Re: [PATCH v3 1/1] hwmon: (k8temp) update to use new hwmon registration API

[Guenter Roeck <linux@roeck-us.net>]

On Sun, Jul 21, 2019 at 02:00:51PM +0200, Robert Karszniewicz wrote:
> Removes:
> - hwmon_dev from k8temp_data struct, as that is now passed
>   to callbacks, anyway.
> - other k8temp_data struct fields, too.
> - k8temp_update_device()
> 
> Also reduces binary size:
>    text    data     bss     dec     hex filename
>    4139    1448       0    5587    15d3 drivers/hwmon/k8temp.ko.bak
>    3103    1220       0    4323    10e3 drivers/hwmon/k8temp.ko
> 
> Signed-off-by: Robert Karszniewicz <avoidr@firemail.cc>
> Signed-off-by: Robert Karszniewicz <avoidr@riseup.net>

Applied.

> ---
> Changes from v2:
> - if (data->swap_core_select)
> -     core ^= 1;
> + core ^= data->swap_core_select;
> 
> However, that produces slightly more .text than v2, and is a tad too
> "tricky", I personally find.
> 
Interesting - for me it produces ~30 bytes less code (with gcc 7.4.0).

> - Changed email service due to problems with the previous one.
> 
> Changes from v1:
> - correct is_visible() and remove unnecessary checks
> - k8temp_read(): remove unnecessary checks and replace the switch
> - use HWMON_CHANNEL_INFO()
> - remove k8temp->name and pass the string directly
> - use PTR_ERR_OR_ZERO()
> - remove k8temp_update_device() and more k8temp_data fields
> 
>  drivers/hwmon/k8temp.c | 233 ++++++++++++-----------------------------
>  1 file changed, 69 insertions(+), 164 deletions(-)
> 
> diff --git a/drivers/hwmon/k8temp.c b/drivers/hwmon/k8temp.c
> index 4994c90c8929..f73bd4eceb28 100644
> --- a/drivers/hwmon/k8temp.c
> +++ b/drivers/hwmon/k8temp.c
> @@ -10,10 +10,8 @@
>  #include <linux/module.h>
>  #include <linux/init.h>
>  #include <linux/slab.h>
> -#include <linux/jiffies.h>
>  #include <linux/pci.h>
>  #include <linux/hwmon.h>
> -#include <linux/hwmon-sysfs.h>
>  #include <linux/err.h>
>  #include <linux/mutex.h>
>  #include <asm/processor.h>
> @@ -24,108 +22,18 @@
>  #define SEL_CORE	0x04
>  
>  struct k8temp_data {
> -	struct device *hwmon_dev;
>  	struct mutex update_lock;
> -	const char *name;
> -	char valid;		/* zero until following fields are valid */
> -	unsigned long last_updated;	/* in jiffies */
>  
>  	/* registers values */
>  	u8 sensorsp;		/* sensor presence bits - SEL_CORE, SEL_PLACE */
> -	u32 temp[2][2];		/* core, place */
>  	u8 swap_core_select;    /* meaning of SEL_CORE is inverted */
>  	u32 temp_offset;
>  };
>  
> -static struct k8temp_data *k8temp_update_device(struct device *dev)
> -{
> -	struct k8temp_data *data = dev_get_drvdata(dev);
> -	struct pci_dev *pdev = to_pci_dev(dev);
> -	u8 tmp;
> -
> -	mutex_lock(&data->update_lock);
> -
> -	if (!data->valid
> -	    || time_after(jiffies, data->last_updated + HZ)) {
> -		pci_read_config_byte(pdev, REG_TEMP, &tmp);
> -		tmp &= ~(SEL_PLACE | SEL_CORE);	/* Select sensor 0, core0 */
> -		pci_write_config_byte(pdev, REG_TEMP, tmp);
> -		pci_read_config_dword(pdev, REG_TEMP, &data->temp[0][0]);
> -
> -		if (data->sensorsp & SEL_PLACE) {
> -			tmp |= SEL_PLACE;	/* Select sensor 1, core0 */
> -			pci_write_config_byte(pdev, REG_TEMP, tmp);
> -			pci_read_config_dword(pdev, REG_TEMP,
> -					      &data->temp[0][1]);
> -		}
> -
