[PATCH v2] i2c: octeon_i2c: Add I2C controller driver for Octeon

* [PATCH v2] i2c: octeon_i2c: Add I2C controller driver for Octeon
@ 2020-05-26 12:13 Stefan Roese
  2020-05-31 14:08 ` Simon Glass
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Stefan Roese @ 2020-05-26 12:13 UTC (permalink / raw)
  To: u-boot

From: Suneel Garapati <sgarapati@marvell.com>

Add support for I2C controllers found on Octeon II/III and Octeon TX
TX2 SoC platforms.

Signed-off-by: Aaron Williams <awilliams@marvell.com>
Signed-off-by: Suneel Garapati <sgarapati@marvell.com>
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Aaron Williams <awilliams@marvell.com>
Cc: Chandrakala Chavva <cchavva@marvell.com>
---
v2 (Stefan):
- Added clk framework support and dropped ad-hoc clock code
- Removed #ifdef's for Octeon vs OcteonTX/TX2 completely
  The differentiation is now made via driver data / compatible
  string
- Added device-tree bindings documentation
- Removed unused macro

RFC -> v1 (Stefan):
- Separated this patch from the OcteonTX/TX2 RFC patch series into a
  single patch. This is useful, as the upcoming MIPS Octeon support will
  use this I2C driver.
- Added MIPS Octeon II/III support (big endian). Rename driver and its
  function names from "octeontx" to "octeon" to better match all Octeon
  platforms.
- Moved from union to defines / bitmasks as suggested by Simon. This makes
  the driver usage on little- and big-endian platforms much easier.
- Enhanced Kconfig text
- Removed all clock macros (use values from DT)
- Removed long driver debug strings. This is only available when a debug
  version of this driver is built. The user / developer can lookup the
  descriptive error messages in the driver in this case anyway.
- Removed static "last_id"
- Dropped misc blank lines. Misc reformatting.
- Dropped "!= 0"
- Added missing function comments
- Added missing strut comments
- Changed comment style
- Renames "result" to "ret"
- Hex numbers uppercase
- Minor other changes
- Reword commit text and subject

 doc/device-tree-bindings/i2c/octeon-i2c.txt |  24 +
 drivers/i2c/Kconfig                         |  10 +
 drivers/i2c/Makefile                        |   1 +
 drivers/i2c/octeon_i2c.c                    | 847 ++++++++++++++++++++
 4 files changed, 882 insertions(+)
 create mode 100644 doc/device-tree-bindings/i2c/octeon-i2c.txt
 create mode 100644 drivers/i2c/octeon_i2c.c

diff --git a/doc/device-tree-bindings/i2c/octeon-i2c.txt b/doc/device-tree-bindings/i2c/octeon-i2c.txt
new file mode 100644
index 0000000000..9c1908ec2c
--- /dev/null
+++ b/doc/device-tree-bindings/i2c/octeon-i2c.txt
@@ -0,0 +1,24 @@
+* I2C controller embedded in Marvell Octeon platforms
+
+Required properties :
+- compatible : Must be "cavium,octeon-7890-twsi" or a compatible string
+- reg : Offset and length of the register set for the device
+- clocks: Must contain the input clock of the I2C instance
+- #address-cells = <1>;
+- #size-cells = <0>;
+
+Optional properties :
+- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified,
+  the default 100 kHz frequency will be used. As only Normal, Fast and Fast+
+  modes are implemented, possible values are 100000, 400000 and 1000000.
+
+Example :
+
+	i2c0: i2c at 1180000001000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "cavium,octeon-7890-twsi";
+		reg = <0x11800 0x00001000 0x0 0x200>;
+		clock-frequency = <100000>;
+		clocks = <&sclk>;
+	};
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index f8b18de8f3..363b899e9c 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -374,6 +374,16 @@ config SYS_I2C_SANDBOX
 	  bus. Devices can be attached to the bus using the device tree
 	  which specifies the driver to use.  See sandbox.dts as an example.
