* [PATCH v2 0/1] Add hwmon debugfs register access
@ 2021-12-27 22:42 Cosmin Tanislav
2021-12-27 22:42 ` [PATCH v2 1/1] hwmon: Add " Cosmin Tanislav
0 siblings, 1 reply; 5+ messages in thread
From: Cosmin Tanislav @ 2021-12-27 22:42 UTC (permalink / raw)
To: Guenter Roeck
Cc: cosmin.tanislav, demonsingur, Jean Delvare, Jonathan Corbet,
linux-hwmon, linux-doc, linux-kernel
V1 -> V2:
* remove error messages that are reported to userspace
* remove IS_ERR checks that are already done by called functions
* unconditionally define hwmon_device_{un,}register_debugfs
* unconditionally define struct hwmon_device members
* match hwmon_debugfs_read_reg parameter indentation with
hwmon_debugfs_write_reg parameter indentation
* inline hdev in reg_access calls
* remove useless initialization of val inside hwmon_debugfs_read_reg
* move checks outside of hwmon_device_register_debugfs
* debugfs_reg_access -> reg_access
* lookup device debugfs dentry rather than storing it in
struct hwmon_device
Cosmin Tanislav (1):
hwmon: Add debugfs register access
Documentation/hwmon/hwmon-kernel-api.rst | 9 +++
drivers/hwmon/hwmon.c | 99 ++++++++++++++++++++++++
include/linux/hwmon.h | 12 +++
3 files changed, 120 insertions(+)
--
2.34.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2 1/1] hwmon: Add debugfs register access
2021-12-27 22:42 [PATCH v2 0/1] Add hwmon debugfs register access Cosmin Tanislav
@ 2021-12-27 22:42 ` Cosmin Tanislav
2021-12-28 16:13 ` Guenter Roeck
0 siblings, 1 reply; 5+ messages in thread
From: Cosmin Tanislav @ 2021-12-27 22:42 UTC (permalink / raw)
To: Guenter Roeck
Cc: cosmin.tanislav, demonsingur, Jean Delvare, Jonathan Corbet,
linux-hwmon, linux-doc, linux-kernel
From: Cosmin Tanislav <cosmin.tanislav@analog.com>
Similar to IIO, create a device directory inside debugfs
mount point, and create a direct_reg_access file inside
that directory, if debugfs_reg_access callback is defined
inside hwmon_ops.
Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
---
Documentation/hwmon/hwmon-kernel-api.rst | 9 +++
drivers/hwmon/hwmon.c | 97 ++++++++++++++++++++++++
include/linux/hwmon.h | 12 +++
3 files changed, 118 insertions(+)
diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst
index c41eb6108103..d568a0bfa5fb 100644
--- a/Documentation/hwmon/hwmon-kernel-api.rst
+++ b/Documentation/hwmon/hwmon-kernel-api.rst
@@ -136,6 +136,8 @@ The list of hwmon operations is defined as::
u32 attr, int, long *);
int (*write)(struct device *, enum hwmon_sensor_types type,
u32 attr, int, long);
+ int (*reg_access)(struct device *dev, unsigned int reg,
+ unsigned int writeval, unsigned int *readval);
};
It defines the following operations.
@@ -152,6 +154,13 @@ It defines the following operations.
Pointer to a function for writing a value to the chip. This function is
optional, but must be provided if any writeable attributes exist.
+* reg_access:
+ Pointer to a function for writing or reading a register to the chip.
+ This function is optional.
+ WARNING: Drivers implementing this function must block any access that
+ may cause issues such as power loss, board resets, flash corruption or
+ bricking.
