[PATCH v9 1/2] i2c: i2c-cortina: added CAxxxx I2C support

[Alex Nemirovsky <alex.nemirovsky@cortina-access.com>]

From: Arthur Li <arthur.li@cortina-access.com>

Add I2C controller support for Cortina Access CAxxxx SoCs

Signed-off-by: Arthur Li <arthur.li@cortina-access.com>
Signed-off-by: Alex Nemirovsky <alex.nemirovsky@cortina-access.com>
CC: Heiko Schocher <hs@denx.de>
Reviewed-by: Heiko Schocher <hs@denx.de>

---

Changes in v9:
- specially include bitops.h and delay.h which
were removed from common.h

Changes in v8:
- No code change
- Split out individual driver from Cortina Package 2 patch series
to help streamline acceptence into master

Changes in v7:
- Added additional description info in I2C KConfig

Changes in v6:
- Add I2C DT binding document

Changes in v4:
- Utilize standard I2C macros from <i2c.h>
- Return ETIMEDOUT in funcs that can timeout
- Return i2c_xfer_init() result to caller of i2c_read() if it
	fails within i2c_read() execution
- Fix misc. style guide conformance issues
- Use printf() to report i2c_xfer() runtime errors
	instead of debug()

 MAINTAINERS                                  |   4 +
 doc/device-tree-bindings/i2c/i2c-cortina.txt |  18 ++
 drivers/i2c/Kconfig                          |   8 +
 drivers/i2c/Makefile                         |   1 +
 drivers/i2c/i2c-cortina.c                    | 346 +++++++++++++++++++++++++++
 drivers/i2c/i2c-cortina.h                    |  87 +++++++
 6 files changed, 464 insertions(+)
 create mode 100644 doc/device-tree-bindings/i2c/i2c-cortina.txt
 create mode 100644 drivers/i2c/i2c-cortina.c
 create mode 100644 drivers/i2c/i2c-cortina.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 8add9d4..ce70ca9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -181,6 +181,8 @@ F:	drivers/gpio/cortina_gpio.c
 F:	drivers/watchdog/cortina_wdt.c
 F:	drivers/serial/serial_cortina.c
 F:	drivers/mmc/ca_dw_mmc.c
+F:	drivers/i2c/i2c-cortina.c
+F:	drivers/i2c/i2c-cortina.h
 
 ARM/CZ.NIC TURRIS MOX SUPPORT
 M:	Marek Behun <marek.behun@nic.cz>
@@ -732,6 +734,8 @@ F:	drivers/gpio/cortina_gpio.c
 F:	drivers/watchdog/cortina_wdt.c
 F:	drivers/serial/serial_cortina.c
 F:	drivers/mmc/ca_dw_mmc.c
+F:	drivers/i2c/i2c-cortina.c
+F:	drivers/i2c/i2c-cortina.h
 
 MIPS MSCC
 M:	Gregory CLEMENT <gregory.clement@bootlin.com>
diff --git a/doc/device-tree-bindings/i2c/i2c-cortina.txt b/doc/device-tree-bindings/i2c/i2c-cortina.txt
new file mode 100644
index 0000000..59d5235
--- /dev/null
+++ b/doc/device-tree-bindings/i2c/i2c-cortina.txt
@@ -0,0 +1,18 @@
+* I2C for Cortina platforms
+
+Required properties :
+- compatible : Must be "cortina,ca-i2c"
+- reg : Offset and length of the register set for the device
+
+Recommended properties :
+- clock-frequency : desired I2C bus clock frequency in Hz. If not specified,
+		    default value is 100000. Possible values are 100000,
+		    400000 and 1000000.
+
+Examples :
+
+	i2c: i2c at f4329120 {
+		compatible = "cortina,ca-i2c";
+		reg = <0x0 0xf4329120 0x28>;
+		clock-frequency = <400000>;
+	};
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index f8b18de..b56e0d9 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -93,6 +93,14 @@ config SYS_I2C_CADENCE
 	  Say yes here to select Cadence I2C Host Controller. This controller is
 	  e.g. used by Xilinx Zynq.
 