 
+config SYS_I2C_OCTEON
+	bool "Octeon II/III/TX/TX2 I2C driver"
+	depends on (ARCH_OCTEON || ARCH_OCTEONTX || ARCH_OCTEONTX2) && DM_I2C
+	default y
+	help
+	  Add support for the Marvell Octeon I2C driver. This is used with
+	  various Octeon parts such as Octeon II/III and OcteonTX/TX2. All
+	  chips have several I2C ports and all are provided, controlled by
+	  the device tree.
+
 config SYS_I2C_S3C24X0
 	bool "Samsung I2C driver"
 	depends on ARCH_EXYNOS4 && DM_I2C
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index 62935b7ebc..2b58aae892 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_SYS_I2C_LPC32XX) += lpc32xx_i2c.o
 obj-$(CONFIG_SYS_I2C_MESON) += meson_i2c.o
 obj-$(CONFIG_SYS_I2C_MVTWSI) += mvtwsi.o
 obj-$(CONFIG_SYS_I2C_MXC) += mxc_i2c.o
+obj-$(CONFIG_SYS_I2C_OCTEON) += octeon_i2c.o
 obj-$(CONFIG_SYS_I2C_OMAP24XX) += omap24xx_i2c.o
 obj-$(CONFIG_SYS_I2C_RCAR_I2C) += rcar_i2c.o
 obj-$(CONFIG_SYS_I2C_RCAR_IIC) += rcar_iic.o
diff --git a/drivers/i2c/octeon_i2c.c b/drivers/i2c/octeon_i2c.c
new file mode 100644
index 0000000000..c11d6ff93d
--- /dev/null
+++ b/drivers/i2c/octeon_i2c.c
@@ -0,0 +1,847 @@
+// SPDX-License-Identifier:    GPL-2.0
+/*
+ * Copyright (C) 2018 Marvell International Ltd.
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <i2c.h>
+#include <pci_ids.h>
+#include <asm/io.h>
+#include <linux/bitfield.h>
+#include <linux/compat.h>
+#include <linux/delay.h>
+
+#define TWSI_SW_TWSI		0x00
+#define TWSI_TWSI_SW		0x08
+#define TWSI_INT		0x10
+#define TWSI_SW_TWSI_EXT	0x18
+
+#define TWSI_SW_DATA_MASK	GENMASK_ULL(31, 0)
+#define TWSI_SW_EOP_IA_MASK	GENMASK_ULL(34, 32)
+#define TWSI_SW_IA_MASK		GENMASK_ULL(39, 35)
+#define TWSI_SW_ADDR_MASK	GENMASK_ULL(49, 40)
+#define TWSI_SW_SCR_MASK	GENMASK_ULL(51, 50)
+#define TWSI_SW_SIZE_MASK	GENMASK_ULL(54, 52)
+#define TWSI_SW_SOVR		BIT_ULL(55)
+#define TWSI_SW_R		BIT_ULL(56)
+#define TWSI_SW_OP_MASK		GENMASK_ULL(60, 57)
+#define TWSI_SW_EIA		GENMASK_ULL(61)
+#define TWSI_SW_SLONLY		BIT_ULL(62)
+#define TWSI_SW_V		BIT_ULL(63)
+
+#define TWSI_INT_SDA_OVR	BIT_ULL(8)
+#define TWSI_INT_SCL_OVR	BIT_ULL(9)
+#define TWSI_INT_SDA		BIT_ULL(10)
+#define TWSI_INT_SCL		BIT_ULL(11)
+
+enum {
+	TWSI_OP_WRITE	= 0,
+	TWSI_OP_READ	= 1,
+};
+
+enum {
+	TWSI_EOP_SLAVE_ADDR = 0,
+	TWSI_EOP_CLK_CTL = 3,
+	TWSI_SW_EOP_IA   = 6,
+};
+
+enum {
+	TWSI_SLAVEADD     = 0,
+	TWSI_DATA         = 1,
+	TWSI_CTL          = 2,
+	TWSI_CLKCTL       = 3,
+	TWSI_STAT         = 3,
+	TWSI_SLAVEADD_EXT = 4,
+	TWSI_RST          = 7,
+};
+
+enum {
+	TWSI_CTL_AAK	= BIT(2),
+	TWSI_CTL_IFLG	= BIT(3),
+	TWSI_CTL_STP	= BIT(4),
+	TWSI_CTL_STA	= BIT(5),
+	TWSI_CTL_ENAB	= BIT(6),
+	TWSI_CTL_CE	= BIT(7),
+};
+
+/*
+ * Internal errors. When debugging is enabled, the driver will report the
+ * error number and the user / developer can check the table below for the
+ * detailed error description.
