Messages in this thread | | | From | Andy Shevchenko <> | Date | Mon, 3 Feb 2020 11:50:42 +0200 | Subject | Re: [PATCH v4 2/2] spi: Add generic SPI multiplexer |
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On Fri, Jan 31, 2020 at 4:34 AM Chris Packham <chris.packham@alliedtelesis.co.nz> wrote: > > Add a SPI device driver that sits in-band and provides a SPI controller > which supports chip selects via a mux-control. This enables extra SPI > devices to be connected with limited native chip selects.
Thanks for an update, my comments below.
...
> # > # Add new SPI master controllers in alphabetical order above this line > #
> +#
Redundant line.
...
> +/* > + * General Purpose SPI multiplexer > + */
I think Mark wants to have this in one line with C++ style of comments.
...
> +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/err.h> > +#include <linux/slab.h> > +#include <linux/spi/spi.h> > +#include <linux/mux/consumer.h>
Perhaps sorted?
...
> + /* do the transfer */ > + ret = spi_async(priv->spi, m); > + return ret;
return spi_async(...);
...
> + priv->mux = devm_mux_control_get(&spi->dev, NULL);
> + ret = PTR_ERR_OR_ZERO(priv->mux);
This is a bit complicated.
> + if (ret) {
Why not simple do
if (IS_ERR(priv->mux)) { ret = PTR_ERR(...); ... }
?
> + if (ret != -EPROBE_DEFER) > + dev_err(&spi->dev, "failed to get control-mux\n"); > + goto err_put_ctlr; > + }
> + ctlr->dev.of_node = spi->dev.of_node;
I'm wondering why SPI core can't handle this by default (like GPIO subsystem does).
> + ret = devm_spi_register_controller(&spi->dev, ctlr); > + if (ret) > + goto err_put_ctlr; > +
> + return ret;
return 0;
...
> +static const struct of_device_id spi_mux_of_match[] = { > + { .compatible = "spi-mux" }, > + { },
Comma is not needed in terminator line.
> +};
-- With Best Regards, Andy Shevchenko
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