diff options
author | Nuno Sa <nuno.sa@analog.com> | 2024-08-02 16:27:00 +0200 |
---|---|---|
committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2024-08-03 14:36:45 +0100 |
commit | cdf01e0809a4c6c7877ea52401c2a6679df7aed6 (patch) | |
tree | 10286bf7a44935dbdd36cc25178858864477b570 | |
parent | 2256f37e24b1979f9a97de0b76cabbf8544a8aff (diff) |
iio: backend: add debugFs interface
This adds a basic debugfs interface for backends. Two new ops are being
added:
* debugfs_reg_access: Analogous to the core IIO one but for backend
devices.
* debugfs_print_chan_status: One useful usecase for this one is for
testing test tones in a digital interface and "ask" the backend to
dump more details on why a test tone might have errors.
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20240802-dev-iio-backend-add-debugfs-v2-2-4cb62852f0d0@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
-rw-r--r-- | Documentation/ABI/testing/debugfs-iio-backend | 20 | ||||
-rw-r--r-- | MAINTAINERS | 1 | ||||
-rw-r--r-- | drivers/iio/industrialio-backend.c | 145 | ||||
-rw-r--r-- | include/linux/iio/backend.h | 14 |
4 files changed, 180 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/debugfs-iio-backend b/Documentation/ABI/testing/debugfs-iio-backend new file mode 100644 index 000000000000..01ab94469432 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-iio-backend @@ -0,0 +1,20 @@ +What: /sys/kernel/debug/iio/iio:deviceX/backendY/name +KernelVersion: 6.11 +Contact: linux-iio@vger.kernel.org +Description: + Name of Backend Y connected to device X. + +What: /sys/kernel/debug/iio/iio:deviceX/backendY/direct_reg_access +KernelVersion: 6.11 +Contact: linux-iio@vger.kernel.org +Description: + Directly access the registers of backend Y. Typical usage is: + + Reading address 0x50 + echo 0x50 > direct_reg_access + cat direct_reg_access + + Writing address 0x50 + echo 0x50 0x3 > direct_reg_access + //readback address 0x50 + cat direct_reg_access diff --git a/MAINTAINERS b/MAINTAINERS index 34281931a649..2708a9e9fc95 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -10894,6 +10894,7 @@ M: Nuno Sa <nuno.sa@analog.com> R: Olivier Moysan <olivier.moysan@foss.st.com> L: linux-iio@vger.kernel.org S: Maintained +F: Documentation/ABI/testing/debugfs-iio-backend F: drivers/iio/industrialio-backend.c F: include/linux/iio/backend.h diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c index 0cf80ffd2e61..468eadeaf23d 100644 --- a/drivers/iio/industrialio-backend.c +++ b/drivers/iio/industrialio-backend.c @@ -32,6 +32,7 @@ #define dev_fmt(fmt) "iio-backend: " fmt #include <linux/cleanup.h> +#include <linux/debugfs.h> #include <linux/device.h> #include <linux/err.h> #include <linux/errno.h> @@ -53,6 +54,14 @@ struct iio_backend { struct device *dev; struct module *owner; void *priv; + const char *name; + unsigned int cached_reg_addr; + /* + * This index is relative to the frontend. Meaning that for + * frontends with multiple backends, this will be the index of this + * backend. Used for the debugfs directory name. + */ + u8 idx; }; /* @@ -117,6 +126,138 @@ static DEFINE_MUTEX(iio_back_lock); __stringify(op)); \ } +static ssize_t iio_backend_debugfs_read_reg(struct file *file, + char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct iio_backend *back = file->private_data; + char read_buf[20]; + unsigned int val; + int ret, len; + + ret = iio_backend_op_call(back, debugfs_reg_access, + back->cached_reg_addr, 0, &val); + if (ret) + return ret; + + len = scnprintf(read_buf, sizeof(read_buf), "0x%X\n", val); + + return simple_read_from_buffer(userbuf, count, ppos, read_buf, len); +} + +static ssize_t iio_backend_debugfs_write_reg(struct file *file, + const char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct iio_backend *back = file->private_data; + unsigned int val; + char buf[80]; + ssize_t rc; + int ret; + + rc = simple_write_to_buffer(buf, sizeof(buf), ppos, userbuf, count); + if (rc < 0) + return rc; + + ret = sscanf(buf, "%i %i", &back->cached_reg_addr, &val); + + switch (ret) { + case 1: + return count; + case 2: + ret = iio_backend_op_call(back, debugfs_reg_access, + back->cached_reg_addr, val, NULL); + if (ret) + return ret; + return count; + default: + return -EINVAL; + } +} + +static const struct file_operations iio_backend_debugfs_reg_fops = { + .open = simple_open, + .read = iio_backend_debugfs_read_reg, + .write = iio_backend_debugfs_write_reg, +}; + +static ssize_t iio_backend_debugfs_read_name(struct file *file, + char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct iio_backend *back = file->private_data; + char name[128]; + int len; + + len = scnprintf(name, sizeof(name), "%s\n", back->name); + + return simple_read_from_buffer(userbuf, count, ppos, name, len); +} + +static const struct file_operations iio_backend_debugfs_name_fops = { + .open = simple_open, + .read = iio_backend_debugfs_read_name, +}; + +/** + * iio_backend_debugfs_add - Add debugfs interfaces for Backends + * @back: Backend device + * @indio_dev: IIO device + */ +void iio_backend_debugfs_add(struct iio_backend *back, + struct iio_dev *indio_dev) +{ + struct dentry *d = iio_get_debugfs_dentry(indio_dev); + struct dentry *back_d; + char name[128]; + + if (!IS_ENABLED(CONFIG_DEBUG_FS) || !d) + return; + if (!back->ops->debugfs_reg_access && !back->name) + return; + + snprintf(name, sizeof(name), "backend%d", back->idx); + + back_d = debugfs_create_dir(name, d); + if (!back_d) + return; + + if (back->ops->debugfs_reg_access) + debugfs_create_file("direct_reg_access", 0600, back_d, back, + &iio_backend_debugfs_reg_fops); + + if (back->name) + debugfs_create_file("name", 0400, back_d, back, + &iio_backend_debugfs_name_fops); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_debugfs_add, IIO_BACKEND); + +/** + * iio_backend_debugfs_print_chan_status - Print channel status + * @back: Backend device + * @chan: Channel number + * @buf: Buffer where to print the status + * @len: Available space + * + * One usecase where this is useful is for testing test tones in a digital + * interface and "ask" the backend to dump more details on why a test tone might + * have errors. + * + * RETURNS: + * Number of copied bytes on success, negative error code on failure. + */ +ssize_t iio_backend_debugfs_print_chan_status(struct iio_backend *back, + unsigned int chan, char *buf, + size_t len) +{ + if (!IS_ENABLED(CONFIG_DEBUG_FS)) + return -ENODEV; + + return iio_backend_op_call(back, debugfs_print_chan_status, chan, buf, + len); +} +EXPORT_SYMBOL_NS_GPL(iio_backend_debugfs_print_chan_status, IIO_BACKEND); + /** * iio_backend_chan_enable - Enable a backend channel * @back: Backend device @@ -577,6 +718,9 @@ struct iio_backend *devm_iio_backend_get(struct device *dev, const char *name) if (ret) return ERR_PTR(ret); + if (name) + back->idx = index; + return back; } @@ -668,6 +812,7 @@ int devm_iio_backend_register(struct device *dev, return -ENOMEM; back->ops = info->ops; + back->name = info->name; back->owner = dev->driver->owner; back->dev = dev; back->priv = priv; diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h index f120fa2e0a43..9d0dba7ab9e7 100644 --- a/include/linux/iio/backend.h +++ b/include/linux/iio/backend.h @@ -22,6 +22,8 @@ enum iio_backend_data_source { IIO_BACKEND_DATA_SOURCE_MAX }; +#define iio_backend_debugfs_ptr(ptr) PTR_IF(IS_ENABLED(CONFIG_DEBUG_FS), ptr) + /** * IIO_BACKEND_EX_INFO - Helper for an IIO extended channel attribute * @_name: Attribute name @@ -81,6 +83,8 @@ enum iio_backend_sample_trigger { * @extend_chan_spec: Extend an IIO channel. * @ext_info_set: Extended info setter. * @ext_info_get: Extended info getter. + * @debugfs_print_chan_status: Print channel status into a buffer. + * @debugfs_reg_access: Read or write register value of backend. **/ struct iio_backend_ops { int (*enable)(struct iio_backend *back); @@ -113,6 +117,11 @@ struct iio_backend_ops { const char *buf, size_t len); int (*ext_info_get)(struct iio_backend *back, uintptr_t private, const struct iio_chan_spec *chan, char *buf); + int (*debugfs_print_chan_status)(struct iio_backend *back, + unsigned int chan, char *buf, + size_t len); + int (*debugfs_reg_access)(struct iio_backend *back, unsigned int reg, + unsigned int writeval, unsigned int *readval); }; /** @@ -163,4 +172,9 @@ __devm_iio_backend_get_from_fwnode_lookup(struct device *dev, int devm_iio_backend_register(struct device *dev, const struct iio_backend_info *info, void *priv); +ssize_t iio_backend_debugfs_print_chan_status(struct iio_backend *back, + unsigned int chan, char *buf, + size_t len); +void iio_backend_debugfs_add(struct iio_backend *back, + struct iio_dev *indio_dev); #endif |