Messages in this thread |  | | Subject | Re: [PATCH v3 08/15] ASoC: tegra: Add audio mclk control through clk_out_1 and extern1 | From | Sowjanya Komatineni <> | Date | Tue, 17 Dec 2019 08:12:24 -0800 |
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On 12/17/19 7:36 AM, Dmitry Osipenko wrote: > 17.12.2019 04:29, Sowjanya Komatineni пишет: >> On 12/7/19 11:20 AM, Sowjanya Komatineni wrote: >>> On 12/7/19 6:58 AM, Dmitry Osipenko wrote: >>>> 06.12.2019 05:48, Sowjanya Komatineni пишет: >>>>> Current ASoC driver uses extern1 as cdev1 clock from Tegra30 onwards >>>>> through device tree. >>>>> >>>>> Actual audio mclk is clk_out_1 and to use PLLA for mclk rate control, >>>>> need to clk_out_1_mux parent to extern1 and extern1 parent to >>>>> PLLA_OUT0. >>>>> >>>>> Currently Tegra clock driver init sets the parents and enables both >>>>> clk_out_1 and extern1 clocks. But these clocks parent and enables >>>>> should >>>>> be controlled by ASoC driver. >>>>> >>>>> Clock parents can be specified in device tree using assigned-clocks >>>>> and assigned-clock-parents. >>>>> >>>>> To enable audio mclk, both clk_out_1 and extern1 clocks need to be >>>>> enabled. >>>>> >>>>> This patch configures parents for clk_out_1 and extern1 clocks if >>>>> device >>>>> tree does not specify clock parents inorder to support old device tree >>>>> and controls mclk using both clk_out_1 and extern1 clocks. >>>>> >>>>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com> >>>>> --- >>>>> sound/soc/tegra/tegra_asoc_utils.c | 66 >>>>> ++++++++++++++++++++++++++++++++++++++ >>>>> sound/soc/tegra/tegra_asoc_utils.h | 1 + >>>>> 2 files changed, 67 insertions(+) >>>>> >>>>> diff --git a/sound/soc/tegra/tegra_asoc_utils.c >>>>> b/sound/soc/tegra/tegra_asoc_utils.c >>>>> index 536a578e9512..8e3a3740df7c 100644 >>>>> --- a/sound/soc/tegra/tegra_asoc_utils.c >>>>> +++ b/sound/soc/tegra/tegra_asoc_utils.c >>>>> @@ -60,6 +60,7 @@ int tegra_asoc_utils_set_rate(struct >>>>> tegra_asoc_utils_data *data, int srate, >>>>> data->set_mclk = 0; >>>>> clk_disable_unprepare(data->clk_cdev1); >>>>> + clk_disable_unprepare(data->clk_extern1); >>>>> clk_disable_unprepare(data->clk_pll_a_out0); >>>>> clk_disable_unprepare(data->clk_pll_a); >>>>> @@ -89,6 +90,14 @@ int tegra_asoc_utils_set_rate(struct >>>>> tegra_asoc_utils_data *data, int srate, >>>>> return err; >>>>> } >>>>> + if (!IS_ERR_OR_NULL(data->clk_extern1)) { >>>>> + err = clk_prepare_enable(data->clk_extern1); >>>>> + if (err) { >>>>> + dev_err(data->dev, "Can't enable extern1: %d\n", err); >>>>> + return err; >>>>> + } >>>>> + } >>>>> + >>>>> err = clk_prepare_enable(data->clk_cdev1); >>>>> if (err) { >>>>> dev_err(data->dev, "Can't enable cdev1: %d\n", err); >>>>> @@ -109,6 +118,7 @@ int tegra_asoc_utils_set_ac97_rate(struct >>>>> tegra_asoc_utils_data *data) >>>>> int err; >>>>> clk_disable_unprepare(data->clk_cdev1); >>>>> + clk_disable_unprepare(data->clk_extern1); >>>>> clk_disable_unprepare(data->clk_pll_a_out0); >>>>> clk_disable_unprepare(data->clk_pll_a); >>>>> @@ -142,6 +152,14 @@ int tegra_asoc_utils_set_ac97_rate(struct >>>>> tegra_asoc_utils_data *data) >>>>> return err; >>>>> } >>>>> + if (!IS_ERR_OR_NULL(data->clk_extern1)) { >>>>> + err = clk_prepare_enable(data->clk_extern1); >>>>> + if (err) { >>>>> + dev_err(data->dev, "Can't enable extern1: %d\n", err); >>>>> + return err; >>>>> + } >>>>> + } >>>> Why this is needed given that clk_extern1 is either a child of MCLK or >>>> MCLK itself (on T20)? The child clocks are enabled when the parent is >>>> enabled. >>> For T30 and later, clk_extern1 is one of the source for clk_out_1_mux. >>> clk_extern1 is in CAR and it has its own gate and mux. >>> >>> As audio mclk related clocks (clk_out_1, clk_out_1_mux, and extern1) >>> are moved into ASoC driver from clock driver >>> >>> need to enable extern1 gate as well along with clk_out1 for T30 >>> through T210. >>> >>> Just FYI, extern1 enable here happens only when data->clk_extern1 is >>> available which is for T30 onwards. >>> >>>>> err = clk_prepare_enable(data->clk_cdev1); >>>>> if (err) { >>>>> dev_err(data->dev, "Can't enable cdev1: %d\n", err); >>>>> @@ -158,6 +176,7 @@ EXPORT_SYMBOL_GPL(tegra_asoc_utils_set_ac97_rate); >>>>> int tegra_asoc_utils_init(struct tegra_asoc_utils_data *data, >>>>> struct device *dev) >>>>> { >>>>> + struct clk *clk_out_1_mux; >>>>> int ret; >>>>> data->dev = dev; >>>>> @@ -196,6 +215,51 @@ int tegra_asoc_utils_init(struct >>>>> tegra_asoc_utils_data *data, >>>>> goto err_put_pll_a_out0; >>>>> } >>>> In a previous patch you added fallback to EXTPERIPH when clk_get(MCLK) >>>> fails. This will work perfectly fine for the older kernels which have >>>> all clocks in the same single CaR driver, but this may not work that >>>> great for the newer kernels because PMC driver isn't registered early >>>> during boot and thus it is possible to get a legit -EPROBE_DEFER which >>>> shouldn't be ignored. In other words, you need to add into this patch a >>>> check for the error code returned by clk_get(MCLK) and fallback only for >>>> -EINVAL. >>> yeah right, will add check in next version. >>>>> + /* >>>>> + * If clock parents are not set in DT, configure here to use >>>>> clk_out_1 >>>>> + * as mclk and extern1 as parent for Tegra30 and higher. >>>>> + */ >>>>> + if (!of_find_property(dev->of_node, "assigned-clock-parents", >>>>> NULL) && >>>>> + data->soc > TEGRA_ASOC_UTILS_SOC_TEGRA20) { >>>>> + data->clk_extern1 = clk_get_sys("clk_out_1", "extern1"); >>>>> + if (IS_ERR(data->clk_extern1)) { >>>>> + dev_err(data->dev, "Can't retrieve clk extern1\n"); >>>>> + ret = PTR_ERR(data->clk_extern1); >>>>> + goto err_put_cdev1; >>>>> + } >>>>> + >>>>> + ret = clk_set_parent(data->clk_extern1, data->clk_pll_a_out0); >>>>> + if (ret < 0) { >>>>> + dev_err(data->dev, >>>>> + "Set parent failed for clk extern1: %d\n", >>>>> + ret); >>>>> + goto err_put_cdev1; >>>>> + } >>>>> + >>>>> + clk_out_1_mux = clk_get_sys(NULL, "clk_out_1_mux"); >>>> Note1: clk_get(dev, "clk_out_1_mux") should work here by letting clk >>>> core to fall back to the clk_get_sys() by itself. Either way should >>>> be good. >> clk_get uses device rather and dev_id will be name of this device and >> when clk_get fall back to __clk_get_sys() it still will use dev id of >> this device rather than actual dev_id that pmc clocks are added to the >> lookup. So clk_get_sys() seems to be correct to use as we can specify >> exact dev_id and con_id. > It should be better to use something "resource managed", thus > devm_clk_get() should be a better choice. > >> Also, clk_find retrieves clock from lookup only when it finds matching >> clock with both dev_id and con_id as pmc clocks are registered with both >> dev_id and con_id. >> >> I see existing clock driver adds both extern and pmc clocks (clk_out) to >> lookup with same dev_id of clk_out_1/2/3 and con_id of extern1/2/3 and >> with this always extern clock will be retrieved and this is probably >> because old DT and audio driver always uses extern1 rather than actual >> clk_out_1 >> >> But this need to be fixed now as we changed to use clk_out directly >> rather than extern (even for other pmc clocks) to match actual hw design. >> >> Will fix this as well to register pmc clocks using con_id as >> clk_out_1/2/3 in pmc driver and extern clocks using con_id of >> extern1/2/3 with dev_id being NULL so we can retrieve these clocks by >> just using con_id only using clk_get_sys as we switched to use clk_out_1 >> directly as pmc clock rather than extern from DT and no longer need to >> pair pmc clocks to extern clocks. > I'm not sure it's worth the effort to care about con_ids if implicit > fallback to clk_get_sys(NULL, "...") does the right thing for the audio > driver. > > IIRC, CCF uses variant of matching clocks by names, although I'm not > sure whether that applies to older stable kernels. > > [snip]
Current clock driver adds EXTERN clock to lookup with dev_id as clk_out_1/2/3 and con_id as extern_1/2/3
With this we can retrieve clock from lookup only with clk_get_sys where we can pass dev_id as clk_out_1/2/3 and con_id as extern_1/2/3.
We cant use devm_clk_get() or clk_get() for retrieving clocks from lookup by passing device object from sound driver as dev_id will be diff and clk_find will return NULL.
But with the fix of having dev_id as NULL and use only con_id to add to lookup, we can use resource managed APIs devm_clk_get.
So was saying will fix this in clock driver as part of removing clk_out_1/2/3 ids and pmc init from clock driver so we can use devm_clk_get API in audio driver.
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