[PATCH] hwmon: (thmc50) Convert to a new-style i2c driver

[PATCH] hwmon: (thmc50) Convert to a new-style i2c driver

[Jean Delvare]

The new-style thmc50 driver implements the optional detect()
callback to cover the use cases of the legacy driver.

Signed-off-by: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
Cc: Krzysztof Helt <krzysztof.h1-5tc4TXWwyLM@public.gmane.org>
---
 drivers/hwmon/thmc50.c |  107 +++++++++++++++++++++++-------------------------
 1 file changed, 53 insertions(+), 54 deletions(-)

--- linux-2.6.26-rc9.orig/drivers/hwmon/thmc50.c	2008-07-12 09:20:29.000000000 +0200
+++ linux-2.6.26-rc9/drivers/hwmon/thmc50.c	2008-07-12 10:27:12.000000000 +0200
@@ -60,7 +60,6 @@ static const u8 THMC50_REG_TEMP_MAX[] = 
 
 /* Each client has this additional data */
 struct thmc50_data {
-	struct i2c_client client;
 	struct device *hwmon_dev;
 
 	struct mutex update_lock;
@@ -77,17 +76,31 @@ struct thmc50_data {
 	u8 alarms;
 };
 
-static int thmc50_attach_adapter(struct i2c_adapter *adapter);
-static int thmc50_detach_client(struct i2c_client *client);
+static int thmc50_detect(struct i2c_client *client, int kind,
+			 struct i2c_board_info *info);
+static int thmc50_probe(struct i2c_client *client,
+			const struct i2c_device_id *id);
+static int thmc50_remove(struct i2c_client *client);
 static void thmc50_init_client(struct i2c_client *client);
 static struct thmc50_data *thmc50_update_device(struct device *dev);
 
+static const struct i2c_device_id thmc50_id[] = {
+	{ "adm1022", adm1022 },
+	{ "thmc50", thmc50 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, thmc50_id);
+
 static struct i2c_driver thmc50_driver = {
+	.class = I2C_CLASS_HWMON,
 	.driver = {
 		.name = "thmc50",
 	},
-	.attach_adapter = thmc50_attach_adapter,
-	.detach_client = thmc50_detach_client,
+	.probe = thmc50_probe,
+	.remove = thmc50_remove,
+	.id_table = thmc50_id,
+	.detect = thmc50_detect,
+	.address_data = &addr_data,
 };
 
 static ssize_t show_analog_out(struct device *dev,
@@ -250,39 +263,23 @@ static const struct attribute_group temp
 	.attrs = temp3_attributes,
 };
 
-static int thmc50_detect(struct i2c_adapter *adapter, int address, int kind)
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int thmc50_detect(struct i2c_client *client, int kind,
+			 struct i2c_board_info *info)
 {
 	unsigned company;
 	unsigned revision;
 	unsigned config;
-	struct i2c_client *client;
-	struct thmc50_data *data;
-	struct device *dev;
+	struct i2c_adapter *adapter = client->adapter;
 	int err = 0;
 	const char *type_name;
 
 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
 		pr_debug("thmc50: detect failed, "
 			 "smbus byte data not supported!\n");
-		goto exit;
-	}
-
-	/* OK. For now, we presume we have a valid client. We now create the
-	   client structure, even though we cannot fill it completely yet.
-	   But it allows us to access thmc50 registers. */
-	if (!(data = kzalloc(sizeof(struct thmc50_data), GFP_KERNEL))) {
-		pr_debug("thmc50: detect failed, kzalloc failed!\n");
-		err = -ENOMEM;
-		goto exit;
+		return -ENODEV;
 	}
 
-	client = &data->client;
-	i2c_set_clientdata(client, data);
-	client->addr = address;
-	client->adapter = adapter;
-	client->driver = &thmc50_driver;
-	dev = &client->dev;
-
 	pr_debug("thmc50: Probing for THMC50 at 0x%2X on bus %d\n",
 		 client->addr, i2c_adapter_id(client->adapter));
 
