dm: i2c: Add driver for Cadence I2C IP

This is a possible drop in replacement for drivers/i2c/zynq-i2c.c

Since this is cadence IP it has been renamed to cdns-i2c,
to make sense with the compatible string.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

drivers/i2c/Kconfig

@@ -58,6 +58,13 @@ config DM_I2C_GPIO
 	  bindings are supported.
 	  Binding info: doc/device-tree-bindings/i2c/i2c-gpio.txt
 
+config SYS_I2C_CADENCE
+	tristate "Cadence I2C Controller"
+	depends on DM_I2C && (ARCH_ZYNQ || ARM64)
+	help
+	  Say yes here to select Cadence I2C Host Controller. This controller is
+	  e.g. used by Xilinx Zynq.
+
 config SYS_I2C_INTEL
 	bool "Intel I2C/SMBUS driver"
 	depends on DM_I2C

drivers/i2c/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_PCA9564_I2C) += pca9564_i2c.o
 obj-$(CONFIG_TSI108_I2C) += tsi108_i2c.o
 obj-$(CONFIG_SH_SH7734_I2C) += sh_sh7734_i2c.o
 obj-$(CONFIG_SYS_I2C) += i2c_core.o
+obj-$(CONFIG_SYS_I2C_CADENCE) += i2c-cdns.o
 obj-$(CONFIG_SYS_I2C_DAVINCI) += davinci_i2c.o
 obj-$(CONFIG_SYS_I2C_DW) += designware_i2c.o
 obj-$(CONFIG_SYS_I2C_FSL) += fsl_i2c.o

