Hello Luis,
On 01/05/2017 07:24 PM, Luis Oliveira wrote:
> This function has the purpose of mode detection by checking the
> device nodes for a reg matching with the I2C_OWN_SLAVE_ADDREESS flag.
> Currently only checks using OF functions (ACPI slave not supported yet).
>
> Signed-off-by: Luis Oliveira <lolivei@xxxxxxxxxxxx>
> ---
> Due to the need of checking if the I2C slave address is our own (in
> other words: if we are the I2C slave) I created a helper function
> (proposed to me by @Andy) to enable that check.
> Currently (because I am not able to test it using ACPI) it only
> supports devicetree declarations.
>
> drivers/i2c/i2c-core.c | 19 +++++++++++++++++++
> include/linux/i2c.h | 1 +
> 2 files changed, 20 insertions(+)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 3de95a29024c..48e705b23c59 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -3691,6 +3691,25 @@ int i2c_slave_unregister(struct i2c_client *client)
> return ret;
> }
> EXPORT_SYMBOL_GPL(i2c_slave_unregister);
> +
> +int i2c_slave_mode_detect(struct device *dev)
> +{
> + struct device_node *child;
> + u32 reg;
> +
> + if (IS_BUILTIN(CONFIG_OF) && dev->of_node) {
IS_BUILTIN(CONFIG_OF) looks excessive, check for non-NULL dev->of_node
should be sufficient.
But then you may do for_each_child_of_node() loop totally unconditionally,
because of_get_next_child() correctly handle NULL as the first argument.
> + for_each_child_of_node(dev->of_node, child) {
> + of_property_read_u32(child, "reg", ®);
> + if (reg & I2C_OWN_SLAVE_ADDRESS)
> + return 1;
Leaked incremented reference to a child device node, please add
of_node_put(child) before return in the loop body.
Also reg variable may be uninitialized here, if child device node
does not have "reg" property.
> + }
> + } else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) {
> + dev_dbg(dev, "ACPI slave is not supported yet\n");
> + }
If so, then it might be better to drop else-if stub for now.
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(i2c_slave_mode_detect);
> +
> #endif
>
> MODULE_AUTHOR("Simon G. Vogl <simon@xxxxxxxxxxxxxxxxx>");
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index b2109c522dec..53cf99569af5 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -282,6 +282,7 @@ enum i2c_slave_event {
>
> extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
> extern int i2c_slave_unregister(struct i2c_client *client);
> +extern int i2c_slave_mode_detect(struct device *dev);
>
> static inline int i2c_slave_event(struct i2c_client *client,
> enum i2c_slave_event event, u8 *val)
>
--
With best wishes,
Vladimir
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