip->byte_len = val;
+
 	err = device_property_read_u32(dev, "pagesize", &val);
 	if (!err) {
 		chip->page_size = val;
-- 
1.9.1

Re: [PATCH v2 2/3] eeprom: at24: add support to fetch eeprom device property "size"

[Sakari Ailus]

Hi Divagar,

On Tue, Aug 15, 2017 at 12:11:58AM +0530, Divagar Mohandass wrote:
> This adds support to fetch device property "size" from _DSD.
> 
> There is a CAT24C16/GT24C16S NVMEM chip part of the OV13858
> camera module and it is connected to i2c bus on Intel KBL board.
> This device will use the existing ACPI ID INT3499 and platform
> fw will expose "read-only", "pagesize" and "size" props via _DSD.

Instead of the two paragraphs, how about:

Obtain the size of the EEPROM chip from DT if the "size" property is
specified for the device.

> 
> Signed-off-by: Divagar Mohandass <divagar.mohandass@intel.com>
> ---
>  drivers/misc/eeprom/at24.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 764ff5df..2199c42 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -570,6 +570,10 @@ static void at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
>  	if (device_property_present(dev, "read-only"))
>  		chip->flags |= AT24_FLAG_READONLY;
>  
> +	err = device_property_read_u32(dev, "size", &val);
> +	if (!err)
> +		chip->byte_len = val;
> +
>  	err = device_property_read_u32(dev, "pagesize", &val);
>  	if (!err) {
>  		chip->page_size = val;
> -- 
> 1.9.1
> 

-- 
Sakari Ailus
e-mail: sakari.ailus@iki.fi

RE: [PATCH v2 2/3] eeprom: at24: add support to fetch eeprom device property "size"

[Mohandass, Divagar]

Hi Sakari,

Thanks for your review comments. Will address it in next patch version.

---
^Divagar

>-----Original Message-----
>From: Sakari Ailus [mailto:sakari.ailus@iki.fi]
>Sent: Tuesday, August 22, 2017 2:43 PM
>To: Mohandass, Divagar <divagar.mohandass@intel.com>
>Cc: robh+dt@kernel.org; mark.rutland@arm.com; wsa@the-dreams.de;
>devicetree@vger.kernel.org; linux-i2c@vger.kernel.org; linux-
>kernel@vger.kernel.org; Mani, Rajmohan <rajmohan.mani@intel.com>
>Subject: Re: [PATCH v2 2/3] eeprom: at24: add support to fetch eeprom
>device property "size"
>
>Hi Divagar,
>
>On Tue, Aug 15, 2017 at 12:11:58AM +0530, Divagar Mohandass wrote:
>> This adds support to fetch device property "size" from _DSD.
>>
>> There is a CAT24C16/GT24C16S NVMEM chip part of the OV13858 camera
>> module and it is connected to i2c bus on Intel KBL board.
>> This device will use the existing ACPI ID INT3499 and platform fw will
>> expose "read-only", "pagesize" and "size" props via _DSD.
>
>Instead of the two paragraphs, how about:
>
>Obtain the size of the EEPROM chip from DT if the "size" property is specified
>for the device.
>
>>
>> Signed-off-by: Divagar Mohandass <divagar.mohandass@intel.com>
>> ---
>>  drivers/misc/eeprom/at24.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
>> index 764ff5df..2199c42 100644
>> --- a/drivers/misc/eeprom/at24.c
>> +++ b/drivers/misc/eeprom/at24.c
>> @@ -570,6 +570,10 @@ static void at24_get_pdata(struct device *dev,
>struct at24_platform_data *chip)
>>  	if (device_property_present(dev, "read-only"))
>>  		chip->flags |= AT24_FLAG_READONLY;
>>
>> +	err = device_property_read_u32(dev, "size", &val);
>> +	if (!err)
>> +		chip->byte_len = val;
>> +
>>  	err = device_property_read_u32(dev, "pagesize", &val);
>>  	if (!err) {
>>  		chip->page_size = val;
>> --
>> 1.9.1
>>
>
>--
>Sakari Ailus
>e-mail: sakari.ailus@iki.fi

[PATCH v2 3/3] eeprom: at24: enable runtime pm support

[Divagar Mohandass]

Currently the device is kept in D0, there is an opportunity
to save power by enabling runtime pm.

