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>
diff --git a/include/sound/cs4271.h b/include/sound/cs4271.h
index dd8c48d..70f4535 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 */