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-rw-r--r--Documentation/ABI/testing/sysfs-bus-spi-spidev8
-rw-r--r--drivers/spi/spidev.c75
2 files changed, 77 insertions, 6 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-spi-spidev b/Documentation/ABI/testing/sysfs-bus-spi-spidev
new file mode 100644
index 000000000000..3f6e092f7c62
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-spi-spidev
@@ -0,0 +1,8 @@
+What: /sys/bus/spi/drivers/spidev/new_id
+Date: March 2016
+Description:
+ This allows to load spidev at runtime. new_id file accepts bus
+ number and chip select in 'B.C' format.
+ e.g.
+ To load spidev1.1 at runtime:
+ $ echo 1.1 > /sys/bus/spi/drivers/spidev/new_id
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index d0e7dfc647cf..bf8406c061eb 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -667,6 +667,57 @@ static int spidev_release(struct inode *inode, struct file *filp)
return 0;
}
+/**
+ * new_id_store - add a new spidevB.C instance
+ * @driver: target device driver
+ * @buf: buffer for scanning bus number and chip select
+ * @count: input size
+ *
+ * Adds a new dynamic spidev instance based on the requested bus number
+ * and chip select.
+ */
+static ssize_t new_id_store(struct device_driver *drv, const char *buf,
+ size_t count)
+{
+ int ret;
+ u32 bus, cs;
+ struct spi_device *spi;
+ struct spi_master *master;
+
+ ret = sscanf(buf, "%u.%u", &bus, &cs);
+
+ if (ret < 2)
+ return -EINVAL;
+
+ master = spi_busnum_to_master(bus);
+ if (!master)
+ return -ENODEV;
+
+ if (cs >= master->num_chipselect)
+ return -ENODEV;
+
+ spi = spi_alloc_device(master);
+ if (!spi) {
+ dev_err(&master->dev, "Couldn't allocate spidev device\n");
+ return -ENOMEM;;
+ }
+
+ spi->chip_select = cs;
+ master->bus_num = bus;
+
+ strlcpy(spi->modalias, "spidev", sizeof(spi->modalias));
+
+ ret = spi_add_device(spi);
+ if (ret) {
+ dev_err(&master->dev, "Couldn't add spidev device\n");
+ spi_dev_put(spi);
+ return ret;
+ }
+
+ return count;
+}
+static DRIVER_ATTR_WO(new_id);
+
static const struct file_operations spidev_fops = {
.owner = THIS_MODULE,
/* REVISIT switch to aio primitives, so that userspace
@@ -817,21 +868,33 @@ static int __init spidev_init(void)
spidev_class = class_create(THIS_MODULE, "spidev");
if (IS_ERR(spidev_class)) {
- unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
- return PTR_ERR(spidev_class);
+ status = PTR_ERR(spidev_class);
+ goto err_unregister_chrdev;
}
status = spi_register_driver(&spidev_spi_driver);
- if (status < 0) {
- class_destroy(spidev_class);
- unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
- }
+ if (status < 0)
+ goto err_destroy_class;
+
+ status = driver_create_file(&spidev_spi_driver.driver, &driver_attr_new_id);
+ if (status < 0)
+ goto err_unregister_driver;
+
+ return status;
+
+err_unregister_driver:
+ spi_unregister_driver(&spidev_spi_driver);
+err_destroy_class:
+ class_destroy(spidev_class);
+err_unregister_chrdev:
+ unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
return status;
}
module_init(spidev_init);
static void __exit spidev_exit(void)
{
+ driver_remove_file(&spidev_spi_driver.driver, &driver_attr_new_id);
spi_unregister_driver(&spidev_spi_driver);
class_destroy(spidev_class);
unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);