+config SYS_I2C_CA
+	tristate "Cortina-Access I2C Controller"
+	depends on DM_I2C && CORTINA_PLATFORM
+	default n
+	help
+	  Add support for the Cortina Access I2C host controller.
+	  Say yes here to select Cortina-Access I2C Host Controller.
+
 config SYS_I2C_DAVINCI
 	bool "Davinci I2C Controller"
 	depends on (ARCH_KEYSTONE || ARCH_DAVINCI)
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index 62935b7..d2b07ce 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SYS_I2C) += i2c_core.o
 obj-$(CONFIG_SYS_I2C_ASPEED) += ast_i2c.o
 obj-$(CONFIG_SYS_I2C_AT91) += at91_i2c.o
 obj-$(CONFIG_SYS_I2C_CADENCE) += i2c-cdns.o
+obj-$(CONFIG_SYS_I2C_CA) += i2c-cortina.o
 obj-$(CONFIG_SYS_I2C_DAVINCI) += davinci_i2c.o
 obj-$(CONFIG_SYS_I2C_DW) += designware_i2c.o
 ifdef CONFIG_DM_PCI
diff --git a/drivers/i2c/i2c-cortina.c b/drivers/i2c/i2c-cortina.c
new file mode 100644
index 0000000..08b812a
--- /dev/null
+++ b/drivers/i2c/i2c-cortina.c
@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2020
+ * Arthur Li, Cortina Access, arthur.li at cortina-access.com.
+ */
+
+#include <common.h>
+#include <i2c.h>
+#include <asm/io.h>
+#include <dm.h>
+#include <mapmem.h>
+#include "i2c-cortina.h"
+
+static void set_speed(struct i2c_regs *regs, int i2c_spd)
+{
+	union ca_biw_cfg i2c_cfg;
+
+	i2c_cfg.wrd = readl(&regs->i2c_cfg);
+	i2c_cfg.bf.core_en = 0;
+	writel(i2c_cfg.wrd, &regs->i2c_cfg);
+
+	switch (i2c_spd) {
+	case IC_SPEED_MODE_FAST_PLUS:
+		i2c_cfg.bf.prer = CORTINA_PER_IO_FREQ /
+				  (5 * I2C_SPEED_FAST_PLUS_RATE) - 1;
+		break;
+
+	case IC_SPEED_MODE_STANDARD:
+		i2c_cfg.bf.prer = CORTINA_PER_IO_FREQ /
+				  (5 * I2C_SPEED_STANDARD_RATE) - 1;
+		break;
+
+	case IC_SPEED_MODE_FAST:
+	default:
+		i2c_cfg.bf.prer = CORTINA_PER_IO_FREQ /
+				  (5 * I2C_SPEED_FAST_RATE) - 1;
+		break;
+	}
+
+	i2c_cfg.bf.core_en = 1;
+	writel(i2c_cfg.wrd, &regs->i2c_cfg);
+}
+
+static int ca_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
+{
+	struct ca_i2c *priv = dev_get_priv(bus);
+	int i2c_spd;
+
+	if (speed >= I2C_SPEED_FAST_PLUS_RATE) {
+		i2c_spd = IC_SPEED_MODE_FAST_PLUS;
+		priv->speed = I2C_SPEED_FAST_PLUS_RATE;
+	} else if (speed >= I2C_SPEED_FAST_RATE) {
+		i2c_spd = IC_SPEED_MODE_FAST;
+		priv->speed = I2C_SPEED_FAST_RATE;
+	} else {
+		i2c_spd = IC_SPEED_MODE_STANDARD;
+		priv->speed = I2C_SPEED_STANDARD_RATE;
+	}
+
+	set_speed(priv->regs, i2c_spd);
+
+	return 0;
+}
+
+static int ca_i2c_get_bus_speed(struct udevice *bus)
+{
+	struct ca_i2c *priv = dev_get_priv(bus);
+
+	return priv->speed;
+}
+
+static void ca_i2c_init(struct i2c_regs *regs)
+{
+	union ca_biw_cfg i2c_cfg;
+
+	i2c_cfg.wrd = readl(&regs->i2c_cfg);
