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authorDaniel Mack <zonque@gmail.com>2012-12-10 13:30:04 +0400
committerMark Brown <broonie@opensource.wolfsonmicro.com>2012-12-24 19:53:28 +0400
commitfd23fb9f6bfd43a6e62b2646d18d5ca3edc3ebe3 (patch)
treea1033cbc88a3ccba164e8d0f6c7469f9efd6713a /include/sound/cs4271.h
parent133d2e6188de86df3ed84cd42ac66e9c5d328c04 (diff)
downloadlinux-fd23fb9f6bfd43a6e62b2646d18d5ca3edc3ebe3.tar.xz
ALSA: ASoC: cs4271: add optional soft reset workaround
The CS4271 requires its LRCLK and MCLK to be stable before its RESET line is de-asserted. That also means that clocks cannot be changed without putting the chip back into hardware reset, which also requires a complete re-initialization of all registers. One (undocumented) workaround is to assert and de-assert the PDN bit in the MODE2 register. This patch adds a new flag to both the DT bindings as well as to the platform data to enable that workaround. Signed-off-by: Daniel Mack <zonque@gmail.com> Acked-by: Alexander Sverdlin <subaparts@yandex.ru> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Diffstat (limited to 'include/sound/cs4271.h')
-rw-r--r--include/sound/cs4271.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/include/sound/cs4271.h b/include/sound/cs4271.h
index dd8c48d14ed9..70f45355acaa 100644
--- a/include/sound/cs4271.h
+++ b/include/sound/cs4271.h
@@ -20,6 +20,21 @@
struct cs4271_platform_data {
int gpio_nreset; /* GPIO driving Reset pin, if any */
bool amutec_eq_bmutec; /* flag to enable AMUTEC=BMUTEC */
+
+ /*
+ * The CS4271 requires its LRCLK and MCLK to be stable before its RESET
+ * line is de-asserted. That also means that clocks cannot be changed
+ * without putting the chip back into hardware reset, which also requires
+ * a complete re-initialization of all registers.
+ *
+ * One (undocumented) workaround is to assert and de-assert the PDN bit
+ * in the MODE2 register. This workaround can be enabled with the
+ * following flag.
+ *
+ * Note that this is not needed in case the clocks are stable
+ * throughout the entire runtime of the codec.
+ */
+ bool enable_soft_reset;
};
#endif /* __CS4271_H */