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 <asm/unaligned.h>

#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/extcon.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/of_graph.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

#include <media/rc-core.h>

#include "sil-sii8620.h"

#define SII8620_BURST_BUF_LEN 288
#define VAL_RX_HDMI_CTRL2_DEFVAL VAL_RX_HDMI_CTRL2_IDLE_CNT(3)
#define MHL1_MAX_LCLK 225000
#define MHL3_MAX_LCLK 600000

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 rc_dev *rc_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;
	int pixel_clock;
	unsigned int use_packed_pixel:1;
	int video_code;
	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[HDMI_INFOFRAME_SIZE(AVI)];
	struct edid *edid;
	unsigned int gen2_write_burst:1;
	enum sii8620_mt_state mt_state;
	struct extcon_dev *extcon;
	struct notifier_block extcon_nb;
	struct work_struct extcon_wq;
	int cable_state;
	struct list_head mt_queue;
	struct {
		int r_size;
		int r_count;
		int rx_ack;
		int rx_count;
		u8 rx_buf[32];
		int tx_count;
		u8 tx_buf[32];
	} burst;
};

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 void sii8620_disconnect(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);
}

#define sii8620_write(ctx, addr, arr...) \
({\
	u8 d[] = { arr }; \
	sii8620_write_buf(ctx, addr, d, ARRAY_SIZE(d)); \
})

static void __sii8620_write_seq(struct sii8620 *ctx, const u16 *seq, int len)
{
	int i;

	for (i = 0; i < len; i += 2)
		sii8620_write(ctx, seq[i], seq[i + 1]);
}

#define sii8620_write_seq(ctx, seq...) \
({\
	const u16 d[] = { seq }; \
	__sii8620_write_seq(ctx, d, ARRAY_SIZE(d)); \
})

#define sii8620_write_seq_static(ctx, seq...) \
({\
	static const u16 d[] = { seq }; \
	__sii8620_write_seq(ctx, d, ARRAY_SIZE(d)); \
})

static void sii8620_setbits(struct sii8620 *ctx, u16 addr, u8 mask, u8 val)
{
	val = (val & mask) | (sii8620_readb(ctx, addr) & ~mask);
	sii8620_write(ctx, addr, val);
}

static inline bool sii8620_is_mhl3(struct sii8620 *ctx)
{
	return ctx->mode >= CM_MHL3;
}

static void sii8620_mt_cleanup(struct sii8620 *ctx)
{
	struct sii8620_mt_msg *msg, *n;

	list_for_each_entry_safe(msg, n, &ctx->mt_queue, node) {
		list_del(&msg->node);
		kfree(msg);
	}
	ctx->mt_state = MT_STATE_READY;
}

static void sii8620_mt_work(struct sii8620 *ctx)
{
	struct sii8620_mt_msg *msg;

	if (ctx->error)
		return;
	if (ctx->mt_state == MT_STATE_BUSY || list_empty(&ctx->mt_queue))
		return;

	if (ctx->mt_state == MT_STATE_DONE) {
		ctx->mt_state = MT_STATE_READY;
		msg = list_first_entry(&ctx->mt_queue, struct sii8620_mt_msg,
				       node);
		list_del(&msg->node);
		if (msg->recv)
			msg->recv(ctx, msg);
		if (msg->continuation)
			msg->continuation(ctx, msg->ret);
		kfree(msg);
	}

	if (ctx->mt_state != MT_STATE_READY || list_empty(&ctx->mt_queue))
		return;

	ctx->mt_state = MT_STATE_BUSY;
	msg = list_first_entry(&ctx->mt_queue, struct sii8620_mt_msg, node);
	if (msg->send)
		msg->send(ctx, msg);
}

static void sii8620_enable_gen2_write_burst(struct sii8620 *ctx)
{
	u8 ctrl = BIT_MDT_RCV_CTRL_MDT_RCV_EN;

	if (ctx->gen2_write_burst)
		return;

	if (ctx->mode >= CM_MHL1)
		ctrl |= BIT_MDT_RCV_CTRL_MDT_DELAY_RCV_EN;

	sii8620_write_seq(ctx,
		REG_MDT_RCV_TIMEOUT, 100,
		REG_MDT_RCV_CTRL, ctrl
	);
	ctx->gen2_write_burst = 1;
}

static void sii8620_disable_gen2_write_burst(struct sii8620 *ctx)
{
	if (!ctx->gen2_write_burst)
		return;