> -		if (data->sensorsp & SEL_CORE) {
> -			tmp &= ~SEL_PLACE;	/* Select sensor 0, core1 */
> -			tmp |= SEL_CORE;
> -			pci_write_config_byte(pdev, REG_TEMP, tmp);
> -			pci_read_config_dword(pdev, REG_TEMP,
> -					      &data->temp[1][0]);
> -
> -			if (data->sensorsp & SEL_PLACE) {
> -				tmp |= SEL_PLACE; /* Select sensor 1, core1 */
> -				pci_write_config_byte(pdev, REG_TEMP, tmp);
> -				pci_read_config_dword(pdev, REG_TEMP,
> -						      &data->temp[1][1]);
> -			}
> -		}
> -
> -		data->last_updated = jiffies;
> -		data->valid = 1;
> -	}
> -
> -	mutex_unlock(&data->update_lock);
> -	return data;
> -}
> -
> -/*
> - * Sysfs stuff
> - */
> -
> -static ssize_t name_show(struct device *dev, struct device_attribute
> -			 *devattr, char *buf)
> -{
> -	struct k8temp_data *data = dev_get_drvdata(dev);
> -
> -	return sprintf(buf, "%s\n", data->name);
> -}
> -
> -
> -static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,
> -			 char *buf)
> -{
> -	struct sensor_device_attribute_2 *attr =
> -	    to_sensor_dev_attr_2(devattr);
> -	int core = attr->nr;
> -	int place = attr->index;
> -	int temp;
> -	struct k8temp_data *data = k8temp_update_device(dev);
> -
> -	if (data->swap_core_select && (data->sensorsp & SEL_CORE))
> -		core = core ? 0 : 1;
> -
> -	temp = TEMP_FROM_REG(data->temp[core][place]) + data->temp_offset;
> -
> -	return sprintf(buf, "%d\n", temp);
> -}
> -
> -/* core, place */
> -
> -static SENSOR_DEVICE_ATTR_2_RO(temp1_input, temp, 0, 0);
> -static SENSOR_DEVICE_ATTR_2_RO(temp2_input, temp, 0, 1);
> -static SENSOR_DEVICE_ATTR_2_RO(temp3_input, temp, 1, 0);
> -static SENSOR_DEVICE_ATTR_2_RO(temp4_input, temp, 1, 1);
> -static DEVICE_ATTR_RO(name);
> -
>  static const struct pci_device_id k8temp_ids[] = {
>  	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
>  	{ 0 },
>  };
> -
>  MODULE_DEVICE_TABLE(pci, k8temp_ids);
>  
>  static int is_rev_g_desktop(u8 model)
> @@ -159,14 +67,76 @@ static int is_rev_g_desktop(u8 model)
>  	return 1;
>  }
>  
> +static umode_t
> +k8temp_is_visible(const void *drvdata, enum hwmon_sensor_types type,
> +		  u32 attr, int channel)
> +{
> +	const struct k8temp_data *data = drvdata;
> +
> +	if ((channel & 1) && !(data->sensorsp & SEL_PLACE))
> +		return 0;
> +
> +	if ((channel & 2) && !(data->sensorsp & SEL_CORE))
> +		return 0;
> +
> +	return 0444;
> +}
> +
> +static int
> +k8temp_read(struct device *dev, enum hwmon_sensor_types type,
> +	    u32 attr, int channel, long *val)
> +{
> +	struct k8temp_data *data = dev_get_drvdata(dev);
> +	struct pci_dev *pdev = to_pci_dev(dev->parent);
> +	int core, place;
> +	u32 temp;
> +	u8 tmp;
> +
> +	core = (channel >> 1) & 1;
> +	place = channel & 1;
> +
> +	core ^= data->swap_core_select;
> +
> +	mutex_lock(&data->update_lock);
> +	pci_read_config_byte(pdev, REG_TEMP, &tmp);
> +	tmp &= ~(SEL_PLACE | SEL_CORE);
> +	if (core)
> +		tmp |= SEL_CORE;
> +	if (place)
> +		tmp |= SEL_PLACE;
> +	pci_write_config_byte(pdev, REG_TEMP, tmp);
> +	pci_read_config_dword(pdev, REG_TEMP, &temp);
> +	mutex_unlock(&data->update_lock);
> +
> +	*val = TEMP_FROM_REG(temp) + data->temp_offset;
> +
> +	return 0;
> +}
> +
> +static const struct hwmon_ops k8temp_ops = {
> +	.is_visible = k8temp_is_visible,
> +	.read = k8temp_read,
> +};
> +
