From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ivaylo Dimitrov Subject: Re: Nokia N900 - audio TPA6130A2 problems Date: Wed, 16 Mar 2016 20:21:31 +0200 Message-ID: <56E9A42B.3010209@gmail.com> References: <201507251228.27128@pali> <201601050034.12810@pali> <20160306152339.GA428@earth> <201603121342.33099@pali> <56E68B71.2030202@ti.com> <20160316133319.GR8413@pali> <20160316144709.GA3389@earth> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20160316144709.GA3389@earth> Sender: linux-kernel-owner@vger.kernel.org To: Sebastian Reichel , =?UTF-8?Q?Pali_Roh=c3=a1r?= Cc: Peter Ujfalusi , Jarkko Nikula , Tony Lindgren , Lars-Peter Clausen , linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, Pavel Machek , Aaro Koskinen , Nishanth Menon , merlijn@wizzup.org List-Id: linux-omap@vger.kernel.org Hi, On 16.03.2016 16:47, Sebastian Reichel wrote: > Hi, > > On Wed, Mar 16, 2016 at 02:33:19PM +0100, Pali Roh=E1r wrote: >> Hi! We found out that tpa6130a2 device is being initialized before >> i2c_2 bus is initialized. So that is reason why tpa6130a2 fails... > > What do you mean by initialize? A call to tpa6130a2_probe()? In that > case I wonder about client->adapter. Is it NULL? > This is (a part of) the log when tpa6130a2 fails to initialize: Jan 1 08:03:07 Nokia-N900 kernel: [ 1.928344] twl 1-0048: PIH (irq = 23) chaining IRQs 340..348 Jan 1 08:03:07 Nokia-N900 kernel: [ 1.934326] twl 1-0048: power (ir= q 345) chaining IRQs 348..355 Jan 1 08:03:07 Nokia-N900 kernel: [ 2.498504] twl4030_gpio twl4030-= gpio: gpio (irq 340) chaining IRQs 356..373 Jan 1 08:03:07 Nokia-N900 kernel: [ 2.858215] twl4030_usb 48070000.= i2c:twl@48:twl4030-usb: Initialized TWL4030 USB module Jan 1 08:03:07 Nokia-N900 kernel: [ 2.888702] input: twl4030_pwrbut= ton as /devices/platform/68000000.ocp/48070000.i2c/i2c-1/1-0048/4807000= 0.i2c:twl@48:pwrbutton/input/input0 Jan 1 08:03:07 Nokia-N900 kernel: [ 2.903594] input: TWL4030 Keypad= as /devices/platform/68000000.ocp/48070000.i2c/i2c-1/1-0048/48070000.i= 2c:twl@48:keypad/input/input1 Jan 1 08:03:07 Nokia-N900 kernel: [ 3.148040] 48070000.i2c:twl@48:m= adc supply vusb3v1 not found, using dummy regulator Jan 1 08:03:07 Nokia-N900 kernel: [ 6.997985] omap_i2c 48070000.i2c= : bus 1 rev3.3 at 2200 kHz Jan 1 08:03:07 Nokia-N900 kernel: [ 7.010528] tpa6130a2 2-0060: Wri= te failed Jan 1 08:03:07 Nokia-N900 kernel: [ 7.015563] omap_i2c 48072000.i2c= : bus 2 rev3.3 at 100 kHz Jan 1 08:03:07 Nokia-N900 kernel: [ 7.023742] omap_i2c 48060000.i2c= : bus 3 rev3.3 at 400 kHz Now, it is either tpa6130a2 probe() is called before i2c-2 is initialized or i2c driver first probes devices on the bus and only then logs successful probe ("omap_i2c 48072000.i2c: bus 2 rev3.3 at 100 kHz"= ) in our case. > --------------- > > I just had another look at the driver and I think there is a race > condition for tpa6130a2_add_controls() and tpa6130a2_stereo_enable(). > > As far as I can see both functions check for "tpa6130a2_client !=3D > NULL". tpa6130a2_client is set before the probe function has finished= , > though. Simplified probe: > > ... > tpa6130a2_client =3D client; > set_default_regs(); > acquire_power_gpio(); > acquire_regulator(); > tpa6130a2_power(1); // needs tpa6130a2_client > check_device(); > tpa6130a2_power(0); // needs tpa6130a2_client > ... > > If tpa6130a2_add_controls() or tpa6130a2_stereo_enable() is called > after tpa6130a2 probe has started, but before probe has completed, > tpa6130a2_client is set, but not yet initialized. The race condition > can be fixed easily by moving the tpa6130a2_client assignment directl= y > after the regulator acquisition. > I'll try that, thanks. Regards, Ivo