linux-kernel - Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional

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Message-ID: <569FC40B.5030902@ti.com>
Date:	Wed, 20 Jan 2016 19:29:47 +0200
From:	Grygorii Strashko <grygorii.strashko@...com>
To:	Lothar Waßmann <LW@...O-electronics.de>,
	Benoît Cousson <bcousson@...libre.com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Pawel Moll <pawel.moll@....com>,
	Rob Herring <robh+dt@...nel.org>,
	Russell King <linux@....linux.org.uk>,
	Tony Lindgren <tony@...mide.com>, <devicetree@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>
Subject: Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional

On 01/20/2016 02:29 PM, Lothar Waßmann wrote:
> On the AM335x SoC rev. <= 1.0 the "Input Function of the EXTINTn
> Terminal is Inverted", for which the only remedy is to "Use an active
> high interrupt source or use an external inverter to change the
> polarity of any active low interrupt source."
> 
> This pin is used as IRQ pin for the LTC3589 PMIC on the Ka-Ro
> electronics TX48 module. Make the IRQ optional in the driver and use a
> polling routine instead if no IRQ is specified in DT.
> Otherwise the driver will continuously generate interrupts and make
> the system unusable.
> 
> Signed-off-by: Lothar Waßmann <LW@...O-electronics.de>
> ---
>   drivers/regulator/ltc3589.c | 49 +++++++++++++++++++++++++++++++++++++++++----
>   1 file changed, 45 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/regulator/ltc3589.c b/drivers/regulator/ltc3589.c

[...]

>   }
> @@ -519,6 +539,16 @@ static int ltc3589_probe(struct i2c_client *client,
>   			return ret;
>   		}
>   	}
> +	if (client->irq <= 0) {
> +		dev_warn(dev,
> +			"No interrupt configured; poll for thermal shutdown and undervoltage events\n");
> +
> +		INIT_DELAYED_WORK(&ltc3589->poll_timer, ltc3589_poll_func);
> +		schedule_delayed_work(&ltc3589->poll_timer,
> +				msecs_to_jiffies(POLL_PERIOD));
> +
> +		return 0;
> +	}
>   
>   	ret = devm_request_threaded_irq(dev, client->irq, NULL, ltc3589_isr,
>   					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
					^^^^^^^^^^^^^^^^

I assume you have issue with IRQ because of the above hard-coded flag.
if yes - Over all approach for such kind of issues - do not hard-code IRQ triggering 
flags in code in case of DT boot. DT core will configure it properly.



[...]

-- 
regards,
-grygorii