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Commit 5f1d980e authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Mark Brown
Browse files

ALSA: ac97: Add helper function to reset the AC97 device 



There is currently a lot of code duplication in ASoC drivers regarding the
reset handling of devices. This patch introduces a new generic reset
function in the generic AC'97 framework that can be used to replace most
the custom reset functions.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Reviewed-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent bc0195aa

include/sound/ac97_codec.h

+2 −0
Original line number Diff line number Diff line
@@ -584,6 +584,8 @@ static inline int snd_ac97_update_power(struct snd_ac97 *ac97, int reg, 
void snd_ac97_suspend(struct snd_ac97 *ac97);

void snd_ac97_resume(struct snd_ac97 *ac97);

#endif

int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,

	unsigned int id_mask);



/* quirk types */

enum {

sound/ac97_bus.c

+62 −0
Original line number Diff line number Diff line
@@ -17,6 +17,68 @@ 
#include <linux/string.h>

#include <sound/ac97_codec.h>



/*

 * snd_ac97_check_id() - Reads and checks the vendor ID of the device

 * @ac97: The AC97 device to check

 * @id: The ID to compare to

 * @id_mask: Mask that is applied to the device ID before comparing to @id

 *

 * If @id is 0 this function returns true if the read device vendor ID is

 * a valid ID. If @id is non 0 this functions returns true if @id

 * matches the read vendor ID. Otherwise the function returns false.

 */

static bool snd_ac97_check_id(struct snd_ac97 *ac97, unsigned int id,

	unsigned int id_mask)

{

	ac97->id = ac97->bus->ops->read(ac97, AC97_VENDOR_ID1) << 16;

	ac97->id |= ac97->bus->ops->read(ac97, AC97_VENDOR_ID2);



	if (ac97->id == 0x0 || ac97->id == 0xffffffff)

		return false;



	if (id != 0 && id != (ac97->id & id_mask))

		return false;



	return true;

}



/**

 * snd_ac97_reset() - Reset AC'97 device

 * @ac97: The AC'97 device to reset

 * @try_warm: Try a warm reset first

 * @id: Expected device vendor ID

 * @id_mask: Mask that is applied to the device ID before comparing to @id

 *

 * This function resets the AC'97 device. If @try_warm is true the function

 * first performs a warm reset. If the warm reset is successful the function

 * returns 1. Otherwise or if @try_warm is false the function issues cold reset

 * followed by a warm reset. If this is successful the function returns 0,

 * otherwise a negative error code. If @id is 0 any valid device ID will be

 * accepted, otherwise only the ID that matches @id and @id_mask is accepted.

 */

int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,

	unsigned int id_mask)

{

	struct snd_ac97_bus_ops *ops = ac97->bus->ops;



	if (try_warm && ops->warm_reset) {

		ops->warm_reset(ac97);

		if (snd_ac97_check_id(ac97, id, id_mask))

			return 1;

	}



	if (ops->reset)

		ops->reset(ac97);

	if (ops->warm_reset)

		ops->warm_reset(ac97);



	if (snd_ac97_check_id(ac97, id, id_mask))

		return 0;



	return -ENODEV;

}

EXPORT_SYMBOL_GPL(snd_ac97_reset);



/*

 * Let drivers decide whether they want to support given codec from their

 * probe method. Drivers have direct access to the struct snd_ac97