sil-sii8620.c

/*
 * Silicon Image SiI8620 HDMI/MHL bridge driver
 *
 * Copyright (C) 2015, Samsung Electronics Co., Ltd.
 * Andrzej Hajda <a.hajda@samsung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <drm/bridge/mhl.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

#include "sil-sii8620.h"

#define VAL_RX_HDMI_CTRL2_DEFVAL	VAL_RX_HDMI_CTRL2_IDLE_CNT(3)

enum sii8620_mode {
	CM_DISCONNECTED,
	CM_DISCOVERY,
	CM_MHL1,
	CM_MHL3,
	CM_ECBUS_S
};

enum sii8620_sink_type {
	SINK_NONE,
	SINK_HDMI,
	SINK_DVI
};

enum sii8620_mt_state {
	MT_STATE_READY,
	MT_STATE_BUSY,
	MT_STATE_DONE
};

struct sii8620 {
	struct drm_bridge bridge;
	struct device *dev;
	struct clk *clk_xtal;
	struct gpio_desc *gpio_reset;
	struct gpio_desc *gpio_int;
	struct regulator_bulk_data supplies[2];
	struct mutex lock; /* context lock, protects fields below */
	int error;
	enum sii8620_mode mode;
	enum sii8620_sink_type sink_type;
	u8 cbus_status;
	u8 stat[MHL_DST_SIZE];
	u8 xstat[MHL_XDS_SIZE];
	u8 devcap[MHL_DCAP_SIZE];
	u8 xdevcap[MHL_XDC_SIZE];
	u8 avif[19];
	struct edid *edid;
	unsigned int gen2_write_burst:1;
	enum sii8620_mt_state mt_state;
	struct list_head mt_queue;
};

struct sii8620_mt_msg;

typedef void (*sii8620_mt_msg_cb)(struct sii8620 *ctx,
				  struct sii8620_mt_msg *msg);

typedef void (*sii8620_cb)(struct sii8620 *ctx, int ret);

struct sii8620_mt_msg {
	struct list_head node;
	u8 reg[4];
	u8 ret;
	sii8620_mt_msg_cb send;
	sii8620_mt_msg_cb recv;
	sii8620_cb continuation;
};

static const u8 sii8620_i2c_page[] = {
	0x39, /* Main System */
	0x3d, /* TDM and HSIC */
	0x49, /* TMDS Receiver, MHL EDID */
	0x4d, /* eMSC, HDCP, HSIC */
	0x5d, /* MHL Spec */
	0x64, /* MHL CBUS */
	0x59, /* Hardware TPI (Transmitter Programming Interface) */
	0x61, /* eCBUS-S, eCBUS-D */
};

static void sii8620_fetch_edid(struct sii8620 *ctx);
static void sii8620_set_upstream_edid(struct sii8620 *ctx);
static void sii8620_enable_hpd(struct sii8620 *ctx);
static void sii8620_mhl_disconnected(struct sii8620 *ctx);

static int sii8620_clear_error(struct sii8620 *ctx)
{
	int ret = ctx->error;

	ctx->error = 0;
	return ret;
}

static void sii8620_read_buf(struct sii8620 *ctx, u16 addr, u8 *buf, int len)
{
	struct device *dev = ctx->dev;
	struct i2c_client *client = to_i2c_client(dev);
	u8 data = addr;
	struct i2c_msg msg[] = {
		{
			.addr = sii8620_i2c_page[addr >> 8],
			.flags = client->flags,
			.len = 1,
			.buf = &data
		},
		{
			.addr = sii8620_i2c_page[addr >> 8],
			.flags = client->flags | I2C_M_RD,
			.len = len,
			.buf = buf
		},
	};
	int ret;

	if (ctx->error)
		return;

	ret = i2c_transfer(client->adapter, msg, 2);
	dev_dbg(dev, "read at %04x: %*ph, %d\n", addr, len, buf, ret);

	if (ret != 2) {
		dev_err(dev, "Read at %#06x of %d bytes failed with code %d.\n",
			addr, len, ret);
		ctx->error = ret < 0 ? ret : -EIO;
	}
}

static u8 sii8620_readb(struct sii8620 *ctx, u16 addr)
{
	u8 ret;

	sii8620_read_buf(ctx, addr, &ret, 1);
	return ret;
}

static void sii8620_write_buf(struct sii8620 *ctx, u16 addr, const u8 *buf,
			      int len)
{
	struct device *dev = ctx->dev;
	struct i2c_client *client = to_i2c_client(dev);
	u8 data[2];
	struct i2c_msg msg = {
		.addr = sii8620_i2c_page[addr >> 8],
		.flags = client->flags,
		.len = len + 1,
	};
	int ret;

	if (ctx->error)
		return;

	if (len > 1) {
		msg.buf = kmalloc(len + 1, GFP_KERNEL);
		if (!msg.buf) {
			ctx->error = -ENOMEM;
			return;
		}
		memcpy(msg.buf + 1, buf, len);
	} else {
		msg.buf = data;
		msg.buf[1] = *buf;
	}

	msg.buf[0] = addr;

	ret = i2c_transfer(client->adapter, &msg, 1);
	dev_dbg(dev, "write at %04x: %*ph, %d\n", addr, len, buf, ret);

	if (ret != 1) {
		dev_err(dev, "Write at %#06x of %*ph failed with code %d.\n",
			addr, len, buf, ret);
		ctx->error = ret ?: -EIO;
	}

	if (len > 1)
		kfree(msg.buf);
}