[PATCH v4] hwmon: (max6650.c) Add devicetree support

[PATCH v4] hwmon: (max6650.c) Add devicetree support

[Mike Looijmans]

Parse devicetree parameters for voltage and prescaler setting. This allows
using multiple max6550 devices with varying settings, and also makes it
possible to instantiate and configure the device using devicetree.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
---
v4: Vendor prefix "maxim," for devicetree properties and compatible string
    Split documentation into separate patch
v3: Resubmit because wrong mailing lists used
    Fix style errors as reported by checkpatch.pl
    Fix bug in DT parsing of fan-prescale
v2: Add devicetree binding documentation
    Code changes as suggested by Guenter
    Reduce log info, output only a single line 
 drivers/hwmon/max6650.c | 47 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 36 insertions(+), 11 deletions(-)

diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c
index 162a520..6beb62c 100644
--- a/drivers/hwmon/max6650.c
+++ b/drivers/hwmon/max6650.c
@@ -39,6 +39,7 @@
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/err.h>
+#include <linux/of_device.h>
 
 /*
  * Insmod parameters
@@ -48,7 +49,7 @@
 static int fan_voltage;
 /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
 static int prescaler;
-/* clock: The clock frequency of the chip the driver should assume */
+/* clock: The clock frequency of the chip (max6651 can be clocked externally) */
 static int clock = 254000;
 
 module_param(fan_voltage, int, S_IRUGO);
@@ -133,6 +134,19 @@ static const u8 tach_reg[] = {
 	MAX6650_REG_TACH3,
 };
 
+static const struct of_device_id max6650_dt_match[] = {
+	{
+		.compatible = "maxim,max6650",
+		.data = (void *)1
+	},
+	{
+		.compatible = "maxim,max6651",
+		.data = (void *)4
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, max6650_dt_match);
+
 static struct max6650_data *max6650_update_device(struct device *dev)
 {
 	struct max6650_data *data = dev_get_drvdata(dev);
@@ -566,6 +580,17 @@ static int max6650_init_client(struct max6650_data *data,
 	struct device *dev = &client->dev;
 	int config;
 	int err = -EIO;
+	u32 voltage;
+	u32 prescale;
+
+	if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
+				 &voltage))
+		voltage = fan_voltage;
+	else
+		voltage = voltage > 5500000 ? 12 : 5;
+	if (of_property_read_u32(dev->of_node, "maxim,fan-prescale",
+				 &prescale))
+		prescale = prescaler;
 
 	config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
 
@@ -574,7 +599,7 @@ static int max6650_init_client(struct max6650_data *data,
 		return err;
 	}
 
-	switch (fan_voltage) {
+	switch (voltage) {
 	case 0:
 		break;
 	case 5:
@@ -584,14 +609,10 @@ static int max6650_init_client(struct max6650_data *data,
 		config |= MAX6650_CFG_V12;
 		break;
 	default:
-		dev_err(dev, "illegal value for fan_voltage (%d)\n",
-			fan_voltage);
+		dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage);
 	}
 
-	dev_info(dev, "Fan voltage is set to %dV.\n",
-		 (config & MAX6650_CFG_V12) ? 12 : 5);
-
-	switch (prescaler) {
+	switch (prescale) {
 	case 0:
 		break;
 	case 1:
@@ -614,10 +635,11 @@ static int max6650_init_client(struct max6650_data *data,
 			 | MAX6650_CFG_PRESCALER_16;
 		break;
 	default:
-		dev_err(dev, "illegal value for prescaler (%d)\n", prescaler);
+		dev_err(dev, "illegal value for prescaler (%d)\n", prescale);
 	}
 
-	dev_info(dev, "Prescaler is set to %d.\n",
+	dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n",
+		 (config & MAX6650_CFG_V12) ? 12 : 5,
 		 1 << (config & MAX6650_CFG_PRESCALER_MASK));
 
