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

Dmitry Osipenko
2019-12-22T21:18:59Z

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.
>
>> #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.
>
>> + 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.
>