+
Each sensor channel is described with struct hwmon_channel_info, which is
defined as follows::
diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index 3501a3ead4ba..027e5fc33114 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -10,6 +10,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/bitops.h>
+#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gfp.h>
@@ -35,6 +36,9 @@ struct hwmon_device {
struct list_head tzdata;
struct attribute_group group;
const struct attribute_group **groups;
+ unsigned int cached_reg_addr;
+ char read_buf[20];
+ unsigned int read_buf_len;
};
#define to_hwmon_device(d) container_of(d, struct hwmon_device, dev)
@@ -64,6 +68,90 @@ struct hwmon_thermal_data {
struct thermal_zone_device *tzd;/* thermal zone device */
};
+static struct dentry *hwmon_debugfs_dentry;
+
+static ssize_t hwmon_debugfs_read_reg(struct file *file,
+ char __user *userbuf,
+ size_t count, loff_t *ppos)
+{
+ struct hwmon_device *hwdev = file->private_data;
+ unsigned int val;
+ int ret;
+
+ if (*ppos > 0)
+ return simple_read_from_buffer(userbuf, count, ppos,
+ hwdev->read_buf,
+ hwdev->read_buf_len);
+
+ ret = hwdev->chip->ops->reg_access(&hwdev->dev, hwdev->cached_reg_addr,
+ 0, &val);
+ if (ret)
+ return ret;
+
+ hwdev->read_buf_len = snprintf(hwdev->read_buf, sizeof(hwdev->read_buf),
+ "0x%X\n", val);
+
+ return simple_read_from_buffer(userbuf, count, ppos, hwdev->read_buf,
+ hwdev->read_buf_len);
+}
+
+static ssize_t hwmon_debugfs_write_reg(struct file *file,
+ const char __user *userbuf,
+ size_t count, loff_t *ppos)
+{
+ struct hwmon_device *hwdev = file->private_data;
+ unsigned int reg, val;
+ char buf[80];
+ int ret;
+
+ count = min_t(size_t, count, sizeof(buf) - 1);
+ if (copy_from_user(buf, userbuf, count))
+ return -EFAULT;
+
+ buf[count] = 0;
+
+ ret = sscanf(buf, "%i %i", ®, &val);
+
+ switch (ret) {
+ case 1:
+ hwdev->cached_reg_addr = reg;
+ break;
+ case 2:
+ hwdev->cached_reg_addr = reg;
+ ret = hwdev->chip->ops->reg_access(&hwdev->dev, reg, val, NULL);
+ if (ret)
+ return ret;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+static const struct file_operations hwmon_debugfs_reg_fops = {
+ .open = simple_open,
+ .read = hwmon_debugfs_read_reg,
+ .write = hwmon_debugfs_write_reg,
+};
+
+static void hwmon_device_register_debugfs(struct hwmon_device *hwdev)
+{
+ struct dentry *dir = debugfs_create_dir(dev_name(&hwdev->dev),
+ hwmon_debugfs_dentry);
+
+ debugfs_create_file("direct_reg_access", 0644, dir, hwdev,
+ &hwmon_debugfs_reg_fops);
+}
+
+static void hwmon_device_unregister_debugfs(struct hwmon_device *hwdev)
+{
+ struct dentry *dir = debugfs_lookup(dev_name(&hwdev->dev),
+ hwmon_debugfs_dentry);
+
+ debugfs_remove_recursive(dir);
+}
+
static ssize_t
name_show(struct device *dev, struct device_attribute *attr, char *buf)
{
@@ -114,6 +202,8 @@ static void hwmon_dev_release(struct device *dev)
{
struct hwmon_device *hwdev = to_hwmon_device(dev);
+ hwmon_device_unregister_debugfs(hwdev);
+
if (hwdev->group.attrs)
hwmon_free_attrs(hwdev->group.attrs);
kfree(hwdev->groups);
@@ -817,6 +907,9 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
}
}
+ if (chip && chip->ops->reg_access)
+ hwmon_device_register_debugfs(hwdev);
+
return hdev;
free_hwmon:
@@ -1062,12 +1155,16 @@ static int __init hwmon_init(void)
pr_err("couldn't register hwmon sysfs class\n");
return err;
}
+
+ hwmon_debugfs_dentry = debugfs_create_dir("hwmon", NULL);
+
return 0;
}
static void __exit hwmon_exit(void)
{
class_unregister(&hwmon_class);
+ debugfs_remove(hwmon_debugfs_dentry);
}
subsys_initcall(hwmon_init);
diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
index fad1f1df26df..587fb2931ac1 100644
--- a/include/linux/hwmon.h
+++ b/include/linux/hwmon.h
@@ -390,6 +390,16 @@ enum hwmon_intrusion_attributes {
* Channel number
* @val: Value to write
* The function returns 0 on success or a negative error number.
+ * @reg_access:
+ * Callback to read or write register values.
