Re: [PATCH v5 12/19] ASoC: tegra: Add initial parent configuration for audio mclk

Sowjanya Komatineni
2019-12-27T21:25:30Z

On 12/22/19 1:18 PM, Dmitry Osipenko wrote:
> 23.12.2019 00:14, Dmitry Osipenko пишет:
>> 21.12.2019 01:26, Sowjanya Komatineni пишет:
>>> Tegra PMC clock clk_out_1 is dedicated for audio mclk from Tegra30
>>> through Tegra210 and currently Tegra clock driver does initial parent
>>> configuration for audio mclk "clk_out_1" and enables them by default.
>>>
>>> With the move of Tera PMC clocks from clock driver to Tegra PMC
>>> driver, initial parent configuration for audio clocks are through
>>> the device tree using assigned-clock-parents property.
>>>
>>> Default clock parents can be specified in device tree using
>>> assigned-clocks and assigned-clock-parents and there is no need
>>> to have clock driver do parent configuration and enable audio related
>>> clocks.
>>>
>>> This patch has implementation for initial parent configuration in
>>> audio driver when default parent configuration is not specified in the
>>> device tree using assigned-clock properties and enables audio clocks
>>> during the clock rate change.
>>>
>>> This patch configures PLLA_OUT0 as parent to extern1 and extern1
>>> as parent to clk_out_1 and uses clk_out_1 as cdev1 clock to allow
>>> mclk control from this driver.
>>>
>>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
>>> ---
>>> sound/soc/tegra/tegra_asoc_utils.c | 71 ++++++++++++++++++++++----------------
>>> 1 file changed, 41 insertions(+), 30 deletions(-)
>>>
>>> diff --git a/sound/soc/tegra/tegra_asoc_utils.c b/sound/soc/tegra/tegra_asoc_utils.c
>>> index 38535962029c..fc3135c08f43 100644
>>> --- a/sound/soc/tegra/tegra_asoc_utils.c
>>> +++ b/sound/soc/tegra/tegra_asoc_utils.c
>>> @@ -7,6 +7,7 @@
>>> */
>>>
>>> #include <linux/clk.h>
>>> +#include <linux/clk-provider.h>
>> This is illegal, it is not a clock provider.
>>
__clk_is_enabled API is used in this patch to disable clock only when
its enabled.