> +static const struct hwmon_channel_info *k8temp_info[] = {
> +	HWMON_CHANNEL_INFO(temp,
> +		HWMON_T_INPUT, HWMON_T_INPUT, HWMON_T_INPUT, HWMON_T_INPUT),
> +	NULL
> +};
> +
> +static const struct hwmon_chip_info k8temp_chip_info = {
> +	.ops = &k8temp_ops,
> +	.info = k8temp_info,
> +};
> +
>  static int k8temp_probe(struct pci_dev *pdev,
>  				  const struct pci_device_id *id)
>  {
> -	int err;
>  	u8 scfg;
>  	u32 temp;
>  	u8 model, stepping;
>  	struct k8temp_data *data;
> +	struct device *hwmon_dev;
>  
>  	data = devm_kzalloc(&pdev->dev, sizeof(struct k8temp_data), GFP_KERNEL);
>  	if (!data)
> @@ -231,86 +201,21 @@ static int k8temp_probe(struct pci_dev *pdev,
>  			data->sensorsp &= ~SEL_CORE;
>  	}
>  
> -	data->name = "k8temp";
>  	mutex_init(&data->update_lock);
> -	pci_set_drvdata(pdev, data);
> -
> -	/* Register sysfs hooks */
> -	err = device_create_file(&pdev->dev,
> -			   &sensor_dev_attr_temp1_input.dev_attr);
> -	if (err)
> -		goto exit_remove;
> -
> -	/* sensor can be changed and reports something */
> -	if (data->sensorsp & SEL_PLACE) {
> -		err = device_create_file(&pdev->dev,
> -				   &sensor_dev_attr_temp2_input.dev_attr);
> -		if (err)
> -			goto exit_remove;
> -	}
> -
> -	/* core can be changed and reports something */
> -	if (data->sensorsp & SEL_CORE) {
> -		err = device_create_file(&pdev->dev,
> -				   &sensor_dev_attr_temp3_input.dev_attr);
> -		if (err)
> -			goto exit_remove;
> -		if (data->sensorsp & SEL_PLACE) {
> -			err = device_create_file(&pdev->dev,
> -					   &sensor_dev_attr_temp4_input.
> -					   dev_attr);
> -			if (err)
> -				goto exit_remove;
> -		}
> -	}
> -
> -	err = device_create_file(&pdev->dev, &dev_attr_name);
> -	if (err)
> -		goto exit_remove;
>  
> -	data->hwmon_dev = hwmon_device_register(&pdev->dev);
> +	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
> +							 "k8temp",
> +							 data,
> +							 &k8temp_chip_info,
> +							 NULL);
>  
> -	if (IS_ERR(data->hwmon_dev)) {
> -		err = PTR_ERR(data->hwmon_dev);
> -		goto exit_remove;
> -	}
> -
> -	return 0;
> -
> -exit_remove:
> -	device_remove_file(&pdev->dev,
> -			   &sensor_dev_attr_temp1_input.dev_attr);
> -	device_remove_file(&pdev->dev,
> -			   &sensor_dev_attr_temp2_input.dev_attr);
> -	device_remove_file(&pdev->dev,
> -			   &sensor_dev_attr_temp3_input.dev_attr);
> -	device_remove_file(&pdev->dev,
> -			   &sensor_dev_attr_temp4_input.dev_attr);
> -	device_remove_file(&pdev->dev, &dev_attr_name);
> -	return err;
> -}
> -
> -static void k8temp_remove(struct pci_dev *pdev)
> -{
> -	struct k8temp_data *data = pci_get_drvdata(pdev);
> -
> -	hwmon_device_unregister(data->hwmon_dev);
> -	device_remove_file(&pdev->dev,
> -			   &sensor_dev_attr_temp1_input.dev_attr);
> -	device_remove_file(&pdev->dev,
> -			   &sensor_dev_attr_temp2_input.dev_attr);
> -	device_remove_file(&pdev->dev,
> -			   &sensor_dev_attr_temp3_input.dev_attr);
> -	device_remove_file(&pdev->dev,
> -			   &sensor_dev_attr_temp4_input.dev_attr);
> -	device_remove_file(&pdev->dev, &dev_attr_name);
> +	return PTR_ERR_OR_ZERO(hwmon_dev);
>  }
>  
>  static struct pci_driver k8temp_driver = {
>  	.name = "k8temp",
>  	.id_table = k8temp_ids,
>  	.probe = k8temp_probe,
> -	.remove = k8temp_remove,
>  };
>  
>  module_pci_driver(k8temp_driver);