[RESEND 0/2] MFD: twl6040-codec: avoid reconfiguring the PLL

[RESEND 0/2] MFD: twl6040-codec: avoid reconfiguring the PLL

[Peter Ujfalusi]

Hello Samual,

This series somehow got lost (the original series has been sent back in
November).
It might be too late for 3.3 :(

The following two patch will optimize the PLL configuration code for the
twl6040, so if the requested configuration is the same as the current we simply
skip configuring the PLL (since no change needed).
We can save considerable amount of time in this way (due to avoiding i2c
accesses, and delays dictated by the configuration protocol).

Regards,
Peter
---
Peter Ujfalusi (2):
  MFD: twl6040-codec: Store mclk configuration
  MFD: twl6040-codec: Avoid PLL reconfiguration when not needed

 drivers/mfd/twl6040-core.c  |  128 ++++++++++++++++++++++++++-----------------
 include/linux/mfd/twl6040.h |    2 +
 2 files changed, 79 insertions(+), 51 deletions(-)

-- 
1.7.8.3

[RESEND 1/2] MFD: twl6040-codec: Store mclk configuration

[Peter Ujfalusi]

Store the last used mclk configuration for the PLL.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 drivers/mfd/twl6040-core.c  |    3 +++
 include/linux/mfd/twl6040.h |    2 ++
 2 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/mfd/twl6040-core.c b/drivers/mfd/twl6040-core.c
index dda8629..c2088f4 100644
--- a/drivers/mfd/twl6040-core.c
+++ b/drivers/mfd/twl6040-core.c
@@ -282,6 +282,7 @@ 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;
 	} else {
 		/* already powered-down */
 		if (!twl6040->power_count) {
@@ -305,6 +306,7 @@ int twl6040_power(struct twl6040 *twl6040, int on)
 			twl6040_power_down(twl6040);
 		}
 		twl6040->sysclk = 0;
+		twl6040->mclk = 0;
 	}
 
 out:
@@ -421,6 +423,7 @@ int twl6040_set_pll(struct twl6040 *twl6040, int pll_id,
 	}
 
 	twl6040->sysclk = freq_out;
+	twl6040->mclk = freq_in;
 	twl6040->pll = pll_id;
 
 pll_out:
diff --git a/include/linux/mfd/twl6040.h b/include/linux/mfd/twl6040.h
index 2463c261..9bc9ac6 100644
--- a/include/linux/mfd/twl6040.h
+++ b/include/linux/mfd/twl6040.h
@@ -187,8 +187,10 @@ struct twl6040 {
 	int rev;
 	u8 vibra_ctrl_cache[2];
 
+	/* PLL configuration */
 	int pll;
 	unsigned int sysclk;
+	unsigned int mclk;
 
 	unsigned int irq;
 	unsigned int irq_base;
-- 
1.7.8.3

[RESEND 2/2] MFD: twl6040-codec: Avoid PLL reconfiguration when not needed

[Peter Ujfalusi]

Do not reconfigure the PLL in case it has been configured already
with the requested parameters.
In case of different PLL configuration do only the needed changes.
This can save considerable amount of time since we can avoid the
defined protocol (with delays) for the PLL configuration.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 drivers/mfd/twl6040-core.c |  125 ++++++++++++++++++++++++++------------------
 1 files changed, 74 insertions(+), 51 deletions(-)

diff --git a/drivers/mfd/twl6040-core.c b/drivers/mfd/twl6040-core.c
index c2088f4..b2d8e51 100644
--- a/drivers/mfd/twl6040-core.c
+++ b/drivers/mfd/twl6040-core.c
@@ -326,23 +326,38 @@ int twl6040_set_pll(struct twl6040 *twl6040, int pll_id,
 	hppllctl = twl6040_reg_read(twl6040, TWL6040_REG_HPPLLCTL);
 	lppllctl = twl6040_reg_read(twl6040, TWL6040_REG_LPPLLCTL);
 
+	/* Force full reconfiguration when switching between PLL */
+	if (pll_id != twl6040->pll) {
+		twl6040->sysclk = 0;
+		twl6040->mclk = 0;
+	}
+
 	switch (pll_id) {
 	case TWL6040_SYSCLK_SEL_LPPLL:
 		/* low-power PLL divider */
-		switch (freq_out) {
-		case 17640000:
-			lppllctl |= TWL6040_LPLLFIN;
-			break;
-		case 19200000:
-			lppllctl &= ~TWL6040_LPLLFIN;
-			break;
-		default:
-			dev_err(twl6040->dev,
-				"freq_out %d not supported\n", freq_out);
-			ret = -EINVAL;
-			goto pll_out;
+		/* Change the sysclk configuration only if it has been canged */
+		if (twl6040->sysclk != freq_out) {
+			switch (freq_out) {
+			case 17640000:
+				lppllctl |= TWL6040_LPLLFIN;
+				break;
+			case 19200000:
+				lppllctl &= ~TWL6040_LPLLFIN;
+				break;
+			default:
+				dev_err(twl6040->dev,
+					"freq_out %d not supported\n",
+					freq_out);
+				ret = -EINVAL;
+				goto pll_out;
+			}
+			twl6040_reg_write(twl6040, TWL6040_REG_LPPLLCTL,
+					  lppllctl);
 		}
-		twl6040_reg_write(twl6040, TWL6040_REG_LPPLLCTL, lppllctl);
+
+		/* The PLL in use has not been change, we can exit */
+		if (twl6040->pll == pll_id)
+			break;
 