+ * Parameters are:
+ * @dev: Pointer to hardware monitoring device
+ * @reg: Register address to read or write
+ * @writeval:
+ * Value to write to register. 0 when reading.
+ * @readval:
+ * Pointer to value read from register. NULL when writing.
+ * The function returns 0 on success or a negative error number.
*/
struct hwmon_ops {
umode_t (*is_visible)(const void *drvdata, enum hwmon_sensor_types type,
@@ -400,6 +410,8 @@ struct hwmon_ops {
u32 attr, int channel, const char **str);
int (*write)(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long val);
+ int (*reg_access)(struct device *dev, unsigned int reg,
+ unsigned int writeval, unsigned int *readval);
};
/**
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2 1/1] hwmon: Add debugfs register access
2021-12-27 22:42 ` [PATCH v2 1/1] hwmon: Add " Cosmin Tanislav
@ 2021-12-28 16:13 ` Guenter Roeck
2021-12-28 16:51 ` Cosmin Tanislav
0 siblings, 1 reply; 5+ messages in thread
From: Guenter Roeck @ 2021-12-28 16:13 UTC (permalink / raw)
To: Cosmin Tanislav
Cc: cosmin.tanislav, Jean Delvare, Jonathan Corbet, linux-hwmon,
linux-doc, linux-kernel
On 12/27/21 2:42 PM, Cosmin Tanislav wrote:
> From: Cosmin Tanislav <cosmin.tanislav@analog.com>
>
> Similar to IIO, create a device directory inside debugfs
> mount point, and create a direct_reg_access file inside
> that directory, if debugfs_reg_access callback is defined
> inside hwmon_ops.
>
Patch looks good afaics. I don't want to apply it now (ie for 5.17),
though, because it is getting close and we don't have a use case.
If you have one in mind, I'd suggest to submit it together with
this patch, or we'll have to wait until there is a user.
Guenter
> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
> ---
> Documentation/hwmon/hwmon-kernel-api.rst | 9 +++
> drivers/hwmon/hwmon.c | 97 ++++++++++++++++++++++++
> include/linux/hwmon.h | 12 +++
> 3 files changed, 118 insertions(+)
>
> diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst
> index c41eb6108103..d568a0bfa5fb 100644
> --- a/Documentation/hwmon/hwmon-kernel-api.rst
> +++ b/Documentation/hwmon/hwmon-kernel-api.rst
> @@ -136,6 +136,8 @@ The list of hwmon operations is defined as::
> u32 attr, int, long *);
> int (*write)(struct device *, enum hwmon_sensor_types type,
> u32 attr, int, long);
> + int (*reg_access)(struct device *dev, unsigned int reg,
> + unsigned int writeval, unsigned int *readval);
> };
>
> It defines the following operations.
> @@ -152,6 +154,13 @@ It defines the following operations.
> Pointer to a function for writing a value to the chip. This function is
> optional, but must be provided if any writeable attributes exist.
>
> +* reg_access:
> + Pointer to a function for writing or reading a register to the chip.
> + This function is optional.
> + WARNING: Drivers implementing this function must block any access that
> + may cause issues such as power loss, board resets, flash corruption or
> + bricking.