__clk_is_enabled API is from clk-provider.h

>>> #include <linux/device.h>
>>> #include <linux/err.h>
>>> #include <linux/kernel.h>
>>> @@ -59,9 +60,8 @@ int tegra_asoc_utils_set_rate(struct tegra_asoc_utils_data *data, int srate,
>>> data->set_baseclock = 0;
>>> data->set_mclk = 0;
>>>
>>> - clk_disable_unprepare(data->clk_cdev1);
>>> - clk_disable_unprepare(data->clk_pll_a_out0);
>>> - clk_disable_unprepare(data->clk_pll_a);
>>> + if (__clk_is_enabled(data->clk_cdev1))
>>> + clk_disable_unprepare(data->clk_cdev1);
>> The root of the problem is that you removed clocks enabling from
>> tegra_asoc_utils_init().
>>
>> I'm not sure why clocks should be disabled during the rate-changing,
>> probably this action is not really needed.
>>
>> diff --git a/sound/soc/tegra/tegra_asoc_utils.c
>> b/sound/soc/tegra/tegra_asoc_utils.c
>> index 46ff70c16b74..789fd03e51a7 100644
>> --- a/sound/soc/tegra/tegra_asoc_utils.c
>> +++ b/sound/soc/tegra/tegra_asoc_utils.c
>> @@ -7,7 +7,6 @@
>> */
>>
>> #include <linux/clk.h>
>> -#include <linux/clk-provider.h>
>> #include <linux/device.h>
>> #include <linux/err.h>
>> #include <linux/kernel.h>
>> @@ -60,9 +59,6 @@ int tegra_asoc_utils_set_rate(struct
>> tegra_asoc_utils_data *data, int srate,
>> data->set_baseclock = 0;
>> data->set_mclk = 0;
>>
>> - if (__clk_is_enabled(data->clk_cdev1))
>> - clk_disable_unprepare(data->clk_cdev1);
>> -
>> err = clk_set_rate(data->clk_pll_a, new_baseclock);
>> if (err) {
>> dev_err(data->dev, "Can't set pll_a rate: %d\n", err);
>> @@ -77,12 +73,6 @@ int tegra_asoc_utils_set_rate(struct
>> tegra_asoc_utils_data *data, int srate,
>>
>> /* Don't set cdev1/extern1 rate; it's locked to pll_a_out0 */
>>
>> - err = clk_prepare_enable(data->clk_cdev1);
>> - if (err) {
>> - dev_err(data->dev, "Can't enable cdev1: %d\n", err);
>> - return err;
>> - }
>> -
>> data->set_baseclock = new_baseclock;
>> data->set_mclk = mclk;
>>
>> @@ -96,9 +86,6 @@ int tegra_asoc_utils_set_ac97_rate(struct
>> tegra_asoc_utils_data *data)
>> const int ac97_rate = 24576000;
>> int err;
>>
>> - if (__clk_is_enabled(data->clk_cdev1))
>> - clk_disable_unprepare(data->clk_cdev1);
>> -
>> /*
>> * AC97 rate is fixed at 24.576MHz and is used for both the host
>> * controller and the external codec
>> @@ -117,12 +104,6 @@ int tegra_asoc_utils_set_ac97_rate(struct
>> tegra_asoc_utils_data *data)
>>
>> /* Don't set cdev1/extern1 rate; it's locked to pll_a_out0 */
>>
>> - err = clk_prepare_enable(data->clk_cdev1);
>> - if (err) {
>> - dev_err(data->dev, "Can't enable cdev1: %d\n", err);
>> - return err;
>> - }
>> -
>> data->set_baseclock = pll_rate;
>> data->set_mclk = ac97_rate;
>>
>> @@ -213,6 +194,12 @@ int tegra_asoc_utils_init(struct
>> tegra_asoc_utils_data *data,
>> data->clk_cdev1 = clk_out_1;
>> }
>>
>> + ret = clk_prepare_enable(data->clk_cdev1);
>> + if (ret) {
>> + dev_err(data->dev, "Can't enable cdev1: %d\n", ret);
>> + return ret;
>> + }
>> +
>> ret = tegra_asoc_utils_set_rate(data, 44100, 256 * 44100);
>>
>> return ret;
>>
>>
>>> err = clk_set_rate(data->clk_pll_a, new_baseclock);
>>> if (err) {
>>> @@ -77,18 +77,6 @@ int tegra_asoc_utils_set_rate(struct tegra_asoc_utils_data *data, int srate,
>>>
>>> /* Don't set cdev1/extern1 rate; it's locked to pll_a_out0 */
>>>
>>> - err = clk_prepare_enable(data->clk_pll_a);
>>> - if (err) {
>>> - dev_err(data->dev, "Can't enable pll_a: %d\n", err);
>>> - return err;
>>> - }
>>> -
>>> - err = clk_prepare_enable(data->clk_pll_a_out0);
>>> - if (err) {
>>> - dev_err(data->dev, "Can't enable pll_a_out0: %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);
>>> @@ -108,9 +96,8 @@ int tegra_asoc_utils_set_ac97_rate(struct tegra_asoc_utils_data *data)
>>> const int ac97_rate = 24576000;
>>> int err;
>>>
>>> - clk_disable_unprepare(data->clk_cdev1);
>>> - clk_disable_unprepare(data->clk_pll_a_out0);
>>> - clk_disable_unprepare(data->clk_pll_a);
>>> + if (__clk_is_enabled(data->clk_cdev1))
>>> + clk_disable_unprepare(data->clk_cdev1);
>>>
>>> /*
>>> * AC97 rate is fixed at 24.576MHz and is used for both the host
>>> @@ -130,18 +117,6 @@ int tegra_asoc_utils_set_ac97_rate(struct tegra_asoc_utils_data *data)
>>>
>>> /* Don't set cdev1/extern1 rate; it's locked to pll_a_out0 */
>>>
>>> - err = clk_prepare_enable(data->clk_pll_a);
>>> - if (err) {
>>> - dev_err(data->dev, "Can't enable pll_a: %d\n", err);
>>> - return err;
>>> - }
>>> -
>>> - err = clk_prepare_enable(data->clk_pll_a_out0);
>>> - if (err) {
>>> - dev_err(data->dev, "Can't enable pll_a_out0: %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);
>>> @@ -158,6 +133,7 @@ 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, *clk_extern1;
>>> int ret;
>>>
>>> data->dev = dev;
>>> @@ -193,6 +169,41 @@ int tegra_asoc_utils_init(struct tegra_asoc_utils_data *data,
>>> return PTR_ERR(data->clk_cdev1);
>>> }
>>>
>>> + /*
>>> + * 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) {
>> Please add a message here about falling back to configuring clocks for a
>> legacy device-tree, telling that device-tree needs to be updated.
>>
Will add in v6
>>> + clk_extern1 = devm_clk_get(dev, "extern1");
>>> + if (IS_ERR(clk_extern1)) {
>>> + dev_err(data->dev, "Can't retrieve clk extern1\n");
>>> + return PTR_ERR(clk_extern1);
>>> + }
>>> +
>>> + ret = clk_set_parent(clk_extern1, data->clk_pll_a_out0);
>>> + if (ret < 0) {
>>> + dev_err(data->dev,
>>> + "Set parent failed for clk extern1\n");
>>> + return ret;
>>> + }
>>> +
>>> + clk_out_1 = devm_clk_get(dev, "clk_out_1");
>>> + if (IS_ERR(clk_out_1)) {
>>> + dev_err(data->dev, "Can't retrieve clk clk_out_1\n");
>>> + return PTR_ERR(clk_out_1);
>>> + }
>>> +
>>> + ret = clk_set_parent(clk_out_1, clk_extern1);
>>> + if (ret < 0) {
>>> + dev_err(data->dev,
>>> + "Set parent failed for clk_out_1\n");
>>> + return ret;
>>> + }
>>> +
>>> + data->clk_cdev1 = clk_out_1;
>>> + }
>>> +
>>> ret = tegra_asoc_utils_set_rate(data, 44100, 256 * 44100);
> Actually, this tegra_asoc_utils_set_rate() should be removed because it
> doesn't do anything useful since drivers configure the clock rate when
> necessary.
>
>>> return ret;
>>>
>> I'd also add tegra_asoc_utils_deinit() to disable clock on drivers removal.
Will add this in v6