[PATCH 2/2] Add the of_find_i2c_device_by_node function, V4

[Jon Smirl]

On 7/1/08, Jean Delvare <khali at linux-fr.org> wrote:
> Hi Jon,
>
>
>  On Mon, 30 Jun 2008 19:01:28 -0400, Jon Smirl wrote:
>  > Add the of_find_i2c_device_by_node function. This allows you to
>  > follow a reference in the device to an i2c device node and then
>  > locate the linux device instantiated by the device tree. Example
>  > use, an i2s codec controlled by i2c.
>  > ---
>  >
>  >  drivers/i2c/i2c-core.c |    2 +-
>  >  drivers/of/of_i2c.c    |   37 ++++++++++++++++++++++++++-----------
>  >  include/linux/i2c.h    |    3 +++
>  >  include/linux/of_i2c.h |    2 ++
>  >  4 files changed, 32 insertions(+), 12 deletions(-)
>  >
>  > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
>  > index d0175f4..e3abe1b 100644
>  > --- a/drivers/i2c/i2c-core.c
>  > +++ b/drivers/i2c/i2c-core.c
>  > @@ -208,7 +208,7 @@ static struct device_attribute i2c_dev_attrs[] = {
>  >       { },
>  >  };
>  >
>  > -static struct bus_type i2c_bus_type = {
>  > +struct bus_type i2c_bus_type = {
>  >       .name           = "i2c",
>  >       .dev_attrs      = i2c_dev_attrs,
>  >       .match          = i2c_device_match,
>
>
> What if i2c-core is built as a module? Don't you need to export the
>  symbol then?

Jean, can you re-export i2c_bus_type and then I'll drop that part from
the patch? That way the patch won't hit multiple maintainers.

>  > diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
>  > index 715a444..ca69a16 100644
>  > --- a/drivers/of/of_i2c.c
>  > +++ b/drivers/of/of_i2c.c
>  > @@ -75,7 +75,7 @@ static int of_find_i2c_driver(struct device_node *node,
>  >  void of_register_i2c_devices(struct i2c_adapter *adap,
>  >                            struct device_node *adap_node)
>  >  {
>  > -     void *result;
>  > +     struct i2c_client *i2c_dev;
>  >       struct device_node *node;
>  >
>  >       for_each_child_of_node(adap_node, node) {
>  > @@ -90,29 +90,44 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
>  >                       continue;
>  >               }
>  >
>  > -             info.irq = irq_of_parse_and_map(node, 0);
>  > -             if (info.irq == NO_IRQ)
>  > -                     info.irq = -1;
>  > -
>  > -             if (of_find_i2c_driver(node, &info) < 0) {
>  > -                     irq_dispose_mapping(info.irq);
>  > +             if (of_find_i2c_driver(node, &info) < 0)
>  >                       continue;
>  > -             }
>  >
>  > +             info.irq = irq_of_parse_and_map(node, 0);
>  >               info.addr = *addr;
>  >
>  > -             request_module(info.type);
>  > +             request_module("%s", info.type);
>
>
> A separate fix for this issue was already sent by Maximilian Attems a
>  few days go:
>  http://lists.lm-sensors.org/pipermail/i2c/2008-June/004030.html
>
>
>  >
>  > -             result = i2c_new_device(adap, &info);
>  > -             if (result == NULL) {
>  > +             i2c_dev = i2c_new_device(adap, &info);
>  > +             if (i2c_dev == NULL) {
>  >                       printk(KERN_ERR
>  >                              "of-i2c: Failed to load driver for %s\n",
>  >                              info.type);
>  >                       irq_dispose_mapping(info.irq);
>  >                       continue;
>  >               }
>  > +
>  > +             i2c_dev->dev.archdata.of_node = of_node_get(node);
>  >       }
>  >  }
>  >  EXPORT_SYMBOL(of_register_i2c_devices);
>  >
>  > +static int of_dev_node_match(struct device *dev, void *data)
>  > +{
>  > +        return dev->archdata.of_node == data;
>  > +}
>  > +
>  > +struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
>  > +{
>  > +     struct device *dev;
>  > +
>  > +     dev = bus_find_device(&i2c_bus_type, NULL, node,
>  > +                                      of_dev_node_match);
>  > +     if (!dev)
>  > +             return NULL;
>  > +
>  > +     return to_i2c_client(dev);
>  > +}
>  > +EXPORT_SYMBOL(of_find_i2c_device_by_node);
>  > +
>  >  MODULE_LICENSE("GPL");
>  > diff --git a/include/linux/i2c.h b/include/linux/i2c.h
>  > index fb9af6a..186b22d 100644
>  > --- a/include/linux/i2c.h
>  > +++ b/include/linux/i2c.h
>  > @@ -92,6 +92,9 @@ extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client * client,
>  >  extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client * client,
>  >                                         u8 command, u8 length,
>  >                                         const u8 *values);
>  > +
>  > +/* Base of the i2c bus */
>  > +extern struct bus_type i2c_bus_type;
>  >
>  >  /*
>  >   * A driver is capable of handling one or more physical devices present on
>  > diff --git a/include/linux/of_i2c.h b/include/linux/of_i2c.h
>  > index bd2a870..17d5897 100644
>  > --- a/include/linux/of_i2c.h
>  > +++ b/include/linux/of_i2c.h
>  > @@ -16,5 +16,7 @@
>  >
>  >  void of_register_i2c_devices(struct i2c_adapter *adap,
>  >                            struct device_node *adap_node);
>  > +struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
>  > +
>  >
>  >  #endif /* __LINUX_OF_I2C_H */
>
>
> I'm fine with this patch. In particular, exporting i2c_bus_type is OK.
>  It was un-exported only because it had no user left, but it can be
>  exported again if needed.
>
>  I'm not the one to push this upstream though, as the patch is
>  essentially an openfirmware patch. That would be something for Jochen
>  Friedrich and Paul Mackerras I guess. Would be nice to have a
>  MAINTAINERS entry for OF...
>
>  --
>
> Jean Delvare
>


-- 
Jon Smirl
jonsmirl at gmail.com