lkml.org 
[lkml]   [2005]   [Aug]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 4/5] add i2c_probe_device and i2c_remove_device
Hi Nathan,

> These functions can be used for special-purpose adapters, such as
> those on TV tuner cards, where we generally know in advance what
> devices are attached. This is important in cases where the adapter
> does not support probing or when probing is potentially dangerous to
> the connected devices.

Do you know of any adapter actually not supporting the SMBus Quick
command (which we use for probing)?

> --- linux-2.6.13-rc6+gregkh.orig/drivers/i2c/i2c-core.c
> +++ linux-2.6.13-rc6+gregkh/drivers/i2c/i2c-core.c
> @@ -671,6 +671,75 @@ int i2c_control(struct i2c_client *clien
> }
>
> /* ----------------------------------------------------
> + * direct add/remove functions to avoid probing
> + * ----------------------------------------------------
> + */
> +
> +int i2c_probe_device(struct i2c_adapter *adapter, int driver_id,
> + int addr, int kind)
> +{
> + struct list_head *item;
> + struct i2c_driver *driver = NULL;
> +
> + /* There's no way to probe addresses on this adapter... */
> + if (kind < 0 && !i2c_check_functionality(adapter,I2C_FUNC_SMBUS_QUICK))
> + return -EINVAL;

Coding style please: one space after the comma.

> +
> + down(&core_lists);
> + list_for_each(item,&drivers) {

Ditto.

> + driver = list_entry(item, struct i2c_driver, list);
> + if (driver->id == driver_id)
> + break;
> + }
> + up(&core_lists);
> + if (!item)
> + return -ENOENT;
> +
> + /* Already in use? */
> + if (i2c_check_addr(adapter, addr))
> + return -EBUSY;
> +
> + /* Make sure there is something at this address, unless forced */
> + if (kind < 0) {
> + if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
> + I2C_SMBUS_QUICK, NULL) < 0)
> + return -ENODEV;
> +
> + /* prevent 24RF08 corruption */
> + if ((addr & ~0x0f) == 0x50)
> + i2c_smbus_xfer(adapter, addr, 0, 0, 0,
> + I2C_SMBUS_QUICK, NULL);
> + }
> +
> + return driver->detect_client(adapter, addr, kind);
> +}

You are duplicating a part of i2c_probe_address() here. Why don't you
simply call it?

This part of the code is very sensible because of the 24RF08 corruption
issue. I have plans to change the probing method, e.g. by using SMBus
Receive Byte instead of SMBus Quick for the 0x50-0x5F address range.
Thus I would really appreciate if this code would not be duplicated.

Thanks,
--
Jean Delvare
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-08-16 00:16    [from the cache]
©2003-2011 Jasper Spaans