	sii8620_write_seq_static(ctx,
		REG_MDT_XMIT_CTRL, 0,
		REG_MDT_RCV_CTRL, 0
	);
	ctx->gen2_write_burst = 0;
}

static void sii8620_start_gen2_write_burst(struct sii8620 *ctx)
{
	sii8620_write_seq_static(ctx,
		REG_MDT_INT_1_MASK, BIT_MDT_RCV_TIMEOUT
			| BIT_MDT_RCV_SM_ABORT_PKT_RCVD | BIT_MDT_RCV_SM_ERROR
			| BIT_MDT_XMIT_TIMEOUT | BIT_MDT_XMIT_SM_ABORT_PKT_RCVD
			| BIT_MDT_XMIT_SM_ERROR,
		REG_MDT_INT_0_MASK, BIT_MDT_XFIFO_EMPTY
			| BIT_MDT_IDLE_AFTER_HAWB_DISABLE
			| BIT_MDT_RFIFO_DATA_RDY
	);
	sii8620_enable_gen2_write_burst(ctx);
}

static void sii8620_mt_msc_cmd_send(struct sii8620 *ctx,
				    struct sii8620_mt_msg *msg)
{
	if (msg->reg[0] == MHL_SET_INT &&
	    msg->reg[1] == MHL_INT_REG(RCHANGE) &&
	    msg->reg[2] == MHL_INT_RC_FEAT_REQ)
		sii8620_enable_gen2_write_burst(ctx);
	else
		sii8620_disable_gen2_write_burst(ctx);

	switch (msg->reg[0]) {
	case MHL_WRITE_STAT:
	case MHL_SET_INT:
		sii8620_write_buf(ctx, REG_MSC_CMD_OR_OFFSET, msg->reg + 1, 2);
		sii8620_write(ctx, REG_MSC_COMMAND_START,
			      BIT_MSC_COMMAND_START_WRITE_STAT);
		break;
	case MHL_MSC_MSG:
		sii8620_write_buf(ctx, REG_MSC_CMD_OR_OFFSET, msg->reg, 3);
		sii8620_write(ctx, REG_MSC_COMMAND_START,
			      BIT_MSC_COMMAND_START_MSC_MSG);
		break;
	case MHL_READ_DEVCAP_REG:
	case MHL_READ_XDEVCAP_REG:
		sii8620_write(ctx, REG_MSC_CMD_OR_OFFSET, msg->reg[1]);
		sii8620_write(ctx, REG_MSC_COMMAND_START,
			      BIT_MSC_COMMAND_START_READ_DEVCAP);
		break;
	default:
		dev_err(ctx->dev, "%s: command %#x not supported\n", __func__,
			msg->reg[0]);
	}
}

static struct sii8620_mt_msg *sii8620_mt_msg_new(struct sii8620 *ctx)
{
	struct sii8620_mt_msg *msg = kzalloc(sizeof(*msg), GFP_KERNEL);

	if (!msg)
		ctx->error = -ENOMEM;
	else
		list_add_tail(&msg->node, &ctx->mt_queue);

	return msg;
}

static void sii8620_mt_set_cont(struct sii8620 *ctx, sii8620_cb cont)
{
	struct sii8620_mt_msg *msg;

	if (ctx->error)
		return;

	if (list_empty(&ctx->mt_queue)) {
		ctx->error = -EINVAL;
		return;
	}
	msg = list_last_entry(&ctx->mt_queue, struct sii8620_mt_msg, node);
	msg->continuation = cont;
}

static void sii8620_mt_msc_cmd(struct sii8620 *ctx, u8 cmd, u8 arg1, u8 arg2)
{
	struct sii8620_mt_msg *msg = sii8620_mt_msg_new(ctx);

	if (!msg)
		return;

	msg->reg[0] = cmd;
	msg->reg[1] = arg1;
	msg->reg[2] = arg2;
	msg->send = sii8620_mt_msc_cmd_send;
}

static void sii8620_mt_write_stat(struct sii8620 *ctx, u8 reg, u8 val)
{
	sii8620_mt_msc_cmd(ctx, MHL_WRITE_STAT, reg, val);
}

static inline void sii8620_mt_set_int(struct sii8620 *ctx, u8 irq, u8 mask)
{
	sii8620_mt_msc_cmd(ctx, MHL_SET_INT, irq, mask);
}