> +
> Each sensor channel is described with struct hwmon_channel_info, which is
> defined as follows::
>
> diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
> index 3501a3ead4ba..027e5fc33114 100644
> --- a/drivers/hwmon/hwmon.c
> +++ b/drivers/hwmon/hwmon.c
> @@ -10,6 +10,7 @@
> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> #include <linux/bitops.h>
> +#include <linux/debugfs.h>
> #include <linux/device.h>
> #include <linux/err.h>
> #include <linux/gfp.h>
> @@ -35,6 +36,9 @@ struct hwmon_device {
> struct list_head tzdata;
> struct attribute_group group;
> const struct attribute_group **groups;
> + unsigned int cached_reg_addr;
> + char read_buf[20];
> + unsigned int read_buf_len;
> };
>
> #define to_hwmon_device(d) container_of(d, struct hwmon_device, dev)
> @@ -64,6 +68,90 @@ struct hwmon_thermal_data {
> struct thermal_zone_device *tzd;/* thermal zone device */
> };
>
> +static struct dentry *hwmon_debugfs_dentry;
> +
> +static ssize_t hwmon_debugfs_read_reg(struct file *file,
> + char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + struct hwmon_device *hwdev = file->private_data;
> + unsigned int val;
> + int ret;
> +
> + if (*ppos > 0)
> + return simple_read_from_buffer(userbuf, count, ppos,
> + hwdev->read_buf,
> + hwdev->read_buf_len);
> +
> + ret = hwdev->chip->ops->reg_access(&hwdev->dev, hwdev->cached_reg_addr,
> + 0, &val);
> + if (ret)
> + return ret;
> +
> + hwdev->read_buf_len = snprintf(hwdev->read_buf, sizeof(hwdev->read_buf),
> + "0x%X\n", val);
> +
> + return simple_read_from_buffer(userbuf, count, ppos, hwdev->read_buf,
> + hwdev->read_buf_len);
> +}
> +
> +static ssize_t hwmon_debugfs_write_reg(struct file *file,
> + const char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + struct hwmon_device *hwdev = file->private_data;
> + unsigned int reg, val;
> + char buf[80];
> + int ret;
> +
> + count = min_t(size_t, count, sizeof(buf) - 1);
> + if (copy_from_user(buf, userbuf, count))
> + return -EFAULT;
> +
> + buf[count] = 0;
> +
> + ret = sscanf(buf, "%i %i", ®, &val);
> +
> + switch (ret) {
> + case 1:
> + hwdev->cached_reg_addr = reg;
> + break;
> + case 2:
> + hwdev->cached_reg_addr = reg;
> + ret = hwdev->chip->ops->reg_access(&hwdev->dev, reg, val, NULL);
> + if (ret)
> + return ret;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return count;
> +}
> +
> +static const struct file_operations hwmon_debugfs_reg_fops = {
> + .open = simple_open,
> + .read = hwmon_debugfs_read_reg,
> + .write = hwmon_debugfs_write_reg,
> +};
> +
> +static void hwmon_device_register_debugfs(struct hwmon_device *hwdev)
> +{
> + struct dentry *dir = debugfs_create_dir(dev_name(&hwdev->dev),
> + hwmon_debugfs_dentry);
> +
> + debugfs_create_file("direct_reg_access", 0644, dir, hwdev,
> + &hwmon_debugfs_reg_fops);
> +}
> +
> +static void hwmon_device_unregister_debugfs(struct hwmon_device *hwdev)
> +{
> + struct dentry *dir = debugfs_lookup(dev_name(&hwdev->dev),
> + hwmon_debugfs_dentry);
> +
> + debugfs_remove_recursive(dir);
> +}
> +
> static ssize_t
> name_show(struct device *dev, struct device_attribute *attr, char *buf)
> {
> @@ -114,6 +202,8 @@ static void hwmon_dev_release(struct device *dev)
> {
> struct hwmon_device *hwdev = to_hwmon_device(dev);
>
> + hwmon_device_unregister_debugfs(hwdev);
> +
> if (hwdev->group.attrs)
> hwmon_free_attrs(hwdev->group.attrs);
> kfree(hwdev->groups);
> @@ -817,6 +907,9 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
> }
> }
>
> + if (chip && chip->ops->reg_access)
> + hwmon_device_register_debugfs(hwdev);
> +
> return hdev;
>
> free_hwmon:
> @@ -1062,12 +1155,16 @@ static int __init hwmon_init(void)
> pr_err("couldn't register hwmon sysfs class\n");
> return err;
> }
> +
> + hwmon_debugfs_dentry = debugfs_create_dir("hwmon", NULL);
> +
> return 0;
> }
>
> static void __exit hwmon_exit(void)
> {
> class_unregister(&hwmon_class);
> + debugfs_remove(hwmon_debugfs_dentry);
> }
>
> subsys_initcall(hwmon_init);
> diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
> index fad1f1df26df..587fb2931ac1 100644
> --- a/include/linux/hwmon.h
> +++ b/include/linux/hwmon.h
> @@ -390,6 +390,16 @@ enum hwmon_intrusion_attributes {
> * Channel number
> * @val: Value to write
> * The function returns 0 on success or a negative error number.
> + * @reg_access:
> + * Callback to read or write register values.
