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From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: florian.vaussard@epfl.ch
Cc: linux-omap <linux-omap@vger.kernel.org>,
	linux-arm <linux-arm-kernel@lists.infradead.org>,
	"Philippe Rétornaz" <philippe.retornaz@epfl.ch>
Subject: Re: TWL6040 fails to initialize
Date: Wed, 26 Feb 2014 09:26:39 +0200	[thread overview]
Message-ID: <530D972F.805@ti.com> (raw)
In-Reply-To: <530CB9C6.60806@epfl.ch>

On 02/25/2014 05:41 PM, Florian Vaussard wrote:
> If the power was not enabled at all, I would be unable to read the
> revision register, no? And delaying the probe by one millisecond would
> be of no help in this case IMHO.

One thing which might cause this is that if the audpwron GPIO is set high
before the twl6040 module is probing. When I request the GPIO I ask it to be
set to low. If the line was high before this means we initiate the power off
sequence.
Can you try something like this:

diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
index 75316fb33448..d2a0bd1539ae 100644
--- a/drivers/mfd/twl6040.c
+++ b/drivers/mfd/twl6040.c
@@ -674,6 +674,9 @@ static int twl6040_probe(struct i2c_client *client,
                                            GPIOF_OUT_INIT_LOW, "audpwron");
                if (ret)
                        goto gpio_err;
+
+               /* power-down sequence latency */
+               usleep_range(500, 700);
        }

        ret = regmap_add_irq_chip(twl6040->regmap, twl6040->irq, IRQF_ONESHOT,


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Péter
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  reply	other threads:[~2014-02-26  7:27 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-25 10:30 TWL6040 fails to initialize Florian Vaussard
2014-02-25 14:29 ` Peter Ujfalusi
2014-02-25 15:41   ` Florian Vaussard
2014-02-26  7:26     ` Peter Ujfalusi [this message]
2014-02-26  9:53       ` Florian Vaussard
2014-02-26 10:28         ` Peter Ujfalusi
2014-02-26 10:31           ` Florian Vaussard
2014-02-27 12:05             ` Peter Ujfalusi
2014-02-27 15:24               ` Florian Vaussard

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