+	i2c_cfg.bf.core_en = 0;
+	i2c_cfg.bf.biw_soft_reset = 1;
+	writel(i2c_cfg.wrd, &regs->i2c_cfg);
+	mdelay(10);
+	i2c_cfg.bf.biw_soft_reset = 0;
+	writel(i2c_cfg.wrd, &regs->i2c_cfg);
+
+	set_speed(regs, IC_SPEED_MODE_STANDARD);
+
+	i2c_cfg.wrd = readl(&regs->i2c_cfg);
+	i2c_cfg.bf.core_en = 1;
+	writel(i2c_cfg.wrd, &regs->i2c_cfg);
+}
+
+static int i2c_wait_complete(struct i2c_regs *regs)
+{
+	union ca_biw_ctrl i2c_ctrl;
+	unsigned long start_time_bb = get_timer(0);
+
+	i2c_ctrl.wrd = readl(&regs->i2c_ctrl);
+
+	while (i2c_ctrl.bf.biwdone == 0) {
+		i2c_ctrl.wrd = readl(&regs->i2c_ctrl);
+
+		if (get_timer(start_time_bb) >
+		   (unsigned long)(I2C_BYTE_TO_BB)) {
+			printf("%s not done!!!\n", __func__);
+			return -ETIMEDOUT;
+		}
+	}
+
+	/* Clear done bit */
+	writel(i2c_ctrl.wrd, &regs->i2c_ctrl);
+
+	return 0;
+}
+
+static void i2c_setaddress(struct i2c_regs *regs, unsigned int i2c_addr,
+			   int write_read)
+{
+	writel(i2c_addr | write_read, &regs->i2c_txr);
+
+	writel(BIW_CTRL_START | BIW_CTRL_WRITE,
+	       &regs->i2c_ctrl);
+
+	i2c_wait_complete(regs);
+}
+
+static int i2c_wait_for_bus_busy(struct i2c_regs *regs)
+{
+	union ca_biw_ack i2c_ack;
+	unsigned long start_time_bb = get_timer(0);
+
+	i2c_ack.wrd = readl(&regs->i2c_ack);
+
+	while (i2c_ack.bf.biw_busy) {
+		i2c_ack.wrd = readl(&regs->i2c_ack);
+
+		if (get_timer(start_time_bb) >
+		   (unsigned long)(I2C_BYTE_TO_BB)) {
+			printf("%s: timeout!\n", __func__);
+			return -ETIMEDOUT;
+		}
+	}
+
+	return 0;
+}
+
+static int i2c_xfer_init(struct i2c_regs *regs, uint8_t chip, uint addr,
+			 int alen, int write_read)
+{
+	int addr_len = alen;
+
+	if (i2c_wait_for_bus_busy(regs))
+		return 1;
+
+	/* First cycle must write addr + offset */
+	chip = ((chip & 0x7F) << 1);
+	if (alen == 0 && write_read == I2C_CMD_RD)
+		i2c_setaddress(regs, chip, I2C_CMD_RD);
+	else
+		i2c_setaddress(regs, chip, I2C_CMD_WT);
+
+	while (alen) {
+		alen--;
+		writel(addr, &regs->i2c_txr);
+		if (write_read == I2C_CMD_RD)
+			writel(BIW_CTRL_WRITE | BIW_CTRL_STOP,
+			       &regs->i2c_ctrl);
+		else
+			writel(BIW_CTRL_WRITE, &regs->i2c_ctrl);
+		i2c_wait_complete(regs);
+	}
+
+	/* Send address again with Read flag if it's read command */
+	if (write_read == I2C_CMD_RD && addr_len > 0)
+		i2c_setaddress(regs, chip, I2C_CMD_RD);
+
+	return 0;
+}
+
+static int i2c_xfer_finish(struct i2c_regs *regs)
+{
+	/* Dummy read makes bus free */
+	writel(BIW_CTRL_READ | BIW_CTRL_STOP, &regs->i2c_ctrl);
+	i2c_wait_complete(regs);
+
+	if (i2c_wait_for_bus_busy(regs)) {
+		printf("Timed out waiting for bus\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int ca_i2c_read(struct i2c_regs *regs, uint8_t chip, uint addr,
