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[PATCH v2 10/10] clk: qcom: Fix .set_rate to handle alpha PLLs w/wo dynamic update

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  [PATCH v2 10/10] clk: qcom: Fix .set_rate to handle alpha PLLs w/wo dynamic update Rajendra Nayak <rnayak@codeaurora.org> - 2016-08-11 10:50 +0200
    Re: [PATCH v2 10/10] clk: qcom: Fix .set_rate to handle alpha PLLs  w/wo dynamic update Stephen Boyd <sboyd@codeaurora.org> - 2016-08-24 08:30 +0200
      Re: [PATCH v2 10/10] clk: qcom: Fix .set_rate to handle alpha PLLs  w/wo dynamic update Rajendra Nayak <rnayak@codeaurora.org> - 2016-08-25 11:20 +0200

#1460268 — [PATCH v2 10/10] clk: qcom: Fix .set_rate to handle alpha PLLs w/wo dynamic update

From: Taniya Das <tdas@codeaurora.org>

Alpha PLLs which do not support dynamic update feature
need to be explicitly disabled before a rate change. The ones which do
support dynamic update don't have to be disabled but need to follow a update
sequence (as implemented by clk_alpha_pll_dynamic_update() in the patch).
They also need the PLL_HW_LOGIC_BYPASS bit set at init.

Signed-off-by: Taniya Das <tdas@codeaurora.org>
Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
---
 drivers/clk/qcom/clk-alpha-pll.c | 48 ++++++++++++++++++++++++++++++++++++++++
 drivers/clk/qcom/clk-alpha-pll.h |  1 +
 2 files changed, 49 insertions(+)

diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
index 2184dc1..68c90f3 100644
--- a/drivers/clk/qcom/clk-alpha-pll.c
+++ b/drivers/clk/qcom/clk-alpha-pll.c
@@ -113,6 +113,11 @@ static int wait_for_pll_offline(struct clk_alpha_pll *pll, u32 mask)
 #define PLL_OFFLINE_ACK		BIT(28)
 #define PLL_ACTIVE_FLAG		BIT(30)
 
+/* alpha pll with dynamic update support */
+#define PLL_UPDATE		BIT(22)
+#define PLL_HW_LOGIC_BYPASS	BIT(23)
+#define PLL_ACK_LATCH		BIT(29)
+
 void clk_alpha_pll_configure(struct clk_alpha_pll *pll, struct regmap *regmap,
 			     const struct alpha_pll_config *config)
 {
@@ -138,6 +143,37 @@ void clk_alpha_pll_configure(struct clk_alpha_pll *pll, struct regmap *regmap,
 	if (pll->flags & SUPPORTS_VOTE_FSM)
 		qcom_pll_set_fsm_mode(regmap, pll->offset + PLL_MODE, 6, 0);
 
+	if (pll->flags & SUPPORTS_DYNAMIC_UPDATE)
+		regmap_update_bits(regmap, pll->offset + PLL_MODE,
+				   PLL_HW_LOGIC_BYPASS,
+				   PLL_HW_LOGIC_BYPASS);
+}
+
+static int clk_alpha_pll_dynamic_update(struct clk_alpha_pll *pll)
+{
+	u32 val;
+
+	/* Latch the input to the PLL */
+	regmap_update_bits(pll->clkr.regmap, pll->offset + PLL_MODE,
+			   PLL_UPDATE, PLL_UPDATE);
+
+	/* Wait for 2 reference cycle before checking ACK bit */
+	udelay(1);
+
+	regmap_read(pll->clkr.regmap, pll->offset + PLL_MODE, &val);
+	if (!(val & PLL_ACK_LATCH)) {
+		WARN(1, "PLL latch failed. Output may be unstable!\n");
+		return -EINVAL;
+	}
+
+	/* Return latch input to 0 */
+	regmap_update_bits(pll->clkr.regmap, pll->offset + PLL_MODE,
+			   PLL_UPDATE, 0);
+
+	/* Wait for PLL output to stabilize */
+	udelay(100);
+
+	return 0;
 }
 
 static int clk_alpha_pll_hwfsm_enable(struct clk_hw *hw)
@@ -366,6 +402,7 @@ clk_alpha_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
 static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 				  unsigned long prate)
 {
+	int enabled;
 	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
 	const struct pll_vco *vco;
 	u32 l, off = pll->offset;
@@ -378,6 +415,11 @@ static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 		return -EINVAL;
 	}
 