static void sii8620_mt_msc_msg(struct sii8620 *ctx, u8 cmd, u8 data)
{
	sii8620_mt_msc_cmd(ctx, MHL_MSC_MSG, cmd, data);
}

static void sii8620_mt_rap(struct sii8620 *ctx, u8 code)
{
	sii8620_mt_msc_msg(ctx, MHL_MSC_MSG_RAP, code);
}

static void sii8620_mt_rcpk(struct sii8620 *ctx, u8 code)
{
	sii8620_mt_msc_msg(ctx, MHL_MSC_MSG_RCPK, code);
}

static void sii8620_mt_rcpe(struct sii8620 *ctx, u8 code)
{
	sii8620_mt_msc_msg(ctx, MHL_MSC_MSG_RCPE, code);
}

static void sii8620_mt_read_devcap_send(struct sii8620 *ctx,
					struct sii8620_mt_msg *msg)
{
	u8 ctrl = BIT_EDID_CTRL_DEVCAP_SELECT_DEVCAP
			| BIT_EDID_CTRL_EDID_FIFO_ADDR_AUTO
			| BIT_EDID_CTRL_EDID_MODE_EN;

	if (msg->reg[0] == MHL_READ_XDEVCAP)
		ctrl |= BIT_EDID_CTRL_XDEVCAP_EN;

	sii8620_write_seq(ctx,
		REG_INTR9_MASK, BIT_INTR9_DEVCAP_DONE,
		REG_EDID_CTRL, ctrl,
		REG_TPI_CBUS_START, BIT_TPI_CBUS_START_GET_DEVCAP_START
	);
}

/* copy src to dst and set changed bits in src */
static void sii8620_update_array(u8 *dst, u8 *src, int count)
{
	while (--count >= 0) {
		*src ^= *dst;
		*dst++ ^= *src++;
	}
}

static void sii8620_sink_detected(struct sii8620 *ctx, int ret)
{
	static const char * const sink_str[] = {
		[SINK_NONE] = "NONE",
		[SINK_HDMI] = "HDMI",
		[SINK_DVI] = "DVI"
	};

	char sink_name[20];
	struct device *dev = ctx->dev;

	if (ret < 0)
		return;

	sii8620_fetch_edid(ctx);
	if (!ctx->edid) {
		dev_err(ctx->dev, "Cannot fetch EDID\n");
		sii8620_mhl_disconnected(ctx);
		return;
	}

	if (drm_detect_hdmi_monitor(ctx->edid))
		ctx->sink_type = SINK_HDMI;
	else
		ctx->sink_type = SINK_DVI;

	drm_edid_get_monitor_name(ctx->edid, sink_name, ARRAY_SIZE(sink_name));

	dev_info(dev, "detected sink(type: %s): %s\n",
		 sink_str[ctx->sink_type], sink_name);
}

static void sii8620_hsic_init(struct sii8620 *ctx)
{
	if (!sii8620_is_mhl3(ctx))
		return;

	sii8620_write(ctx, REG_FCGC,
		BIT_FCGC_HSIC_HOSTMODE | BIT_FCGC_HSIC_ENABLE);
	sii8620_setbits(ctx, REG_HRXCTRL3,
		BIT_HRXCTRL3_HRX_STAY_RESET | BIT_HRXCTRL3_STATUS_EN, ~0);
	sii8620_setbits(ctx, REG_TTXNUMB, MSK_TTXNUMB_TTX_NUMBPS, 4);
	sii8620_setbits(ctx, REG_TRXCTRL, BIT_TRXCTRL_TRX_FROM_SE_COC, ~0);
	sii8620_setbits(ctx, REG_HTXCTRL, BIT_HTXCTRL_HTX_DRVCONN1, 0);
	sii8620_setbits(ctx, REG_KEEPER, MSK_KEEPER_MODE, VAL_KEEPER_MODE_HOST);
	sii8620_write_seq_static(ctx,
		REG_TDMLLCTL, 0,
		REG_UTSRST, BIT_UTSRST_HRX_SRST | BIT_UTSRST_HTX_SRST |
			BIT_UTSRST_KEEPER_SRST | BIT_UTSRST_FC_SRST,
		REG_UTSRST, BIT_UTSRST_HRX_SRST | BIT_UTSRST_HTX_SRST,
		REG_HRXINTL, 0xff,
		REG_HRXINTH, 0xff,
		REG_TTXINTL, 0xff,
		REG_TTXINTH, 0xff,
		REG_TRXINTL, 0xff,
		REG_TRXINTH, 0xff,
		REG_HTXINTL, 0xff,
		REG_HTXINTH, 0xff,
		REG_FCINTR0, 0xff,
		REG_FCINTR1, 0xff,
		REG_FCINTR2, 0xff,
		REG_FCINTR3, 0xff,
		REG_FCINTR4, 0xff,
		REG_FCINTR5, 0xff,
		REG_FCINTR6, 0xff,
		REG_FCINTR7, 0xff
	);
}