+ */
+enum {
+	/** Bus error */
+	TWSI_STAT_BUS_ERROR		= 0x00,
+	/** Start condition transmitted */
+	TWSI_STAT_START			= 0x08,
+	/** Repeat start condition transmitted */
+	TWSI_STAT_RSTART		= 0x10,
+	/** Address + write bit transmitted, ACK received */
+	TWSI_STAT_TXADDR_ACK		= 0x18,
+	/** Address + write bit transmitted, /ACK received */
+	TWSI_STAT_TXADDR_NAK		= 0x20,
+	/** Data byte transmitted in master mode, ACK received */
+	TWSI_STAT_TXDATA_ACK		= 0x28,
+	/** Data byte transmitted in master mode, ACK received */
+	TWSI_STAT_TXDATA_NAK		= 0x30,
+	/** Arbitration lost in address or data byte */
+	TWSI_STAT_TX_ARB_LOST		= 0x38,
+	/** Address + read bit transmitted, ACK received */
+	TWSI_STAT_RXADDR_ACK		= 0x40,
+	/** Address + read bit transmitted, /ACK received */
+	TWSI_STAT_RXADDR_NAK		= 0x48,
+	/** Data byte received in master mode, ACK transmitted */
+	TWSI_STAT_RXDATA_ACK_SENT	= 0x50,
+	/** Data byte received, NACK transmitted */
+	TWSI_STAT_RXDATA_NAK_SENT	= 0x58,
+	/** Slave address received, sent ACK */
+	TWSI_STAT_SLAVE_RXADDR_ACK	= 0x60,
+	/**
+	 * Arbitration lost in address as master, slave address + write bit
+	 * received, ACK transmitted
+	 */
+	TWSI_STAT_TX_ACK_ARB_LOST	= 0x68,
+	/** General call address received, ACK transmitted */
+	TWSI_STAT_RX_GEN_ADDR_ACK	= 0x70,
+	/**
+	 * Arbitration lost in address as master, general call address
+	 * received, ACK transmitted
+	 */
+	TWSI_STAT_RX_GEN_ADDR_ARB_LOST	= 0x78,
+	/** Data byte received after slave address received, ACK transmitted */
+	TWSI_STAT_SLAVE_RXDATA_ACK	= 0x80,
+	/** Data byte received after slave address received, /ACK transmitted */
+	TWSI_STAT_SLAVE_RXDATA_NAK	= 0x88,
+	/**
+	 * Data byte received after general call address received, ACK
+	 * transmitted
+	 */
+	TWSI_STAT_GEN_RXADDR_ACK	= 0x90,
+	/**
+	 * Data byte received after general call address received, /ACK
+	 * transmitted
+	 */
+	TWSI_STAT_GEN_RXADDR_NAK	= 0x98,
+	/** STOP or repeated START condition received in slave mode */
+	TWSI_STAT_STOP_MULTI_START	= 0xa0,
+	/** Slave address + read bit received, ACK transmitted */
+	TWSI_STAT_SLAVE_RXADDR2_ACK	= 0xa8,
+	/**
+	 * Arbitration lost in address as master, slave address + read bit
+	 * received, ACK transmitted
+	 */
+	TWSI_STAT_RXDATA_ACK_ARB_LOST	= 0xb0,
+	/** Data byte transmitted in slave mode, ACK received */
+	TWSI_STAT_SLAVE_TXDATA_ACK	= 0xb8,
+	/** Data byte transmitted in slave mode, /ACK received */
+	TWSI_STAT_SLAVE_TXDATA_NAK	= 0xc0,
+	/** Last byte transmitted in slave mode, ACK received */
+	TWSI_STAT_SLAVE_TXDATA_END_ACK	= 0xc8,
+	/** Second address byte + write bit transmitted, ACK received */
+	TWSI_STAT_TXADDR2DATA_ACK	= 0xd0,
+	/** Second address byte + write bit transmitted, /ACK received */
+	TWSI_STAT_TXADDR2DATA_NAK	= 0xd8,
