Re: [PATCH] usb: add sysfs configuration interface for CP2101

From: Dirk Eibach
Date: Fri Feb 29 2008 - 07:31:34 EST


So here is a new try.

---
diff -purN linux-2.6.24/drivers/usb/serial/cp2101.c linux-2.6.24-diff/drivers/usb/serial/cp2101.c
--- linux-2.6.24/drivers/usb/serial/cp2101.c 2008-01-24 23:58:37.000000000 +0100
+++ linux-2.6.24-diff/drivers/usb/serial/cp2101.c 2008-02-29 13:15:58.168233146 +0100
@@ -18,6 +18,8 @@
*/

#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/platform_device.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
@@ -52,6 +54,8 @@ static void cp2101_shutdown(struct usb_s

static int debug;

+static int enable_config = false;
+
static struct usb_device_id id_table [] = {
{ USB_DEVICE(0x08e6, 0x5501) }, /* Gemalto Prox-PU/CU contactless smartcard reader */
{ USB_DEVICE(0x0FCF, 0x1003) }, /* Dynastream ANT development board */
@@ -125,6 +129,7 @@ static struct usb_serial_driver cp2101_d
#define CP2101_CONTROL 0x07 /* Flow control line states */
#define CP2101_MODEMCTL 0x13 /* Modem controls */
#define CP2101_CONFIG_6 0x19 /* 6 bytes of config data ??? */
+#define CP2101_EEPROM 0xFF /* write configuration eeprom */

/* CP2101_UART */
#define UART_ENABLE 0x0001
@@ -167,6 +172,20 @@ static struct usb_serial_driver cp2101_d
#define CONTROL_WRITE_DTR 0x0100
#define CONTROL_WRITE_RTS 0x0200

+/* CP2101 CONFIGURATION EEPROM */
+#define EEPROM_RELOAD 0x0008
+#define EEPROM_VENDOR_ID 0x3701
+#define EEPROM_PRODUCT_ID 0x3702
+#define EEPROM_PRODUCTSTRING 0x3703
+#define EEPROM_SERIALNUMBER 0x3704
+#define EEPROM_POWER_ATTRIB 0x3705
+#define EEPROM_MAX_POWER 0x3706
+#define EEPROM_RELEASE_VERSION 0x3707
+#define EEPROM_LOCK 0x370a
+
+#define SERIALNUMBER_MAX_CHARS 63
+#define PRODUCTSTRING_MAX_CHARS 126
+
/*
* cp2101_get_config
* Reads from the CP2101 configuration registers
@@ -704,11 +723,286 @@ static void cp2101_break_ctl (struct usb
cp2101_set_config(port, CP2101_BREAK, &state, 2);
}

