i2c: UniPhier: add driver for UniPhier FIFO-builtin i2c controller

This commit adds on-chip I2C driver used on newer SoCs of Panasonic
UniPhier platform.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>

1 files changed, 379 insertions, 0 deletions

diff --git a/drivers/i2c/i2c-uniphier-f.c b/drivers/i2c/i2c-uniphier-f.c
new file mode 100644
index 00000000000..b0d30f76c61
--- /dev/null
+++ b/drivers/i2c/i2c-uniphier-f.c
@@ -0,0 +1,379 @@
+/*
+ * Copyright (C) 2014 Panasonic Corporation
+ *   Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <linux/types.h>
+#include <asm/io.h>
+#include <asm/errno.h>
+#include <dm/device.h>
+#include <dm/root.h>
+#include <i2c.h>
+#include <fdtdec.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct uniphier_fi2c_regs {
+	u32 cr;				/* control register */
+#define I2C_CR_MST	(1 << 3)	/* master mode */
+#define I2C_CR_STA	(1 << 2)	/* start condition */
+#define I2C_CR_STO	(1 << 1)	/* stop condition */
+#define I2C_CR_NACK	(1 << 0)	/* not ACK */
+	u32 dttx;			/* send FIFO (write-only) */
+#define dtrx		dttx		/* receive FIFO (read-only) */
+#define I2C_DTTX_CMD	(1 << 8)	/* send command (slave addr) */
+#define I2C_DTTX_RD	(1 << 0)	/* read */
+	u32 __reserved;			/* no register at offset 0x08 */
+	u32 slad;			/* slave address */
+	u32 cyc;			/* clock cycle control */
+	u32 lctl;			/* clock low period control */
+	u32 ssut;			/* restart/stop setup time control */
+	u32 dsut;			/* data setup time control */
+	u32 intr;			/* interrupt status */
+	u32 ie;				/* interrupt enable */
+	u32 ic;				/* interrupt clear */
+#define I2C_INT_TE	(1 << 9)	/* TX FIFO empty */
+#define I2C_INT_RB	(1 << 4)	/* received specified bytes */
+#define I2C_INT_NA	(1 << 2)	/* no answer */
+#define I2C_INT_AL	(1 << 1)	/* arbitration lost */
+	u32 sr;				/* status register */
+#define I2C_SR_DB	(1 << 12)	/* device busy */
+#define I2C_SR_BB	(1 << 8)	/* bus busy */
+#define I2C_SR_RFF	(1 << 3)	/* Rx FIFO full */
+#define I2C_SR_RNE	(1 << 2)	/* Rx FIFO not empty */
+#define I2C_SR_TNF	(1 << 1)	/* Tx FIFO not full */
+#define I2C_SR_TFE	(1 << 0)	/* Tx FIFO empty */
+	u32 __reserved2;		/* no register at offset 0x30 */
+	u32 rst;			/* reset control */
+#define I2C_RST_TBRST	(1 << 2)	/* clear Tx FIFO */
+#define I2C_RST_RBRST	(1 << 1)	/* clear Rx FIFO */
+#define I2C_RST_RST	(1 << 0)	/* forcible bus reset */
+	u32 bm;				/* bus monitor */
+	u32 noise;			/* noise filter control */
+	u32 tbc;			/* Tx byte count setting */
+	u32 rbc;			/* Rx byte count setting */
+	u32 tbcm;			/* Tx byte count monitor */
+	u32 rbcm;			/* Rx byte count monitor */
+	u32 brst;			/* bus reset */
+#define I2C_BRST_FOEN	(1 << 1)	/* normal operation */
+#define I2C_BRST_RSCLO	(1 << 0)	/* release SCL low fixing */
+};
+
+#define FIOCLK	50000000
+
+struct uniphier_fi2c_dev {
+	struct uniphier_fi2c_regs __iomem *regs;	/* register base */
+	unsigned long fioclk;			/* internal operation clock */
+	unsigned long timeout;			/* time out (us) */
+};
+
+static int poll_status(u32 __iomem *reg, u32 flag)
+{
+	int wait = 1000000; /* 1 sec is long enough */
+
+	while (readl(reg) & flag) {
+		if (wait-- < 0)
+			return -EREMOTEIO;
+		udelay(1);
+	}
+
+	return 0;
+}
+
+static int reset_bus(struct uniphier_fi2c_regs __iomem *regs)
+{
+	int ret;
+
+	/* bus forcible reset */
+	writel(I2C_RST_RST, &regs->rst);
+	ret = poll_status(&regs->rst, I2C_RST_RST);
+	if (ret < 0)
+		debug("error: fail to reset I2C controller\n");
