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/* * Linux driver model AC97 bus interface * * Author: Nicolas Pitre * Created: Jan 14, 2005 * Copyright: (C) MontaVista Software Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. *//* * 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 * structure and may decide based on the id field amongst other things. */static int ac97_bus_match(struct device *dev, struct device_driver *drv){ return 1;}struct bus_type ac97_bus_type = {