On Saturday 06 June 2009 22:40:21 Eduardo Valentin wrote:
> Hi Hans,
>
> On Sat, Jun 6, 2009 at 8:09 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
> > On Saturday 06 June 2009 14:49:46 Hans Verkuil wrote:
> > > On Saturday 06 June 2009 13:59:19 Hans Verkuil wrote:
> > > > On Friday 29 May 2009 09:33:21 Eduardo Valentin wrote:
> > > > > # HG changeset patch
> > > > > # User Eduardo Valentin <eduardo.valentin@xxxxxxxxx>
> > > > > # Date 1243414605 -10800
> > > > > # Branch export
> > > > > # Node ID 4fb354645426f8b187c2c90cd8528b2518461005
> > > > > # Parent 142fd6020df3b4d543068155e49a2618140efa49
> > > > > Device drivers of v4l2_subdev devices may want to have
> > > > > board specific data. This patch adds an helper function
> > > > > to allow bridge drivers to pass board specific data to
> > > > > v4l2_subdev drivers.
> > > > >
> > > > > For those drivers which need to support kernel versions
> > > > > bellow 2.6.26, a .s_config callback was added. The
> > > > > idea of this callback is to pass board configuration
> > > > > as well. In that case, subdev driver should set .s_config
> > > > > properly, because v4l2_i2c_new_subdev_board will call
> > > > > the .s_config directly. Of course, if we are >= 2.6.26,
> > > > > the same data will be passed through i2c board info as well.
> > > >
> > > > Hi Eduardo,
> > > >
> > > > I finally had some time to look at this. After some thought I
> > > > realized that the main problem is really that the API is becoming
> > > > quite messy. Basically there are 9 different ways of loading and
> > > > initializing a subdev:
> > > >
> > > > First there are three basic initialization calls: no
> > > > initialization, passing irq and platform_data, and passing the
> > > > i2c_board_info struct directly (preferred for drivers that don't
> > > > need pre-2.6.26 compatibility).
> > > >
> > > > And for each flavor you would like to see three different versions
> > > > as well: one with a fixed known i2c address, one where you probe
> > > > for a list of addresses, and one where you can probe for a single
> > > > i2c address.
> > > >
> > > > I propose to change the API as follows:
> > > >
> > > > #define V4L2_I2C_ADDRS(addr, addrs...) \
> > > > ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
> > > >
> > > > struct v4l2_subdev *v4l2_i2c_new_subdev(struct v4l2_device
> > > > *v4l2_dev, struct i2c_adapter *adapter,
> > > > const char *module_name, const char *client_type,
> > > > u8 addr, const unsigned short *addrs);
> > > >
> > > > struct v4l2_subdev *v4l2_i2c_new_subdev_cfg(struct v4l2_device
> > > > *v4l2_dev, struct i2c_adapter *adapter,
> > > > const char *module_name, const char *client_type,
> > > > int irq, void *platform_data,
> > > > u8 addr, const unsigned short *addrs);
> > > >
> > > > /* Only available for kernels >= 2.6.26 */
> > > > struct v4l2_subdev *v4l2_i2c_new_subdev_board(struct v4l2_device
> > > > *v4l2_dev, struct i2c_adapter *adapter, const char *module_name,
> > > > struct i2c_board_info *info, const unsigned short *addrs);
> > > >
> > > > If you use a fixed address, then only set addr (or info.addr) and
> > > > set addrs to NULL. If you want to probe for a list of addrs, then
> > > > set addrs to the list of addrs. If you want to probe for a single
> > > > addr, then use V4L2_I2C_ADDRS(addr) as the addrs argument. This
> > > > constructs an array with just two entries. Actually, this macro can
> > > > also create arrays with more entries.
> > > >
> > > > Note that v4l2_i2c_new_subdev will be an inline that calls
> > > > v4l2_i2c_new_subdev_cfg with 0, NULL for the irq and platform_data.
> > > >
> > > > And for kernels >= 2.6.26 v4l2_i2c_new_subdev_cfg can be an inline
> > > > calling v4l2_i2c_new_subdev_board.
> > > >
> > > > This approach reduces the number of functions to just one (not
> > > > counting the inlines) and simplifies things all around. It does
> > > > mean that all sources need to be changed, but if we go this route,
> > > > then now is the time before the 2.6.31 window is closed. And I
> > > > would also like to remove the '_new' from these function names. I
> > > > never thought it added anything useful.
> > > >
> > > > Comments? If we decide to go this way, then I need to know soon so
> > > > that I can make the changes before the 2.6.31 window closes.
> > > >
> > > > BTW, if the new s_config subdev call is present, then it should
> > > > always be called. That way the subdev driver can safely do all of
> > > > its initialization in s_config, no matter how it was initialized.
> > > >
> > > > Sorry about the long delay in replying to this: it's been very
> > > > hectic lately at the expense of my v4l-dvb work.
> > >
> > > I've done the initial conversion to the new API (no _cfg or _board
> > > version yet) in my ~hverkuil/v4l-dvb-subdev tree. It really
> > > simplifies things and if nobody objects then I'd like to get this in
> > > before 2.6.31.
> >
> > I've added the new _cfg and _board fucntions as well in this tree. It
> > needs a bit of a cleanup before I can do a pull request (the last two
> > patches should be merged to one), but otherwise this is the code as I
> > think it should be:
> >
> > /* Construct an I2C_CLIENT_END-terminated array of i2c addresses on the
> > fly */
> > #define V4L2_I2C_ADDRS(addr, addrs...) \
> > ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
> >
> > /* Load an i2c module and return an initialized v4l2_subdev struct.
> > Only call request_module if module_name != NULL.
> > The client_type argument is the name of the chip that's on the
> > adapter. */
> > struct v4l2_subdev *v4l2_i2c_new_subdev_cfg(struct v4l2_device
> > *v4l2_dev, struct i2c_adapter *adapter,
> > const char *module_name, const char *client_type,
> > int irq, void *platform_data,
> > u8 addr, const unsigned short *addrs);
> >
> > static inline struct v4l2_subdev *v4l2_i2c_new_subdev(
> > struct v4l2_device *v4l2_dev,
> > struct i2c_adapter *adapter,
> > const char *module_name, const char *client_type,
> > u8 addr, const unsigned short *addrs)
> > {
> > return v4l2_i2c_new_subdev_cfg(v4l2_dev, adapter, module_name,
> > client_type, 0, NULL, addr, addrs);
> > }
> >
> > #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 26)
> > struct i2c_board_info;
> >
> > struct v4l2_subdev *v4l2_i2c_new_subdev_board(struct v4l2_device
> > *v4l2_dev, struct i2c_adapter *adapter, const char *module_name, struct
> > i2c_board_info *info, const unsigned short *addrs); #endif
> >
> > Regards,
> >
> > Hans
>
> I've cloned your tree and took a look at your code. Well, looks like
> the proper way to do this change.
> I didn't take this approach because it touchs other drivers. However,
> concentrating the code in only one
> function is better. I also saw that you have fixed the kernel version
> check in the v4l2_device_unregister
> function. Great!
>
> I will resend my series without this patch. I will rebase it on top of
> your subdev tree so the new api
> can be used straight. Is that ok?
Yes, sure. Just be aware that there may be some small changes to my patch
based on feedback I get. But it is a good test anyway of this API to see if
it works well for you.
Regards,
Hans
>
> > --
> > Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom
> > --
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>
> --
> Eduardo Bezerra Valentin
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--
Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom
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