static void sii8620_edid_read(struct sii8620 *ctx, int ret)
{
	if (ret < 0)
		return;

	sii8620_set_upstream_edid(ctx);
	sii8620_hsic_init(ctx);
	sii8620_enable_hpd(ctx);
}

static void sii8620_mr_devcap(struct sii8620 *ctx)
{
	u8 dcap[MHL_DCAP_SIZE];
	struct device *dev = ctx->dev;

	sii8620_read_buf(ctx, REG_EDID_FIFO_RD_DATA, dcap, MHL_DCAP_SIZE);
	if (ctx->error < 0)
		return;

	dev_info(dev, "detected dongle MHL %d.%d, ChipID %02x%02x:%02x%02x\n",
		 dcap[MHL_DCAP_MHL_VERSION] / 16,
		 dcap[MHL_DCAP_MHL_VERSION] % 16,
		 dcap[MHL_DCAP_ADOPTER_ID_H], dcap[MHL_DCAP_ADOPTER_ID_L],
		 dcap[MHL_DCAP_DEVICE_ID_H], dcap[MHL_DCAP_DEVICE_ID_L]);
	sii8620_update_array(ctx->devcap, dcap, MHL_DCAP_SIZE);
}

static void sii8620_mr_xdevcap(struct sii8620 *ctx)
{
	sii8620_read_buf(ctx, REG_EDID_FIFO_RD_DATA, ctx->xdevcap,
			 MHL_XDC_SIZE);
}

static void sii8620_mt_read_devcap_recv(struct sii8620 *ctx,
					struct sii8620_mt_msg *msg)
{
	u8 ctrl = BIT_EDID_CTRL_DEVCAP_SELECT_DEVCAP
		| BIT_EDID_CTRL_EDID_FIFO_ADDR_AUTO
		| BIT_EDID_CTRL_EDID_MODE_EN;

	if (msg->reg[0] == MHL_READ_XDEVCAP)
		ctrl |= BIT_EDID_CTRL_XDEVCAP_EN;

	sii8620_write_seq(ctx,
		REG_INTR9_MASK, BIT_INTR9_DEVCAP_DONE | BIT_INTR9_EDID_DONE
			| BIT_INTR9_EDID_ERROR,
		REG_EDID_CTRL, ctrl,
		REG_EDID_FIFO_ADDR, 0
	);

	if (msg->reg[0] == MHL_READ_XDEVCAP)
		sii8620_mr_xdevcap(ctx);
	else
		sii8620_mr_devcap(ctx);
}

static void sii8620_mt_read_devcap(struct sii8620 *ctx, bool xdevcap)
{
	struct sii8620_mt_msg *msg = sii8620_mt_msg_new(ctx);

	if (!msg)
		return;

	msg->reg[0] = xdevcap ? MHL_READ_XDEVCAP : MHL_READ_DEVCAP;
	msg->send = sii8620_mt_read_devcap_send;
	msg->recv = sii8620_mt_read_devcap_recv;
}

static void sii8620_mt_read_devcap_reg_recv(struct sii8620 *ctx,
		struct sii8620_mt_msg *msg)
{
	u8 reg = msg->reg[1] & 0x7f;

	if (msg->reg[1] & 0x80)
		ctx->xdevcap[reg] = msg->ret;
	else
		ctx->devcap[reg] = msg->ret;
}

static void sii8620_mt_read_devcap_reg(struct sii8620 *ctx, u8 reg)
{
	struct sii8620_mt_msg *msg = sii8620_mt_msg_new(ctx);

	if (!msg)
		return;

	msg->reg[0] = (reg & 0x80) ? MHL_READ_XDEVCAP_REG : MHL_READ_DEVCAP_REG;
	msg->reg[1] = reg;
	msg->send = sii8620_mt_msc_cmd_send;
	msg->recv = sii8620_mt_read_devcap_reg_recv;
}

