Re: [PATCH 1/2] i2c: mux: pinctrl: remove platform_data

From: Peter Rosin
Date: Wed Aug 02 2017 - 17:20:08 EST


On 2017-08-02 21:05, Stephen Warren wrote:
> On 08/02/2017 01:27 AM, Peter Rosin wrote:
>> No platform (at least no upstreamed platform) has ever used this
>> platform_data. Just drop it and simplify the code.
>
>> diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
>
>> static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
>
> (eliding some - lines for brevity in the following):
>
>> + for (i = 0; i < num_names; i++) {
>> + ret = of_property_read_string_index(np, "pinctrl-names", i,
>> + &name);
>> + if (ret < 0) {
>> + dev_err(dev, "Cannot parse pinctrl-names: %d\n", ret);
>> + goto err_put_parent;
>> + }
>> +
>> + mux->states[i] = pinctrl_lookup_state(mux->pinctrl, name);
>> if (IS_ERR(mux->states[i])) {
>> ret = PTR_ERR(mux->states[i]);
>> + dev_err(dev, "Cannot look up pinctrl state %s: %d\n",
>> + name, ret);
>> + goto err_put_parent;
>
> This error path doesn't undo pinctrl_lookup_state. Is that OK? I think
> so, but wanted to check.

I also think so, looking at pinctrl_lookup_state, it seems to just match
strings and return a pointer. No refcounts or other state change involved
that I can see. Either way, the preexisting code would have the same issue
so it would be orthogonal and fodder for another patch...

>> + muxc = i2c_mux_alloc(parent, dev, num_names,
>> + sizeof(*mux) + num_names * sizeof(*mux->states),
>> + 0, i2c_mux_pinctrl_select, NULL);
> ...
>> + /* Do not add any adapter for the idle state (if it's there at all). */
>> + for (i = 0; i < num_names - !!mux->state_idle; i++) {
>> + ret = i2c_mux_add_adapter(muxc, 0, i, 0);
>
> Is it OK to potentially add one fewer adapter here than the child bus
> count passed to i2c_mux_alloc() earlier? The old code specifically
> excluded the idle state (if present) from the child bus count passed to
> i2c_mux_alloc(), which was aided by the fact that it parsed the DT
> before calling i2c_mux_alloc().

Yes, that is perfectly fine. The only issue is wasting space for one extra
pointer.

> If those two things are OK, then:
> Reviewed-by: Stephen Warren <swarren@xxxxxxxxxx>

Thanks!

Cheers,
Peter