---

static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx)
{
	unsigned long orig_jiffies = jiffies;
	unsigned int temp;

	writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);

	do {
		temp = readl(lpi2c_imx->base + LPI2C_MSR);
		if (temp & MSR_SDF)
			break;

		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
			dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n");
			if (lpi2c_imx->adapter.bus_recovery_info)
				i2c_recover_bus(&lpi2c_imx->adapter);
			break;
		}
		schedule();

	} while (1);
}

/*
 * CLKLO = (1 - I2C_CLK_HIGH / I2C_CLK_ALL) * clk_cycle, SETHOLD = CLKHI, DATAVD = CLKHI/2
 * CLKHI = I2C_CLK_HIGH / I2C_CLK_ALL * clk_cycle
 */
static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
{
	u8 prescale, filt, sethold, datavd;
	unsigned int clk_rate, clk_cycle, clkhi, clklo;
	enum lpi2c_imx_pincfg pincfg;
	unsigned int temp;

	lpi2c_imx_set_mode(lpi2c_imx);

	clk_rate = lpi2c_imx->rate_per;

	if (lpi2c_imx->mode == HS || lpi2c_imx->mode == ULTRA_FAST)
		filt = 0;
	else
		filt = 2;

	for (prescale = 0; prescale <= 7; prescale++) {
		clk_cycle = clk_rate / ((1 << prescale) * lpi2c_imx->bitrate)
			    - (2 + filt) / (1 << prescale);
		clkhi = clk_cycle * I2C_CLK_HIGH / I2C_CLK_ALL;
		clklo = clk_cycle - clkhi;
		if (clklo < 64)
			break;
	}

	if (prescale > 7)
		return -EINVAL;

	/* set MCFGR1: PINCFG, PRESCALE, IGNACK */
	if (lpi2c_imx->mode == ULTRA_FAST)
		pincfg = TWO_PIN_OO;
	else
		pincfg = TWO_PIN_OD;
	temp = prescale | pincfg << 24;

	if (lpi2c_imx->mode == ULTRA_FAST)
		temp |= MCFGR1_IGNACK;

	writel(temp, lpi2c_imx->base + LPI2C_MCFGR1);

	/* set MCFGR2: FILTSDA, FILTSCL */
	temp = (filt << 16) | (filt << 24);
	writel(temp, lpi2c_imx->base + LPI2C_MCFGR2);

	/* set MCCR: DATAVD, SETHOLD, CLKHI, CLKLO */
	sethold = clkhi;
	datavd = clkhi >> 1;
	temp = datavd << 24 | sethold << 16 | clkhi << 8 | clklo;

	if (lpi2c_imx->mode == HS)
		writel(temp, lpi2c_imx->base + LPI2C_MCCR1);
	else
		writel(temp, lpi2c_imx->base + LPI2C_MCCR0);

	return 0;
}

static int lpi2c_imx_master_enable(struct lpi2c_imx_struct *lpi2c_imx)
{
	unsigned int temp;
	bool enable_runtime_pm = false;
	int ret;

	if (!pm_runtime_enabled(lpi2c_imx->adapter.dev.parent)) {
		pm_runtime_enable(lpi2c_imx->adapter.dev.parent);
		enable_runtime_pm = true;
	}

	ret = pm_runtime_resume_and_get(lpi2c_imx->adapter.dev.parent);
	if (ret < 0) {
		if (enable_runtime_pm)
			pm_runtime_disable(lpi2c_imx->adapter.dev.parent);
		return ret;
	}

	temp = MCR_RST;
	writel(temp, lpi2c_imx->base + LPI2C_MCR);
	writel(0, lpi2c_imx->base + LPI2C_MCR);

	ret = lpi2c_imx_config(lpi2c_imx);
	if (ret)
		goto rpm_put;

	temp = readl(lpi2c_imx->base + LPI2C_MCR);
	temp |= MCR_MEN;
	writel(temp, lpi2c_imx->base + LPI2C_MCR);

	if (enable_runtime_pm)
		pm_runtime_disable(lpi2c_imx->adapter.dev.parent);

	return 0;

rpm_put:
	pm_runtime_mark_last_busy(lpi2c_imx->adapter.dev.parent);
	pm_runtime_put_autosuspend(lpi2c_imx->adapter.dev.parent);

	if (enable_runtime_pm)
		pm_runtime_disable(lpi2c_imx->adapter.dev.parent);

	return ret;
}

static int lpi2c_imx_master_disable(struct lpi2c_imx_struct *lpi2c_imx)
{
	u32 temp;