+	/** No relevant status information */
+	TWSI_STAT_IDLE			= 0xf8
+};
+
+#define CONFIG_SYS_I2C_OCTEON_SLAVE_ADDR	0x77
+
+enum {
+	PROBE_PCI = 0,		/* PCI based probing */
+	PROBE_DT,		/* DT based probing */
+};
+
+enum {
+	CLK_METHOD_OCTEON = 0,
+	CLK_METHOD_OCTEONTX2,
+};
+
+/**
+ * struct octeon_i2c_data - SoC specific data of this driver
+ *
+ * @probe:	Probing of this SoC (DT vs PCI)
+ * @reg_offs:	Register offset
+ * @thp:	THP define for divider calculation
+ * @clk_method:	Clock calculation method
+ */
+struct octeon_i2c_data {
+	int probe;
+	u32 reg_offs;
+	int thp;
+	int clk_method;
+};
+
+/**
+ * struct octeon_twsi - Private data of this driver
+ *
+ * @base:	Base address of i2c registers
+ * @data:	Pointer to SoC specific data struct
+ */
+struct octeon_twsi {
+	void __iomem *base;
+	const struct octeon_i2c_data *data;
+	struct clk clk;
+};
+
+static void twsi_unblock(void *base);
+static int twsi_stop(void *base);
+
+/**
+ * Returns true if we lost arbitration
+ *
+ * @code	status code
+ * @final_read	true if this is the final read operation
+ * @return	true if arbitration has been lost, false if it hasn't been lost.
+ */
+static int twsi_i2c_lost_arb(u8 code, int final_read)
+{
+	switch (code) {
+	case TWSI_STAT_TX_ARB_LOST:
+	case TWSI_STAT_TX_ACK_ARB_LOST:
+	case TWSI_STAT_RX_GEN_ADDR_ARB_LOST:
+	case TWSI_STAT_RXDATA_ACK_ARB_LOST:
+		/* Arbitration lost */
+		return -EAGAIN;
+
+	case TWSI_STAT_SLAVE_RXADDR_ACK:
+	case TWSI_STAT_RX_GEN_ADDR_ACK:
+	case TWSI_STAT_GEN_RXADDR_ACK:
+	case TWSI_STAT_GEN_RXADDR_NAK:
+		/* Being addressed as slave, should back off and listen */
+		return -EIO;
+
+	case TWSI_STAT_SLAVE_RXDATA_ACK:
+	case TWSI_STAT_SLAVE_RXDATA_NAK:
+	case TWSI_STAT_STOP_MULTI_START:
+	case TWSI_STAT_SLAVE_RXADDR2_ACK:
+	case TWSI_STAT_SLAVE_TXDATA_ACK:
+	case TWSI_STAT_SLAVE_TXDATA_NAK:
+	case TWSI_STAT_SLAVE_TXDATA_END_ACK:
+		/* Core busy as slave */
+		return  -EIO;
+
+	case TWSI_STAT_RXDATA_ACK_SENT:
+		/* Ack allowed on pre-terminal bytes only */
+		if (!final_read)
+			return 0;
+		return -EAGAIN;
+
+	case TWSI_STAT_RXDATA_NAK_SENT:
+		/* NAK allowed on terminal byte only */
+		if (!final_read)
+			return 0;
+		return -EAGAIN;
+
+	case TWSI_STAT_TXDATA_NAK:
+	case TWSI_STAT_TXADDR_NAK:
+	case TWSI_STAT_RXADDR_NAK:
+	case TWSI_STAT_TXADDR2DATA_NAK:
+		return -EAGAIN;
+	}
+
+	return 0;
+}
+
+/**
+ * Writes to the MIO_TWS(0..5)_SW_TWSI register
+ *
+ * @base	Base address of i2c registers
+ * @val		value to write
+ * @return	0 for success, otherwise error
+ */
+static u64 twsi_write_sw(void __iomem *base, u64 val)
+{
+	unsigned long start = get_timer(0);
+
+	val &= ~TWSI_SW_R;
+	val |= TWSI_SW_V;
+
+	debug("%s(%p, 0x%llx)\n", __func__, base, val);
+	writeq(val, base + TWSI_SW_TWSI);
+	do {
+		val = readq(base + TWSI_SW_TWSI);
