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SubjectRe: [PATCH V2 2/2] Input: misc: introduce palmas-pwrbutton
On Thu, Aug 21, 2014 at 12:37:15PM -0500, Nishanth Menon wrote:
> On 12:32-20140821, Murphy, Dan wrote:
> > On 08/21/2014 12:19 PM, Menon, Nishanth wrote:
> > > On 08/21/2014 11:59 AM, Murphy, Dan wrote:
> > > [...]
> > > Ooops.. missed answering one addition statement:
> > >
> > >>> + of_property_read_u32(np, "ti,palmas-long-press-seconds", &val);
> > >>
> > >> Probably should check the return to make sure the value exists and that is is
> > >> within an expected range.
> > > It is an optional parameter and may not exist in dt. when it does
> > > exist, the logic tries to do a best match (this is the for loop in the
> > > logic just below).
> > >
> >
> > The issue is val might be returned as a negative which will then proceed to
> > set the config->long_press_time_val to the lowest time value which then overrides
> > your initial setting of config->long_press_time_val = ARRAY_SIZE(lpk_times) - 1;
> >
>
> Does the following as a replacement look OK? if yes, I can incorporate
> as part of v3 of this series.
> /**
> * palmas_pwron_params_ofinit() - device tree parameter parser
> * @dev: palmas button device
> * @config: configuration params that this fills up
> */
> static void palmas_pwron_params_ofinit(struct device *dev,
> struct palmas_pwron_config *config)
> {
> struct device_node *np;
> u32 val;
> int i, ret;
> u8 lpk_times[] = { 6, 8, 10, 12 };
> int pwr_on_deb_ms[] = { 15, 100, 500, 1000 };
>
> /* Handle cases where device node based configuration is not present */
> if (!of_have_populated_dt())
> return;
> np = of_node_get(dev->of_node);
> if (!np)
> return;
>
> /* Default config parameters - least debounce, max long key press */
> config->pwron_debounce_val = 0;
> config->long_press_time_val = ARRAY_SIZE(lpk_times) - 1;
>
> ret = of_property_read_u32(np, "ti,palmas-long-press-seconds", &val);
> if (ret)
> goto skip_lpk;

Just without gotos please. They are nice in error handling paths and in some
other rare circumstances, but not here.

> for (i = 0; i < ARRAY_SIZE(lpk_times); i++) {
> if (val <= lpk_times[i]) {
> config->long_press_time_val = i;
> break;
> }
> }
>
> skip_lpk:
> ret = of_property_read_u32(np, "ti,palmas-pwron-debounce-milli-seconds",
> &val);
> if (ret)
> goto skip_debounce;
> for (i = 0; i < ARRAY_SIZE(pwr_on_deb_ms); i++) {
> if (val <= pwr_on_deb_ms[i]) {
> config->pwron_debounce_val = i;
> break;
> }
> }
>
> skip_debounce:
> dev_info(dev, "h/w controlled shutdown duration=%d seconds\n",
> lpk_times[config->long_press_time_val]);
>
> of_node_put(np);

BTW, I do not think you need to use of_node_get/put here, it's not going anywhere.

Thanks.

--
Dmitry


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