i2c: rcar_i2c: Add DM and DT capable I2C driver

Add derivative of the rcar_i2c driver which is capable of
probing itself from DM and uses DT.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

1 files changed, 353 insertions, 0 deletions

diff --git a/drivers/i2c/rcar_i2c.c b/drivers/i2c/rcar_i2c.c
new file mode 100644
index 0000000000..8d87c73713
--- /dev/null
+++ b/drivers/i2c/rcar_i2c.c
@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * drivers/i2c/rcar_i2c.c
+ *
+ * Copyright (C) 2018 Marek Vasut <marek.vasut@gmail.com>
+ *
+ * Clock configuration based on Linux i2c-rcar.c:
+ * Copyright (C) 2014-15 Wolfram Sang <wsa@sang-engineering.com>
+ * Copyright (C) 2011-2015 Renesas Electronics Corporation
+ * Copyright (C) 2012-14 Renesas Solutions Corp.
+ *   Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <i2c.h>
+#include <asm/io.h>
+#include <wait_bit.h>
+
+#define RCAR_I2C_ICSCR			0x00
+#define RCAR_I2C_ICMCR			0x04
+#define RCAR_I2C_ICMCR_MDBS		BIT(7)
+#define RCAR_I2C_ICMCR_FSCL		BIT(6)
+#define RCAR_I2C_ICMCR_FSDA		BIT(5)
+#define RCAR_I2C_ICMCR_OBPC		BIT(4)
+#define RCAR_I2C_ICMCR_MIE		BIT(3)
+#define RCAR_I2C_ICMCR_TSBE		BIT(2)
+#define RCAR_I2C_ICMCR_FSB		BIT(1)
+#define RCAR_I2C_ICMCR_ESG		BIT(0)
+#define RCAR_I2C_ICSSR			0x08
+#define RCAR_I2C_ICMSR			0x0c
+#define RCAR_I2C_ICMSR_MASK		0x7f
+#define RCAR_I2C_ICMSR_MNR		BIT(6)
+#define RCAR_I2C_ICMSR_MAL		BIT(5)
+#define RCAR_I2C_ICMSR_MST		BIT(4)
+#define RCAR_I2C_ICMSR_MDE		BIT(3)
+#define RCAR_I2C_ICMSR_MDT		BIT(2)
+#define RCAR_I2C_ICMSR_MDR		BIT(1)
+#define RCAR_I2C_ICMSR_MAT		BIT(0)
+#define RCAR_I2C_ICSIER			0x10
+#define RCAR_I2C_ICMIER			0x14
+#define RCAR_I2C_ICCCR			0x18
+#define RCAR_I2C_ICCCR_SCGD_OFF		3
+#define RCAR_I2C_ICSAR			0x1c
+#define RCAR_I2C_ICMAR			0x20
+#define RCAR_I2C_ICRXD_ICTXD		0x24
+
+struct rcar_i2c_priv {
+	void __iomem		*base;
+	struct clk		clk;
+	u32			intdelay;
+	u32			icccr;
+};
+
+static int rcar_i2c_finish(struct udevice *dev)
+{
+	struct rcar_i2c_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMSR, RCAR_I2C_ICMSR_MST,
+				true, 10, true);
+
+	writel(0, priv->base + RCAR_I2C_ICSSR);
+	writel(0, priv->base + RCAR_I2C_ICMSR);
+	writel(0, priv->base + RCAR_I2C_ICMCR);
+
+	return ret;
+}
+
+static void rcar_i2c_recover(struct udevice *dev)
+{
+	struct rcar_i2c_priv *priv = dev_get_priv(dev);
+	u32 mcr = RCAR_I2C_ICMCR_MDBS | RCAR_I2C_ICMCR_OBPC;
+	u32 mcra = mcr | RCAR_I2C_ICMCR_FSDA;
+	int i;
+
+	/* Send 9 SCL pulses */
+	for (i = 0; i < 9; i++) {
+		writel(mcra | RCAR_I2C_ICMCR_FSCL, priv->base + RCAR_I2C_ICMCR);
+		udelay(5);
+		writel(mcra, priv->base + RCAR_I2C_ICMCR);
+		udelay(5);
+	}
+
+	/* Send stop condition */
+	udelay(5);
+	writel(mcra, priv->base + RCAR_I2C_ICMCR);
+	udelay(5);
+	writel(mcr, priv->base + RCAR_I2C_ICMCR);
+	udelay(5);
+	writel(mcr | RCAR_I2C_ICMCR_FSCL, priv->base + RCAR_I2C_ICMCR);
+	udelay(5);
+	writel(mcra | RCAR_I2C_ICMCR_FSCL, priv->base + RCAR_I2C_ICMCR);
+	udelay(5);
+}
+
+static int rcar_i2c_set_addr(struct udevice *dev, u8 chip, u8 read)
+{
+	struct rcar_i2c_priv *priv = dev_get_priv(dev);
+	u32 mask = RCAR_I2C_ICMSR_MAT |
+		   (read ? RCAR_I2C_ICMSR_MDR : RCAR_I2C_ICMSR_MDE);
+	u32 val;
+	int ret;
+
+	writel(0, priv->base + RCAR_I2C_ICMIER);