+	} while ((val & TWSI_SW_V) && (get_timer(start) < 50));
+
+	if (val & TWSI_SW_V)
+		debug("%s: timed out\n", __func__);
+	return val;
+}
+
+/**
+ * Reads the MIO_TWS(0..5)_SW_TWSI register
+ *
+ * @base	Base address of i2c registers
+ * @val		value for eia and op, etc. to read
+ * @return	value of the register
+ */
+static u64 twsi_read_sw(void __iomem *base, u64 val)
+{
+	unsigned long start = get_timer(0);
+
+	val |= TWSI_SW_R | TWSI_SW_V;
+
+	debug("%s(%p, 0x%llx)\n", __func__, base, val);
+	writeq(val, base + TWSI_SW_TWSI);
+
+	do {
+		val = readq(base + TWSI_SW_TWSI);
+	} while ((val & TWSI_SW_V) && (get_timer(start) < 50));
+
+	if (val & TWSI_SW_V)
+		debug("%s: Error writing 0x%llx\n", __func__, val);
+
+	debug("%s: Returning 0x%llx\n", __func__, val);
+	return val;
+}
+
+/**
+ * Write control register
+ *
+ * @base	Base address for i2c registers
+ * @data	data to write
+ */
+static void twsi_write_ctl(void __iomem *base, u8 data)
+{
+	u64 val;
+
+	debug("%s(%p, 0x%x)\n", __func__, base, data);
+	val = data | FIELD_PREP(TWSI_SW_EOP_IA_MASK, TWSI_CTL) |
+		FIELD_PREP(TWSI_SW_OP_MASK, TWSI_SW_EOP_IA);
+	twsi_write_sw(base, val);
+}
+
+/**
+ * Reads the TWSI Control Register
+ *
+ * @base	Base address for i2c
+ * @return	8-bit TWSI control register
+ */
+static u8 twsi_read_ctl(void __iomem *base)
+{
+	u64 val;
+
+	val = FIELD_PREP(TWSI_SW_EOP_IA_MASK, TWSI_CTL) |
+		FIELD_PREP(TWSI_SW_OP_MASK, TWSI_SW_EOP_IA);
+	val = twsi_read_sw(base, val);
+
+	debug("%s(%p): 0x%x\n", __func__, base, (u8)val);
+	return (u8)val;
+}
+
+/**
+ * Read i2c status register
+ *
+ * @base	Base address of i2c registers
+ * @return	value of status register
+ */
+static u8 twsi_read_status(void __iomem *base)
+{
+	u64 val;
+
+	val = FIELD_PREP(TWSI_SW_EOP_IA_MASK, TWSI_STAT) |
+		FIELD_PREP(TWSI_SW_OP_MASK, TWSI_SW_EOP_IA);
+
+	return twsi_read_sw(base, val);
+}
+
+/**
+ * Waits for an i2c operation to complete
+ *
+ * @param	base	Base address of registers
+ * @return	0 for success, 1 if timeout
+ */
+static int twsi_wait(void __iomem *base)
+{
+	unsigned long start = get_timer(0);
+	u8 twsi_ctl;
+
+	debug("%s(%p)\n", __func__, base);
+	do {
+		twsi_ctl = twsi_read_ctl(base);
+		twsi_ctl &= TWSI_CTL_IFLG;
+	} while (!twsi_ctl && get_timer(start) < 50);
+
+	debug("  return: %u\n", !twsi_ctl);
+	return !twsi_ctl;
+}
+
+/**
+ * Unsticks the i2c bus
+ *
+ * @base	base address of registers
+ */
+static int twsi_start_unstick(void __iomem *base)
+{
+	twsi_stop(base);
+	twsi_unblock(base);
+
+	return 0;
+}
+
+/**
+ * Sends an i2c start condition
+ *
+ * @base	base address of registers
+ * @return	0 for success, otherwise error
+ */
+static int twsi_start(void __iomem *base)
+{
+	int ret;
+	u8 stat;
+
+	debug("%s(%p)\n", __func__, base);
+	twsi_write_ctl(base, TWSI_CTL_STA | TWSI_CTL_ENAB);