@@ -307,21 +304,22 @@ static int thmc50_detect(struct i2c_adap
 	}
 	if (err == -ENODEV) {
 		pr_debug("thmc50: Detection of THMC50/ADM1022 failed\n");
-		goto exit_free;
+		return err;
 	}
-	data->type = kind;
 
 	if (kind == adm1022) {
 		int id = i2c_adapter_id(client->adapter);
 		int i;
 
 		type_name = "adm1022";
-		data->has_temp3 = (config >> 7) & 1;	/* config MSB */
 		for (i = 0; i + 1 < adm1022_temp3_num; i += 2)
 			if (adm1022_temp3[i] == id &&
-			    adm1022_temp3[i + 1] == address) {
+			    adm1022_temp3[i + 1] == client->addr) {
 				/* enable 2nd remote temp */
-				data->has_temp3 = 1;
+				config |= (1 << 7);
+				i2c_smbus_write_byte_data(client,
+							  THMC50_REG_CONF,
+							  config);
 				break;
 			}
 	} else {
@@ -330,19 +328,33 @@ static int thmc50_detect(struct i2c_adap
 	pr_debug("thmc50: Detected %s (version %x, revision %x)\n",
 		 type_name, (revision >> 4) - 0xc, revision & 0xf);
 
-	/* Fill in the remaining client fields & put it into the global list */
-	strlcpy(client->name, type_name, I2C_NAME_SIZE);
-	mutex_init(&data->update_lock);
+	strlcpy(info->type, type_name, I2C_NAME_SIZE);
 
-	/* Tell the I2C layer a new client has arrived */
-	if ((err = i2c_attach_client(client)))
-		goto exit_free;
+	return 0;
+}
+
+static int thmc50_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct thmc50_data *data;
+	int err;
+
+	data = kzalloc(sizeof(struct thmc50_data), GFP_KERNEL);
+	if (!data) {
+		pr_debug("thmc50: detect failed, kzalloc failed!\n");
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	i2c_set_clientdata(client, data);
+	data->type = id->driver_data;
+	mutex_init(&data->update_lock);
 
 	thmc50_init_client(client);
 
 	/* Register sysfs hooks */
 	if ((err = sysfs_create_group(&client->dev.kobj, &thmc50_group)))
-		goto exit_detach;
+		goto exit_free;
 
 	/* Register ADM1022 sysfs hooks */
 	if (data->has_temp3)
@@ -364,34 +376,21 @@ exit_remove_sysfs:
 		sysfs_remove_group(&client->dev.kobj, &temp3_group);
 exit_remove_sysfs_thmc50:
 	sysfs_remove_group(&client->dev.kobj, &thmc50_group);
-exit_detach:
-	i2c_detach_client(client);
 exit_free:
 	kfree(data);
 exit:
 	return err;
 }
 
-static int thmc50_attach_adapter(struct i2c_adapter *adapter)
-{
-	if (!(adapter->class & I2C_CLASS_HWMON))
-		return 0;
-	return i2c_probe(adapter, &addr_data, thmc50_detect);
-}
-
-static int thmc50_detach_client(struct i2c_client *client)
+static int thmc50_remove(struct i2c_client *client)
 {
 	struct thmc50_data *data = i2c_get_clientdata(client);
-	int err;
 
 	hwmon_device_unregister(data->hwmon_dev);
 	sysfs_remove_group(&client->dev.kobj, &thmc50_group);
 	if (data->has_temp3)
 		sysfs_remove_group(&client->dev.kobj, &temp3_group);
 
-	if ((err = i2c_detach_client(client)))
-		return err;
-
 	kfree(data);
 
 	return 0;
@@ -412,8 +411,8 @@ static void thmc50_init_client(struct i2
 	}
 	config = i2c_smbus_read_byte_data(client, THMC50_REG_CONF);
 	config |= 0x1;	/* start the chip if it is in standby mode */
-	if (data->has_temp3)
-		config |= 0x80;		/* enable 2nd remote temp */
+	if (data->type == adm1022 && (config & (1 << 7)))
+		data->has_temp3 = 1;
 	i2c_smbus_write_byte_data(client, THMC50_REG_CONF, config);
 }
 


-- 
Jean Delvare

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Re: [lm-sensors] [PATCH] hwmon: (thmc50) Convert to a new-style i2c driver

[Hans de Goede]