Device can be daisy chained from PMIC and we can't rely on I2C core
for auto resume/suspend. Driver will decide when to resume/suspend.

Signed-off-by: Divagar Mohandass <divagar.mohandass@intel.com>
---
 drivers/misc/eeprom/at24.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 2199c42..0d26681 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -24,6 +24,7 @@
 #include <linux/i2c.h>
 #include <linux/nvmem-provider.h>
 #include <linux/platform_data/at24.h>
+#include <linux/pm_runtime.h>
 
 /*
  * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable.
@@ -501,11 +502,21 @@ static ssize_t at24_eeprom_write_i2c(struct at24_data *at24, const char *buf,
 static int at24_read(void *priv, unsigned int off, void *val, size_t count)
 {
 	struct at24_data *at24 = priv;
+	struct i2c_client *client;
 	char *buf = val;
+	int ret;
 
 	if (unlikely(!count))
 		return count;
 
+	client = at24_translate_offset(at24, &off);
+
+	ret = pm_runtime_get_sync(&client->dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(&client->dev);
+		return ret;
+	}
+
 	/*
 	 * Read data from chip, protecting against concurrent updates
 	 * from this host, but not from other I2C masters.
@@ -527,17 +538,29 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
 
 	mutex_unlock(&at24->lock);
 
+	pm_runtime_put(&client->dev);
+
 	return 0;
 }
 
 static int at24_write(void *priv, unsigned int off, void *val, size_t count)
 {
 	struct at24_data *at24 = priv;
+	struct i2c_client *client;
 	char *buf = val;
+	int ret;
 
 	if (unlikely(!count))
 		return -EINVAL;
 
+	client = at24_translate_offset(at24, &off);
+
+	ret = pm_runtime_get_sync(&client->dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(&client->dev);
+		return ret;
+	}
+
 	/*
 	 * Write data to chip, protecting against concurrent updates
 	 * from this host, but not from other I2C masters.
@@ -559,6 +582,8 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
 
 	mutex_unlock(&at24->lock);
 
+	pm_runtime_put(&client->dev);
+
 	return 0;
 }
 
@@ -743,6 +768,13 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	i2c_set_clientdata(client, at24);
 
+	/* enable runtime pm */
+	err = pm_runtime_set_active(&client->dev);
+	if (err < 0)
+		goto err_clients;
+
+	pm_runtime_enable(&client->dev);
+
 	/*
 	 * Perform a one-byte test read to verify that the
 	 * chip is functional.
@@ -810,6 +842,8 @@ static int at24_remove(struct i2c_client *client)
 	for (i = 1; i < at24->num_addresses; i++)
 		i2c_unregister_device(at24->client[i]);
 
+	pm_runtime_disable(&client->dev);
+
 	return 0;
 }
 
-- 
1.9.1

Re: [PATCH v2 3/3] eeprom: at24: enable runtime pm support

[Sakari Ailus]

Hi Divagar,

Thanks for the patch. Please see my comments below.

On Tue, Aug 15, 2017 at 12:11:59AM +0530, Divagar Mohandass wrote:
> Currently the device is kept in D0, there is an opportunity
> to save power by enabling runtime pm.
> 
> Device can be daisy chained from PMIC and we can't rely on I2C core
> for auto resume/suspend. Driver will decide when to resume/suspend.
> 
> Signed-off-by: Divagar Mohandass <divagar.mohandass@intel.com>
> ---
>  drivers/misc/eeprom/at24.c | 34 ++++++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 2199c42..0d26681 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -24,6 +24,7 @@
>  #include <linux/i2c.h>
>  #include <linux/nvmem-provider.h>
>  #include <linux/platform_data/at24.h>
> +#include <linux/pm_runtime.h>
>  
>  /*
>   * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable.
> @@ -501,11 +502,21 @@ static ssize_t at24_eeprom_write_i2c(struct at24_data *at24, const char *buf,
>  static int at24_read(void *priv, unsigned int off, void *val, size_t count)
>  {
>  	struct at24_data *at24 = priv;
> +	struct i2c_client *client;
>  	char *buf = val;
> +	int ret;
>  
>  	if (unlikely(!count))
>  		return count;
>  
> +	client = at24_translate_offset(at24, &off);
> +
> +	ret = pm_runtime_get_sync(&client->dev);
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(&client->dev);
> +		return ret;
> +	}
> +