static inline void sii8620_mt_read_xdevcap_reg(struct sii8620 *ctx, u8 reg)
{
	sii8620_mt_read_devcap_reg(ctx, reg | 0x80);
}

static void *sii8620_burst_get_tx_buf(struct sii8620 *ctx, int len)
{
	u8 *buf = &ctx->burst.tx_buf[ctx->burst.tx_count];
	int size = len + 2;

	if (ctx->burst.tx_count + size > ARRAY_SIZE(ctx->burst.tx_buf)) {
		dev_err(ctx->dev, "TX-BLK buffer exhausted\n");
		ctx->error = -EINVAL;
		return NULL;
	}

	ctx->burst.tx_count += size;
	buf[1] = len;

	return buf + 2;
}

static u8 *sii8620_burst_get_rx_buf(struct sii8620 *ctx, int len)
{
	u8 *buf = &ctx->burst.rx_buf[ctx->burst.rx_count];
	int size = len + 1;

	if (ctx->burst.tx_count + size > ARRAY_SIZE(ctx->burst.tx_buf)) {
		dev_err(ctx->dev, "RX-BLK buffer exhausted\n");
		ctx->error = -EINVAL;
		return NULL;
	}

	ctx->burst.rx_count += size;
	buf[0] = len;

	return buf + 1;
}

static void sii8620_burst_send(struct sii8620 *ctx)
{
	int tx_left = ctx->burst.tx_count;
	u8 *d = ctx->burst.tx_buf;

	while (tx_left > 0) {
		int len = d[1] + 2;

		if (ctx->burst.r_count + len > ctx->burst.r_size)
			break;
		d[0] = min(ctx->burst.rx_ack, 255);
		ctx->burst.rx_ack -= d[0];
		sii8620_write_buf(ctx, REG_EMSC_XMIT_WRITE_PORT, d, len);
		ctx->burst.r_count += len;
		tx_left -= len;
		d += len;
	}

	ctx->burst.tx_count = tx_left;

	while (ctx->burst.rx_ack > 0) {
		u8 b[2] = { min(ctx->burst.rx_ack, 255), 0 };

		if (ctx->burst.r_count + 2 > ctx->burst.r_size)
			break;
		ctx->burst.rx_ack -= b[0];
		sii8620_write_buf(ctx, REG_EMSC_XMIT_WRITE_PORT, b, 2);
		ctx->burst.r_count += 2;
	}
}

static void sii8620_burst_receive(struct sii8620 *ctx)
{
	u8 buf[3], *d;
	int count;

	sii8620_read_buf(ctx, REG_EMSCRFIFOBCNTL, buf, 2);
	count = get_unaligned_le16(buf);
	while (count > 0) {
		int len = min(count, 3);

		sii8620_read_buf(ctx, REG_EMSC_RCV_READ_PORT, buf, len);
		count -= len;
		ctx->burst.rx_ack += len - 1;
		ctx->burst.r_count -= buf[1];
		if (ctx->burst.r_count < 0)
			ctx->burst.r_count = 0;

		if (len < 3 || !buf[2])
			continue;

		len = buf[2];
		d = sii8620_burst_get_rx_buf(ctx, len);
		if (!d)
			continue;
		sii8620_read_buf(ctx, REG_EMSC_RCV_READ_PORT, d, len);
		count -= len;
		ctx->burst.rx_ack += len;
	}
}

static void sii8620_burst_tx_rbuf_info(struct sii8620 *ctx, int size)
{
	struct mhl_burst_blk_rcv_buffer_info *d =
		sii8620_burst_get_tx_buf(ctx, sizeof(*d));
	if (!d)
		return;

	d->id = cpu_to_be16(MHL_BURST_ID_BLK_RCV_BUFFER_INFO);
	d->size = cpu_to_le16(size);
}

static u8 sii8620_checksum(void *ptr, int size)
{
	u8 *d = ptr, sum = 0;

	while (size--)
		sum += *d++;

	return sum;
}

static void sii8620_mhl_burst_hdr_set(struct mhl3_burst_header *h,
	enum mhl_burst_id id)
{
	h->id = cpu_to_be16(id);
	h->total_entries = 1;
	h->sequence_index = 1;
}

static void sii8620_burst_tx_bits_per_pixel_fmt(struct sii8620 *ctx, u8 fmt)
{
	struct mhl_burst_bits_per_pixel_fmt *d;
	const int size = sizeof(*d) + sizeof(d->desc[0]);