Jean Delvare wrote:
> The new-style thmc50 driver implements the optional detect()
> callback to cover the use cases of the legacy driver.
> 
> Signed-off-by: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
> Cc: Krzysztof Helt <krzysztof.h1-5tc4TXWwyLM@public.gmane.org>

> @@ -307,21 +304,22 @@ static int thmc50_detect(struct i2c_adap
>  	}
>  	if (err == -ENODEV) {
>  		pr_debug("thmc50: Detection of THMC50/ADM1022 failed\n");
> -		goto exit_free;
> +		return err;
>  	}
> -	data->type = kind;
>  
>  	if (kind == adm1022) {
>  		int id = i2c_adapter_id(client->adapter);
>  		int i;
>  
>  		type_name = "adm1022";
> -		data->has_temp3 = (config >> 7) & 1;	/* config MSB */
>  		for (i = 0; i + 1 < adm1022_temp3_num; i += 2)
>  			if (adm1022_temp3[i] == id &&
> -			    adm1022_temp3[i + 1] == address) {
> +			    adm1022_temp3[i + 1] == client->addr) {
>  				/* enable 2nd remote temp */
> -				data->has_temp3 = 1;
> +				config |= (1 << 7);
> +				i2c_smbus_write_byte_data(client,
> +							  THMC50_REG_CONF,
> +							  config);
>  				break;
>  			}
>  	} else {

Hmm, This does not seem right, you are _writing_ to the device in a the detect 
function changing its configuration. I understand you can no longer set 
data->has_temp3 as there is no data yet in the detect, instead the entire loop 
which checks if the device has temp3 forced through a module option should be 
moved to the probe function. Writing to a config register in the detect 
function feels wrong to me.

Regards,

Hans

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Re: [PATCH] hwmon: (thmc50) Convert to a new-style i2c driver

[Jean Delvare]

Hi Hans,

Thanks for all the reviews :)

On Wed, 16 Jul 2008 23:04:11 +0200, Hans de Goede wrote:
> Jean Delvare wrote:
> > The new-style thmc50 driver implements the optional detect()
> > callback to cover the use cases of the legacy driver.
> > 
> > Signed-off-by: Jean Delvare <khali@linux-fr.org>
> > Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
> 
> > @@ -307,21 +304,22 @@ static int thmc50_detect(struct i2c_adap
> >  	}
> >  	if (err == -ENODEV) {
> >  		pr_debug("thmc50: Detection of THMC50/ADM1022 failed\n");
> > -		goto exit_free;
> > +		return err;
> >  	}
> > -	data->type = kind;
> >  
> >  	if (kind == adm1022) {
> >  		int id = i2c_adapter_id(client->adapter);
> >  		int i;
> >  
> >  		type_name = "adm1022";
> > -		data->has_temp3 = (config >> 7) & 1;	/* config MSB */
> >  		for (i = 0; i + 1 < adm1022_temp3_num; i += 2)
> >  			if (adm1022_temp3[i] == id &&
> > -			    adm1022_temp3[i + 1] == address) {
> > +			    adm1022_temp3[i + 1] == client->addr) {
> >  				/* enable 2nd remote temp */
> > -				data->has_temp3 = 1;
> > +				config |= (1 << 7);
> > +				i2c_smbus_write_byte_data(client,
> > +							  THMC50_REG_CONF,
> > +							  config);
> >  				break;
> >  			}
> >  	} else {
> 
> Hmm, This does not seem right, you are _writing_ to the device in a the detect 
> function changing its configuration. I understand you can no longer set 
> data->has_temp3 as there is no data yet in the detect, instead the entire loop 
> which checks if the device has temp3 forced through a module option should be 
> moved to the probe function. Writing to a config register in the detect 
> function feels wrong to me.

Note that:
* This is only done when the user passes a specific kernel module
  parameter. By default the chip configuration is left unchanged.
* The behavior is exactly the same as those of the original code. It is
  more clearly visible now, but the original code would set
  data->has_temp3, and then call the initialization function which
  itself would write to the chip if data->has_temp3 is set.

So I don't think there is any problem here. If you think that my patch
changes the behavior, then please point this out to me, as this was not
my intent.