 	/*
@@ -651,6 +673,8 @@ static int max6650_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
+	const struct of_device_id *of_id =
+		of_match_device(of_match_ptr(max6650_dt_match), dev);
 	struct max6650_data *data;
 	struct device *hwmon_dev;
 	int err;
@@ -661,7 +685,7 @@ static int max6650_probe(struct i2c_client *client,
 
 	data->client = client;
 	mutex_init(&data->update_lock);
-	data->nr_fans = id->driver_data;
+	data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : id->driver_data;
 
 	/*
 	 * Initialize the max6650 chip
@@ -691,6 +715,7 @@ MODULE_DEVICE_TABLE(i2c, max6650_id);
 static struct i2c_driver max6650_driver = {
 	.driver = {
 		.name	= "max6650",
+		.of_match_table = of_match_ptr(max6650_dt_match),
 	},
 	.probe		= max6650_probe,
 	.id_table	= max6650_id,
-- 
1.9.1

Re: [PATCH v4] hwmon: (max6650.c) Add devicetree support

[Guenter Roeck]

On 08/16/2016 12:20 AM, Mike Looijmans wrote:
> Parse devicetree parameters for voltage and prescaler setting. This allows
> using multiple max6550 devices with varying settings, and also makes it
> possible to instantiate and configure the device using devicetree.
>
> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
> ---
> v4: Vendor prefix "maxim," for devicetree properties and compatible string
>     Split documentation into separate patch
> v3: Resubmit because wrong mailing lists used
>     Fix style errors as reported by checkpatch.pl
>     Fix bug in DT parsing of fan-prescale
> v2: Add devicetree binding documentation
>     Code changes as suggested by Guenter
>     Reduce log info, output only a single line
>  drivers/hwmon/max6650.c | 47 ++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 36 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c
> index 162a520..6beb62c 100644
> --- a/drivers/hwmon/max6650.c
> +++ b/drivers/hwmon/max6650.c
> @@ -39,6 +39,7 @@
>  #include <linux/hwmon.h>
>  #include <linux/hwmon-sysfs.h>
>  #include <linux/err.h>
> +#include <linux/of_device.h>
>
>  /*
>   * Insmod parameters
> @@ -48,7 +49,7 @@
>  static int fan_voltage;
>  /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
>  static int prescaler;
> -/* clock: The clock frequency of the chip the driver should assume */
> +/* clock: The clock frequency of the chip (max6651 can be clocked externally) */
>  static int clock = 254000;
>
>  module_param(fan_voltage, int, S_IRUGO);
> @@ -133,6 +134,19 @@ static const u8 tach_reg[] = {
>  	MAX6650_REG_TACH3,
>  };
>
> +static const struct of_device_id max6650_dt_match[] = {
> +	{
> +		.compatible = "maxim,max6650",
> +		.data = (void *)1
> +	},
> +	{
> +		.compatible = "maxim,max6651",
> +		.data = (void *)4
> +	},
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, max6650_dt_match);
> +
>  static struct max6650_data *max6650_update_device(struct device *dev)
>  {
>  	struct max6650_data *data = dev_get_drvdata(dev);
> @@ -566,6 +580,17 @@ static int max6650_init_client(struct max6650_data *data,
>  	struct device *dev = &client->dev;
>  	int config;
>  	int err = -EIO;
> +	u32 voltage;
> +	u32 prescale;
> +
> +	if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
> +				 &voltage))
> +		voltage = fan_voltage;
> +	else
> +		voltage = voltage > 5500000 ? 12 : 5;

I think this should only accept 5V or 12V.

