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

Dmitry Osipenko
2019-12-22T21:14:40Z

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);
>
> return ret;
>

I'd also add tegra_asoc_utils_deinit() to disable clock on drivers removal.