From 5f1d980ee9b6353f18765bfa6774a5a08d6cb944 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Tue, 21 Jul 2015 21:53:00 +0200 Subject: 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: Lars-Peter Clausen Reviewed-by: Takashi Iwai Signed-off-by: Mark Brown --- sound/ac97_bus.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) (limited to 'sound/ac97_bus.c') diff --git a/sound/ac97_bus.c b/sound/ac97_bus.c index 2b50cbe6aca9..55791a0b3943 100644 --- a/sound/ac97_bus.c +++ b/sound/ac97_bus.c @@ -17,6 +17,68 @@ #include #include +/* + * 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 -- cgit