+/*
+ * When loaded with module parameter "enable_config=1" the driver offers the
+ * following sysfs attributes to customize USB configuration data:
+ * reload: write "1" to reboot CP210x and activate the new configuration
+ * vendor_id: write 16 bit value to set
+ * product_id: write 16 bit value to set
+ * productstring: write up to 126 characters to set
+ * serialnumber: write up to 63 characters to set
+ * self_powered: write "1" to set, "0" to unset
+ * max_power: write 8 bit value (unit 2 mA) to set
+ * release_version: write 16 bit BCD-value to set (0x1234 => version 12.34)
+ * lock_forever: write 0xabadbabe to lock the settings permanently
+ */
+
+static ssize_t write_reload(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int result;
+ struct usb_device *usbdev = container_of(dev, struct usb_device, dev);
+
+ /* writing "0" does not trigger */
+ if (!strict_strtoul(buf, NULL, 0))
+ return count;
+
+ result = usb_control_msg(usbdev,
+ usb_sndctrlpipe(usbdev, 0),
+ CP2101_EEPROM, REQTYPE_HOST_TO_DEVICE, EEPROM_RELOAD,
+ 0, NULL, 0, 300);
+
+ /* this request is expected to fail because cp210x reboots */
+
+ return count;
+}
+
+static DEVICE_ATTR(reload, S_IWUGO, NULL, write_reload);
+
+static ssize_t write_vendor_id(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int result;
+ struct usb_device *usbdev = container_of(dev, struct usb_device, dev);
+
+ unsigned long vendor_id = strict_strtoul(buf, NULL, 0);
+
+ if (!vendor_id || vendor_id > 0xffff)
+ return -EINVAL;
+
+ result = usb_control_msg(usbdev,
+ usb_sndctrlpipe(usbdev, 0),
+ CP2101_EEPROM, REQTYPE_HOST_TO_DEVICE, EEPROM_VENDOR_ID,
+ vendor_id, NULL, 0, 300);
+
+ if (result)
+ return -EIO;
+
+ return count;
+}
+
+static DEVICE_ATTR(vendor_id, S_IWUGO, NULL, write_vendor_id);
+
+static ssize_t write_product_id(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int result;
+ struct usb_device *usbdev = container_of(dev, struct usb_device, dev);
+
+ unsigned long product_id = strict_strtoul(buf, NULL, 0);
+
+ if (!product_id || product_id > 0xffff)
+ return -EINVAL;
+
+ result = usb_control_msg(usbdev,
+ usb_sndctrlpipe(usbdev, 0),
+ CP2101_EEPROM, REQTYPE_HOST_TO_DEVICE, EEPROM_PRODUCT_ID,
+ product_id, NULL, 0, 300);
+
+ if (result)
+ return -EIO;
+
+ return count;
+}
+
+static DEVICE_ATTR(product_id, S_IWUGO, NULL, write_product_id);
+
+static ssize_t write_serialnumber(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int result;
+ unsigned int k;
+ struct usb_device *usbdev = container_of(dev, struct usb_device, dev);
+ u8 serial_stringsize = 2 + 2*count;
+ char serial[2 + 2*SERIALNUMBER_MAX_CHARS];
+
+ if (count > SERIALNUMBER_MAX_CHARS)
+ return -EINVAL;
+
+ serial[0] = serial_stringsize;
+ serial[1] = USB_DT_STRING;
+
+ /* convert to utf-16 */
+ printk("#Max index: %d\n", serial_stringsize - 1);
+ for (k = 0; k < count; ++k) {
+ printk("Address index %d and %d\n", 2+2*k, 2+2*k+1);
+ serial[2+2*k] = buf[k];
+ serial[2+2*k+1] = 0;
+ }
+
+ result = usb_control_msg(usbdev,
+ usb_sndctrlpipe(usbdev, 0),
+ CP2101_EEPROM, REQTYPE_HOST_TO_DEVICE, EEPROM_SERIALNUMBER,
+ 0, serial, serial_stringsize, 300);
+
+ if (result != serial_stringsize)
+ return -EIO;
+
+ return count;
+}
+
+static DEVICE_ATTR(serialnumber, S_IWUGO, NULL, write_serialnumber);
+
+
+static ssize_t write_productstring(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int result;
+ unsigned int k;
+ struct usb_device *usbdev = container_of(dev, struct usb_device, dev);
+ u8 product_stringsize = 2 + 2*count;
+ char product[2 + 2*PRODUCTSTRING_MAX_CHARS];
+
+ if (count > PRODUCTSTRING_MAX_CHARS)
+ return -EINVAL;
+
+ product[0] = product_stringsize;
+ product[1] = USB_DT_STRING;
+
+ /* convert to utf-16 */
+ for (k = 0; k < count; ++k) {
+ product[2+2*k] = buf[k];
+ product[2+2*k+1] = 0;
+ }
+
+ result = usb_control_msg(usbdev,
+ usb_sndctrlpipe(usbdev, 0),
+ CP2101_EEPROM, REQTYPE_HOST_TO_DEVICE,
