From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [PATCH v4 13/19] ASoC: tegra: Add fallback implementation for audio mclk Date: Wed, 18 Dec 2019 19:29:11 +0300 Message-ID: <13074e67-2807-d494-b8b4-b2e3b529117a@gmail.com> References: <1576613046-17159-1-git-send-email-skomatineni@nvidia.com> <1576613046-17159-14-git-send-email-skomatineni@nvidia.com> <7e49fef8-112c-1694-9316-7a23db8a01a4@gmail.com> <66a28f8a-82e8-5b12-464c-4c91441d1511@nvidia.com> <1499a012-f5e1-3c76-6750-5858765a0532@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <1499a012-f5e1-3c76-6750-5858765a0532@nvidia.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Sowjanya Komatineni , thierry.reding@gmail.com, jonathanh@nvidia.com, mperttunen@nvidia.com, gregkh@linuxfoundation.org, sboyd@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com Cc: pdeschrijver@nvidia.com, pgaikwad@nvidia.com, spujar@nvidia.com, josephl@nvidia.com, daniel.lezcano@linaro.org, mmaddireddy@nvidia.com, markz@nvidia.com, devicetree@vger.kernel.org, linux-clk@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-tegra@vger.kernel.org 18.12.2019 18:43, Sowjanya Komatineni пишет: > > On 12/17/19 11:31 PM, Dmitry Osipenko wrote: >> 18.12.2019 10:22, Dmitry Osipenko пишет: >>> 18.12.2019 10:14, Sowjanya Komatineni пишет: >>>> On 12/17/19 11:01 PM, Dmitry Osipenko wrote: >>>>> 18.12.2019 09:59, Dmitry Osipenko пишет: >>>>>> 17.12.2019 23:04, Sowjanya Komatineni пишет: >>>>>>> mclk is from clk_out_1 which is part of Tegra PMC block and pmc >>>>>>> clocks >>>>>>> are moved to Tegra PMC driver with pmc as clock provider and >>>>>>> using pmc >>>>>>> clock ids. >>>>>>> >>>>>>> New device tree uses clk_out_1 from pmc clock provider. >>>>>>> >>>>>>> So, this patch adds implementation for mclk fallback to extern1 when >>>>>>> retrieving mclk returns -ENOENT to be backward compatible of new >>>>>>> device >>>>>>> tree with older kernels. >>>>>>> >>>>>>> Signed-off-by: Sowjanya Komatineni >>>>>>> --- >>>>>>>    sound/soc/tegra/tegra_asoc_utils.c | 11 ++++++++++- >>>>>>>    1 file changed, 10 insertions(+), 1 deletion(-) >>>>>>> >>>>>>> diff --git a/sound/soc/tegra/tegra_asoc_utils.c >>>>>>> b/sound/soc/tegra/tegra_asoc_utils.c >>>>>>> index fe9ca8acd0fb..1b88c6043082 100644 >>>>>>> --- a/sound/soc/tegra/tegra_asoc_utils.c >>>>>>> +++ b/sound/soc/tegra/tegra_asoc_utils.c >>>>>>> @@ -191,7 +191,16 @@ int tegra_asoc_utils_init(struct >>>>>>> tegra_asoc_utils_data *data, >>>>>>>        data->clk_cdev1 = devm_clk_get(dev, "mclk"); >>>>>>>        if (IS_ERR(data->clk_cdev1)) { >>>>>>>            dev_err(data->dev, "Can't retrieve clk cdev1\n"); >>>>>>> -        return PTR_ERR(data->clk_cdev1); >>>>>>> +        if (PTR_ERR(data->clk_cdev1) != -ENOENT) >>>>>>> +            return PTR_ERR(data->clk_cdev1); >>>>>>> +        /* Fall back to extern1 */ >>>>>>> +        data->clk_cdev1 = devm_clk_get(dev, "extern1"); >>>>>>> +        if (IS_ERR(data->clk_cdev1)) { >>>>>>> +            dev_err(data->dev, "Can't retrieve clk extern1\n"); >>>>>>> +            return PTR_ERR(data->clk_cdev1); >>>>>>> +        } >>>>>>> + >>>>>>> +        dev_err(data->dev, "Falling back to extern1\n"); >>>>>>>        } >>>>>>>          /* >>>>>>> >>>>>> [    1.769091] ------------[ cut here ]------------ >>>>>> [    1.769249] WARNING: CPU: 2 PID: 1 at drivers/clk/clk.c:954 >>>>>> clk_core_disable+0xa5/0x1d4 >>>>>> [    1.769330] clk_out_1 already disabled >>>>>> [    1.769459] Modules linked in: >>>>>> [    1.769541] CPU: 2 PID: 1 Comm: swapper/0 Not tainted >>>>>> 5.5.0-rc1-next-20191213-00167-g6b9fbcdac8f3-dirty #266 >>>>>> [    1.769676] Hardware name: NVIDIA Tegra SoC (Flattened Device >>>>>> Tree) >>>>>> [    1.769775] [] (unwind_backtrace) from [] >>>>>> (show_stack+0x11/0x14) >>>>>> [    1.769918] [] (show_stack) from [] >>>>>> (dump_stack+0x85/0x94) >>>>>> [    1.770061] [] (dump_stack) from [] >>>>>> (__warn+0xc1/0xc4) >>>>>> [    1.770144] [] (__warn) from [] >>>>>> (warn_slowpath_fmt+0x61/0x78) >>>>>> [    1.770285] [] (warn_slowpath_fmt) from [] >>>>>> (clk_core_disable+0xa5/0x1d4) >>>>>> [    1.770427] [] (clk_core_disable) from [] >>>>>> (clk_core_disable_lock+0x17/0x20) >>>>>> [    1.770516] [] (clk_core_disable_lock) from [] >>>>>> (tegra_asoc_utils_set_rate+0x53/0x208) >>>>>> [    1.770662] [] (tegra_asoc_utils_set_rate) from >>>>>> [] (tegra_rt5640_probe+0xd5/0x128) >>>>>> [    1.770808] [] (tegra_rt5640_probe) from [] >>>>>> (platform_drv_probe+0x33/0x68) >>>>>> [    1.770958] [] (platform_drv_probe) from [] >>>>>> (really_probe+0x14d/0x240) >>>>>> [    1.771099] [] (really_probe) from [] >>>>>> (driver_probe_device+0x43/0x11c) >>>>>> [    1.771187] [] (driver_probe_device) from [] >>>>>> (device_driver_attach+0x3d/0x40) >>>>>> [    1.771328] [] (device_driver_attach) from [] >>>>>> (__driver_attach+0x37/0x78) >>>>>> [    1.771469] [] (__driver_attach) from [] >>>>>> (bus_for_each_dev+0x43/0x6c) >>>>>> [    1.771609] [] (bus_for_each_dev) from [] >>>>>> (bus_add_driver+0xe3/0x148) >>>>>> [    1.771692] [] (bus_add_driver) from [] >>>>>> (driver_register+0x39/0xa0) >>>>>> [    1.771833] [] (driver_register) from [] >>>>>> (do_one_initcall+0x43/0x1bc) >>>>>> [    1.771979] [] (do_one_initcall) from [] >>>>>> (kernel_init_freeable+0x121/0x194) >>>>>> [    1.772129] [] (kernel_init_freeable) from [] >>>>>> (kernel_init+0xd/0xd0) >>>>>> [    1.772215] [] (kernel_init) from [] >>>>>> (ret_from_fork+0x11/0x34) >>>>>> [    1.772349] Exception stack(0xde907fb0 to 0xde907ff8) >>>>>> >>>>> Although, that's probably related to the "ASoC: tegra: Add initial >>>>> parent configuration for audio mclk". >>>>> >>>> Actually I see these warnings of already unprepared and already >>>> disabled >>>> for pll_a, pll_a_out0, and clk_out_1 even without this whole patch >>>> series as well. >>>> >>>> I think its from tegra_asoc_utils_set_rate() doing >>>> clk_disable_unprepare >>>> and these clocks are already unprepared and disabled so its just >>>> warning >>>> from clk_core_unprepare and clk_core_disable. >>> Doesn't happen for me without this series. > > I looked at wrong log, right earlier clock driver keeps them enabled so > asoc_utils_set_rate() disables the clock fine but now enabling audio > clock should be done in asoc_utils_init() to let the > clk_disable_unprepare from asoc_utils_set_rate not to show this warning. > > But actually we don't need to have clock enabled in asoc_utils_init > prior to invoking asoc_utils_set_rate from utils_init and its just warns > during sound driver probe because clock is already in disabled state. At > same time it doesn't harm to have it kept enabled in utils_init. So will > keep it enabled in asoc_utils_init to prevent this warning to show up. > >> But sound works with both old/new device-trees. The rule of thumb: don't enable anything when it shouldn't be enabled. If clocks are disabled at the time of drivers probe, then drivers shouldn't disable the clocks.