+	enabled = hw->init->ops->is_enabled(hw);
+
+	if (!(pll->flags & SUPPORTS_DYNAMIC_UPDATE) && enabled)
+		hw->init->ops->disable(hw);
+
 	a <<= (ALPHA_REG_BITWIDTH - ALPHA_BITWIDTH);
 
 	regmap_write(pll->clkr.regmap, off + PLL_L_VAL, l);
@@ -391,6 +433,12 @@ static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 	regmap_update_bits(pll->clkr.regmap, off + PLL_USER_CTL, PLL_ALPHA_EN,
 			   PLL_ALPHA_EN);
 
+	if (!(pll->flags & SUPPORTS_DYNAMIC_UPDATE) && enabled)
+		hw->init->ops->enable(hw);
+
+	if (pll->flags & SUPPORTS_DYNAMIC_UPDATE)
+		clk_alpha_pll_dynamic_update(pll);
+
 	return 0;
 }
 
diff --git a/drivers/clk/qcom/clk-alpha-pll.h b/drivers/clk/qcom/clk-alpha-pll.h
index 4bd42fd..23e32db 100644
--- a/drivers/clk/qcom/clk-alpha-pll.h
+++ b/drivers/clk/qcom/clk-alpha-pll.h
@@ -36,6 +36,7 @@ struct clk_alpha_pll {
 	size_t num_vco;
 
 #define SUPPORTS_VOTE_FSM	BIT(0)
+#define SUPPORTS_DYNAMIC_UPDATE	BIT(1)
 	u8 flags;
 	struct clk_regmap clkr;
 };
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

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#1469101 — Re: [PATCH v2 10/10] clk: qcom: Fix .set_rate to handle alpha PLLs w/wo dynamic update

On 08/11, Rajendra Nayak wrote:
> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
> index 2184dc1..68c90f3 100644
> --- a/drivers/clk/qcom/clk-alpha-pll.c
> +++ b/drivers/clk/qcom/clk-alpha-pll.c
> @@ -113,6 +113,11 @@ static int wait_for_pll_offline(struct clk_alpha_pll *pll, u32 mask)
>  #define PLL_OFFLINE_ACK		BIT(28)
>  #define PLL_ACTIVE_FLAG		BIT(30)
>  
> +/* alpha pll with dynamic update support */
> +#define PLL_UPDATE		BIT(22)
> +#define PLL_HW_LOGIC_BYPASS	BIT(23)
> +#define PLL_ACK_LATCH		BIT(29)

These need to move next to associated registers.

> +
>  void clk_alpha_pll_configure(struct clk_alpha_pll *pll, struct regmap *regmap,
>  			     const struct alpha_pll_config *config)
>  {
> @@ -366,6 +402,7 @@ clk_alpha_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
>  static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>  				  unsigned long prate)
>  {
> +	int enabled;

bool

>  	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
>  	const struct pll_vco *vco;
>  	u32 l, off = pll->offset;
> @@ -378,6 +415,11 @@ static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>  		return -EINVAL;
>  	}
>  
> +	enabled = hw->init->ops->is_enabled(hw);

We have clk_hw_is_enabled() for this.

> +
> +	if (!(pll->flags & SUPPORTS_DYNAMIC_UPDATE) && enabled)
> +		hw->init->ops->disable(hw);

Please call the function directly instead of going through the
init structure to get the clk ops.