I am not shocked by the fact that the detect function is processing the
module parameter. After all, the other module parameters (force,
ignore, etc.) are also handled at this point in the code too (just
before, actually.) And I don't want to do it later because the
initialization function is shared between legacy clients and new-style
ones, and module parameters should not affect new-style clients IMHO.
Chip-specific configuration for new-style clients should be done
through platform data, not module parameters.

If you insist on doing it clean, then the solution would be to convert
the module parameter to platform data in the detection function, and
process that platform data in the probe function (or initialization
function - that's pretty much the same.) If there ever is a new-style
THMC50 or ADM1022 device, we will certainly do that anyway. But I hope
that we agree that this is only moving the code around and not changing
the functional behavior.

Thanks,
-- 
Jean Delvare

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Re: [PATCH] hwmon: (thmc50) Convert to a new-style i2c driver

[Hans de Goede]

Jean Delvare wrote:
> Hi Hans,
> 
> Thanks for all the reviews :)
> 
> On Wed, 16 Jul 2008 23:04:11 +0200, Hans de Goede wrote:
>> Jean Delvare wrote:
>>> The new-style thmc50 driver implements the optional detect()
>>> callback to cover the use cases of the legacy driver.
>>>
>>> Signed-off-by: Jean Delvare <khali@linux-fr.org>
>>> Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
>>> @@ -307,21 +304,22 @@ static int thmc50_detect(struct i2c_adap
>>>  	}
>>>  	if (err == -ENODEV) {
>>>  		pr_debug("thmc50: Detection of THMC50/ADM1022 failed\n");
>>> -		goto exit_free;
>>> +		return err;
>>>  	}
>>> -	data->type = kind;
>>>  
>>>  	if (kind == adm1022) {
>>>  		int id = i2c_adapter_id(client->adapter);
>>>  		int i;
>>>  
>>>  		type_name = "adm1022";
>>> -		data->has_temp3 = (config >> 7) & 1;	/* config MSB */
>>>  		for (i = 0; i + 1 < adm1022_temp3_num; i += 2)
>>>  			if (adm1022_temp3[i] == id &&
>>> -			    adm1022_temp3[i + 1] == address) {
>>> +			    adm1022_temp3[i + 1] == client->addr) {
>>>  				/* enable 2nd remote temp */
>>> -				data->has_temp3 = 1;
>>> +				config |= (1 << 7);
>>> +				i2c_smbus_write_byte_data(client,
>>> +							  THMC50_REG_CONF,
>>> +							  config);
>>>  				break;
>>>  			}
>>>  	} else {
>> Hmm, This does not seem right, you are _writing_ to the device in a the detect 
>> function changing its configuration. I understand you can no longer set 
>> data->has_temp3 as there is no data yet in the detect, instead the entire loop 
>> which checks if the device has temp3 forced through a module option should be 
>> moved to the probe function. Writing to a config register in the detect 
>> function feels wrong to me.
> 
> Note that:
> * This is only done when the user passes a specific kernel module
>   parameter. By default the chip configuration is left unchanged.
> * The behavior is exactly the same as those of the original code. It is
>   more clearly visible now, but the original code would set
>   data->has_temp3, and then call the initialization function which
>   itself would write to the chip if data->has_temp3 is set.
> 
> So I don't think there is any problem here. If you think that my patch
> changes the behavior, then please point this out to me, as this was not
> my intent.
> 
> I am not shocked by the fact that the detect function is processing the
> module parameter. After all, the other module parameters (force,
> ignore, etc.) are also handled at this point in the code too (just
> before, actually.) And I don't want to do it later because the
> initialization function is shared between legacy clients and new-style
> ones, and module parameters should not affect new-style clients IMHO.
> Chip-specific configuration for new-style clients should be done
> through platform data, not module parameters.
> 
> If you insist on doing it clean, then the solution would be to convert
> the module parameter to platform data in the detection function, and
> process that platform data in the probe function (or initialization
> function - that's pretty much the same.) If there ever is a new-style
> THMC50 or ADM1022 device, we will certainly do that anyway. But I hope
> that we agree that this is only moving the code around and not changing
> the functional behavior.
> 

Hmm, me still thinks its not pretty, but I accept your explanation:

Acked-by: Hans de Goede <j.w.r.degoede@hhs.nl>

Regards,

Hans




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