Messages in this thread | | | Date | Fri, 29 Feb 2008 12:35:12 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] usb: add sysfs configuration interface for CP2101 |
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On Fri, 29 Feb 2008 13:31:11 +0100 Dirk Eibach <eibach@gdsys.de> wrote:
> So here is a new try. >
Please reissue the possibly-updated changelog and signed-off-by: with each revision of a patch.
Please cc linux-usb on usb patches.
> 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;
Should be either
static int enable_config;
or, if you're being very formal,
static bool enable_config = false;
or, if you're being less formal and want to avoid bloating the kernel image,
static bool enable_config;
> +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; > +}
The comment will suffice - there's no need to add the do-nothing `result'.
> +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; > +}
usb_control_msg() already returns an errno - we should just propagate that back to the caller rather than overwriting, say, -ENOMEM with -EIO.
> +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; > +}
ditto
> +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];
128 bytes of stack is a little more than we'd like (the kernel is really squeezy on stack space sometimes). kmalloc would be better...
> + 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);
checkpatch...
> + 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 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;
this is incomprehehsible without docs
> + 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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