On 05/11/2012 04:53 PM, Lars-Peter Clausen wrote: > We often have the case were we do have a enum style channel attribute. These > attributes have in common that they are a list of string values which usually > map in a 1-to-1 fashion to integer values. > > This patch implements some common helper code for implementing enum style > channel attributes using extended channel attributes. The helper functions take > care of converting between the string and integer values, as well providing a > function for "_available" attributes which list all available enum items. > General principal is good, but needs some documentation :) Also couple of trivial points inline. > Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx> > --- > drivers/iio/industrialio-core.c | 57 +++++++++++++++++++++++++++++++++++++++ > include/linux/iio/iio.h | 32 ++++++++++++++++++++++ > 2 files changed, 89 insertions(+) > > diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c > index b39a587..241be03 100644 > --- a/drivers/iio/industrialio-core.c > +++ b/drivers/iio/industrialio-core.c > @@ -288,6 +288,63 @@ static ssize_t iio_write_channel_ext_info(struct device *dev, > this_attr->c, buf, len); > } > > +ssize_t iio_enum_available_read(struct iio_dev *indio_dev, > + uintptr_t priv, const struct iio_chan_spec *chan, char *buf) > +{ > + const struct iio_enum *e = (const struct iio_enum *)priv; > + char *tmp = buf; > + unsigned int i; > + > + if (!e->num_items) > + return 0; > + Best to add some santify checking on the length of the resulting string given it's technically unbounded. > + for (i = 0; i < e->num_items; ++i) > + tmp += sprintf(tmp, "%s ", e->items[i]); > + > + /* replace last space with a newline */ > + *(tmp - 1) = '\n'; > + > + return tmp - buf; > +} > +EXPORT_SYMBOL_GPL(iio_enum_available_read); > + > +ssize_t iio_enum_read(struct iio_dev *indio_dev, > + uintptr_t priv, const struct iio_chan_spec *chan, char *buf) > +{ > + const struct iio_enum *e = (const struct iio_enum *)priv; > + int i; > + > + i = e->get(indio_dev, chan); > + if (i < 0) > + return i; > + else if (i >= e->num_items) > + return -EINVAL; > + > + return sprintf(buf, "%s\n", e->items[i]); > +} > +EXPORT_SYMBOL_GPL(iio_enum_read); > + > +ssize_t iio_enum_write(struct iio_dev *indio_dev, > + uintptr_t priv, const struct iio_chan_spec *chan, const char *buf, > + size_t len) > +{ > + const struct iio_enum *e = (const struct iio_enum *)priv; > + unsigned int i; > + int ret; > + excess brackets. > + for (i = 0; i < e->num_items; i++) { > + if (sysfs_streq(buf, e->items[i])) > + break; > + } > + > + if (i == e->num_items) > + return -EINVAL; > + > + ret = e->set(indio_dev, chan, i); > + return ret ? ret : len; > +} > +EXPORT_SYMBOL_GPL(iio_enum_write); > + > static ssize_t iio_read_channel_info(struct device *dev, > struct device_attribute *attr, > char *buf) > diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h > index 6fdbdb8..602f118 100644 > --- a/include/linux/iio/iio.h > +++ b/include/linux/iio/iio.h > @@ -124,6 +124,38 @@ struct iio_chan_spec_ext_info { > uintptr_t private; > }; > > +struct iio_enum { > + const char * const *items; > + unsigned int num_items; > + int (*set)(struct iio_dev *, const struct iio_chan_spec *, unsigned int); > + int (*get)(struct iio_dev *, const struct iio_chan_spec *); > +}; > + > +ssize_t iio_enum_available_read(struct iio_dev *indio_dev, > + uintptr_t priv, const struct iio_chan_spec *chan, char *buf); > +ssize_t iio_enum_read(struct iio_dev *indio_dev, > + uintptr_t priv, const struct iio_chan_spec *chan, char *buf); > +ssize_t iio_enum_write(struct iio_dev *indio_dev, > + uintptr_t priv, const struct iio_chan_spec *chan, const char *buf, > + size_t len); > + Document these two... > +#define IIO_ENUM(_name, _shared, _e) \ > +{ \ > + .name = (_name), \ > + .shared = (_shared), \ > + .read = iio_enum_read, \ > + .write = iio_enum_write, \ > + .private = (uintptr_t)(_e), \ > +} > + > +#define IIO_ENUM_AVAILABLE(_name, _e) \ > +{ \ > + .name = (_name "_available"), \ > + .shared = true, \ > + .read = iio_enum_available_read, \ > + .private = (uintptr_t)(_e), \ > +} > + > /** > * struct iio_chan_spec - specification of a single channel > * @type: What type of measurement is the channel making. -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html