Guenter

> +	if (of_property_read_u32(dev->of_node, "maxim,fan-prescale",
> +				 &prescale))
> +		prescale = prescaler;
>
>  	config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
>
> @@ -574,7 +599,7 @@ static int max6650_init_client(struct max6650_data *data,
>  		return err;
>  	}
>
> -	switch (fan_voltage) {
> +	switch (voltage) {
>  	case 0:
>  		break;
>  	case 5:
> @@ -584,14 +609,10 @@ static int max6650_init_client(struct max6650_data *data,
>  		config |= MAX6650_CFG_V12;
>  		break;
>  	default:
> -		dev_err(dev, "illegal value for fan_voltage (%d)\n",
> -			fan_voltage);
> +		dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage);
>  	}
>
> -	dev_info(dev, "Fan voltage is set to %dV.\n",
> -		 (config & MAX6650_CFG_V12) ? 12 : 5);
> -
> -	switch (prescaler) {
> +	switch (prescale) {
>  	case 0:
>  		break;
>  	case 1:
> @@ -614,10 +635,11 @@ static int max6650_init_client(struct max6650_data *data,
>  			 | MAX6650_CFG_PRESCALER_16;
>  		break;
>  	default:
> -		dev_err(dev, "illegal value for prescaler (%d)\n", prescaler);
> +		dev_err(dev, "illegal value for prescaler (%d)\n", prescale);
>  	}
>
> -	dev_info(dev, "Prescaler is set to %d.\n",
> +	dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n",
> +		 (config & MAX6650_CFG_V12) ? 12 : 5,
>  		 1 << (config & MAX6650_CFG_PRESCALER_MASK));
>
>  	/*
> @@ -651,6 +673,8 @@ static int max6650_probe(struct i2c_client *client,
>  			 const struct i2c_device_id *id)
>  {
>  	struct device *dev = &client->dev;
> +	const struct of_device_id *of_id =
> +		of_match_device(of_match_ptr(max6650_dt_match), dev);
>  	struct max6650_data *data;
>  	struct device *hwmon_dev;
>  	int err;
> @@ -661,7 +685,7 @@ static int max6650_probe(struct i2c_client *client,
>
>  	data->client = client;
>  	mutex_init(&data->update_lock);
> -	data->nr_fans = id->driver_data;
> +	data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : id->driver_data;
>
>  	/*
>  	 * Initialize the max6650 chip
> @@ -691,6 +715,7 @@ MODULE_DEVICE_TABLE(i2c, max6650_id);
>  static struct i2c_driver max6650_driver = {
>  	.driver = {
>  		.name	= "max6650",
> +		.of_match_table = of_match_ptr(max6650_dt_match),
>  	},
>  	.probe		= max6650_probe,
>  	.id_table	= max6650_id,
>

Re: [PATCH v4] hwmon: (max6650.c) Add devicetree support

[Mike Looijmans]

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Re: [PATCH v4] hwmon: (max6650.c) Add devicetree support

[Mike Looijmans]

(resent through different SMTP server, bounced as spam because of company 
server's unwanted modifications, sorry if you received this twice now)

On 19-08-16 04:43, Guenter Roeck wrote:
> On 08/16/2016 12:20 AM, Mike Looijmans wrote:
>> Parse devicetree parameters for voltage and prescaler setting. This allows
>> using multiple max6550 devices with varying settings, and also makes it
>> possible to instantiate and configure the device using devicetree.
>>
>> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
>> ---
>> v4: Vendor prefix "maxim," for devicetree properties and compatible string
>>     Split documentation into separate patch
>> v3: Resubmit because wrong mailing lists used
>>     Fix style errors as reported by checkpatch.pl
>>     Fix bug in DT parsing of fan-prescale
>> v2: Add devicetree binding documentation
>>     Code changes as suggested by Guenter
>>     Reduce log info, output only a single line
>>  drivers/hwmon/max6650.c | 47 ++++++++++++++++++++++++++++++++++++-----------
>>  1 file changed, 36 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c
>> index 162a520..6beb62c 100644
>> --- a/drivers/hwmon/max6650.c
>> +++ b/drivers/hwmon/max6650.c
>> @@ -39,6 +39,7 @@
>>  #include <linux/hwmon.h>
>>  #include <linux/hwmon-sysfs.h>
>>  #include <linux/err.h>
>> +#include <linux/of_device.h>
>>
>>  /*
>>   * Insmod parameters
>> @@ -48,7 +49,7 @@
>>  static int fan_voltage;
>>  /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
>>  static int prescaler;
>> -/* clock: The clock frequency of the chip the driver should assume */
>> +/* clock: The clock frequency of the chip (max6651 can be clocked
>> externally) */
>>  static int clock = 254000;
>>
>>  module_param(fan_voltage, int, S_IRUGO);
>> @@ -133,6 +134,19 @@ static const u8 tach_reg[] = {
>>      MAX6650_REG_TACH3,
>>  };
>>
>> +static const struct of_device_id max6650_dt_match[] = {
>> +    {
>> +        .compatible = "maxim,max6650",
>> +        .data = (void *)1
>> +    },
>> +    {
>> +        .compatible = "maxim,max6651",
>> +        .data = (void *)4
>> +    },
>> +    { },
>> +};
>> +MODULE_DEVICE_TABLE(of, max6650_dt_match);
>> +
>>  static struct max6650_data *max6650_update_device(struct device *dev)
>>  {
>>      struct max6650_data *data = dev_get_drvdata(dev);
>> @@ -566,6 +580,17 @@ static int max6650_init_client(struct max6650_data *data,
>>      struct device *dev = &client->dev;
>>      int config;
>>      int err = -EIO;
>> +    u32 voltage;
>> +    u32 prescale;
>> +
>> +    if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
>> +                 &voltage))
>> +        voltage = fan_voltage;
>> +    else
>> +        voltage = voltage > 5500000 ? 12 : 5;
>
> I think this should only accept 5V or 12V.
>
> Guenter

