Re: [PATCH v2] mfd: twl6040: Handle mclk used for HPPLL and optional internal clock source

[Lee Jones]

On Mon, 20 Jun 2016, Peter Ujfalusi wrote:

> On some boards, like omap5-uevm the MCLK is gated by default and in order
> to be able to use the High performance modes of twl6040 it need to be
> enabled by SW.
> Add support for handling the MCLK source clock via CCF.
> At the same time lower the print priority of the notification that the 32K
> clock is not provided and it is not going to be handled by the driver.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> ---
> Hi,
> 
> Changes since v1:
> - Keep the clk32k name and use mclk for the new clock
> - rename the old mclk variable to mclk_rate and use it only to track the MCLK
>   frequency
> - rename the sysclk to sysclk_rate also to be more explicit on the meaning of
>   this variabe.
> 
> Regards,
> Peter
> 
>  Documentation/devicetree/bindings/mfd/twl6040.txt |  4 +--
>  drivers/mfd/twl6040.c                             | 41 ++++++++++++++++-------
>  include/linux/mfd/twl6040.h                       |  5 +--
>  3 files changed, 34 insertions(+), 16 deletions(-)

Applied, thanks.

> diff --git a/Documentation/devicetree/bindings/mfd/twl6040.txt b/Documentation/devicetree/bindings/mfd/twl6040.txt
> index a41157b5d930..e6afdfa3543d 100644
> --- a/Documentation/devicetree/bindings/mfd/twl6040.txt
> +++ b/Documentation/devicetree/bindings/mfd/twl6040.txt
> @@ -19,8 +19,8 @@ Required properties:
>  
>  Optional properties, nodes:
>  - enable-active-high: To power on the twl6040 during boot.
> -- clocks: phandle to the clk32k clock provider
> -- clock-names: Must be "clk32k"
> +- clocks: phandle to the clk32k and/or to mclk clock provider
> +- clock-names: Must be "clk32k" for the 32K clock and "mclk" for the MCLK.
>  
>  Vibra functionality
>  Required properties:
> diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
> index 852d5874aabb..ab328ec49353 100644
> --- a/drivers/mfd/twl6040.c
> +++ b/drivers/mfd/twl6040.c
> @@ -323,8 +323,7 @@ int twl6040_power(struct twl6040 *twl6040, int on)
>  
>  		/* Default PLL configuration after power up */
>  		twl6040->pll = TWL6040_SYSCLK_SEL_LPPLL;
> -		twl6040->sysclk = 19200000;
> -		twl6040->mclk = 32768;
> +		twl6040->sysclk_rate = 19200000;
>  	} else {
>  		/* already powered-down */
>  		if (!twl6040->power_count) {
> @@ -352,8 +351,12 @@ int twl6040_power(struct twl6040 *twl6040, int on)
>  		regcache_cache_only(twl6040->regmap, true);
>  		regcache_mark_dirty(twl6040->regmap);
>  
> -		twl6040->sysclk = 0;
> -		twl6040->mclk = 0;
> +		twl6040->sysclk_rate = 0;
> +
> +		if (twl6040->pll == TWL6040_SYSCLK_SEL_HPPLL) {
> +			clk_disable_unprepare(twl6040->mclk);
> +			twl6040->mclk_rate = 0;
> +		}
>  
>  		clk_disable_unprepare(twl6040->clk32k);
>  	}
> @@ -377,15 +380,15 @@ int twl6040_set_pll(struct twl6040 *twl6040, int pll_id,
>  
>  	/* Force full reconfiguration when switching between PLL */
>  	if (pll_id != twl6040->pll) {
> -		twl6040->sysclk = 0;
> -		twl6040->mclk = 0;
> +		twl6040->sysclk_rate = 0;
> +		twl6040->mclk_rate = 0;
>  	}
>  
>  	switch (pll_id) {
>  	case TWL6040_SYSCLK_SEL_LPPLL:
>  		/* low-power PLL divider */
>  		/* Change the sysclk configuration only if it has been canged */
> -		if (twl6040->sysclk != freq_out) {