+	ret = twsi_wait(base);
+	if (ret) {
+		stat = twsi_read_status(base);
+		debug("%s: ret: 0x%x, status: 0x%x\n", __func__, ret, stat);
+		switch (stat) {
+		case TWSI_STAT_START:
+		case TWSI_STAT_RSTART:
+			return 0;
+		case TWSI_STAT_RXADDR_ACK:
+		default:
+			return twsi_start_unstick(base);
+		}
+	}
+
+	debug("%s: success\n", __func__);
+	return 0;
+}
+
+/**
+ * Sends an i2c stop condition
+ *
+ * @base	register base address
+ * @return	0 for success, -1 if error
+ */
+static int twsi_stop(void __iomem *base)
+{
+	u8 stat;
+
+	twsi_write_ctl(base, TWSI_CTL_STP | TWSI_CTL_ENAB);
+
+	stat = twsi_read_status(base);
+	if (stat != TWSI_STAT_IDLE) {
+		debug("%s: Bad status on bus@%p\n", __func__, base);
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * Writes data to the i2c bus
+ *
+ * @base	register base address
+ * @slave_addr	address of slave to write to
+ * @buffer	Pointer to buffer to write
+ * @length	Number of bytes in buffer to write
+ * @return	0 for success, otherwise error
+ */
+static int twsi_write_data(void __iomem *base, u8  slave_addr,
+			   u8 *buffer, unsigned int length)
+{
+	unsigned int curr = 0;
+	u64 val;
+	int ret;
+
+	debug("%s(%p, 0x%x, %p, 0x%x)\n", __func__, base, slave_addr,
+	      buffer, length);
+	ret = twsi_start(base);
+	if (ret) {
+		debug("%s: Could not start BUS transaction\n", __func__);
+		return -1;
+	}
+
+	ret = twsi_wait(base);
+	if (ret) {
+		debug("%s: wait failed\n", __func__);
+		return ret;
+	}
+
+	val = (u32)(slave_addr << 1) | TWSI_OP_WRITE |
+		FIELD_PREP(TWSI_SW_EOP_IA_MASK, TWSI_DATA) |
+		FIELD_PREP(TWSI_SW_OP_MASK, TWSI_SW_EOP_IA);
+	twsi_write_sw(base, val);
+	twsi_write_ctl(base, TWSI_CTL_ENAB);
+
+	debug("%s: Waiting\n", __func__);
+	ret = twsi_wait(base);
+	if (ret) {
+		debug("%s: Timed out writing slave address 0x%x to target\n",
+		      __func__, slave_addr);
+		return ret;
+	}
+
+	ret = twsi_read_status(base);
+	debug("%s: status: 0x%x\n", __func__, ret);
+	if (ret != TWSI_STAT_TXADDR_ACK) {
+		debug("%s: status: 0x%x\n", __func__, ret);
+		twsi_stop(base);
+		return twsi_i2c_lost_arb(ret, 0);
+	}
+
+	while (curr < length) {
+		val = buffer[curr++] |
+			FIELD_PREP(TWSI_SW_EOP_IA_MASK, TWSI_DATA) |
+			FIELD_PREP(TWSI_SW_OP_MASK, TWSI_SW_EOP_IA);
+		twsi_write_sw(base, val);
+		twsi_write_ctl(base, TWSI_CTL_ENAB);
+
+		debug("%s: Writing 0x%llx\n", __func__, val);
+
+		ret = twsi_wait(base);
+		if (ret) {
+			debug("%s: Timed out writing data to 0x%x\n",
+			      __func__, slave_addr);
+			return ret;
+		}
+		ret = twsi_read_status(base);
+		debug("%s: status: 0x%x\n", __func__, ret);
+	}
+
+	debug("%s: Stopping\n", __func__);
+	return twsi_stop(base);
+}
+
+/**
+ * Manually clear the I2C bus and send a stop
+ *
+ * @base	register base address
+ */