	d = sii8620_burst_get_tx_buf(ctx, size);
	if (!d)
		return;

	sii8620_mhl_burst_hdr_set(&d->hdr, MHL_BURST_ID_BITS_PER_PIXEL_FMT);
	d->num_entries = 1;
	d->desc[0].stream_id = 0;
	d->desc[0].pixel_format = fmt;
	d->hdr.checksum -= sii8620_checksum(d, size);
}

static void sii8620_burst_rx_all(struct sii8620 *ctx)
{
	u8 *d = ctx->burst.rx_buf;
	int count = ctx->burst.rx_count;

	while (count-- > 0) {
		int len = *d++;
		int id = get_unaligned_be16(&d[0]);

		switch (id) {
		case MHL_BURST_ID_BLK_RCV_BUFFER_INFO:
			ctx->burst.r_size = get_unaligned_le16(&d[2]);
			break;
		default:
			break;
		}
		count -= len;
		d += len;
	}
	ctx->burst.rx_count = 0;
}

static void sii8620_fetch_edid(struct sii8620 *ctx)
{
	u8 lm_ddc, ddc_cmd, int3, cbus;
	int fetched, i;
	int edid_len = EDID_LENGTH;
	u8 *edid;

	sii8620_readb(ctx, REG_CBUS_STATUS);
	lm_ddc = sii8620_readb(ctx, REG_LM_DDC);
	ddc_cmd = sii8620_readb(ctx, REG_DDC_CMD);

	sii8620_write_seq(ctx,
		REG_INTR9_MASK, 0,
		REG_EDID_CTRL, BIT_EDID_CTRL_EDID_FIFO_ADDR_AUTO,
		REG_HDCP2X_POLL_CS, 0x71,
		REG_HDCP2X_CTRL_0, BIT_HDCP2X_CTRL_0_HDCP2X_HDCPTX,
		REG_LM_DDC, lm_ddc | BIT_LM_DDC_SW_TPI_EN_DISABLED,
	);

	for (i = 0; i < 256; ++i) {
		u8 ddc_stat = sii8620_readb(ctx, REG_DDC_STATUS);

		if (!(ddc_stat & BIT_DDC_STATUS_DDC_I2C_IN_PROG))
			break;
		sii8620_write(ctx, REG_DDC_STATUS,
			      BIT_DDC_STATUS_DDC_FIFO_EMPTY);
	}

	sii8620_write(ctx, REG_DDC_ADDR, 0x50 << 1);

	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
	if (!edid) {
		ctx->error = -ENOMEM;
		return;
	}

#define FETCH_SIZE 16
	for (fetched = 0; fetched < edid_len; fetched += FETCH_SIZE) {
		sii8620_readb(ctx, REG_DDC_STATUS);
		sii8620_write_seq(ctx,
			REG_DDC_CMD, ddc_cmd | VAL_DDC_CMD_DDC_CMD_ABORT,
			REG_DDC_CMD, ddc_cmd | VAL_DDC_CMD_DDC_CMD_CLEAR_FIFO,
			REG_DDC_STATUS, BIT_DDC_STATUS_DDC_FIFO_EMPTY
		);
		sii8620_write_seq(ctx,
			REG_DDC_SEGM, fetched >> 8,
			REG_DDC_OFFSET, fetched & 0xff,
			REG_DDC_DIN_CNT1, FETCH_SIZE,
			REG_DDC_DIN_CNT2, 0,
			REG_DDC_CMD, ddc_cmd | VAL_DDC_CMD_ENH_DDC_READ_NO_ACK
		);

		do {
			int3 = sii8620_readb(ctx, REG_INTR3);
			cbus = sii8620_readb(ctx, REG_CBUS_STATUS);

			if (int3 & BIT_DDC_CMD_DONE)
				break;

			if (!(cbus & BIT_CBUS_STATUS_CBUS_CONNECTED)) {
				kfree(edid);
				edid = NULL;
				goto end;
			}
		} while (1);

		sii8620_readb(ctx, REG_DDC_STATUS);
		while (sii8620_readb(ctx, REG_DDC_DOUT_CNT) < FETCH_SIZE)
			usleep_range(10, 20);

		sii8620_read_buf(ctx, REG_DDC_DATA, edid + fetched, FETCH_SIZE);
		if (fetched + FETCH_SIZE == EDID_LENGTH) {
			u8 ext = ((struct edid *)edid)->extensions;