> + * Parameters are:
> + * @dev: Pointer to hardware monitoring device
> + * @reg: Register address to read or write
> + * @writeval:
> + * Value to write to register. 0 when reading.
> + * @readval:
> + * Pointer to value read from register. NULL when writing.
> + * The function returns 0 on success or a negative error number.
> */
> struct hwmon_ops {
> umode_t (*is_visible)(const void *drvdata, enum hwmon_sensor_types type,
> @@ -400,6 +410,8 @@ struct hwmon_ops {
> u32 attr, int channel, const char **str);
> int (*write)(struct device *dev, enum hwmon_sensor_types type,
> u32 attr, int channel, long val);
> + int (*reg_access)(struct device *dev, unsigned int reg,
> + unsigned int writeval, unsigned int *readval);
> };
>
> /**
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 1/1] hwmon: Add debugfs register access
2021-12-28 16:13 ` Guenter Roeck
@ 2021-12-28 16:51 ` Cosmin Tanislav
2021-12-28 17:09 ` Guenter Roeck
0 siblings, 1 reply; 5+ messages in thread
From: Cosmin Tanislav @ 2021-12-28 16:51 UTC (permalink / raw)
To: Guenter Roeck
Cc: cosmin.tanislav, Jean Delvare, Jonathan Corbet, linux-hwmon,
linux-doc, linux-kernel
On 12/28/21 18:13, Guenter Roeck wrote:
> On 12/27/21 2:42 PM, Cosmin Tanislav wrote:
>> From: Cosmin Tanislav <cosmin.tanislav@analog.com>
>>
>> Similar to IIO, create a device directory inside debugfs
>> mount point, and create a direct_reg_access file inside
>> that directory, if debugfs_reg_access callback is defined
>> inside hwmon_ops.
>>
>
> Patch looks good afaics. I don't want to apply it now (ie for 5.17),
> though, because it is getting close and we don't have a use case.
> If you have one in mind, I'd suggest to submit it together with
> this patch, or we'll have to wait until there is a user.
>
> Guenter
As I mentioned previously I have a local patch on top of the ADT7X10
refactor that uses this. I tested your modifications to my patchset on
the ADT7420 part and it seems to work just fine. I can push it on top of
either this patch or that patchset, your choice.
>
>> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
>> ---
>> Documentation/hwmon/hwmon-kernel-api.rst | 9 +++
>> drivers/hwmon/hwmon.c | 97 ++++++++++++++++++++++++
>> include/linux/hwmon.h | 12 +++
>> 3 files changed, 118 insertions(+)
>>
>> diff --git a/Documentation/hwmon/hwmon-kernel-api.rst
>> b/Documentation/hwmon/hwmon-kernel-api.rst
>> index c41eb6108103..d568a0bfa5fb 100644
>> --- a/Documentation/hwmon/hwmon-kernel-api.rst
>> +++ b/Documentation/hwmon/hwmon-kernel-api.rst
>> @@ -136,6 +136,8 @@ The list of hwmon operations is defined as::
>> u32 attr, int, long *);
>> int (*write)(struct device *, enum hwmon_sensor_types type,
>> u32 attr, int, long);
>> + int (*reg_access)(struct device *dev, unsigned int reg,
>> + unsigned int writeval, unsigned int *readval);
>> };
>> It defines the following operations.
>> @@ -152,6 +154,13 @@ It defines the following operations.
>> Pointer to a function for writing a value to the chip. This
>> function is
>> optional, but must be provided if any writeable attributes exist.
>> +* reg_access:
>> + Pointer to a function for writing or reading a register to the chip.
>> + This function is optional.
>> + WARNING: Drivers implementing this function must block any access
>> that
>> + may cause issues such as power loss, board resets, flash
>> corruption or
>> + bricking.