+
+	return ret;
+}
+
+static int check_device_busy(struct uniphier_fi2c_regs __iomem *regs)
+{
+	int ret;
+
+	ret = poll_status(&regs->sr, I2C_SR_DB);
+	if (ret < 0) {
+		debug("error: device busy too long. reset...\n");
+		ret = reset_bus(regs);
+	}
+
+	return ret;
+}
+
+static int uniphier_fi2c_probe(struct udevice *dev)
+{
+	fdt_addr_t addr;
+	fdt_size_t size;
+	struct uniphier_fi2c_dev *priv = dev_get_priv(dev);
+	int ret;
+
+	addr = fdtdec_get_addr_size(gd->fdt_blob, dev->of_offset, "reg",
+				    &size);
+
+	priv->regs = map_sysmem(addr, size);
+
+	if (!priv->regs)
+		return -ENOMEM;
+
+	priv->fioclk = FIOCLK;
+
+	/* bus forcible reset */
+	ret = reset_bus(priv->regs);
+	if (ret < 0)
+		return ret;
+
+	writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, &priv->regs->brst);
+
+	return 0;
+}
+
+static int uniphier_fi2c_remove(struct udevice *dev)
+{
+	struct uniphier_fi2c_dev *priv = dev_get_priv(dev);
+
+	unmap_sysmem(priv->regs);
+
+	return 0;
+}
+
+static int uniphier_fi2c_child_pre_probe(struct udevice *dev)
+{
+	struct dm_i2c_chip *i2c_chip = dev_get_parentdata(dev);
+
+	if (dev->of_offset == -1)
+		return 0;
+	return i2c_chip_ofdata_to_platdata(gd->fdt_blob, dev->of_offset,
+					   i2c_chip);
+}
+
+static int wait_for_irq(struct uniphier_fi2c_dev *dev, u32 flags,
+			bool *stop)
+{
+	u32 irq;
+	unsigned long wait = dev->timeout;
+	int ret = -EREMOTEIO;
+
+	do {
+		udelay(1);
+		irq = readl(&dev->regs->intr);
+	} while (!(irq & flags) && wait--);
+
+	if (wait < 0) {
+		debug("error: time out\n");
+		return ret;
+	}
+
+	if (irq & I2C_INT_AL) {
+		debug("error: arbitration lost\n");
+		*stop = false;
+		return ret;
+	}
+
+	if (irq & I2C_INT_NA) {
+		debug("error: no answer\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int issue_stop(struct uniphier_fi2c_dev *dev, int old_ret)
+{
+	int ret;
+
+	debug("stop condition\n");
+	writel(I2C_CR_MST | I2C_CR_STO, &dev->regs->cr);
+
+	ret = poll_status(&dev->regs->sr, I2C_SR_DB);
+	if (ret < 0)
+		debug("error: device busy after operation\n");
+
+	return old_ret ? old_ret : ret;
+}
+
+static int uniphier_fi2c_transmit(struct uniphier_fi2c_dev *dev, uint addr,
+				  uint len, const u8 *buf, bool *stop)
+{
+	int ret;
+	const u32 irq_flags = I2C_INT_TE | I2C_INT_NA | I2C_INT_AL;
+	struct uniphier_fi2c_regs __iomem *regs = dev->regs;
+
+	debug("%s: addr = %x, len = %d\n", __func__, addr, len);
+
+	writel(I2C_DTTX_CMD | addr << 1, &regs->dttx);
+
+	writel(irq_flags, &regs->ie);
+	writel(irq_flags, &regs->ic);
+
+	debug("start condition\n");
+	writel(I2C_CR_MST | I2C_CR_STA, &regs->cr);
+
+	ret = wait_for_irq(dev, irq_flags, stop);
+	if (ret < 0)
+		goto error;
+
+	while (len--) {
+		debug("sending %x\n", *buf);
+		writel(*buf++, &regs->dttx);
+
+		writel(irq_flags, &regs->ic);
+
+		ret = wait_for_irq(dev, irq_flags, stop);
+		if (ret < 0)
+			goto error;
+	}
+
+error:
+	writel(irq_flags, &regs->ic);
+
+	if (*stop)
+		ret = issue_stop(dev, ret);
+
+	return ret;
+}
+
+static int uniphier_fi2c_receive(struct uniphier_fi2c_dev *dev, uint addr,
+				 uint len, u8 *buf, bool *stop)
+{
+	int ret = 0;
+	const u32 irq_flags = I2C_INT_RB | I2C_INT_NA | I2C_INT_AL;
+	struct uniphier_fi2c_regs __iomem *regs = dev->regs;
+
+	debug("%s: addr = %x, len = %d\n", __func__, addr, len);
+
+	/*
+	 * In case 'len == 0', only the slave address should be sent
+	 * for probing, which is covered by the transmit function.