at24_read() may fail between the two chunks here. You'll need
pm_runtime_put() before returning the error code.

>  	/*
>  	 * Read data from chip, protecting against concurrent updates
>  	 * from this host, but not from other I2C masters.
> @@ -527,17 +538,29 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
>  
>  	mutex_unlock(&at24->lock);
>  
> +	pm_runtime_put(&client->dev);
> +
>  	return 0;
>  }
>  
>  static int at24_write(void *priv, unsigned int off, void *val, size_t count)
>  {
>  	struct at24_data *at24 = priv;
> +	struct i2c_client *client;
>  	char *buf = val;
> +	int ret;
>  
>  	if (unlikely(!count))
>  		return -EINVAL;
>  
> +	client = at24_translate_offset(at24, &off);
> +
> +	ret = pm_runtime_get_sync(&client->dev);
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(&client->dev);
> +		return ret;
> +	}
> +
>  	/*
>  	 * Write data to chip, protecting against concurrent updates
>  	 * from this host, but not from other I2C masters.

Ditto for write.

> @@ -559,6 +582,8 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
>  
>  	mutex_unlock(&at24->lock);
>  
> +	pm_runtime_put(&client->dev);
> +
>  	return 0;
>  }
>  
> @@ -743,6 +768,13 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  
>  	i2c_set_clientdata(client, at24);
>  
> +	/* enable runtime pm */
> +	err = pm_runtime_set_active(&client->dev);
> +	if (err < 0)
> +		goto err_clients;
> +
> +	pm_runtime_enable(&client->dev);
> +

Here, too: at24_read() below can fail, as well as nvmem_register().

>  	/*
>  	 * Perform a one-byte test read to verify that the
>  	 * chip is functional.
> @@ -810,6 +842,8 @@ static int at24_remove(struct i2c_client *client)
>  	for (i = 1; i < at24->num_addresses; i++)
>  		i2c_unregister_device(at24->client[i]);
>  
> +	pm_runtime_disable(&client->dev);

pm_runtime_set_suspended(&client->dev)

> +
>  	return 0;
>  }
>  

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi

RE: [PATCH v2 3/3] eeprom: at24: enable runtime pm support

[Mohandass, Divagar]

Hi Sakari,

Thanks for your review comments.
My comments below.