> +
>  	a <<= (ALPHA_REG_BITWIDTH - ALPHA_BITWIDTH);
>  
>  	regmap_write(pll->clkr.regmap, off + PLL_L_VAL, l);
> @@ -391,6 +433,12 @@ static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>  	regmap_update_bits(pll->clkr.regmap, off + PLL_USER_CTL, PLL_ALPHA_EN,
>  			   PLL_ALPHA_EN);
>  
> +	if (!(pll->flags & SUPPORTS_DYNAMIC_UPDATE) && enabled)
> +		hw->init->ops->enable(hw);
> +
> +	if (pll->flags & SUPPORTS_DYNAMIC_UPDATE)
> +		clk_alpha_pll_dynamic_update(pll);
> +

Perhaps write it as

	if (pll->flags & SUPPORTS_DYNAMIC_UPDATE)
		clk_alpha_pll_dynamic_update()
	else if (enabled)
		toggle the enable bit...

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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#1469999 — Re: [PATCH v2 10/10] clk: qcom: Fix .set_rate to handle alpha PLLs w/wo dynamic update

On 08/24/2016 11:56 AM, Stephen Boyd wrote:
> On 08/11, Rajendra Nayak wrote:
>> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
>> index 2184dc1..68c90f3 100644
>> --- a/drivers/clk/qcom/clk-alpha-pll.c
>> +++ b/drivers/clk/qcom/clk-alpha-pll.c
>> @@ -113,6 +113,11 @@ static int wait_for_pll_offline(struct clk_alpha_pll *pll, u32 mask)
>>  #define PLL_OFFLINE_ACK		BIT(28)
>>  #define PLL_ACTIVE_FLAG		BIT(30)
>>  
>> +/* alpha pll with dynamic update support */
>> +#define PLL_UPDATE		BIT(22)
>> +#define PLL_HW_LOGIC_BYPASS	BIT(23)
>> +#define PLL_ACK_LATCH		BIT(29)
> 
> These need to move next to associated registers.

will do

> 
>> +
>>  void clk_alpha_pll_configure(struct clk_alpha_pll *pll, struct regmap *regmap,
>>  			     const struct alpha_pll_config *config)
>>  {
>> @@ -366,6 +402,7 @@ clk_alpha_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
>>  static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>>  				  unsigned long prate)
>>  {
>> +	int enabled;
> 
> bool

sure

> 
>>  	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
>>  	const struct pll_vco *vco;
>>  	u32 l, off = pll->offset;
>> @@ -378,6 +415,11 @@ static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>>  		return -EINVAL;
>>  	}
>>  
>> +	enabled = hw->init->ops->is_enabled(hw);
> 
> We have clk_hw_is_enabled() for this.

sure, will change it to use clk_hw_is_enabled

> 
>> +
>> +	if (!(pll->flags & SUPPORTS_DYNAMIC_UPDATE) && enabled)
>> +		hw->init->ops->disable(hw);
> 
> Please call the function directly instead of going through the
> init structure to get the clk ops.

okay

> 
>> +
>>  	a <<= (ALPHA_REG_BITWIDTH - ALPHA_BITWIDTH);
>>  
>>  	regmap_write(pll->clkr.regmap, off + PLL_L_VAL, l);
>> @@ -391,6 +433,12 @@ static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>>  	regmap_update_bits(pll->clkr.regmap, off + PLL_USER_CTL, PLL_ALPHA_EN,
>>  			   PLL_ALPHA_EN);
>>  
>> +	if (!(pll->flags & SUPPORTS_DYNAMIC_UPDATE) && enabled)
>> +		hw->init->ops->enable(hw);
>> +
>> +	if (pll->flags & SUPPORTS_DYNAMIC_UPDATE)
>> +		clk_alpha_pll_dynamic_update(pll);
>> +
> 
> Perhaps write it as
> 
> 	if (pll->flags & SUPPORTS_DYNAMIC_UPDATE)
> 		clk_alpha_pll_dynamic_update()
> 	else if (enabled)
> 		toggle the enable bit...

okay will update, thanks
> 

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

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