+		       int alen, uint8_t *buffer, int len)
+{
+	unsigned long start_time_rx;
+	int rc = 0;
+
+	rc = i2c_xfer_init(regs, chip, addr, alen, I2C_CMD_RD);
+	if (rc)
+		return rc;
+
+	start_time_rx = get_timer(0);
+	while (len) {
+		/* ACK_IN is ack value to send during read.
+		 * ack high only on the very last byte!
+		 */
+		if (len == 1)
+			writel(BIW_CTRL_READ | BIW_CTRL_ACK_IN | BIW_CTRL_STOP,
+			       &regs->i2c_ctrl);
+		else
+			writel(BIW_CTRL_READ, &regs->i2c_ctrl);
+
+		rc = i2c_wait_complete(regs);
+		udelay(1);
+
+		if (rc == 0) {
+			*buffer++ =
+				(uchar) readl(&regs->i2c_rxr);
+			len--;
+			start_time_rx = get_timer(0);
+
+		} else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
+			return -ETIMEDOUT;
+		}
+	}
+	i2c_xfer_finish(regs);
+	return rc;
+}
+
+static int ca_i2c_write(struct i2c_regs *regs, uint8_t chip, uint addr,
+			int alen, uint8_t *buffer, int len)
+{
+	int rc, nb = len;
+	unsigned long start_time_tx;
+
+	rc = i2c_xfer_init(regs, chip, addr, alen, I2C_CMD_WT);
+	if (rc)
+		return rc;
+
+	start_time_tx = get_timer(0);
+	while (len) {
+		writel(*buffer, &regs->i2c_txr);
+		if (len == 1)
+			writel(BIW_CTRL_WRITE | BIW_CTRL_STOP,
+			       &regs->i2c_ctrl);
+		else
+			writel(BIW_CTRL_WRITE, &regs->i2c_ctrl);
+
+		rc = i2c_wait_complete(regs);
+
+		if (rc == 0) {
+			len--;
+			buffer++;
+			start_time_tx = get_timer(0);
+		} else if (get_timer(start_time_tx) > (nb * I2C_BYTE_TO)) {
+			return -ETIMEDOUT;
+		}
+	}
+
+	return 0;
+}
+
+static int ca_i2c_probe_chip(struct udevice *bus, uint chip_addr,
+			     uint chip_flags)
+{
+	struct ca_i2c *priv = dev_get_priv(bus);
+	int ret;
+	u32 tmp;
+
+	/* Try to read the first location of the chip */
+	ret = ca_i2c_read(priv->regs, chip_addr, 0, 1, (uchar *)&tmp, 1);
+	if (ret)
+		ca_i2c_init(priv->regs);
+
+	return ret;
+}
+
+static int ca_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
+{
+	struct ca_i2c *priv = dev_get_priv(bus);
+	int ret;
+
+	debug("i2c_xfer: %d messages\n", nmsgs);
+	for (; nmsgs > 0; nmsgs--, msg++) {
+		debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
+		if (msg->flags & I2C_M_RD)
+			ret = ca_i2c_read(priv->regs, msg->addr, 0, 0,
+					  msg->buf, msg->len);
+		else
+			ret = ca_i2c_write(priv->regs, msg->addr, 0, 0,
+					   msg->buf, msg->len);
+
+		if (ret) {
+			printf("i2c_xfer: %s error\n",
+			       msg->flags & I2C_M_RD ? "read" : "write");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const struct dm_i2c_ops ca_i2c_ops = {
+	.xfer		= ca_i2c_xfer,
+	.probe_chip	= ca_i2c_probe_chip,
+	.set_bus_speed	= ca_i2c_set_bus_speed,