---
^Divagar

>-----Original Message-----
>From: Sakari Ailus [mailto:sakari.ailus-X3B1VOXEql0@public.gmane.org]
>Sent: Tuesday, August 22, 2017 2:26 PM
>To: Mohandass, Divagar <divagar.mohandass-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>Cc: robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org; mark.rutland-5wv7dgnIgG8@public.gmane.org; wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org;
>devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-
>kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Mani, Rajmohan <rajmohan.mani-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>Subject: Re: [PATCH v2 3/3] eeprom: at24: enable runtime pm support
>
>Hi Divagar,
>
>Thanks for the patch. Please see my comments below.
>
>On Tue, Aug 15, 2017 at 12:11:59AM +0530, Divagar Mohandass wrote:
>> Currently the device is kept in D0, there is an opportunity to save
>> power by enabling runtime pm.
>>
>> Device can be daisy chained from PMIC and we can't rely on I2C core
>> for auto resume/suspend. Driver will decide when to resume/suspend.
>>
>> Signed-off-by: Divagar Mohandass <divagar.mohandass-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>> ---
>>  drivers/misc/eeprom/at24.c | 34 ++++++++++++++++++++++++++++++++++
>>  1 file changed, 34 insertions(+)
>>
>> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
>> index 2199c42..0d26681 100644
>> --- a/drivers/misc/eeprom/at24.c
>> +++ b/drivers/misc/eeprom/at24.c
>> @@ -24,6 +24,7 @@
>>  #include <linux/i2c.h>
>>  #include <linux/nvmem-provider.h>
>>  #include <linux/platform_data/at24.h>
>> +#include <linux/pm_runtime.h>
>>
>>  /*
>>   * I2C EEPROMs from most vendors are inexpensive and mostly
>interchangeable.
>> @@ -501,11 +502,21 @@ static ssize_t at24_eeprom_write_i2c(struct
>> at24_data *at24, const char *buf,  static int at24_read(void *priv,
>> unsigned int off, void *val, size_t count)  {
>>  	struct at24_data *at24 = priv;
>> +	struct i2c_client *client;
>>  	char *buf = val;
>> +	int ret;
>>
>>  	if (unlikely(!count))
>>  		return count;
>>
>> +	client = at24_translate_offset(at24, &off);
>> +
>> +	ret = pm_runtime_get_sync(&client->dev);
>> +	if (ret < 0) {
>> +		pm_runtime_put_noidle(&client->dev);
>> +		return ret;
>> +	}
>> +
>
>at24_read() may fail between the two chunks here. You'll need
>pm_runtime_put() before returning the error code.

Ack

>
>>  	/*
>>  	 * Read data from chip, protecting against concurrent updates
>>  	 * from this host, but not from other I2C masters.
>> @@ -527,17 +538,29 @@ static int at24_read(void *priv, unsigned int
>> off, void *val, size_t count)
>>
>>  	mutex_unlock(&at24->lock);
>>
>> +	pm_runtime_put(&client->dev);
>> +
>>  	return 0;
>>  }
>>
>>  static int at24_write(void *priv, unsigned int off, void *val, size_t
>> count)  {
>>  	struct at24_data *at24 = priv;
>> +	struct i2c_client *client;
>>  	char *buf = val;
>> +	int ret;
>>
>>  	if (unlikely(!count))
>>  		return -EINVAL;
>>
>> +	client = at24_translate_offset(at24, &off);
>> +
>> +	ret = pm_runtime_get_sync(&client->dev);
>> +	if (ret < 0) {
>> +		pm_runtime_put_noidle(&client->dev);
>> +		return ret;
>> +	}
>> +
>>  	/*
>>  	 * Write data to chip, protecting against concurrent updates
>>  	 * from this host, but not from other I2C masters.
>
>Ditto for write.

Ack

>
>> @@ -559,6 +582,8 @@ static int at24_write(void *priv, unsigned int
>> off, void *val, size_t count)
>>
>>  	mutex_unlock(&at24->lock);
>>
>> +	pm_runtime_put(&client->dev);
>> +
>>  	return 0;
>>  }
>>
>> @@ -743,6 +768,13 @@ static int at24_probe(struct i2c_client *client,
>> const struct i2c_device_id *id)
>>
>>  	i2c_set_clientdata(client, at24);
>>
>> +	/* enable runtime pm */
>> +	err = pm_runtime_set_active(&client->dev);
>> +	if (err < 0)
>> +		goto err_clients;
>> +
>> +	pm_runtime_enable(&client->dev);
>> +
>
>Here, too: at24_read() below can fail, as well as nvmem_register().

Ack
In addition to that calling pm_runtime_get_noresume before enabling pm.

>
>>  	/*
>>  	 * Perform a one-byte test read to verify that the
>>  	 * chip is functional.
>> @@ -810,6 +842,8 @@ static int at24_remove(struct i2c_client *client)
>>  	for (i = 1; i < at24->num_addresses; i++)
>>  		i2c_unregister_device(at24->client[i]);
>>
>> +	pm_runtime_disable(&client->dev);
>
>pm_runtime_set_suspended(&client->dev)

Ack

>
>> +
>>  	return 0;
>>  }
>>
>
>--
>Regards,
>
>Sakari Ailus
>e-mail: sakari.ailus-X3B1VOXEql0@public.gmane.org
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