A 4V, 10V or 13V fan will also work just fine, the voltage register just sets 
the range of the feedback tachometer.

I don't have strong feelings either way, so if you feel the drive should bail 
out on anything but 5 or 12, that's fine with me too.

Should I change this and send a v5 patch?



>> +    if (of_property_read_u32(dev->of_node, "maxim,fan-prescale",
>> +                 &prescale))
>> +        prescale = prescaler;
>>
>>      config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
>>
>> @@ -574,7 +599,7 @@ static int max6650_init_client(struct max6650_data *data,
>>          return err;
>>      }
>>
>> -    switch (fan_voltage) {
>> +    switch (voltage) {
>>      case 0:
>>          break;
>>      case 5:
>> @@ -584,14 +609,10 @@ static int max6650_init_client(struct max6650_data *data,
>>          config |= MAX6650_CFG_V12;
>>          break;
>>      default:
>> -        dev_err(dev, "illegal value for fan_voltage (%d)\n",
>> -            fan_voltage);
>> +        dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage);
>>      }
>>
>> -    dev_info(dev, "Fan voltage is set to %dV.\n",
>> -         (config & MAX6650_CFG_V12) ? 12 : 5);
>> -
>> -    switch (prescaler) {
>> +    switch (prescale) {
>>      case 0:
>>          break;
>>      case 1:
>> @@ -614,10 +635,11 @@ static int max6650_init_client(struct max6650_data *data,
>>               | MAX6650_CFG_PRESCALER_16;
>>          break;
>>      default:
>> -        dev_err(dev, "illegal value for prescaler (%d)\n", prescaler);
>> +        dev_err(dev, "illegal value for prescaler (%d)\n", prescale);
>>      }
>>
>> -    dev_info(dev, "Prescaler is set to %d.\n",
>> +    dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n",
>> +         (config & MAX6650_CFG_V12) ? 12 : 5,
>>           1 << (config & MAX6650_CFG_PRESCALER_MASK));
>>
>>      /*
>> @@ -651,6 +673,8 @@ static int max6650_probe(struct i2c_client *client,
>>               const struct i2c_device_id *id)
>>  {
>>      struct device *dev = &client->dev;
>> +    const struct of_device_id *of_id =
>> +        of_match_device(of_match_ptr(max6650_dt_match), dev);
>>      struct max6650_data *data;
>>      struct device *hwmon_dev;
>>      int err;
>> @@ -661,7 +685,7 @@ static int max6650_probe(struct i2c_client *client,
>>
>>      data->client = client;
>>      mutex_init(&data->update_lock);
>> -    data->nr_fans = id->driver_data;
>> +    data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : id->driver_data;
>>
>>      /*
>>       * Initialize the max6650 chip
>> @@ -691,6 +715,7 @@ MODULE_DEVICE_TABLE(i2c, max6650_id);
>>  static struct i2c_driver max6650_driver = {
>>      .driver = {
>>          .name    = "max6650",
>> +        .of_match_table = of_match_ptr(max6650_dt_match),
>>      },
>>      .probe        = max6650_probe,
>>      .id_table    = max6650_id,
>>
>

