Messages in this thread Patch in this message | | | From | Mark Brown <> | Subject | [PATCH] mfd: Allow WM8994 LDO enable pulls to be disabled | Date | Fri, 12 Aug 2011 10:18:20 +0900 |
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In systems where the LDO enables are always driven (for example, being connected to an always on supply rail or a GPIO which is driven by the CPU even in suspend) then we can disable the pull downs on the LDO for a small power savings.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> --- drivers/mfd/wm8994-core.c | 19 +++++++++++++++++++ include/linux/mfd/wm8994/core.h | 2 ++ include/linux/mfd/wm8994/pdata.h | 7 +++++++ 3 files changed, 28 insertions(+), 0 deletions(-)
diff --git a/drivers/mfd/wm8994-core.c b/drivers/mfd/wm8994-core.c index b03be1d..5690102 100644 --- a/drivers/mfd/wm8994-core.c +++ b/drivers/mfd/wm8994-core.c @@ -217,6 +217,13 @@ static int wm8994_suspend(struct device *dev) return 0; } + /* Disable LDO pulldowns while the device is suspended if we + * don't know that something will be driving them. */ + if (!wm8994->ldo_ena_always_driven) + wm8994_set_bits(wm8994, WM8994_PULL_CONTROL_2, + WM8994_LDO1ENA_PD | WM8994_LDO2ENA_PD, + WM8994_LDO1ENA_PD | WM8994_LDO2ENA_PD); + /* GPIO configuration state is saved here since we may be configuring * the GPIO alternate functions even if we're not using the gpiolib * driver for them. @@ -286,6 +293,11 @@ static int wm8994_resume(struct device *dev) if (ret < 0) dev_err(dev, "Failed to restore GPIO registers: %d\n", ret); + /* Disable LDO pulldowns while the device is active */ + wm8994_set_bits(wm8994, WM8994_PULL_CONTROL_2, + WM8994_LDO1ENA_PD | WM8994_LDO2ENA_PD, + 0); + wm8994->suspended = false; return 0; @@ -467,8 +479,15 @@ static int wm8994_device_init(struct wm8994 *wm8994, int irq) pdata->gpio_defaults[i]); } } + + wm8994->ldo_ena_always_driven = pdata->ldo_ena_always_driven; } + /* Disable LDO pulldowns while the device is active */ + wm8994_set_bits(wm8994, WM8994_PULL_CONTROL_2, + WM8994_LDO1ENA_PD | WM8994_LDO2ENA_PD, + 0); + /* In some system designs where the regulators are not in use, * we can achieve a small reduction in leakage currents by * floating LDO outputs. This bit makes no difference if the diff --git a/include/linux/mfd/wm8994/core.h b/include/linux/mfd/wm8994/core.h index 6268091..f44bdb7 100644 --- a/include/linux/mfd/wm8994/core.h +++ b/include/linux/mfd/wm8994/core.h @@ -59,6 +59,8 @@ struct wm8994 { struct device *dev; struct regmap *regmap; + bool ldo_ena_always_driven; + int gpio_base; int irq_base; diff --git a/include/linux/mfd/wm8994/pdata.h b/include/linux/mfd/wm8994/pdata.h index 97cf4f2..ea32f30 100644 --- a/include/linux/mfd/wm8994/pdata.h +++ b/include/linux/mfd/wm8994/pdata.h @@ -167,6 +167,13 @@ struct wm8994_pdata { /* WM8958 microphone bias configuration */ int micbias[2]; + + /* Disable the internal pull downs on the LDOs if they are + * always driven (eg, connected to an always on supply or + * GPIO that always drives an output. If they float power + * consumption will rise. + */ + bool ldo_ena_always_driven; }; #endif -- 1.7.5.4
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