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Commit 881de670 authored by Mark Brown's avatar Mark Brown Committed by Samuel Ortiz
Browse files

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: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
parent 862de70c

drivers/mfd/wm8994-core.c

+19 −0
Original line number Diff line number Diff line
@@ -281,6 +281,13 @@ 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.
@@ -350,6 +357,11 @@ 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;
@@ -513,8 +525,15 @@ 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

include/linux/mfd/wm8994/core.h

+2 −0
Original line number Diff line number Diff line
@@ -63,6 +63,8 @@ struct wm8994 { 


	void *control_data;



	bool ldo_ena_always_driven;



	int gpio_base;

	int irq_base;

include/linux/mfd/wm8994/pdata.h

+7 −0
Original line number Diff line number Diff line
@@ -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