305 lines
9.0 KiB
C
305 lines
9.0 KiB
C
/* skeleton.c */
|
|
#include <linux/init.h> /* needed for macros */
|
|
#include <linux/kernel.h> /* needed for debugging */
|
|
#include <linux/module.h> /* needed by all modules */
|
|
|
|
#include <linux/cdev.h> /* needed for char device driver */
|
|
#include <linux/fs.h> /* needed for device drivers */
|
|
#include <linux/uaccess.h> /* needed to copy data to/from user */
|
|
|
|
#include <linux/device.h> /* needed for sysfs handling */
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/of.h>
|
|
#include <linux/platform_device.h> /* needed for sysfs handling */
|
|
|
|
#define BUFFER_SZ 10000
|
|
|
|
struct mydata {
|
|
char buffer[BUFFER_SZ];
|
|
|
|
struct class* sysfs_class;
|
|
struct device* sysfs_device;
|
|
struct miscdevice misc;
|
|
struct skeleton_attr {
|
|
long val;
|
|
int id;
|
|
struct device_attribute dev_attr;
|
|
} attr;
|
|
};
|
|
|
|
#define ATTR_INSTANCE(a, i, v) \
|
|
{ \
|
|
a.attr.val = v; \
|
|
a.attr.id = i; \
|
|
a.attr.dev_attr.attr.name = "val"; \
|
|
a.attr.dev_attr.attr.mode = 0664; \
|
|
a.attr.dev_attr.show = sysfs_show_val; \
|
|
a.attr.dev_attr.store = sysfs_store_val; \
|
|
}
|
|
|
|
// --- sysfs file opers ------------------------------------------------------
|
|
|
|
static ssize_t sysfs_show_val(struct device* dev,
|
|
struct device_attribute* attr,
|
|
char* buf)
|
|
{
|
|
struct mydata* mydata = container_of(attr, struct mydata, attr.dev_attr);
|
|
|
|
sprintf(buf, "%ld\n", mydata->attr.val);
|
|
|
|
pr_info("skeleton-sysfs_show: val[%d]=%ld\n",
|
|
mydata->attr.id,
|
|
mydata->attr.val);
|
|
|
|
return strlen(buf);
|
|
}
|
|
|
|
static ssize_t sysfs_store_val(struct device* dev,
|
|
struct device_attribute* attr,
|
|
const char* buf,
|
|
size_t count)
|
|
{
|
|
struct mydata* mydata = container_of(attr, struct mydata, attr.dev_attr);
|
|
|
|
int err = kstrtol(buf, 10, &mydata->attr.val);
|
|
|
|
pr_info("skeleton-sysfs_store: val[%d]=%ld\n",
|
|
mydata->attr.id,
|
|
mydata->attr.val);
|
|
|
|
return err == 0 ? count : err;
|
|
}
|
|
|
|
// --- file opers ------------------------------------------------------------
|
|
|
|
static int skeleton_open(struct inode* i, struct file* f)
|
|
{
|
|
pr_info("skeleton : open operation... major:%d, minor:%d, p_data=%llx\n",
|
|
imajor(i),
|
|
iminor(i),
|
|
(long long)f->private_data);
|
|
return 0;
|
|
}
|
|
|
|
static int skeleton_release(struct inode* i, struct file* f)
|
|
{
|
|
pr_info("skeleton: release operation...p_data=%llx\n",
|
|
(long long)f->private_data);
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t skeleton_read(struct file* f,
|
|
char __user* buf,
|
|
size_t count,
|
|
loff_t* off)
|
|
{
|
|
struct mydata* mydata = container_of(f->private_data, struct mydata, misc);
|
|
|
|
// compute remaining bytes to copy, update count and pointers
|
|
ssize_t remaining = strlen(mydata->buffer) - (ssize_t)(*off);
|
|
char* ptr = mydata->buffer + *off;
|
|
if (count > remaining) count = remaining;
|
|
*off += count;
|
|
|
|
// copy required number of bytes
|
|
if (copy_to_user(buf, ptr, count) != 0) count = -EFAULT;
|
|
|
|
pr_info("skeleton: read operation...p_data=%llx read=%ld\n",
|
|
(long long)f->private_data,
|
|
count);
|
|
|
|
return count;
|
|
}
|
|
|
|
static ssize_t skeleton_write(struct file* f,
|
|
const char __user* buf,
|
|
size_t count,
|
|
loff_t* off)
|
|
{
|
|
struct mydata* mydata = container_of(f->private_data, struct mydata, misc);
|
|
|
|
// compute remaining space in buffer and update pointers
|
|
ssize_t remaining = sizeof(mydata->buffer) - (ssize_t)(*off);
|
|
char* ptr = mydata->buffer + *off;
|
|
*off += count;
|
|
|
|
// check if still remaining space to store additional bytes
|
|
if (count >= remaining) count = -EIO;
|
|
|
|
// store additional bytes into internal buffer
|
|
if (count > 0) {
|
|
ptr[count] = 0; // make sure string is null terminated
|
|
if (copy_from_user(ptr, buf, count)) count = -EFAULT;
|
|
}
|
|
|
|
pr_info("skeleton: write operation... written=%ld\n", count);
|
|
return count;
|
|
}
|
|
|
|
static struct file_operations fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = skeleton_open,
|
|
.read = skeleton_read,
|
|
.write = skeleton_write,
|
|
.release = skeleton_release,
