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Date: Sat, 20 Jul 2019 07:08:39 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Robert Karszniewicz <avoidr@...email.cc>,
Rudolf Marek <r.marek@...embler.cz>,
Jean Delvare <jdelvare@...e.com>
Cc: linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] hwmon: (k8temp) update to use new hwmon registration
API
Hi Robert,
On 7/20/19 6:16 AM, Robert Karszniewicz wrote:
> Also removes hwmon_dev from k8temp_data struct, as that is now passed
> to callbacks, anyway.
>
> Also reduces binary size:
> text data bss dec hex filename
> 4185 1384 0 5569 15c1 drivers/hwmon/k8temp.ko.bak
> 3877 1120 0 4997 1385 drivers/hwmon/k8temp.ko
>
Excellent. Couple of comments below.
> Signed-off-by: Robert Karszniewicz <avoidr@...email.cc>
> ---
> drivers/hwmon/k8temp.c | 204 +++++++++++++++++++----------------------
> 1 file changed, 92 insertions(+), 112 deletions(-)
>
> diff --git a/drivers/hwmon/k8temp.c b/drivers/hwmon/k8temp.c
> index 4994c90c8929..2e8fa1e07398 100644
> --- a/drivers/hwmon/k8temp.c
> +++ b/drivers/hwmon/k8temp.c
> @@ -13,7 +13,6 @@
> #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>
> @@ -24,7 +23,6 @@
> #define SEL_CORE 0x04
>
> struct k8temp_data {
> - struct device *hwmon_dev;
> struct mutex update_lock;
> const char *name;
No longer needed (see below)
> char valid; /* zero until following fields are valid */
> @@ -40,7 +38,7 @@ struct k8temp_data {
> 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);
> + struct pci_dev *pdev = to_pci_dev(dev->parent);
> u8 tmp;
>
> mutex_lock(&data->update_lock);
> @@ -82,50 +80,10 @@ static struct k8temp_data *k8temp_update_device(struct device *dev)
> 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 +117,97 @@ 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)
> +{
> + if (type != hwmon_temp)
> + return 0;
Not really needed since only temperature sensors are registered in the first place.
> +
> + if (attr != hwmon_temp_input)
> + return 0;
> +
The idea here is to only create sensors if they actually exist, so I would expect
something like the following here.
struct k8temp_data *data = drvdata;
if (attr != hwmon_temp_input)
return 0;
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 = k8temp_update_device(dev);
It might make sense to remove all the caching. Reading the sensors
isn't that expensive, after all. More on that see below.
> + int core, place;
> +
> + if (type != hwmon_temp)
> + return -EINVAL;
> +
> + if (attr != hwmon_temp_input)
> + return -EINVAL;
> +
The above checks are not needed here, since other sensors and types
have not been instantiated.
> + switch (channel) {
> + case 0:
> + core = 0;
> + place = 0;
> + break;
> + case 1:
> + core = 0;
> + place = 1;
> + break;
> + case 2:
> + core = 1;
> + place = 0;
> + break;
> + case 3:
> + core = 1;
> + place = 1;
> + break;
> + default:
> + return -EINVAL;
> + }
How about
core = (channel >> 1) & 1;
place = channel & 1;
instead ?
> +
> + if (data->swap_core_select)
> + core = core ? 0 : 1;
core = 1 - core;
would accomplish the same without conditional.
As for caching, let's see. Something like the following should do.
struct pci_dev *pdev = to_pci_dev(dev);
u32 temp;
u8 tmp;
...
mutex_lock(&data->update_lock);
pci_read_config_byte(pdev, REG_TEMP, &tmp);
tmp &= ~(SEL_PLACE | SEL_CORE);
if (channel)
tmp |= SEL_PLACE;
if (core)
tmp |= SEL_CORE;
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;
... and then you could drop a lot of code.
> +
> + *val = TEMP_FROM_REG(data->temp[core][place]) + data->temp_offset;
> +
> + return 0;
> +}
> +
> +static const struct hwmon_ops k8temp_ops = {
> + .is_visible = k8temp_is_visible,
> + .read = k8temp_read,
> +};
> +
> +static const u32 k8temp_config[] = {
> + HWMON_T_INPUT,
> + HWMON_T_INPUT,
> + HWMON_T_INPUT,
> + HWMON_T_INPUT,
> + 0
> +};
> +
> +static const struct hwmon_channel_info k8temp_temp_info = {
> + .type = hwmon_temp,
> + .config = k8temp_config,
> +};
> +
> +static const struct hwmon_channel_info *k8temp_info[] = {
> + &k8temp_temp_info,
> + NULL
> +};
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)
> @@ -233,84 +274,23 @@ static int k8temp_probe(struct pci_dev *pdev,
>
> 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;
> + hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
> + data->name,
data->name isn't needed. Just pass "k8temp" directly.
> + data,
> + &k8temp_chip_info,
> + NULL);
>
> - data->hwmon_dev = hwmon_device_register(&pdev->dev);
> -
> - if (IS_ERR(data->hwmon_dev)) {
> - err = PTR_ERR(data->hwmon_dev);
> - goto exit_remove;
> - }
> + if (IS_ERR(hwmon_dev))
> + return PTR_ERR(hwmon_dev);
>
> return 0;
return PTR_ERR_OR_ZERO(hwmon_dev);
> -
> -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);
> }
>
> static struct pci_driver k8temp_driver = {
> .name = "k8temp",
> .id_table = k8temp_ids,
> .probe = k8temp_probe,
> - .remove = k8temp_remove,
> };
>
> module_pci_driver(k8temp_driver);
>
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