kernel-ark/include/sound/cs4271.h
Daniel Mack fd23fb9f6b 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>
2012-12-24 15:53:28 +00:00

41 lines
1.4 KiB
C

/*
* Definitions for CS4271 ASoC codec driver
*
* Copyright (c) 2010 Alexander Sverdlin <subaparts@yandex.ru>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef __CS4271_H
#define __CS4271_H
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 */