Re: [PATCH v2] ASoC: mxs-saif: add mclk enable/disable ops

["Jörg Krause" <joerg.krause@embedded.rocks>]

Hi Mans,

On Thu, 2016-12-22 at 16:49 +0000, Mans Rullgard wrote:
> This makes normal clk_enable/disable() calls on mxs_saif_mclk work as
> expected, i.e. actually turn the mclk output on or (when safe) off.
> The existing mxs_saif_get/put_mclk() functions are rewritten to use
> common clk operations on mxs_saif_mclk rather than accessing
> registers
> directly.
> 
> With these changes mxs-saif can be used together with the simple-card
> driver.

I can confirm that this works for me using the pcm5102a, wm8524 and the
wm8731 codec driver. But I was able only to test playback on saif0 for
those drivers as I failed to setup the simple-card device tree node
both for saif0 and saif1.

However, when using this patch with a platform driver, e.g. mxs-wm8524, 
instead of the simple-card device tree node configuration, it fails for
me. Note, that the platform driver mxs-wm8524 is just a mere copy of
the mxs-sgtl5000 driver. The error happens when probing the platform
driver at calling mxs_saif_get_mclk(): "failed to get mclk".

As I am testing on a custom board not mainlined yet it is possible that
I did something wrong. So maybe someone having access to a mxs-board
with a sgtl5000 codec can verify this?

