On 11/19/2013 10:10 AM, Tomasz Figa wrote:
> One of remaining limitations of current pinctrl-samsung driver was
> the inability to parse multiple pinmux/pinconf group nodes grouped
> inside a single device tree node. It made defining groups of pins for
> single purpose, but with different parameters very inconvenient.
>
> This patch implements Tegra-like support for grouping multiple pinctrl
> groups inside one device tree node, by completely changing the way
> pin groups and functions are parsed from device tree.
> The code creating
> pinctrl maps from DT nodes has been borrowed from pinctrl-tegra,
A lot of the Tegra code has been slightly generalized and put into
pinconf-generic.c. Can the Samsung driver be converted to use that core
code rather than adding another copy of it? Perhaps this isn't possible
given the backwards-compatibility requirements that allow either 1- or
2-level nodes though, although I imagine that could be added to the core
code. One thing you'd certainly need to do is enhance the code in
pinconf-generic.c so that you could substitute your own
pinconf_generic_parse_dt_config() function or dt_params[] table, to
allow for the SoC-specific property names, but I doubt that's too hard.
Tegra could be converted then too:-)
> while
> the initial creation of groups and functions has been completely
> rewritten with following assumptions:
> - each group consists of just one pin and does not depend on data
> from device tree,
> - each function is represented by a device tree child node of the
> pin controller, which in turn can contain multiple child nodes
> for pins that need to have different configuration values.
OK, I think that sounds reasonable.
> Device Tree bindings are fully backwards compatible. New functionality
> can be used by defining a new pinctrl group consisting of several child
> nodes, as on following example:
>
> sd4_bus8: sd4-bus-width8 {
> part-1 {
> samsung,pins = "gpk0-3", "gpk0-4",
> "gpk0-5", "gpk0-6";
> samsung,pin-function = <3>;
> samsung,pin-pud = <3>;
> samsung,pin-drv = <3>;
> };
> part-2 {
> samsung,pins = "gpk1-3", "gpk1-4",
> "gpk1-5", "gpk1-6";
> samsung,pin-function = <4>;
> samsung,pin-pud = <4>;
> samsung,pin-drv = <3>;
> };
> };
OK, that all looks great!
> diff --git a/Documentation/devicetree/bindings/pinctrl/samsung-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/samsung-pinctrl.txt
The DT changes fully, and the code a little briefly,
Reviewed-by: Stephen Warren <swarren@xxxxxxxxxx>
Just a minor comment below,
> diff --git a/drivers/pinctrl/pinctrl-samsung.c b/drivers/pinctrl/pinctrl-samsung.c
> +static int samsung_pinctrl_create_function(struct device *dev,
> + struct samsung_pinctrl_drv_data *drvdata,
> + struct device_node *func_np,
> + struct samsung_pmx_func *func)
...
> + for (i = 0; i < npins; ++i) {
> + const char *gname;
> + char *gname_copy;
> +
> + ret = of_property_read_string_index(func_np, "samsung,pins",
> + i, &gname);
> + if (ret) {
> + dev_err(dev,
> + "failed to read pin name %d from %s node\n",
> + i, func_np->name);
> + return ret;
> }
> +
> + gname_copy = devm_kzalloc(dev, strlen(gname) + 1, GFP_KERNEL);
> + if (!gname_copy)
> + return -ENOMEM;
> + strcpy(gname_copy, gname);
Is the lifetime of the string "returned" by
of_property_read_string_index() really so short that you must copy the
string? I'd be tempted just to store the pointer, although perhaps you
need to get() the node so that's safe.
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