drivers/i2c/i2c-cdns.c

@@ -0,0 +1,335 @@
+/*
+ * Copyright (C) 2015 Moritz Fischer <moritz.fischer@ettus.com>
+ * IP from Cadence (ID T-CS-PE-0007-100, Version R1p10f2)
+ *
+ * This file is based on: drivers/i2c/zynq_i2c.c,
+ * with added driver-model support and code cleanup.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <linux/types.h>
+#include <linux/io.h>
+#include <asm/errno.h>
+#include <dm/device.h>
+#include <dm/root.h>
+#include <i2c.h>
+#include <fdtdec.h>
+#include <mapmem.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* i2c register set */
+struct cdns_i2c_regs {
+	u32 control;
+	u32 status;
+	u32 address;
+	u32 data;
+	u32 interrupt_status;
+	u32 transfer_size;
+	u32 slave_mon_pause;
+	u32 time_out;
+	u32 interrupt_mask;
+	u32 interrupt_enable;
+	u32 interrupt_disable;
+};
+
+/* Control register fields */
+#define CDNS_I2C_CONTROL_RW		0x00000001
+#define CDNS_I2C_CONTROL_MS		0x00000002
+#define CDNS_I2C_CONTROL_NEA		0x00000004
+#define CDNS_I2C_CONTROL_ACKEN		0x00000008
+#define CDNS_I2C_CONTROL_HOLD		0x00000010
+#define CDNS_I2C_CONTROL_SLVMON		0x00000020
+#define CDNS_I2C_CONTROL_CLR_FIFO	0x00000040
+#define CDNS_I2C_CONTROL_DIV_B_SHIFT	8
+#define CDNS_I2C_CONTROL_DIV_B_MASK	0x00003F00
+#define CDNS_I2C_CONTROL_DIV_A_SHIFT	14
+#define CDNS_I2C_CONTROL_DIV_A_MASK	0x0000C000
+
+/* Status register values */
+#define CDNS_I2C_STATUS_RXDV	0x00000020
+#define CDNS_I2C_STATUS_TXDV	0x00000040
+#define CDNS_I2C_STATUS_RXOVF	0x00000080
+#define CDNS_I2C_STATUS_BA	0x00000100
+
+/* Interrupt register fields */
+#define CDNS_I2C_INTERRUPT_COMP		0x00000001
+#define CDNS_I2C_INTERRUPT_DATA		0x00000002
+#define CDNS_I2C_INTERRUPT_NACK		0x00000004
+#define CDNS_I2C_INTERRUPT_TO		0x00000008
+#define CDNS_I2C_INTERRUPT_SLVRDY	0x00000010
+#define CDNS_I2C_INTERRUPT_RXOVF	0x00000020
+#define CDNS_I2C_INTERRUPT_TXOVF	0x00000040
+#define CDNS_I2C_INTERRUPT_RXUNF	0x00000080
+#define CDNS_I2C_INTERRUPT_ARBLOST	0x00000200
+
+#define CDNS_I2C_FIFO_DEPTH		16
+#define CDNS_I2C_TRANSFER_SIZE_MAX	255 /* Controller transfer limit */
+
+#ifdef DEBUG
+static void cdns_i2c_debug_status(struct cdns_i2c_regs *cdns_i2c)
+{
+	int int_status;
+	int status;
+	int_status = readl(&cdns_i2c->interrupt_status);
+
+	status = readl(&cdns_i2c->status);
+	if (int_status || status) {
+		debug("Status: ");
+		if (int_status & CDNS_I2C_INTERRUPT_COMP)
+			debug("COMP ");
+		if (int_status & CDNS_I2C_INTERRUPT_DATA)
+			debug("DATA ");
+		if (int_status & CDNS_I2C_INTERRUPT_NACK)
+			debug("NACK ");
+		if (int_status & CDNS_I2C_INTERRUPT_TO)
+			debug("TO ");
+		if (int_status & CDNS_I2C_INTERRUPT_SLVRDY)
+			debug("SLVRDY ");
+		if (int_status & CDNS_I2C_INTERRUPT_RXOVF)
+			debug("RXOVF ");
+		if (int_status & CDNS_I2C_INTERRUPT_TXOVF)
+			debug("TXOVF ");
+		if (int_status & CDNS_I2C_INTERRUPT_RXUNF)
+			debug("RXUNF ");
+		if (int_status & CDNS_I2C_INTERRUPT_ARBLOST)
+			debug("ARBLOST ");
+		if (status & CDNS_I2C_STATUS_RXDV)
+			debug("RXDV ");
+		if (status & CDNS_I2C_STATUS_TXDV)
+			debug("TXDV ");
+		if (status & CDNS_I2C_STATUS_RXOVF)
+			debug("RXOVF ");
+		if (status & CDNS_I2C_STATUS_BA)
+			debug("BA ");
+		debug("TS%d ", readl(&cdns_i2c->transfer_size));
+		debug("\n");
+	}
+}
+#endif
+
+struct i2c_cdns_bus {
+	int id;
+	struct cdns_i2c_regs __iomem *regs;	/* register base */
+};
+
+
+/** cdns_i2c_probe() - Probe method
+ * @dev: udevice pointer
+ *
+ * DM callback called when device is probed
+ */
+static int cdns_i2c_probe(struct udevice *dev)
+{
+	struct i2c_cdns_bus *bus = dev_get_priv(dev);
+
+	bus->regs = (struct cdns_i2c_regs *)dev_get_addr(dev);
+	if (!bus->regs)
+		return -ENOMEM;
+
+	/* TODO: Calculate dividers based on CPU_CLK_1X */
+	/* 111MHz / ( (3 * 17) * 22 ) = ~100KHz */
+	writel((16 << CDNS_I2C_CONTROL_DIV_B_SHIFT) |
+		(2 << CDNS_I2C_CONTROL_DIV_A_SHIFT), &bus->regs->control);
+
+	/* Enable master mode, ack, and 7-bit addressing */
+	setbits_le32(&bus->regs->control, CDNS_I2C_CONTROL_MS |
+		CDNS_I2C_CONTROL_ACKEN | CDNS_I2C_CONTROL_NEA);
+
+	debug("%s bus %d at %p\n", __func__, dev->seq, bus->regs);
+
+	return 0;
+}
+
+static int cdns_i2c_remove(struct udevice *dev)
+{
+	struct i2c_cdns_bus *bus = dev_get_priv(dev);
+
+	debug("%s bus %d at %p\n", __func__, dev->seq, bus->regs);
+
+	unmap_sysmem(bus->regs);
+
+	return 0;
+}
+
+/* Wait for an interrupt */
+static u32 cdns_i2c_wait(struct cdns_i2c_regs *cdns_i2c, u32 mask)
+{
+	int timeout, int_status;
+
+	for (timeout = 0; timeout < 100; timeout++) {
+		udelay(100);
+		int_status = readl(&cdns_i2c->interrupt_status);