+	writel(RCAR_I2C_ICMCR_MDBS, priv->base + RCAR_I2C_ICMCR);
+	writel(0, priv->base + RCAR_I2C_ICMSR);
+	writel(priv->icccr, priv->base + RCAR_I2C_ICCCR);
+
+	ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMCR,
+				RCAR_I2C_ICMCR_FSDA, false, 2, true);
+	if (ret) {
+		rcar_i2c_recover(dev);
+		val = readl(priv->base + RCAR_I2C_ICMSR);
+		if (val & RCAR_I2C_ICMCR_FSDA) {
+			dev_err(dev, "Bus busy, aborting\n");
+			return ret;
+		}
+	}
+
+	writel((chip << 1) | read, priv->base + RCAR_I2C_ICMAR);
+	writel(0, priv->base + RCAR_I2C_ICMSR);
+	writel(RCAR_I2C_ICMCR_MDBS | RCAR_I2C_ICMCR_MIE | RCAR_I2C_ICMCR_ESG,
+	       priv->base + RCAR_I2C_ICMCR);
+
+	ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMSR, mask,
+				true, 100, true);
+	if (ret)
+		return ret;
+
+	/* Check NAK */
+	if (readl(priv->base + RCAR_I2C_ICMSR) & RCAR_I2C_ICMSR_MNR)
+		return -EREMOTEIO;
+
+	return 0;
+}
+
+static int rcar_i2c_read_common(struct udevice *dev, struct i2c_msg *msg)
+{
+	struct rcar_i2c_priv *priv = dev_get_priv(dev);
+	u32 icmcr = RCAR_I2C_ICMCR_MDBS | RCAR_I2C_ICMCR_MIE;
+	int i, ret = -EREMOTEIO;
+
+	ret = rcar_i2c_set_addr(dev, msg->addr, 1);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < msg->len; i++) {
+		if (msg->len - 1 == i)
+			icmcr |= RCAR_I2C_ICMCR_FSB;
+
+		writel(icmcr, priv->base + RCAR_I2C_ICMCR);
+		writel(~RCAR_I2C_ICMSR_MDR, priv->base + RCAR_I2C_ICMSR);
+
+		ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMSR,
+					RCAR_I2C_ICMSR_MDR, true, 100, true);
+		if (ret)
+			return ret;
+
+		msg->buf[i] = readl(priv->base + RCAR_I2C_ICRXD_ICTXD) & 0xff;
+	}
+
+	writel(~RCAR_I2C_ICMSR_MDR, priv->base + RCAR_I2C_ICMSR);
+
+	return rcar_i2c_finish(dev);
+}
+
+static int rcar_i2c_write_common(struct udevice *dev, struct i2c_msg *msg)
+{
+	struct rcar_i2c_priv *priv = dev_get_priv(dev);
+	u32 icmcr = RCAR_I2C_ICMCR_MDBS | RCAR_I2C_ICMCR_MIE;
+	int i, ret = -EREMOTEIO;
+
+	ret = rcar_i2c_set_addr(dev, msg->addr, 0);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < msg->len; i++) {
+		writel(msg->buf[i], priv->base + RCAR_I2C_ICRXD_ICTXD);
+		writel(icmcr, priv->base + RCAR_I2C_ICMCR);
+		writel(~RCAR_I2C_ICMSR_MDE, priv->base + RCAR_I2C_ICMSR);
+
+		ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMSR,
+					RCAR_I2C_ICMSR_MDE, true, 100, true);
+		if (ret)
+			return ret;
+	}
+
+	writel(~RCAR_I2C_ICMSR_MDE, priv->base + RCAR_I2C_ICMSR);
+	icmcr |= RCAR_I2C_ICMCR_FSB;
+	writel(icmcr, priv->base + RCAR_I2C_ICMCR);
+
+	return rcar_i2c_finish(dev);
+}
+
+static int rcar_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
+{
+	int ret;
+
+	for (; nmsgs > 0; nmsgs--, msg++) {
+		if (msg->flags & I2C_M_RD)
+			ret = rcar_i2c_read_common(dev, msg);
+		else
+			ret = rcar_i2c_write_common(dev, msg);
+
+		if (ret)
+			return -EREMOTEIO;
+	}
+
+	return ret;
+}
+
+static int rcar_i2c_probe_chip(struct udevice *dev, uint addr, uint flags)
+{
+	struct rcar_i2c_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	/* Ignore address 0, slave address */
+	if (addr == 0)
+		return -EINVAL;
+
+	ret = rcar_i2c_set_addr(dev, addr, 1);
+	writel(0, priv->base + RCAR_I2C_ICMSR);
+	return ret;
+}
+
+static int rcar_i2c_set_speed(struct udevice *dev, uint bus_freq_hz)
