Re: [PATCH v2 1/1] iio: multiplexer: Make use of device properties

Jonathan Cameron
2022-02-27T11:20:09Z

On Sun, 27 Feb 2022 03:28:15 +0100
Peter Rosin <peda@axentia.se> wrote:

> Hi!
>
> Sorry for the late reply.
>
> On 2022-02-02 21:44, Andy Shevchenko wrote:
> > Convert the module to be property provider agnostic and allow
> > it to be used on non-OF platforms.
> >
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > ---
> > v2: dropped depends on OF
> > drivers/iio/multiplexer/Kconfig | 1 -
> > drivers/iio/multiplexer/iio-mux.c | 48 ++++++++++++++-----------------
> > 2 files changed, 22 insertions(+), 27 deletions(-)
> >
> > diff --git a/drivers/iio/multiplexer/Kconfig b/drivers/iio/multiplexer/Kconfig
> > index a1e1332d1206..928f424a1ed3 100644
> > --- a/drivers/iio/multiplexer/Kconfig
> > +++ b/drivers/iio/multiplexer/Kconfig
> > @@ -9,7 +9,6 @@ menu "Multiplexers"
> > config IIO_MUX
> > tristate "IIO multiplexer driver"
> > select MULTIPLEXER
> > - depends on OF || COMPILE_TEST
> > help
> > Say yes here to build support for the IIO multiplexer.
> >
> > diff --git a/drivers/iio/multiplexer/iio-mux.c b/drivers/iio/multiplexer/iio-mux.c
> > index f422d44377df..e6f0fef96494 100644
> > --- a/drivers/iio/multiplexer/iio-mux.c
> > +++ b/drivers/iio/multiplexer/iio-mux.c
> > @@ -10,11 +10,12 @@
> > #include <linux/err.h>
> > #include <linux/iio/consumer.h>
> > #include <linux/iio/iio.h>
> > +#include <linux/mod_devicetable.h>
> > #include <linux/module.h>
> > #include <linux/mutex.h>
> > #include <linux/mux/consumer.h>
> > -#include <linux/of.h>
> > #include <linux/platform_device.h>
> > +#include <linux/property.h>
> >
> > struct mux_ext_info_cache {
> > char *data;
> > @@ -324,37 +325,20 @@ static int mux_configure_channel(struct device *dev, struct mux *mux,
> > return 0;
> > }
> >
> > -/*
> > - * Same as of_property_for_each_string(), but also keeps track of the
> > - * index of each string.
> > - */
> > -#define of_property_for_each_string_index(np, propname, prop, s, i) \
> > - for (prop = of_find_property(np, propname, NULL), \
> > - s = of_prop_next_string(prop, NULL), \
> > - i = 0; \
> > - s; \
> > - s = of_prop_next_string(prop, s), \
> > - i++)
> > -
> > static int mux_probe(struct platform_device *pdev)
> > {
> > struct device *dev = &pdev->dev;
> > - struct device_node *np = pdev->dev.of_node;
> > struct iio_dev *indio_dev;
> > struct iio_channel *parent;
> > struct mux *mux;
> > - struct property *prop;
> > - const char *label;
> > + const char **labels;
> > u32 state;
> > + int children, all_children;
>
> I dislike that the pattern with one declaration per line is broken here.
> There are perhaps a few too many variables, but introducing one instance
> of two declarations on one line is disturbing for me.
>
> So, with that fixed,
>
> Acked-by: Peter Rosin <peda@axentia.se>
>
> > int sizeof_ext_info;
> > - int children;
> > int sizeof_priv;
> > int i;
> > int ret;
> >
> > - if (!np)
> > - return -ENODEV;
> > -
> > parent = devm_iio_channel_get(dev, "parent");
> > if (IS_ERR(parent))
> > return dev_err_probe(dev, PTR_ERR(parent),
> > @@ -366,9 +350,21 @@ static int mux_probe(struct platform_device *pdev)
> > sizeof_ext_info *= sizeof(*mux->ext_info);
> > }
> >
> > + all_children = device_property_count_string_array(dev, "channels");
> > + if (all_children < 0)
> > + return all_children;

Function seems to be called device_property_string_array_count() so this will need
a v3 anyway as it doesn't currently build.

Thanks,

Jonathan

> > +
> > + labels = devm_kmalloc_array(dev, all_children, sizeof(char *), GFP_KERNEL);
>
> I'm a bit sad to see the copy of the labels array. No big deal,
> but it seems inelegant. But the of_property_for_each_string_index
> macro was also misplaced and therefore inelegant. My guess is
> that the device properties should be fairly static and that the
> copy is a waste?
>
> So, anyway, I'm just whining here, and the labels copy is ok.
>
> Cheers,
> Peter
>
> > + if (!labels)
> > + return -ENOMEM;
> > +
> > + ret = device_property_read_string_array(dev, "channels", labels, all_children);
> > + if (ret < 0)
> > + return ret;
> > +
> > children = 0;
> > - of_property_for_each_string(np, "channels", prop, label) {
> > - if (*label)
> > + for (state = 0; state < all_children; state++) {
> > + if (*labels[state])
> > children++;
> > }
> > if (children <= 0) {
> > @@ -395,7 +391,7 @@ static int mux_probe(struct platform_device *pdev)
> > mux->cached_state = -1;
> >
> > mux->delay_us = 0;
> > - of_property_read_u32(np, "settle-time-us", &mux->delay_us);
> > + device_property_read_u32(dev, "settle-time-us", &mux->delay_us);
> >
> > indio_dev->name = dev_name(dev);
> > indio_dev->info = &mux_info;
> > @@ -426,11 +422,11 @@ static int mux_probe(struct platform_device *pdev)
> > }
> >
> > i = 0;
> > - of_property_for_each_string_index(np, "channels", prop, label, state) {
> > - if (!*label)
> > + for (state = 0; state < all_children; state++) {
> > + if (!*labels[state])
> > continue;
> >
> > - ret = mux_configure_channel(dev, mux, state, label, i++);
> > + ret = mux_configure_channel(dev, mux, state, labels[state], i++);
> > if (ret < 0)
> > return ret;
> > }