+	 */
+	if (len == 0)
+		return uniphier_fi2c_transmit(dev, addr, len, buf, stop);
+
+	writel(I2C_DTTX_CMD | I2C_DTTX_RD | addr << 1, &regs->dttx);
+
+	writel(0, &regs->rbc);
+	writel(irq_flags, &regs->ie);
+	writel(irq_flags, &regs->ic);
+
+	debug("start condition\n");
+	writel(I2C_CR_MST | I2C_CR_STA | (len == 1 ? I2C_CR_NACK : 0),
+	       &regs->cr);
+
+	while (len--) {
+		ret = wait_for_irq(dev, irq_flags, stop);
+		if (ret < 0)
+			goto error;
+
+		*buf++ = readl(&regs->dtrx);
+		debug("received %x\n", *(buf - 1));
+
+		if (len == 1)
+			writel(I2C_CR_MST | I2C_CR_NACK, &regs->cr);
+
+		writel(irq_flags, &regs->ic);
+	}
+
+error:
+	writel(irq_flags, &regs->ic);
+
+	if (*stop)
+		ret = issue_stop(dev, ret);
+
+	return ret;
+}
+
+static int uniphier_fi2c_xfer(struct udevice *bus, struct i2c_msg *msg,
+			     int nmsgs)
+{
+	int ret;
+	struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
+	bool stop;
+
+	ret = check_device_busy(dev->regs);
+	if (ret < 0)
+		return ret;
+
+	for (; nmsgs > 0; nmsgs--, msg++) {
+		/* If next message is read, skip the stop condition */
+		stop = nmsgs > 1 && msg[1].flags & I2C_M_RD ? false : true;
+
+		if (msg->flags & I2C_M_RD)
+			ret = uniphier_fi2c_receive(dev, msg->addr, msg->len,
+						    msg->buf, &stop);
+		else
+			ret = uniphier_fi2c_transmit(dev, msg->addr, msg->len,
+						     msg->buf, &stop);
+
+		if (ret < 0)
+			break;
+	}
+
+	return ret;
+}
+
+static int uniphier_fi2c_set_bus_speed(struct udevice *bus, unsigned int speed)
+{
+	int ret;
+	unsigned int clk_count;
+	struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
+	struct uniphier_fi2c_regs __iomem *regs = dev->regs;
+
+	/* max supported frequency is 400 kHz */
+	if (speed > 400000)
+		return -EINVAL;
+
+	ret = check_device_busy(dev->regs);
+	if (ret < 0)
+		return ret;
+
+	/* make sure the bus is idle when changing the frequency */
+	writel(I2C_BRST_RSCLO, &regs->brst);
+
+	clk_count = dev->fioclk / speed;
+
+	writel(clk_count, &regs->cyc);
+	writel(clk_count / 2, &regs->lctl);
+	writel(clk_count / 2, &regs->ssut);
+	writel(clk_count / 16, &regs->dsut);
+
+	writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, &regs->brst);
+
+	/*
+	 * Theoretically, each byte can be transferred in
+	 * 1000000 * 9 / speed usec.
+	 * This time out value is long enough.
+	 */
+	dev->timeout = 100000000L / speed;
+
+	return 0;
+}
+
+static const struct dm_i2c_ops uniphier_fi2c_ops = {
+	.xfer = uniphier_fi2c_xfer,
+	.set_bus_speed = uniphier_fi2c_set_bus_speed,
+};
+
+static const struct udevice_id uniphier_fi2c_of_match[] = {
+	{ .compatible = "panasonic,uniphier-fi2c" },
+	{},
+};
+
+U_BOOT_DRIVER(uniphier_fi2c) = {
+	.name = "uniphier-fi2c",
+	.id = UCLASS_I2C,
+	.of_match = uniphier_fi2c_of_match,
+	.probe = uniphier_fi2c_probe,
+	.remove = uniphier_fi2c_remove,
+	.per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
+	.child_pre_probe = uniphier_fi2c_child_pre_probe,
+	.priv_auto_alloc_size = sizeof(struct uniphier_fi2c_dev),
+	.ops = &uniphier_fi2c_ops,
+};