>> +
>> Each sensor channel is described with struct hwmon_channel_info,
>> which is
>> defined as follows::
>> diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
>> index 3501a3ead4ba..027e5fc33114 100644
>> --- a/drivers/hwmon/hwmon.c
>> +++ b/drivers/hwmon/hwmon.c
>> @@ -10,6 +10,7 @@
>> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> #include <linux/bitops.h>
>> +#include <linux/debugfs.h>
>> #include <linux/device.h>
>> #include <linux/err.h>
>> #include <linux/gfp.h>
>> @@ -35,6 +36,9 @@ struct hwmon_device {
>> struct list_head tzdata;
>> struct attribute_group group;
>> const struct attribute_group **groups;
>> + unsigned int cached_reg_addr;
>> + char read_buf[20];
>> + unsigned int read_buf_len;
>> };
>> #define to_hwmon_device(d) container_of(d, struct hwmon_device, dev)
>> @@ -64,6 +68,90 @@ struct hwmon_thermal_data {
>> struct thermal_zone_device *tzd;/* thermal zone device */
>> };
>> +static struct dentry *hwmon_debugfs_dentry;
>> +
>> +static ssize_t hwmon_debugfs_read_reg(struct file *file,
>> + char __user *userbuf,
>> + size_t count, loff_t *ppos)
>> +{
>> + struct hwmon_device *hwdev = file->private_data;
>> + unsigned int val;
>> + int ret;
>> +
>> + if (*ppos > 0)
>> + return simple_read_from_buffer(userbuf, count, ppos,
>> + hwdev->read_buf,
>> + hwdev->read_buf_len);
>> +
>> + ret = hwdev->chip->ops->reg_access(&hwdev->dev,
>> hwdev->cached_reg_addr,
>> + 0, &val);
>> + if (ret)
>> + return ret;
>> +
>> + hwdev->read_buf_len = snprintf(hwdev->read_buf,
>> sizeof(hwdev->read_buf),
>> + "0x%X\n", val);
>> +
>> + return simple_read_from_buffer(userbuf, count, ppos,
>> hwdev->read_buf,
>> + hwdev->read_buf_len);
>> +}
>> +
>> +static ssize_t hwmon_debugfs_write_reg(struct file *file,
>> + const char __user *userbuf,
>> + size_t count, loff_t *ppos)
>> +{
>> + struct hwmon_device *hwdev = file->private_data;
>> + unsigned int reg, val;
>> + char buf[80];
>> + int ret;
>> +
>> + count = min_t(size_t, count, sizeof(buf) - 1);
>> + if (copy_from_user(buf, userbuf, count))
>> + return -EFAULT;
>> +
>> + buf[count] = 0;
>> +
>> + ret = sscanf(buf, "%i %i", ®, &val);
>> +
>> + switch (ret) {
>> + case 1:
>> + hwdev->cached_reg_addr = reg;
>> + break;
>> + case 2:
>> + hwdev->cached_reg_addr = reg;
>> + ret = hwdev->chip->ops->reg_access(&hwdev->dev, reg, val, NULL);
>> + if (ret)
>> + return ret;
>> + break;
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + return count;
>> +}
>> +
>> +static const struct file_operations hwmon_debugfs_reg_fops = {
>> + .open = simple_open,
>> + .read = hwmon_debugfs_read_reg,
>> + .write = hwmon_debugfs_write_reg,
>> +};
>> +
>> +static void hwmon_device_register_debugfs(struct hwmon_device *hwdev)
>> +{
>> + struct dentry *dir = debugfs_create_dir(dev_name(&hwdev->dev),
>> + hwmon_debugfs_dentry);
>> +
>> + debugfs_create_file("direct_reg_access", 0644, dir, hwdev,
>> + &hwmon_debugfs_reg_fops);
>> +}
>> +
>> +static void hwmon_device_unregister_debugfs(struct hwmon_device *hwdev)
>> +{
>> + struct dentry *dir = debugfs_lookup(dev_name(&hwdev->dev),
>> + hwmon_debugfs_dentry);
>> +
>> + debugfs_remove_recursive(dir);
>> +}
>> +
>> static ssize_t
>> name_show(struct device *dev, struct device_attribute *attr, char *buf)
>> {
>> @@ -114,6 +202,8 @@ static void hwmon_dev_release(struct device *dev)
>> {
>> struct hwmon_device *hwdev = to_hwmon_device(dev);
>> + hwmon_device_unregister_debugfs(hwdev);
>> +
>> if (hwdev->group.attrs)
>> hwmon_free_attrs(hwdev->group.attrs);
>> kfree(hwdev->groups);
>> @@ -817,6 +907,9 @@ __hwmon_device_register(struct device *dev, const
>> char *name, void *drvdata,
>> }
>> }
>> + if (chip && chip->ops->reg_access)
>> + hwmon_device_register_debugfs(hwdev);
>> +
>> return hdev;
>> free_hwmon:
>> @@ -1062,12 +1155,16 @@ static int __init hwmon_init(void)
>> pr_err("couldn't register hwmon sysfs class\n");
>> return err;
>> }
>> +
>> + hwmon_debugfs_dentry = debugfs_create_dir("hwmon", NULL);
>> +
>> return 0;
>> }
>> static void __exit hwmon_exit(void)
>> {
>> class_unregister(&hwmon_class);
>> + debugfs_remove(hwmon_debugfs_dentry);
>> }
>> subsys_initcall(hwmon_init);
>> diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
>> index fad1f1df26df..587fb2931ac1 100644
>> --- a/include/linux/hwmon.h
>> +++ b/include/linux/hwmon.h
>> @@ -390,6 +390,16 @@ enum hwmon_intrusion_attributes {
>> * Channel number
>> * @val: Value to write
>> * The function returns 0 on success or a negative error number.
