| Message ID | 20211227224201.508331-2-demonsingur@gmail.com (mailing list archive) |
|---|---|
| State | Under Review |
| Headers | show |
| Series | Add hwmon debugfs register access | expand |
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); > }; > > /** >
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); >> }; >> /** >> >
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
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); }; /**