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Date: Fri, 12 Aug 2011 10:18:20 +0900
From: Mark Brown <broonie@...nsource.wolfsonmicro.com>
To: Samuel Ortiz <sameo@...ux.intel.com>
Cc: linux-kernel@...r.kernel.org, patches@...nsource.wolfsonmicro.com,
Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [PATCH] mfd: Allow WM8994 LDO enable pulls to be disabled
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@...nsource.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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