linux-kernel - Re: [PATCH V2 2/2] Input: misc: introduce palmas-pwrbutton

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Date:	Thu, 21 Aug 2014 12:37:15 -0500
From:	Nishanth Menon <nm@...com>
To:	"Murphy, Dan" <dmurphy@...com>
CC:	Dmitry Torokhov <dtor@...l.ru>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH V2 2/2] Input: misc: introduce palmas-pwrbutton

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;
	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);
}
-- 
Regards,
Nishanth Menon
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