remarkable-linux/include/drm/bridge/dw_hdmi.h
Russell King b90120a966 drm: bridge/dw_hdmi: introduce interfaces to enable and disable audio
iMX6 devices suffer from an errata (ERR005174) where the audio FIFO can
be emptied while it is partially full, resulting in misalignment of the
audio samples.

To prevent this, the errata workaround recommends writing N as zero
until the audio FIFO has been loaded by DMA.  Writing N=0 prevents the
HDMI bridge from reading from the audio FIFO, effectively disabling
audio.

This means we need to provide the audio driver with a pair of functions
to enable/disable audio.  These are dw_hdmi_audio_enable() and
dw_hdmi_audio_disable().

A spinlock is introduced to ensure that setting the CTS/N values can't
race, ensuring that the audio driver calling the enable/disable
functions (which are called in an atomic context) can't race with a
modeset.

Tested-by: Yakir Yang <ykk@rock-chips.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-08-18 11:27:15 +01:00

70 lines
1.7 KiB
C

/*
* Copyright (C) 2011 Freescale Semiconductor, 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.
*/
#ifndef __DW_HDMI__
#define __DW_HDMI__
#include <drm/drmP.h>
struct dw_hdmi;
enum {
DW_HDMI_RES_8,
DW_HDMI_RES_10,
DW_HDMI_RES_12,
DW_HDMI_RES_MAX,
};
enum dw_hdmi_devtype {
IMX6Q_HDMI,
IMX6DL_HDMI,
RK3288_HDMI,
};
struct dw_hdmi_mpll_config {
unsigned long mpixelclock;
struct {
u16 cpce;
u16 gmp;
} res[DW_HDMI_RES_MAX];
};
struct dw_hdmi_curr_ctrl {
unsigned long mpixelclock;
u16 curr[DW_HDMI_RES_MAX];
};
struct dw_hdmi_phy_config {
unsigned long mpixelclock;
u16 sym_ctr; /*clock symbol and transmitter control*/
u16 term; /*transmission termination value*/
u16 vlev_ctr; /* voltage level control */
};
struct dw_hdmi_plat_data {
enum dw_hdmi_devtype dev_type;
const struct dw_hdmi_mpll_config *mpll_cfg;
const struct dw_hdmi_curr_ctrl *cur_ctr;
const struct dw_hdmi_phy_config *phy_config;
enum drm_mode_status (*mode_valid)(struct drm_connector *connector,
struct drm_display_mode *mode);
};
void dw_hdmi_unbind(struct device *dev, struct device *master, void *data);
int dw_hdmi_bind(struct device *dev, struct device *master,
void *data, struct drm_encoder *encoder,
struct resource *iores, int irq,
const struct dw_hdmi_plat_data *plat_data);
void dw_hdmi_set_sample_rate(struct dw_hdmi *hdmi, unsigned int rate);
void dw_hdmi_audio_enable(struct dw_hdmi *hdmi);
void dw_hdmi_audio_disable(struct dw_hdmi *hdmi);
#endif /* __IMX_HDMI_H__ */