	temp = readl(lpi2c_imx->base + LPI2C_MCR);
	temp &= ~MCR_MEN;
	writel(temp, lpi2c_imx->base + LPI2C_MCR);

	pm_runtime_mark_last_busy(lpi2c_imx->adapter.dev.parent);
	pm_runtime_put_autosuspend(lpi2c_imx->adapter.dev.parent);

	return 0;
}

static int lpi2c_imx_pio_msg_complete(struct lpi2c_imx_struct *lpi2c_imx)
{
	unsigned long time_left;

	time_left = wait_for_completion_timeout(&lpi2c_imx->complete, HZ);

	return time_left ? 0 : -ETIMEDOUT;
}

static int lpi2c_imx_txfifo_empty(struct lpi2c_imx_struct *lpi2c_imx)
{
	unsigned long orig_jiffies = jiffies;
	u32 txcnt;

	do {
		txcnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff;

		if (readl(lpi2c_imx->base + LPI2C_MSR) & MSR_NDF) {
			dev_dbg(&lpi2c_imx->adapter.dev, "NDF detected\n");
			return -EIO;
		}

		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
			dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n");
			if (lpi2c_imx->adapter.bus_recovery_info)
				i2c_recover_bus(&lpi2c_imx->adapter);
			return -ETIMEDOUT;
		}
		schedule();

	} while (txcnt);

	return 0;
}

static void lpi2c_imx_set_tx_watermark(struct lpi2c_imx_struct *lpi2c_imx)
{
	writel(lpi2c_imx->txfifosize >> 1, lpi2c_imx->base + LPI2C_MFCR);
}

static void lpi2c_imx_set_rx_watermark(struct lpi2c_imx_struct *lpi2c_imx)
{
	unsigned int temp, remaining;

	remaining = lpi2c_imx->msglen - lpi2c_imx->delivered;

	if (remaining > (lpi2c_imx->rxfifosize >> 1))
		temp = lpi2c_imx->rxfifosize >> 1;
	else
		temp = 0;

	writel(temp << 16, lpi2c_imx->base + LPI2C_MFCR);
}

static void lpi2c_imx_write_txfifo(struct lpi2c_imx_struct *lpi2c_imx)
{
	unsigned int data, txcnt;

	txcnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff;

	while (txcnt < lpi2c_imx->txfifosize) {
		if (lpi2c_imx->delivered == lpi2c_imx->msglen)
			break;

		data = lpi2c_imx->tx_buf[lpi2c_imx->delivered++];
		writel(data, lpi2c_imx->base + LPI2C_MTDR);
		txcnt++;
	}

	if (lpi2c_imx->delivered < lpi2c_imx->msglen)
		lpi2c_imx_intctrl(lpi2c_imx, MIER_TDIE | MIER_NDIE);
	else
		complete(&lpi2c_imx->complete);
}

static void lpi2c_imx_read_rxfifo(struct lpi2c_imx_struct *lpi2c_imx)
{
	unsigned int blocklen, remaining;
	unsigned int temp, data;

	do {
		data = readl(lpi2c_imx->base + LPI2C_MRDR);
		if (data & MRDR_RXEMPTY)
			break;

		lpi2c_imx->rx_buf[lpi2c_imx->delivered++] = data & 0xff;
	} while (1);

	/*
	 * First byte is the length of remaining packet in the SMBus block
	 * data read. Add it to msgs->len.
	 */
	if (lpi2c_imx->block_data) {
		blocklen = lpi2c_imx->rx_buf[0];
		lpi2c_imx->msglen += blocklen;
	}

	remaining = lpi2c_imx->msglen - lpi2c_imx->delivered;

	if (!remaining) {
		complete(&lpi2c_imx->complete);
		return;
	}

	/* not finished, still waiting for rx data */
	lpi2c_imx_set_rx_watermark(lpi2c_imx);

	/* multiple receive commands */
	if (lpi2c_imx->block_data) {
		lpi2c_imx->block_data = 0;
		temp = remaining;
		temp |= (RECV_DATA << 8);
		writel(temp, lpi2c_imx->base + LPI2C_MTDR);
	} else if (!(lpi2c_imx->delivered & 0xff)) {
		temp = (remaining > CHUNK_DATA ? CHUNK_DATA : remaining) - 1;
		temp |= (RECV_DATA << 8);
		writel(temp, lpi2c_imx->base + LPI2C_MTDR);
	}

	lpi2c_imx_intctrl(lpi2c_imx, MIER_RDIE);
}