Re: [PATCH v4] hwmon: (max6650.c) Add devicetree support

[Guenter Roeck]

On 08/19/2016 01:57 AM, Mike Looijmans wrote:
> (resent through different SMTP server, bounced as spam because of company server's unwanted modifications, sorry if you received this twice now)
>
> On 19-08-16 04:43, Guenter Roeck wrote:
>> On 08/16/2016 12:20 AM, Mike Looijmans wrote:
>>> Parse devicetree parameters for voltage and prescaler setting. This allows
>>> using multiple max6550 devices with varying settings, and also makes it
>>> possible to instantiate and configure the device using devicetree.
>>>
>>> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
>>> ---
>>> v4: Vendor prefix "maxim," for devicetree properties and compatible string
>>>     Split documentation into separate patch
>>> v3: Resubmit because wrong mailing lists used
>>>     Fix style errors as reported by checkpatch.pl
>>>     Fix bug in DT parsing of fan-prescale
>>> v2: Add devicetree binding documentation
>>>     Code changes as suggested by Guenter
>>>     Reduce log info, output only a single line
>>>  drivers/hwmon/max6650.c | 47 ++++++++++++++++++++++++++++++++++++-----------
>>>  1 file changed, 36 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c
>>> index 162a520..6beb62c 100644
>>> --- a/drivers/hwmon/max6650.c
>>> +++ b/drivers/hwmon/max6650.c
>>> @@ -39,6 +39,7 @@
>>>  #include <linux/hwmon.h>
>>>  #include <linux/hwmon-sysfs.h>
>>>  #include <linux/err.h>
>>> +#include <linux/of_device.h>
>>>
>>>  /*
>>>   * Insmod parameters
>>> @@ -48,7 +49,7 @@
>>>  static int fan_voltage;
>>>  /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
>>>  static int prescaler;
>>> -/* clock: The clock frequency of the chip the driver should assume */
>>> +/* clock: The clock frequency of the chip (max6651 can be clocked
>>> externally) */
>>>  static int clock = 254000;
>>>
>>>  module_param(fan_voltage, int, S_IRUGO);
>>> @@ -133,6 +134,19 @@ static const u8 tach_reg[] = {
>>>      MAX6650_REG_TACH3,
>>>  };
>>>
>>> +static const struct of_device_id max6650_dt_match[] = {
>>> +    {
>>> +        .compatible = "maxim,max6650",
>>> +        .data = (void *)1
>>> +    },
>>> +    {
>>> +        .compatible = "maxim,max6651",
>>> +        .data = (void *)4
>>> +    },
>>> +    { },
>>> +};
>>> +MODULE_DEVICE_TABLE(of, max6650_dt_match);
>>> +
>>>  static struct max6650_data *max6650_update_device(struct device *dev)
>>>  {
>>>      struct max6650_data *data = dev_get_drvdata(dev);
>>> @@ -566,6 +580,17 @@ static int max6650_init_client(struct max6650_data *data,
>>>      struct device *dev = &client->dev;
>>>      int config;
>>>      int err = -EIO;
>>> +    u32 voltage;
>>> +    u32 prescale;
>>> +
>>> +    if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
>>> +                 &voltage))
>>> +        voltage = fan_voltage;
>>> +    else
>>> +        voltage = voltage > 5500000 ? 12 : 5;
>>
>> I think this should only accept 5V or 12V.
>>
>> Guenter
>
> A 4V, 10V or 13V fan will also work just fine, the voltage register just sets the range of the feedback tachometer.
>
> I don't have strong feelings either way, so if you feel the drive should bail out on anything but 5 or 12, that's fine with me too.
>
Problem with above code is that it isn't clear when the 5V vs. the 12V limit is set.
0V results in 5V, 5.5V results in 5V, 5.500001V results in 12V. That looks pretty
arbitrary. On top of that, the datasheet only mentions 5V and 12V fans, and I am
not aware of the others you are talking about. Per datasheet, the bit selects
either 5V or 12V as fan voltage. So we should stick with that.

> Should I change this and send a v5 patch?
>
Yes, please.

Guenter