> +		if (twl6040->sysclk_rate != freq_out) {
>  			switch (freq_out) {
>  			case 17640000:
>  				lppllctl |= TWL6040_LPLLFIN;
> @@ -427,6 +430,8 @@ int twl6040_set_pll(struct twl6040 *twl6040, int pll_id,
>  			ret = -EINVAL;
>  			goto pll_out;
>  		}
> +
> +		clk_disable_unprepare(twl6040->mclk);
>  		break;
>  	case TWL6040_SYSCLK_SEL_HPPLL:
>  		/* high-performance PLL can provide only 19.2 MHz */
> @@ -437,7 +442,7 @@ int twl6040_set_pll(struct twl6040 *twl6040, int pll_id,
>  			goto pll_out;
>  		}
>  
> -		if (twl6040->mclk != freq_in) {
> +		if (twl6040->mclk_rate != freq_in) {
>  			hppllctl &= ~TWL6040_MCLK_MSK;
>  
>  			switch (freq_in) {
> @@ -468,6 +473,9 @@ int twl6040_set_pll(struct twl6040 *twl6040, int pll_id,
>  				goto pll_out;
>  			}
>  
> +			/* When switching to HPPLL, enable the mclk first */
> +			if (pll_id != twl6040->pll)
> +				clk_prepare_enable(twl6040->mclk);
>  			/*
>  			 * enable clock slicer to ensure input waveform is
>  			 * square
> @@ -483,6 +491,8 @@ int twl6040_set_pll(struct twl6040 *twl6040, int pll_id,
>  			lppllctl &= ~TWL6040_LPLLENA;
>  			twl6040_reg_write(twl6040, TWL6040_REG_LPPLLCTL,
>  					  lppllctl);
> +
> +			twl6040->mclk_rate = freq_in;
>  		}
>  		break;
>  	default:
> @@ -491,8 +501,7 @@ int twl6040_set_pll(struct twl6040 *twl6040, int pll_id,
>  		goto pll_out;
>  	}
>  
> -	twl6040->sysclk = freq_out;
> -	twl6040->mclk = freq_in;
> +	twl6040->sysclk_rate = freq_out;
>  	twl6040->pll = pll_id;
>  
>  pll_out:
> @@ -512,7 +521,7 @@ EXPORT_SYMBOL(twl6040_get_pll);
>  
>  unsigned int twl6040_get_sysclk(struct twl6040 *twl6040)
>  {
> -	return twl6040->sysclk;
> +	return twl6040->sysclk_rate;
>  }
>  EXPORT_SYMBOL(twl6040_get_sysclk);
>  
> @@ -655,10 +664,18 @@ static int twl6040_probe(struct i2c_client *client,
>  	if (IS_ERR(twl6040->clk32k)) {
>  		if (PTR_ERR(twl6040->clk32k) == -EPROBE_DEFER)
>  			return -EPROBE_DEFER;
> -		dev_info(&client->dev, "clk32k is not handled\n");
> +		dev_dbg(&client->dev, "clk32k is not handled\n");
>  		twl6040->clk32k = NULL;
>  	}
>  
> +	twl6040->mclk = devm_clk_get(&client->dev, "mclk");
> +	if (IS_ERR(twl6040->mclk)) {
> +		if (PTR_ERR(twl6040->mclk) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +		dev_dbg(&client->dev, "mclk is not handled\n");
> +		twl6040->mclk = NULL;
> +	}
> +
>  	twl6040->supplies[0].supply = "vio";
>  	twl6040->supplies[1].supply = "v2v1";
>  	ret = devm_regulator_bulk_get(&client->dev, TWL6040_NUM_SUPPLIES,
> diff --git a/include/linux/mfd/twl6040.h b/include/linux/mfd/twl6040.h
> index 8e95cd87cd74..36795a1be479 100644
> --- a/include/linux/mfd/twl6040.h
> +++ b/include/linux/mfd/twl6040.h
> @@ -226,6 +226,7 @@ struct twl6040 {
>  	struct regmap_irq_chip_data *irq_data;
>  	struct regulator_bulk_data supplies[2]; /* supplies for vio, v2v1 */
>  	struct clk *clk32k;
> +	struct clk *mclk;
>  	struct mutex mutex;
>  	struct mutex irq_mutex;
>  	struct mfd_cell cells[TWL6040_CELLS];
> @@ -237,8 +238,8 @@ struct twl6040 {
>  
>  	/* PLL configuration */
>  	int pll;
> -	unsigned int sysclk;
> -	unsigned int mclk;
> +	unsigned int sysclk_rate;
> +	unsigned int mclk_rate;
>  
>  	unsigned int irq;
>  	unsigned int irq_ready;

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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