			if (ext) {
				u8 *new_edid;

				edid_len += ext * EDID_LENGTH;
				new_edid = krealloc(edid, edid_len, GFP_KERNEL);
				if (!new_edid) {
					kfree(edid);
					ctx->error = -ENOMEM;
					return;
				}
				edid = new_edid;
			}
		}
	}

	sii8620_write_seq(ctx,
		REG_INTR3_MASK, BIT_DDC_CMD_DONE,
		REG_LM_DDC, lm_ddc
	);

end:
	kfree(ctx->edid);
	ctx->edid = (struct edid *)edid;
}

static void sii8620_set_upstream_edid(struct sii8620 *ctx)
{
	sii8620_setbits(ctx, REG_DPD, BIT_DPD_PDNRX12 | BIT_DPD_PDIDCK_N
			| BIT_DPD_PD_MHL_CLK_N, 0xff);

	sii8620_write_seq_static(ctx,
		REG_RX_HDMI_CTRL3, 0x00,
		REG_PKT_FILTER_0, 0xFF,
		REG_PKT_FILTER_1, 0xFF,
		REG_ALICE0_BW_I2C, 0x06
	);

	sii8620_setbits(ctx, REG_RX_HDMI_CLR_BUFFER,
			BIT_RX_HDMI_CLR_BUFFER_VSI_CLR_EN, 0xff);

	sii8620_write_seq_static(ctx,
		REG_EDID_CTRL, BIT_EDID_CTRL_EDID_FIFO_ADDR_AUTO
			| BIT_EDID_CTRL_EDID_MODE_EN,
		REG_EDID_FIFO_ADDR, 0,
	);

	sii8620_write_buf(ctx, REG_EDID_FIFO_WR_DATA, (u8 *)ctx->edid,
			  (ctx->edid->extensions + 1) * EDID_LENGTH);

	sii8620_write_seq_static(ctx,
		REG_EDID_CTRL, BIT_EDID_CTRL_EDID_PRIME_VALID
			| BIT_EDID_CTRL_EDID_FIFO_ADDR_AUTO
			| BIT_EDID_CTRL_EDID_MODE_EN,
		REG_INTR5_MASK, BIT_INTR_SCDT_CHANGE,
		REG_INTR9_MASK, 0
	);
}

static void sii8620_xtal_set_rate(struct sii8620 *ctx)
{
	static const struct {
		unsigned int rate;
		u8 div;
		u8 tp1;
	} rates[] = {
		{ 19200, 0x04, 0x53 },
		{ 20000, 0x04, 0x62 },
		{ 24000, 0x05, 0x75 },
		{ 30000, 0x06, 0x92 },
		{ 38400, 0x0c, 0xbc },
	};
	unsigned long rate = clk_get_rate(ctx->clk_xtal) / 1000;
	int i;

	for (i = 0; i < ARRAY_SIZE(rates) - 1; ++i)
		if (rate <= rates[i].rate)
			break;

	if (rate != rates[i].rate)
		dev_err(ctx->dev, "xtal clock rate(%lukHz) not supported, setting MHL for %ukHz.\n",
			rate, rates[i].rate);

	sii8620_write(ctx, REG_DIV_CTL_MAIN, rates[i].div);
	sii8620_write(ctx, REG_HDCP2X_TP1, rates[i].tp1);
}

static int sii8620_hw_on(struct sii8620 *ctx)
{
	int ret;

	ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
	if (ret)
		return ret;

	usleep_range(10000, 20000);
	ret = clk_prepare_enable(ctx->clk_xtal);
	if (ret)
		return ret;

	msleep(100);
	gpiod_set_value(ctx->gpio_reset, 0);
	msleep(100);

	return 0;
}

static int sii8620_hw_off(struct sii8620 *ctx)
{
	clk_disable_unprepare(ctx->clk_xtal);
	gpiod_set_value(ctx->gpio_reset, 1);
	return regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
}

static void sii8620_cbus_reset(struct sii8620 *ctx)
{
	sii8620_write(ctx, REG_PWD_SRST, BIT_PWD_SRST_CBUS_RST
		      | BIT_PWD_SRST_CBUS_RST_SW_EN);
	usleep_range(10000, 20000);
	sii8620_write(ctx, REG_PWD_SRST, BIT_PWD_SRST_CBUS_RST_SW_EN);
}