[PATCH 3/6] drivers: Introduce AIODEV subsystem

[Sascha Hauer]

On Fri, Apr 29, 2016 at 10:24:03AM -0700, Andrey Smirnov wrote:
> From: Sascha Hauer <s.hauer at pengutronix.de>
> 
> AIODEV/Aiodevice is a analog I/O framework that can be thought of as a
> simplified hybrid between 'hwmon' and 'IIO' subsystems of Linux kernel
> 
> This commit is very heavily based on 'iodevice' framework proposal
> written by Sascha Hauer.
> 
> Signed-off-by: Andrey Smirnov <andrew.smrinov at gmail.com>
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
>  drivers/Kconfig         |   1 +
>  drivers/Makefile        |   1 +
>  drivers/aiodev/Kconfig  |   8 +++
>  drivers/aiodev/Makefile |   2 +
>  drivers/aiodev/core.c   | 135 ++++++++++++++++++++++++++++++++++++++++++++++++
>  include/aiodev.h        |  39 ++++++++++++++
>  6 files changed, 186 insertions(+)
>  create mode 100644 drivers/aiodev/Kconfig
>  create mode 100644 drivers/aiodev/Makefile
>  create mode 100644 drivers/aiodev/core.c
>  create mode 100644 include/aiodev.h
> 
> diff --git a/drivers/aiodev/Makefile b/drivers/aiodev/Makefile
> new file mode 100644
> index 0000000..806464e
> --- /dev/null
> +++ b/drivers/aiodev/Makefile
> @@ -0,0 +1,2 @@
> +
> +obj-$(CONFIG_AIODEV) += core.o
> diff --git a/drivers/aiodev/core.c b/drivers/aiodev/core.c
> new file mode 100644
> index 0000000..6dcb917
> --- /dev/null
> +++ b/drivers/aiodev/core.c
> @@ -0,0 +1,135 @@
> +#include <common.h>
> +#include <aiodev.h>
> +#include <linux/list.h>
> +#include <malloc.h>

GPL Header missing.

> +
> +LIST_HEAD(aiodevices);
> +EXPORT_SYMBOL(aiodevices);
> +
> +struct aiochannel *aiochannel_get_by_name(const char *name)
> +{
> +	struct aiodevice *aiodev;
> +	int i;
> +
> +	list_for_each_entry(aiodev, &aiodevices, list) {
> +		for (i = 0; i < aiodev->num_channels; i++)
> +			if (!strcmp(name, aiodev->channels[i]->name))
> +				return aiodev->channels[i];
> +	}
> +
> +	return ERR_PTR(-ENOENT);
> +}
> +EXPORT_SYMBOL(aiochannel_get_by_name);
> +
> +struct aiochannel *aiochannel_get(struct device_d *dev, int index)
> +{
> +	struct of_phandle_args spec;
> +	struct aiodevice *aiodev;
> +	int ret, chnum = 0;
> +
> +	if (!dev->device_node)
> +		return ERR_PTR(-EINVAL);
> +
> +	ret = of_parse_phandle_with_args(dev->device_node,
> +					 "aio-channels",
> +					 "#aio-channel-cells",
> +					 index, &spec);

#io-channel-cells is part of the official binding in
/dts/Bindings/iio/iio-bindings.txt. We should work with this existing
binding.

> +        if (ret)
> +                return ERR_PTR(ret);
> +
> +	list_for_each_entry(aiodev, &aiodevices, list) {
> +		if (aiodev->hwdev->device_node == spec.np)
> +			goto found;
> +	}
> +
> +	return ERR_PTR(-EPROBE_DEFER);
> +
> +found:
> +	if (spec.args_count)
> +		chnum = spec.args[0];
> +
> +	if (chnum >= aiodev->num_channels)
> +		return ERR_PTR(-EINVAL);
> +
> +	return aiodev->channels[chnum];
> +}
> +EXPORT_SYMBOL(aiochannel_get);
> +
> +int aiochannel_get_value(struct aiochannel *aiochan, int *value)
> +{
> +	struct aiodevice *aiodev = aiochan->aiodev;
> +
> +	return aiodev->read(aiochan, value);
> +}
> +EXPORT_SYMBOL(aiochannel_get_value);
> +
> +int aiochannel_get_index(struct aiochannel *aiochan)
> +{
> +	int i;
> +	struct aiodevice *aiodev = aiochan->aiodev;
> +
> +	for (i = 0; i < aiodev->num_channels; i++)
> +		if (aiodev->channels[i] == aiochan)
> +			return i;

This function is unused in your patches. If the information this
function provides is needed, maybe better add a index member to struct
aiochannel to get rid of this loop?

> +
> +	return -ENOENT;
> +}
> +EXPORT_SYMBOL(aiochannel_get_index);
> +
> +static int aiochannel_param_get_value(struct param_d *p, void *priv)
> +{
> +	struct aiochannel *aiochan = priv;
> +
> +	return aiochannel_get_value(aiochan, &aiochan->value);
> +}
> +
> +int aiodevice_register(struct aiodevice *aiodev)
> +{
> +	int i, ret;
> +
> +	if (!aiodev->name) {
> +		if (aiodev->hwdev &&
> +		    aiodev->hwdev->device_node) {

	if (!aiodev->name && aiodev->hwdev &&
	    aiodev->hwdev->device_node)

?

Sascha

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