+{
+	struct rcar_i2c_priv *priv = dev_get_priv(dev);
+	u32 scgd, cdf, round, ick, sum, scl;
+	unsigned long rate;
+
+	/*
+	 * calculate SCL clock
+	 * see
+	 *	ICCCR
+	 *
+	 * ick	= clkp / (1 + CDF)
+	 * SCL	= ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
+	 *
+	 * ick  : I2C internal clock < 20 MHz
+	 * ticf : I2C SCL falling time
+	 * tr   : I2C SCL rising  time
+	 * intd : LSI internal delay
+	 * clkp : peripheral_clk
+	 * F[]  : integer up-valuation
+	 */
+	rate = clk_get_rate(&priv->clk);
+	cdf = rate / 20000000;
+	if (cdf >= 8) {
+		dev_err(dev, "Input clock %lu too high\n", rate);
+		return -EIO;
+	}
+	ick = rate / (cdf + 1);
+
+	/*
+	 * it is impossible to calculate large scale
+	 * number on u32. separate it
+	 *
+	 * F[(ticf + tr + intd) * ick] with sum = (ticf + tr + intd)
+	 *  = F[sum * ick / 1000000000]
+	 *  = F[(ick / 1000000) * sum / 1000]
+	 */
+	sum = 35 + 200 + priv->intdelay;
+	round = (ick + 500000) / 1000000 * sum;
+	round = (round + 500) / 1000;
+
+	/*
+	 * SCL	= ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
+	 *
+	 * Calculation result (= SCL) should be less than
+	 * bus_speed for hardware safety
+	 *
+	 * We could use something along the lines of
+	 *	div = ick / (bus_speed + 1) + 1;
+	 *	scgd = (div - 20 - round + 7) / 8;
+	 *	scl = ick / (20 + (scgd * 8) + round);
+	 * (not fully verified) but that would get pretty involved
+	 */
+	for (scgd = 0; scgd < 0x40; scgd++) {
+		scl = ick / (20 + (scgd * 8) + round);
+		if (scl <= bus_freq_hz)
+			goto scgd_find;
+	}
+	dev_err(dev, "it is impossible to calculate best SCL\n");
+	return -EIO;
+
+scgd_find:
+	dev_dbg(dev, "clk %d/%d(%lu), round %u, CDF:0x%x, SCGD: 0x%x\n",
+		scl, bus_freq_hz, clk_get_rate(&priv->clk), round, cdf, scgd);
+
+	priv->icccr = (scgd << RCAR_I2C_ICCCR_SCGD_OFF) | cdf;
+	writel(priv->icccr, priv->base + RCAR_I2C_ICCCR);
+
+	return 0;
+}
+
+static int rcar_i2c_probe(struct udevice *dev)
+{
+	struct rcar_i2c_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	priv->base = dev_read_addr_ptr(dev);
+	priv->intdelay = dev_read_u32_default(dev,
+					      "i2c-scl-internal-delay-ns", 5);
+
+	ret = clk_get_by_index(dev, 0, &priv->clk);
+	if (ret)
+		return ret;
+
+	ret = clk_enable(&priv->clk);
+	if (ret)
+		return ret;
+
+	/* reset slave mode */
+	writel(0, priv->base + RCAR_I2C_ICSIER);
+	writel(0, priv->base + RCAR_I2C_ICSAR);
+	writel(0, priv->base + RCAR_I2C_ICSCR);
+	writel(0, priv->base + RCAR_I2C_ICSSR);
+
+	/* reset master mode */
+	writel(0, priv->base + RCAR_I2C_ICMIER);
+	writel(0, priv->base + RCAR_I2C_ICMCR);
+	writel(0, priv->base + RCAR_I2C_ICMSR);
+	writel(0, priv->base + RCAR_I2C_ICMAR);
+
+	ret = rcar_i2c_set_speed(dev, 100000);
+	if (ret)
+		clk_disable(&priv->clk);
+
+	return ret;
+}
+
+static const struct dm_i2c_ops rcar_i2c_ops = {
+	.xfer		= rcar_i2c_xfer,
+	.probe_chip	= rcar_i2c_probe_chip,
+	.set_bus_speed	= rcar_i2c_set_speed,
+};
+
+static const struct udevice_id rcar_i2c_ids[] = {
+	{ .compatible = "renesas,rcar-gen2-i2c" },
+	{ }
+};
+
+U_BOOT_DRIVER(i2c_rcar) = {
+	.name		= "i2c_rcar",
+	.id		= UCLASS_I2C,
+	.of_match	= rcar_i2c_ids,
+	.probe		= rcar_i2c_probe,
+	.priv_auto_alloc_size = sizeof(struct rcar_i2c_priv),
+	.ops		= &rcar_i2c_ops,
+};