Jörg

> 
> Signed-off-by: Mans Rullgard <mans@mansr.com>
> ---
> v2: add #include <linux/clk-provider.h> needed by some configs
> ---
>  sound/soc/mxs/mxs-saif.c | 144 +++++++++++++++++++++++++++++++----
> ------------
>  sound/soc/mxs/mxs-saif.h |   3 +
>  2 files changed, 99 insertions(+), 48 deletions(-)
> 
> diff --git a/sound/soc/mxs/mxs-saif.c b/sound/soc/mxs/mxs-saif.c
> index a002ab892772..7c620399f96b 100644
> --- a/sound/soc/mxs/mxs-saif.c
> +++ b/sound/soc/mxs/mxs-saif.c
> @@ -204,27 +204,15 @@ static int mxs_saif_set_clk(struct mxs_saif
> *saif,
>   */
>  int mxs_saif_put_mclk(unsigned int saif_id)
>  {
> -	struct mxs_saif *saif = mxs_saif[saif_id];
> -	u32 stat;
> +	struct clk *clk;
>  
> -	if (!saif)
> -		return -EINVAL;
> +	clk = clk_get(NULL, "mxs_saif_mclk");
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
>  
> -	stat = __raw_readl(saif->base + SAIF_STAT);
> -	if (stat & BM_SAIF_STAT_BUSY) {
> -		dev_err(saif->dev, "error: busy\n");
> -		return -EBUSY;
> -	}
> +	clk_disable_unprepare(clk);
> +	clk_put(clk);
>  
> -	clk_disable_unprepare(saif->clk);
> -
> -	/* disable MCLK output */
> -	__raw_writel(BM_SAIF_CTRL_CLKGATE,
> -		saif->base + SAIF_CTRL + MXS_SET_ADDR);
> -	__raw_writel(BM_SAIF_CTRL_RUN,
> -		saif->base + SAIF_CTRL + MXS_CLR_ADDR);
> -
> -	saif->mclk_in_use = 0;
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(mxs_saif_put_mclk);
> @@ -239,47 +227,33 @@ int mxs_saif_get_mclk(unsigned int saif_id,
> unsigned int mclk,
>  					unsigned int rate)
>  {
>  	struct mxs_saif *saif = mxs_saif[saif_id];
> -	u32 stat;
>  	int ret;
>  	struct mxs_saif *master_saif;
> +	struct clk *clk;
>  
>  	if (!saif)
>  		return -EINVAL;
>  
> -	/* Clear Reset */
> -	__raw_writel(BM_SAIF_CTRL_SFTRST,
> -		saif->base + SAIF_CTRL + MXS_CLR_ADDR);
> -
> -	/* FIXME: need clear clk gate for register r/w */
> -	__raw_writel(BM_SAIF_CTRL_CLKGATE,
> -		saif->base + SAIF_CTRL + MXS_CLR_ADDR);
> -
>  	master_saif = mxs_saif_get_master(saif);
>  	if (saif != master_saif) {
>  		dev_err(saif->dev, "can not get mclk from a non-
> master saif\n");
>  		return -EINVAL;
>  	}
>  
> -	stat = __raw_readl(saif->base + SAIF_STAT);
> -	if (stat & BM_SAIF_STAT_BUSY) {
> -		dev_err(saif->dev, "error: busy\n");
> -		return -EBUSY;
> -	}
> +	clk = clk_get(NULL, "mxs_saif_mclk");
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	ret = clk_prepare_enable(clk);
> +	if (ret)
> +		goto out;
>  
> -	saif->mclk_in_use = 1;
>  	ret = mxs_saif_set_clk(saif, mclk, rate);
> -	if (ret)
> -		return ret;
>  
> -	ret = clk_prepare_enable(saif->clk);
> -	if (ret)
> -		return ret;
> +out:
> +	clk_put(clk);
>  
> -	/* enable MCLK output */
> -	__raw_writel(BM_SAIF_CTRL_RUN,
> -		saif->base + SAIF_CTRL + MXS_SET_ADDR);
> -
> -	return 0;
> +	return ret;
>  }
>  EXPORT_SYMBOL_GPL(mxs_saif_get_mclk);
>  
> @@ -687,18 +661,92 @@ static irqreturn_t mxs_saif_irq(int irq, void
> *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +#define to_mxs_saif(c) container_of(c, struct mxs_saif, div_clk.hw)
> +
> +static int mxs_saif_mclk_enable(struct clk_hw *hw)
> +{
> +	struct mxs_saif *saif = to_mxs_saif(hw);
> +
> +	/* Clear Reset */
> +	__raw_writel(BM_SAIF_CTRL_SFTRST,
> +		saif->base + SAIF_CTRL + MXS_CLR_ADDR);
> +
> +	/* Clear clk gate */
> +	__raw_writel(BM_SAIF_CTRL_CLKGATE,
> +		saif->base + SAIF_CTRL + MXS_CLR_ADDR);
> +
> +	/* enable MCLK output */
> +	__raw_writel(BM_SAIF_CTRL_RUN,
> +		saif->base + SAIF_CTRL + MXS_SET_ADDR);
> +
> +	saif->mclk_in_use = 1;
> +
> +	return 0;
> +}
> +
> +static void mxs_saif_mclk_disable(struct clk_hw *hw)
> +{
> +	struct mxs_saif *saif = to_mxs_saif(hw);
> +
> +	if (!saif->ongoing)
> +		__raw_writel(BM_SAIF_CTRL_RUN,
> +			     saif->base + SAIF_CTRL + MXS_CLR_ADDR);
> +
> +	saif->mclk_in_use = 0;
> +}
> +
> +static unsigned long mxs_saif_mclk_recalc_rate(struct clk_hw *hw,
> +					       unsigned long
> parent_rate)
> +{
> +	return clk_divider_ops.recalc_rate(hw, parent_rate);
> +}
> +
> +static long mxs_saif_mclk_round_rate(struct clk_hw *hw, unsigned
> long rate,
> +				     unsigned long *parent_rate)
> +{
> +	return clk_divider_ops.round_rate(hw, rate, parent_rate);
> +}
> +
> +static int mxs_saif_mclk_set_rate(struct clk_hw *hw, unsigned long
> rate,
> +				  unsigned long parent_rate)
> +{
> +	return clk_divider_ops.set_rate(hw, rate, parent_rate);
> +}
> +
> +static const struct clk_ops mxs_saif_mclk_ops = {
> +	.enable		= mxs_saif_mclk_enable,
> +	.disable	= mxs_saif_mclk_disable,
> +	.recalc_rate	= mxs_saif_mclk_recalc_rate,
> +	.round_rate	= mxs_saif_mclk_round_rate,
> +	.set_rate	= mxs_saif_mclk_set_rate,
> +};
> +
>  static int mxs_saif_mclk_init(struct platform_device *pdev)
>  {
>  	struct mxs_saif *saif = platform_get_drvdata(pdev);
>  	struct device_node *np = pdev->dev.of_node;
> +	struct clk_init_data init;
> +	struct clk_divider *div;
>  	struct clk *clk;
> +	const char *parent_name;
>  	int ret;
>  
> -	clk = clk_register_divider(&pdev->dev, "mxs_saif_mclk",
> -				   __clk_get_name(saif->clk), 0,
> -				   saif->base + SAIF_CTRL,
> -				   BP_SAIF_CTRL_BITCLK_MULT_RATE, 3,
> -				   0, NULL);
> +	parent_name = __clk_get_name(saif->clk);
> +
> +	init.name = "mxs_saif_mclk";
> +	init.ops = &mxs_saif_mclk_ops;
> +	init.flags = CLK_GET_RATE_NOCACHE | CLK_IS_BASIC;
> +	init.parent_names = &parent_name;
> +	init.num_parents = 1;
> +
> +	div = &saif->div_clk;
> +	div->reg = saif->base + SAIF_CTRL;
> +	div->shift = BP_SAIF_CTRL_BITCLK_MULT_RATE;
> +	div->width = 3;
> +	div->flags = CLK_DIVIDER_POWER_OF_TWO;
> +	div->hw.init = &init;
> +
> +	clk = clk_register(&pdev->dev, &div->hw);
>  	if (IS_ERR(clk)) {
>  		ret = PTR_ERR(clk);
>  		if (ret == -EEXIST)
> diff --git a/sound/soc/mxs/mxs-saif.h b/sound/soc/mxs/mxs-saif.h
> index 9a4c0b291b9e..e1bb5cb00ec0 100644
> --- a/sound/soc/mxs/mxs-saif.h
> +++ b/sound/soc/mxs/mxs-saif.h
> @@ -108,6 +108,7 @@
>  
>  #define MXS_SAIF_MCLK		0
>  
> +#include <linux/clk-provider.h>
>  #include "mxs-pcm.h"
>  
>  struct mxs_saif {
> @@ -128,6 +129,8 @@ struct mxs_saif {
>  		MXS_SAIF_STATE_STOPPED,
>  		MXS_SAIF_STATE_RUNNING,
>  	} state;
> +
> +	struct clk_divider div_clk;
>  };
>  
>  extern int mxs_saif_put_mclk(unsigned int saif_id);
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