|
|
};
|
|
|
|
int drv_probe(struct platform_device* pdev)
|
|
{
|
|
int ret = 0;
|
|
struct device_node* dt_node = pdev->dev.of_node;
|
|
struct mydata* mydata = 0;
|
|
const char* prop_str = 0;
|
|
|
|
pr_info("skeleton - driver probe %llx (%s)- M.m=%d.%d\n",
|
|
(unsigned long long)pdev,
|
|
pdev->name,
|
|
MAJOR(pdev->dev.devt),
|
|
MINOR(pdev->dev.devt));
|
|
|
|
ret = of_property_read_string(dt_node, "attribute", &prop_str);
|
|
if (prop_str && ret == 0) pr_info("attribute=%s (ret=%d)\n", prop_str, ret);
|
|
|
|
if (pdev->num_resources) {
|
|
pr_info("resources: name=%s, start=%lld, end=%lld\n",
|
|
pdev->resource[0].name,
|
|
pdev->resource[0].start,
|
|
pdev->resource[0].end);
|
|
}
|
|
|
|
if (dt_node) {
|
|
int ret = 0;
|
|
const char* prop_str = 0;
|
|
const unsigned int* prop_reg = 0;
|
|
unsigned long reg = 0;
|
|
|
|
struct device_node* child;
|
|
for_each_available_child_of_node(dt_node, child)
|
|
{
|
|
mydata = devm_kzalloc(&pdev->dev, sizeof(*mydata), GFP_KERNEL);
|
|
pr_info("miscdev=%llx\n", (long long)mydata);
|
|
if (mydata == 0) {
|
|
dev_err(&pdev->dev,
|
|
"Failed to allocate resource for miscdev\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
pr_info("child found: name=%s, fullname=%s\n",
|
|
child->name,
|
|
child->full_name);
|
|
prop_reg = of_get_property(child, "reg", NULL);
|
|
if (prop_reg != 0) {
|
|
reg = of_read_ulong(prop_reg, 1);
|
|
pr_info("reg:%lu\n", reg);
|
|
}
|
|
|
|
ret = of_property_read_string(child, "attribute", &prop_str);
|
|
if (prop_str && ret == 0)
|
|
pr_info("attribute=%s (ret=%d)\n", prop_str, ret);
|
|
|
|
// register misc device ...
|
|
platform_set_drvdata(pdev, mydata);
|
|
mydata->misc.minor = MISC_DYNAMIC_MINOR;
|
|
mydata->misc.fops = &fops;
|
|
mydata->misc.name = child->full_name;
|
|
mydata->misc.mode = 0664;
|
|
ret = misc_register(&(mydata->misc));
|
|
if (ret != 0) {
|
|
dev_err(&pdev->dev, "Failed to register miscdev\n");
|
|
return ret;
|
|
}
|
|
|
|
// register misc device sysfs attribute...
|
|
ATTR_INSTANCE((*mydata), reg, reg);
|
|
ret = device_create_file(mydata->misc.this_device,
|
|
&mydata->attr.dev_attr);
|
|
if (ret != 0) {
|
|
dev_err(&pdev->dev,
|
|
"Failed to register miscdev sysfs attribute\n");
|
|
return ret;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
int drv_remove(struct platform_device* pdev)
|
|
{
|
|
struct mydata* mydata = platform_get_drvdata(pdev);
|
|
pr_info("skeleton - sysfs driver remove %s\n", pdev->name);
|
|
misc_deregister(&(mydata->misc));
|
|
return 0;
|
|
}
|
|
|
|
void drv_shutdown(struct platform_device* pdev)
|
|
{
|
|
pr_info("skeleton - sysfs driver shutdown %s\n", pdev->name);
|
|
}
|
|
int drv_suspend(struct platform_device* pdev, pm_message_t state)
|
|
{
|
|
pr_info("skeleton - sysfs driver suspend %s (state=%d)\n",
|
|
pdev->name,
|
|
state.event);
|
|
return 0;
|
|
}
|
|
int drv_resume(struct platform_device* pdev)
|
|
{
|
|
pr_info("skeleton - sysfs driver resume %s\n", pdev->name);
|
|
return 0;
|
|
}
|
|
|
|
struct of_device_id of_drv[] = {
|
|
{
|
|
.compatible = "mydevice",
|
|
},
|
|
{},
|
|
};
|
|
MODULE_DEVICE_TABLE(of, of_drv);
|
|
|
|
static struct platform_driver sysfs_driver = {
|
|
.probe = drv_probe,
|
|
.remove = drv_remove,
|
|
.shutdown = drv_shutdown,
|
|
.suspend = drv_suspend,
|
|
.resume = drv_resume,
|
|
.driver =
|
|
{
|
|
.name = "mydriver",
|
|
.of_match_table = of_match_ptr(of_drv),
|
|
},
|
|
};
|
|
#if 1
|
|
static int __init sysfs_driver_init(void)
|
|
{
|
|
int status = 0;
|
|
|
|
pr_info("Linux module skeleton loading...\n");
|
|
|
|
/* install sysfs */
|
|
if (status == 0) status = platform_driver_register(&sysfs_driver);
|
|
|
|
pr_info("Linux module skeleton loaded\n");
|
|
return 0;
|
|
}
|
|
|
|
static void __exit sysfs_driver_exit(void)
|
|
{
|
|
pr_info("Linux module skeleton exiting...\n");
|
|
|
|
/* uninstall sysfs */
|
|
platform_driver_unregister(&sysfs_driver);
|
|
|
|
pr_info("Linux module skeleton unloaded\n");
|
|
}
|
|
|
|
module_init(sysfs_driver_init);
|
|
module_exit(sysfs_driver_exit);
|
|
|
|
#else
|
|
module_platform_driver(sysfs_driver);
|
|
#endif
|
|
|
|
MODULE_AUTHOR("Daniel Gachet <daniel.gachet@hefr.ch>");
|
|
MODULE_DESCRIPTION("Module skeleton");
|
|
MODULE_LICENSE("GPL");
|