 		switch (freq_in) {
 		case 32768:
@@ -373,48 +388,56 @@ int twl6040_set_pll(struct twl6040 *twl6040, int pll_id,
 			goto pll_out;
 		}
 
-		hppllctl &= ~TWL6040_MCLK_MSK;
+		if (twl6040->mclk != freq_in) {
+			hppllctl &= ~TWL6040_MCLK_MSK;
+
+			switch (freq_in) {
+			case 12000000:
+				/* PLL enabled, active mode */
+				hppllctl |= TWL6040_MCLK_12000KHZ |
+					    TWL6040_HPLLENA;
+				break;
+			case 19200000:
+				/*
+				* PLL disabled
+				* (enable PLL if MCLK jitter quality
+				*  doesn't meet specification)
+				*/
+				hppllctl |= TWL6040_MCLK_19200KHZ;
+				break;
+			case 26000000:
+				/* PLL enabled, active mode */
+				hppllctl |= TWL6040_MCLK_26000KHZ |
+					    TWL6040_HPLLENA;
+				break;
+			case 38400000:
+				/* PLL enabled, active mode */
+				hppllctl |= TWL6040_MCLK_38400KHZ |
+					    TWL6040_HPLLENA;
+				break;
+			default:
+				dev_err(twl6040->dev,
+					"freq_in %d not supported\n", freq_in);
+				ret = -EINVAL;
+				goto pll_out;
+			}
 
-		switch (freq_in) {
-		case 12000000:
-			/* PLL enabled, active mode */
-			hppllctl |= TWL6040_MCLK_12000KHZ |
-				    TWL6040_HPLLENA;
-			break;
-		case 19200000:
 			/*
-			 * PLL disabled
-			 * (enable PLL if MCLK jitter quality
-			 *  doesn't meet specification)
+			 * enable clock slicer to ensure input waveform is
+			 * square
 			 */
-			hppllctl |= TWL6040_MCLK_19200KHZ;
-			break;
-		case 26000000:
-			/* PLL enabled, active mode */
-			hppllctl |= TWL6040_MCLK_26000KHZ |
-				    TWL6040_HPLLENA;
-			break;
-		case 38400000:
-			/* PLL enabled, active mode */
-			hppllctl |= TWL6040_MCLK_38400KHZ |
-				    TWL6040_HPLLENA;
-			break;
-		default:
-			dev_err(twl6040->dev,
-				"freq_in %d not supported\n", freq_in);
-			ret = -EINVAL;
-			goto pll_out;
-		}
+			hppllctl |= TWL6040_HPLLSQRENA;
 
-		/* enable clock slicer to ensure input waveform is square */
-		hppllctl |= TWL6040_HPLLSQRENA;
-
-		twl6040_reg_write(twl6040, TWL6040_REG_HPPLLCTL, hppllctl);
-		usleep_range(500, 700);
-		lppllctl |= TWL6040_HPLLSEL;
-		twl6040_reg_write(twl6040, TWL6040_REG_LPPLLCTL, lppllctl);
-		lppllctl &= ~TWL6040_LPLLENA;
-		twl6040_reg_write(twl6040, TWL6040_REG_LPPLLCTL, lppllctl);
+			twl6040_reg_write(twl6040, TWL6040_REG_HPPLLCTL,
+					  hppllctl);
+			usleep_range(500, 700);
+			lppllctl |= TWL6040_HPLLSEL;
+			twl6040_reg_write(twl6040, TWL6040_REG_LPPLLCTL,
+					  lppllctl);
+			lppllctl &= ~TWL6040_LPLLENA;
+			twl6040_reg_write(twl6040, TWL6040_REG_LPPLLCTL,
+					  lppllctl);
+		}
 		break;
 	default:
 		dev_err(twl6040->dev, "unknown pll id %d\n", pll_id);
-- 
1.7.8.3

Re: [RESEND 0/2] MFD: twl6040-codec: avoid reconfiguring the PLL

[Samuel Ortiz]

Hi Peter,

On Sat, Jan 14, 2012 at 08:58:42PM +0100, Peter Ujfalusi wrote:
> Hello Samual,
> 
> This series somehow got lost (the original series has been sent back in
> November).
My bad, sorry. Could you please use my sameo@linux.intel.com email address for
MFD patches ?


> It might be too late for 3.3 :(
I will try to send those 2 to Linus in a few days, let's see if he still takes
it or not.

Cheers,
Samuel.

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