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authorLars-Peter Clausen <lars@metafoo.de>2015-07-21 21:53:00 +0200
committerMark Brown <broonie@kernel.org>2015-07-23 17:33:14 +0100
commit5f1d980ee9b6353f18765bfa6774a5a08d6cb944 (patch)
treee2bda67a94dd6927dabe242a249f4d38e4c8a894 /sound/ac97_bus.c
parentbc0195aad0daa2ad5b0d76cce22b167bc3435590 (diff)
downloadlinux-stericsson-5f1d980ee9b6353f18765bfa6774a5a08d6cb944.tar.gz
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 <lars@metafoo.de> Reviewed-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'sound/ac97_bus.c')
-rw-r--r--sound/ac97_bus.c62
1 files changed, 62 insertions, 0 deletions
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
@@ -18,6 +18,68 @@
#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
* structure and may decide based on the id field amongst other things.