>> + * @reg_access:
>> + * Callback to read or write register values.
>> + * Parameters are:
>> + * @dev: Pointer to hardware monitoring device
>> + * @reg: Register address to read or write
>> + * @writeval:
>> + * Value to write to register. 0 when reading.
>> + * @readval:
>> + * Pointer to value read from register. NULL when writing.
>> + * The function returns 0 on success or a negative error number.
>> */
>> struct hwmon_ops {
>> umode_t (*is_visible)(const void *drvdata, enum
>> hwmon_sensor_types type,
>> @@ -400,6 +410,8 @@ struct hwmon_ops {
>> u32 attr, int channel, const char **str);
>> int (*write)(struct device *dev, enum hwmon_sensor_types type,
>> u32 attr, int channel, long val);
>> + int (*reg_access)(struct device *dev, unsigned int reg,
>> + unsigned int writeval, unsigned int *readval);
>> };
>> /**
>>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 1/1] hwmon: Add debugfs register access
2021-12-28 16:51 ` Cosmin Tanislav
@ 2021-12-28 17:09 ` Guenter Roeck
0 siblings, 0 replies; 5+ messages in thread
From: Guenter Roeck @ 2021-12-28 17:09 UTC (permalink / raw)
To: Cosmin Tanislav
Cc: cosmin.tanislav, Jean Delvare, Jonathan Corbet, linux-hwmon,
linux-doc, linux-kernel
On Tue, Dec 28, 2021 at 06:51:40PM +0200, Cosmin Tanislav wrote:
>
>
> On 12/28/21 18:13, Guenter Roeck wrote:
> > On 12/27/21 2:42 PM, Cosmin Tanislav wrote:
> > > From: Cosmin Tanislav <cosmin.tanislav@analog.com>
> > >
> > > Similar to IIO, create a device directory inside debugfs
> > > mount point, and create a direct_reg_access file inside
> > > that directory, if debugfs_reg_access callback is defined
> > > inside hwmon_ops.
> > >
> >
> > Patch looks good afaics. I don't want to apply it now (ie for 5.17),
> > though, because it is getting close and we don't have a use case.
> > If you have one in mind, I'd suggest to submit it together with
> > this patch, or we'll have to wait until there is a user.
> >
> > Guenter
>
> As I mentioned previously I have a local patch on top of the ADT7X10
> refactor that uses this. I tested your modifications to my patchset on
> the ADT7420 part and it seems to work just fine. I can push it on top of
> either this patch or that patchset, your choice.
>
The adt7x10 patches won't make it into 5.17 either, so all that will
have to wait until 5.18. If I don't get a use case by then I may write
one myself, but that won't happen now because I am about to be away
from my computers for the next two weeks.
Guenter
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-12-28 17:10 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2021-12-27 22:42 [PATCH v2 0/1] Add hwmon debugfs register access Cosmin Tanislav
2021-12-27 22:42 ` [PATCH v2 1/1] hwmon: Add " Cosmin Tanislav
2021-12-28 16:13 ` Guenter Roeck
2021-12-28 16:51 ` Cosmin Tanislav
2021-12-28 17:09 ` Guenter Roeck
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