Re: [PATCH v7 1/9] spmi: add a helper to look up an SPMI device from a device node

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 16 Feb 2022 13:49:12 +0000
Caleb Connolly <caleb.connolly@linaro.org> wrote:

> The helper function spmi_device_from_of() takes a device node and
> returns the SPMI device associated with it.
> This is like of_find_device_by_node but for SPMI devices.
> 
> Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
> ---
>  drivers/spmi/spmi.c  | 17 +++++++++++++++++
>  include/linux/spmi.h |  2 ++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/drivers/spmi/spmi.c b/drivers/spmi/spmi.c
> index b37ead9e2fad..de550b777451 100644
> --- a/drivers/spmi/spmi.c
> +++ b/drivers/spmi/spmi.c
> @@ -386,6 +386,23 @@ static struct bus_type spmi_bus_type = {
>  	.uevent		= spmi_drv_uevent,
>  };
>  
> +/**
> + * spmi_device_from_of() - get the associated SPMI device from a device node
> + *

https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html
"Each function argument should be described in order, immediately following the
 short function description. Do not leave a blank line between the function
 description and the arguments, nor between the arguments."

> + * @np:		device node
> + *
> + * Returns the struct spmi_device associated with a device node or NULL.
> + */
> +inline struct spmi_device *spmi_device_from_of(struct device_node *np)
> +{
> +	struct device *dev = bus_find_device_by_of_node(&spmi_bus_type, np);
> +
> +	if (dev)
> +		return to_spmi_device(dev);
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(spmi_device_from_of);
> +
>  /**
>   * spmi_controller_alloc() - Allocate a new SPMI device
>   * @ctrl:	associated controller
> diff --git a/include/linux/spmi.h b/include/linux/spmi.h
> index 729bcbf9f5ad..6ee476bc1cd6 100644
> --- a/include/linux/spmi.h
> +++ b/include/linux/spmi.h
> @@ -7,6 +7,7 @@
>  #include <linux/types.h>
>  #include <linux/device.h>
>  #include <linux/mod_devicetable.h>
> +#include <linux/of.h>

If all you need is struct device_node * then normally preferred to
use a forwards definition rather than including the header.

struct device_node;

>  
>  /* Maximum slave identifier */
>  #define SPMI_MAX_SLAVE_ID		16
> @@ -164,6 +165,7 @@ static inline void spmi_driver_unregister(struct spmi_driver *sdrv)
>  	module_driver(__spmi_driver, spmi_driver_register, \
>  			spmi_driver_unregister)
>  
> +inline struct spmi_device *spmi_device_from_of(struct device_node *np);
>  int spmi_register_read(struct spmi_device *sdev, u8 addr, u8 *buf);
>  int spmi_ext_register_read(struct spmi_device *sdev, u8 addr, u8 *buf,
>  			   size_t len);