+ EEPROM_PRODUCTSTRING, 0,
+ product, product_stringsize, 300);
+
+ if (result != product_stringsize)
+ return -EIO;
+
+ return count;
+}
+
+static DEVICE_ATTR(productstring, S_IWUGO, NULL, write_productstring);
+
+static ssize_t write_self_powered(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int result;
+ struct usb_device *usbdev = container_of(dev, struct usb_device, dev);
+
+ unsigned long self_powered = strict_strtoul(buf, NULL, 0);
+
+ result = usb_control_msg(usbdev,
+ usb_sndctrlpipe(usbdev, 0),
+ CP2101_EEPROM, REQTYPE_HOST_TO_DEVICE, EEPROM_POWER_ATTRIB,
+ self_powered ? 0x00c0 : 0x0080, NULL, 0, 300);
+
+ if (result)
+ return -EIO;
+
+ return count;
+}
+
+static DEVICE_ATTR(self_powered, S_IWUGO, NULL, write_self_powered);
+
+static ssize_t write_max_power(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int result;
+ struct usb_device *usbdev = container_of(dev, struct usb_device, dev);
+
+ unsigned long max_power = strict_strtoul(buf, NULL, 0);
+
+ if (!max_power || max_power > 0xff)
+ return -EINVAL;
+
+ result = usb_control_msg(usbdev,
+ usb_sndctrlpipe(usbdev, 0),
+ CP2101_EEPROM, REQTYPE_HOST_TO_DEVICE, EEPROM_MAX_POWER,
+ max_power, NULL, 0, 300);
+
+ if (result)
+ return -EIO;
+
+ return count;
+}
+
+static DEVICE_ATTR(max_power, S_IWUGO, NULL, write_max_power);
+
+static ssize_t write_release_version(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int result;
+ struct usb_device *usbdev = container_of(dev, struct usb_device, dev);
+
+ unsigned long release_version = strict_strtoul(buf, NULL, 0);
+
+ if (release_version > 0xffff)
+ return -EINVAL;
+
+ result = usb_control_msg(usbdev,
+ usb_sndctrlpipe(usbdev, 0),
+ CP2101_EEPROM, REQTYPE_HOST_TO_DEVICE, EEPROM_RELEASE_VERSION,
+ release_version, NULL, 0, 300);
+
+ if (result)
+ return -EIO;
+
+ return count;
+}
+
+static DEVICE_ATTR(release_version, S_IWUGO, NULL, write_release_version);
+
+static ssize_t write_lock_forever(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int result;
+ struct usb_device *usbdev = container_of(dev, struct usb_device, dev);
+
+ unsigned long lock = strict_strtoul(buf, NULL, 0);
+
+ /* be really, really sure to know what you are doing here */
+ if (lock != 0xabadbabe)
+ return -EINVAL;
+
+ result = usb_control_msg(usbdev,
+ usb_sndctrlpipe(usbdev, 0),
+ CP2101_EEPROM, REQTYPE_HOST_TO_DEVICE, EEPROM_LOCK,
+ 0x00f0, NULL, 0, 300);
+
+ if (result)
+ return -EIO;
+
+ return count;
+}
+
+static DEVICE_ATTR(lock_forever, S_IWUGO, NULL, write_lock_forever);
+
+static struct attribute *cp2101_attributes[] = {
+ &dev_attr_reload.attr,
+ &dev_attr_vendor_id.attr,
+ &dev_attr_product_id.attr,
+ &dev_attr_productstring.attr,
+ &dev_attr_serialnumber.attr,
+ &dev_attr_self_powered.attr,
+ &dev_attr_max_power.attr,
+ &dev_attr_release_version.attr,
+ &dev_attr_lock_forever.attr,
+ NULL
+};
+
+static const struct attribute_group cp2101_group = {
+ .attrs = cp2101_attributes,
+};
+
static int cp2101_startup (struct usb_serial *serial)
{
+ int err;
+
/* CP2101 buffers behave strangely unless device is reset */
usb_reset_device(serial->dev);
- return 0;
+
+ if (!enable_config)
+ return 0;
+
+ err = sysfs_create_group(&serial->dev->dev.kobj, &cp2101_group);
+
+ return err;
}

static void cp2101_shutdown (struct usb_serial *serial)
@@ -721,6 +1015,11 @@ static void cp2101_shutdown (struct usb_
for (i=0; i < serial->num_ports; ++i) {
cp2101_cleanup(serial->port[i]);
}
+
+ if (!enable_config)
+ return;
+
+ sysfs_remove_group(&serial->dev->dev.kobj, &cp2101_group);
}

static int __init cp2101_init (void)
@@ -758,3 +1057,6 @@ MODULE_LICENSE("GPL");

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Enable verbose debugging messages");
+
+module_param(enable_config, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(enable_config, "Enable sysfs access to configuration eeprom.");



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