* [PATCH 0/2] MFD: twl6040-codec: avoid reconfiguring the PLL
@ 2011-11-25 14:57 Peter Ujfalusi
2011-11-25 14:57 ` [PATCH 1/2] MFD: twl6040-codec: Store mclk configuration Peter Ujfalusi
2011-11-25 14:57 ` [PATCH 2/2] MFD: twl6040-codec: Avoid PLL reconfiguration when not needed Peter Ujfalusi
0 siblings, 2 replies; 3+ messages in thread
From: Peter Ujfalusi @ 2011-11-25 14:57 UTC (permalink / raw)
To: Samuel Ortiz; +Cc: linux-kernel, Misael Lopez Cruz
Hi,
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.rc3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 1/2] MFD: twl6040-codec: Store mclk configuration
2011-11-25 14:57 [PATCH 0/2] MFD: twl6040-codec: avoid reconfiguring the PLL Peter Ujfalusi
@ 2011-11-25 14:57 ` Peter Ujfalusi
2011-11-25 14:57 ` [PATCH 2/2] MFD: twl6040-codec: Avoid PLL reconfiguration when not needed Peter Ujfalusi
1 sibling, 0 replies; 3+ messages in thread
From: Peter Ujfalusi @ 2011-11-25 14:57 UTC (permalink / raw)
To: Samuel Ortiz; +Cc: linux-kernel, Misael Lopez Cruz
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 268f80f..e738678 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.rc3
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 2/2] MFD: twl6040-codec: Avoid PLL reconfiguration when not needed
2011-11-25 14:57 [PATCH 0/2] MFD: twl6040-codec: avoid reconfiguring the PLL Peter Ujfalusi
2011-11-25 14:57 ` [PATCH 1/2] MFD: twl6040-codec: Store mclk configuration Peter Ujfalusi
@ 2011-11-25 14:57 ` Peter Ujfalusi
1 sibling, 0 replies; 3+ messages in thread
From: Peter Ujfalusi @ 2011-11-25 14:57 UTC (permalink / raw)
To: Samuel Ortiz; +Cc: linux-kernel, Misael Lopez Cruz
Do not reconfigure configure 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 e738678..8f01c64 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 the 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.rc3
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-11-25 14:57 UTC | newest]
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