HID: Documentation for hidraw

Documenation for the hidraw driver, with sample program.

Signed-off-by: Alan Ott <alan@signal11.us>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

4 files changed, 182 insertions, 1 deletions

diff --git a/samples/Kconfig b/samples/Kconfig
index e03cf0e374d7..52f4264b3006 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -61,4 +61,10 @@ config SAMPLE_KDB
           Build an example of how to dynamically add the hello
           command to the kdb shell.
 
+config SAMPLE_HIDRAW
+        tristate "Build simple hidraw example"
+        depends on HIDRAW
+        help
+          Build an example of how to use hidraw from userspace.
+
 endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
index f26c0959fd86..6280817c2b7e 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -1,4 +1,4 @@
 # Makefile for Linux samples code
 
 obj-$(CONFIG_SAMPLES)   += kobject/ kprobes/ tracepoints/ trace_events/ \
-                           hw_breakpoint/ kfifo/ kdb/
+                           hw_breakpoint/ kfifo/ kdb/ hidraw/
diff --git a/samples/hidraw/Makefile b/samples/hidraw/Makefile
new file mode 100644
index 000000000000..7811cb0289aa
--- /dev/null
+++ b/samples/hidraw/Makefile
@@ -0,0 +1,8 @@
+# kbuild trick to avoid linker error. Can be omitted if a module is built.
+obj- := dummy.o
+
+# List of programs to build
+hostprogs-y := hid-example
+
+# Tell kbuild to always build the programs
+always := $(hostprogs-y)
diff --git a/samples/hidraw/hid-example.c b/samples/hidraw/hid-example.c
new file mode 100644
index 000000000000..40e3d6200582
--- /dev/null
+++ b/samples/hidraw/hid-example.c
@@ -0,0 +1,167 @@
+/*
+ * Hidraw Userspace Example
+ *
+ * Copyright (c) 2010 Alan Ott <alan@signal11.us>
+ * Copyright (c) 2010 Signal 11 Software
+ *
+ * The code may be used by anyone for any purpose,
+ * and can serve as a starting point for developing
+ * applications using hidraw.
+ */
+
+/* Linux */
+#include <linux/types.h>
+#include <linux/input.h>
+#include <linux/hidraw.h>
+
+/* Unix */
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+/* C */
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+
+const char *bus_str(int bus);
+
+int main(int argc, char **argv)
+{
+        int fd;
+        int i, res, desc_size = 0;
+        char buf[256];
+        struct hidraw_report_descriptor rpt_desc;
+        struct hidraw_devinfo info;
+
+        /* Open the Device with non-blocking reads. In real life,
+           don't use a hard coded path; use libudev instead. */
+        fd = open("/dev/hidraw0", O_RDWR|O_NONBLOCK);
+
+        if (fd < 0) {
+                perror("Unable to open device");
+                return 1;
+        }
+
+        memset(&rpt_desc, 0x0, sizeof(rpt_desc));
+        memset(&info, 0x0, sizeof(info));
+        memset(buf, 0x0, sizeof(buf));
+
+        /* Get Report Descriptor Size */
+        res = ioctl(fd, HIDIOCGRDESCSIZE, &desc_size);
+        if (res < 0)
+                perror("HIDIOCGRDESCSIZE");
+        else
+                printf("Report Descriptor Size: %d\n", desc_size);
+
+        /* Get Report Descriptor */
+        rpt_desc.size = desc_size;
+        res = ioctl(fd, HIDIOCGRDESC, &rpt_desc);
+        if (res < 0) {
+                perror("HIDIOCGRDESC");
+        } else {
+                printf("Report Descriptor:\n");
+                for (i = 0; i < rpt_desc.size; i++)
+                        printf("%hhx ", rpt_desc.value[i]);
+                puts("\n");
+        }
+
+        /* Get Raw Name */
+        res = ioctl(fd, HIDIOCGRAWNAME(256), buf);
+        if (res < 0)
+                perror("HIDIOCGRAWNAME");
+        else
+                printf("Raw Name: %s\n", buf);
+
+        /* Get Physical Location */
+        res = ioctl(fd, HIDIOCGRAWPHYS(256), buf);
+        if (res < 0)
+                perror("HIDIOCGRAWPHYS");
+        else
+                printf("Raw Phys: %s\n", buf);
+
+        /* Get Raw Info */
+        res = ioctl(fd, HIDIOCGRAWINFO, &info);
+        if (res < 0) {
+                perror("HIDIOCGRAWINFO");
+        } else {
+                printf("Raw Info:\n");
+                printf("\tbustype: %d (%s)\n",
+                        info.bustype, bus_str(info.bustype));
+                printf("\tvendor: 0x%04hx\n", info.vendor);
+                printf("\tproduct: 0x%04hx\n", info.product);
+        }
+
+        /* Set Feature */
+        buf[0] = 0x9; /* Report Number */
+        buf[1] = 0xff;
+        buf[2] = 0xff;
+        buf[3] = 0xff;
+        res = ioctl(fd, HIDIOCSFEATURE(4), buf);
+        if (res < 0)
+                perror("HIDIOCSFEATURE");
+        else
+                printf("ioctl HIDIOCGFEATURE returned: %d\n", res);
+
+        /* Get Feature */
+        buf[0] = 0x9; /* Report Number */
+        res = ioctl(fd, HIDIOCGFEATURE(256), buf);
+        if (res < 0) {
+                perror("HIDIOCGFEATURE");
+        } else {
+                printf("ioctl HIDIOCGFEATURE returned: %d\n", res);
+                printf("Report data (not containing the report number):\n\t");
+                for (i = 0; i < res; i++)
+                        printf("%hhx ", buf[i]);
+                puts("\n");
+        }
+
+        /* Send a Report to the Device */
+        buf[0] = 0x1; /* Report Number */
+        buf[1] = 0x77;
+        res = write(fd, buf, 2);
+        if (res < 0) {
+                printf("Error: %d\n", errno);
+                perror("write");
+        } else {
+                printf("write() wrote %d bytes\n", res);
+        }
+
+        /* Get a report from the device */
+        res = read(fd, buf, 16);
+        if (res < 0) {
+                perror("read");
+        } else {
+                printf("read() read %d bytes:\n\t", res);
+                for (i = 0; i < res; i++)
+                        printf("%hhx ", buf[i]);
+                puts("\n");
+        }
+        close(fd);
+        return 0;
+}
+
+const char *
+bus_str(int bus)
+{
+        switch (bus) {
+        case BUS_USB:
+                return "USB";
+                break;
+        case BUS_HIL:
+                return "HIL";
+                break;
+        case BUS_BLUETOOTH:
+                return "Bluetooth";
+                break;
+        case BUS_VIRTUAL:
+                return "Virtual";
+                break;
+        default:
+                return "Other";
+                break;
+        }
+}