+		if (int_status & mask)
+			break;
+	}
+
+	/* Clear interrupt status flags */
+	writel(int_status & mask, &cdns_i2c->interrupt_status);
+
+	return int_status & mask;
+}
+
+static int cdns_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
+{
+	if (speed != 100000) {
+		printf("%s, failed to set clock speed to %u\n", __func__,
+		       speed);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Probe to see if a chip is present. */
+static int cdns_i2c_probe_chip(struct udevice *bus, uint chip_addr,
+				uint chip_flags)
+{
+	struct i2c_cdns_bus *i2c_bus = dev_get_priv(bus);
+	struct cdns_i2c_regs *regs = i2c_bus->regs;
+
+	/* Attempt to read a byte */
+	setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
+		CDNS_I2C_CONTROL_RW);
+	clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+	writel(0xFF, &regs->interrupt_status);
+	writel(chip_addr, &regs->address);
+	writel(1, &regs->transfer_size);
+
+	return (cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
+		CDNS_I2C_INTERRUPT_NACK) &
+		CDNS_I2C_INTERRUPT_COMP) ? 0 : -ETIMEDOUT;
+}
+
+static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
+			       u32 len, bool next_is_read)
+{
+	u8 *cur_data = data;
+
+	struct cdns_i2c_regs *regs = i2c_bus->regs;
+
+	setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
+		CDNS_I2C_CONTROL_HOLD);
+
+	/* if next is a read, we need to clear HOLD, doesn't work */
+	if (next_is_read)
+		clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+
+	clrbits_le32(&regs->control, CDNS_I2C_CONTROL_RW);
+
+	writel(0xFF, &regs->interrupt_status);
+	writel(addr, &regs->address);
+
+	while (len--) {
+		writel(*(cur_data++), &regs->data);
+		if (readl(&regs->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
+			if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) {
+				/* Release the bus */
+				clrbits_le32(&regs->control,
+					     CDNS_I2C_CONTROL_HOLD);
+				return -ETIMEDOUT;
+			}
+		}
+	}
+
+	/* All done... release the bus */
+	clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+	/* Wait for the address and data to be sent */
+	if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP))
+		return -ETIMEDOUT;
+	return 0;
+}
+
+static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
+			      u32 len)
+{
+	u32 status;
+	u32 i = 0;
+	u8 *cur_data = data;
+
+	/* TODO: Fix this */
+	struct cdns_i2c_regs *regs = i2c_bus->regs;
+
+	/* Check the hardware can handle the requested bytes */
+	if ((len < 0) || (len > CDNS_I2C_TRANSFER_SIZE_MAX))
+		return -EINVAL;
+
+	setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
+		CDNS_I2C_CONTROL_RW);
+
+	/* Start reading data */
+	writel(addr, &regs->address);
+	writel(len, &regs->transfer_size);
+
+	/* Wait for data */
+	do {
+		status = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
+			CDNS_I2C_INTERRUPT_DATA);
+		if (!status) {
+			/* Release the bus */
+			clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+			return -ETIMEDOUT;
+		}
+		debug("Read %d bytes\n",
+		      len - readl(&regs->transfer_size));
+		for (; i < len - readl(&regs->transfer_size); i++)
+			*(cur_data++) = readl(&regs->data);
+	} while (readl(&regs->transfer_size) != 0);
+	/* All done... release the bus */
+	clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+
+#ifdef DEBUG
+	cdns_i2c_debug_status(regs);
+#endif
+	return 0;
+}
+
+static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
+			 int nmsgs)
+{
+	struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
+	int ret;
+
+	debug("i2c_xfer: %d messages\n", nmsgs);
+	for (; nmsgs > 0; nmsgs--, msg++) {
+		bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD);
+
+		debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
+		if (msg->flags & I2C_M_RD) {
+			ret = cdns_i2c_read_data(i2c_bus, msg->addr, msg->buf,
+						 msg->len);
+		} else {
+			ret = cdns_i2c_write_data(i2c_bus, msg->addr, msg->buf,
+						  msg->len, next_is_read);
+		}
+		if (ret) {
+			debug("i2c_write: error sending\n");
+			return -EREMOTEIO;
+		}
+	}
+
+	return 0;
+}
+
+static const struct dm_i2c_ops cdns_i2c_ops = {
+	.xfer = cdns_i2c_xfer,
+	.probe_chip = cdns_i2c_probe_chip,
+	.set_bus_speed = cdns_i2c_set_bus_speed,
+};
+
+static const struct udevice_id cdns_i2c_of_match[] = {
+	{ .compatible = "cdns,i2c-r1p10" },
+	{ /* end of table */ }
+};
+
+U_BOOT_DRIVER(cdns_i2c) = {
+	.name = "i2c-cdns",
+	.id = UCLASS_I2C,
+	.of_match = cdns_i2c_of_match,
+	.probe = cdns_i2c_probe,
+	.remove = cdns_i2c_remove,
+	.priv_auto_alloc_size = sizeof(struct i2c_cdns_bus),
+	.ops = &cdns_i2c_ops,
+};