+	.get_bus_speed	= ca_i2c_get_bus_speed,
+};
+
+static const struct udevice_id ca_i2c_ids[] = {
+	{ .compatible = "cortina,ca-i2c", },
+	{ }
+};
+
+static int ca_i2c_probe(struct udevice *bus)
+{
+	struct ca_i2c *priv = dev_get_priv(bus);
+
+	ca_i2c_init(priv->regs);
+
+	return 0;
+}
+
+static int ca_i2c_ofdata_to_platdata(struct udevice *bus)
+{
+	struct ca_i2c *priv = dev_get_priv(bus);
+
+	priv->regs = map_sysmem(dev_read_addr(bus), sizeof(struct i2c_regs));
+	if (!priv->regs) {
+		printf("I2C: base address is invalid\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+U_BOOT_DRIVER(i2c_cortina) = {
+	.name	= "i2c_cortina",
+	.id	= UCLASS_I2C,
+	.of_match = ca_i2c_ids,
+	.ofdata_to_platdata = ca_i2c_ofdata_to_platdata,
+	.probe	= ca_i2c_probe,
+	.priv_auto_alloc_size = sizeof(struct ca_i2c),
+	.ops	= &ca_i2c_ops,
+	.flags  = DM_FLAG_PRE_RELOC,
+};
diff --git a/drivers/i2c/i2c-cortina.h b/drivers/i2c/i2c-cortina.h
new file mode 100644
index 0000000..7e406b5
--- /dev/null
+++ b/drivers/i2c/i2c-cortina.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2019
+ * Cortina Access, <www.cortina-access.com>
+ */
+
+#ifndef __CA_I2C_H_
+#define __CA_I2C_H_
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+
+#if !defined(__ASSEMBLER__) && !defined(__ASSEMBLY__)
+struct i2c_regs {
+	u32 i2c_cfg;
+	u32 i2c_ctrl;
+	u32 i2c_txr;
+	u32 i2c_rxr;
+	u32 i2c_ack;
+	u32 i2c_ie0;
+	u32 i2c_int0;
+	u32 i2c_ie1;
+	u32 i2c_int1;
+	u32 i2c_stat;
+};
+
+union ca_biw_cfg {
+	struct biw_cfg {
+		u32 core_en		: 1;
+		u32 biw_soft_reset	: 1;
+		u32 busywait_en		: 1;
+		u32 stretch_en		: 1;
+		u32 arb_en		: 1;
+		u32 clksync_en		: 1;
+		u32 rsrvd1		: 2;
+		u32 spike_cnt		: 4;
+		u32 rsrvd2		: 4;
+		u32 prer		: 16;
+	} bf;
+	unsigned int wrd;
+};
+
+union ca_biw_ctrl {
+	struct biw_ctrl {
+		u32 biwdone	: 1;
+		u32 rsrvd1	: 2;
+		u32 ack_in	: 1;
+		u32 write	: 1;
+		u32 read	: 1;
+		u32 stop	: 1;
+		u32 start	: 1;
+		u32 rsrvd2	: 24;
+	} bf;
+	unsigned int wrd;
+};
+
+union ca_biw_ack {
+	struct biw_ack {
+		u32 al		:1;
+		u32 biw_busy	:1;
+		u32 ack_out	:1;
+		u32 rsrvd1	:29;
+	} bf;
+	unsigned int wrd;
+};
+#endif /* !__ASSEMBLER__*/
+
+struct ca_i2c {
+	struct i2c_regs *regs;
+	unsigned int speed;
+};
+
+#define I2C_CMD_WT			0
+#define I2C_CMD_RD			1
+
+#define BIW_CTRL_DONE		BIT(0)
+#define BIW_CTRL_ACK_IN		BIT(3)
+#define BIW_CTRL_WRITE		BIT(4)
+#define BIW_CTRL_READ		BIT(5)
+#define BIW_CTRL_STOP		BIT(6)
+#define BIW_CTRL_START		BIT(7)
+
+#define I2C_BYTE_TO		(CONFIG_SYS_HZ / 500)
+#define I2C_STOPDET_TO		(CONFIG_SYS_HZ / 500)
+#define I2C_BYTE_TO_BB		(10)
+
+#endif							/* __CA_I2C_H_ */
-- 
2.7.4