+static void twsi_unblock(void __iomem *base)
+{
+	int i;
+
+	for (i = 0; i < 9; i++) {
+		writeq(0, base + TWSI_INT);
+		udelay(5);
+		writeq(TWSI_INT_SCL_OVR, base + TWSI_INT);
+		udelay(5);
+	}
+	writeq(TWSI_INT_SCL_OVR | TWSI_INT_SDA_OVR, base + TWSI_INT);
+	udelay(5);
+	writeq(TWSI_INT_SDA_OVR, base + TWSI_INT);
+	udelay(5);
+	writeq(0, base + TWSI_INT);
+	udelay(5);
+}
+
+/**
+ * Performs a read transaction on the i2c bus
+ *
+ * @base	Base address of twsi registers
+ * @slave_addr	i2c bus address to read from
+ * @buffer	buffer to read into
+ * @length	number of bytes to read
+ * @return	0 for success, otherwise error
+ */
+static int twsi_read_data(void __iomem *base, u8 slave_addr,
+			  u8 *buffer, unsigned int length)
+{
+	unsigned int curr = 0;
+	u64 val;
+	int ret;
+
+	debug("%s(%p, 0x%x, %p, %u)\n", __func__, base, slave_addr,
+	      buffer, length);
+	ret = twsi_start(base);
+	if (ret) {
+		debug("%s: start failed\n", __func__);
+		return ret;
+	}
+
+	ret = twsi_wait(base);
+	if (ret) {
+		debug("%s: wait failed\n", __func__);
+		return ret;
+	}
+
+	val = (u32)(slave_addr << 1) | TWSI_OP_READ |
+		FIELD_PREP(TWSI_SW_EOP_IA_MASK, TWSI_DATA) |
+		FIELD_PREP(TWSI_SW_OP_MASK, TWSI_SW_EOP_IA);
+	twsi_write_sw(base, val);
+	twsi_write_ctl(base, TWSI_CTL_ENAB);
+
+	ret = twsi_wait(base);
+	if (ret) {
+		debug("%s: waiting for sending addr failed\n", __func__);
+		return ret;
+	}
+
+	ret = twsi_read_status(base);
+	debug("%s: status: 0x%x\n", __func__, ret);
+	if (ret != TWSI_STAT_RXADDR_ACK) {
+		debug("%s: status: 0x%x\n", __func__, ret);
+		twsi_stop(base);
+		return twsi_i2c_lost_arb(ret, 0);
+	}
+
+	while (curr < length) {
+		twsi_write_ctl(base, TWSI_CTL_ENAB |
+			       ((curr < length - 1) ? TWSI_CTL_AAK : 0));
+
+		ret = twsi_wait(base);
+		if (ret) {
+			debug("%s: waiting for data failed\n", __func__);
+			return ret;
+		}
+
+		val = twsi_read_sw(base, val);
+		buffer[curr++] = (u8)val;
+	}
+
+	twsi_stop(base);
+
+	return 0;
+}
+
+/**
+ * Calculate the divisor values
+ *
+ * @speed	Speed to set
+ * @m_div	Pointer to M divisor
+ * @n_div	Pointer to N divisor
+ * @return	0 for success, otherwise error
+ */
+static void twsi_calc_div(struct udevice *bus, ulong sclk, unsigned int speed,
+			  int *m_div, int *n_div)
+{
+	struct octeon_twsi *twsi = dev_get_priv(bus);
+	int thp = twsi->data->thp;
+	int tclk, fsamp;
+	int ndiv, mdiv;
+
+	if (twsi->data->clk_method == CLK_METHOD_OCTEON) {
+		tclk = sclk / (2 * (thp + 1));
+	} else {
+		/* Refclk src in mode register defaults to 100MHz clock */
+		sclk = 100000000; /* 100 Mhz */
+		tclk = sclk / (thp + 2);
+	}
+	debug("%s( io_clock %lu tclk %u)\n", __func__, sclk, tclk);
+
+	/*
+	 * Compute the clocks M divider:
+	 *
+	 * TWSI freq = (core freq) / (10 x (M+1) x 2 * (thp+1) x 2^N)
+	 * M = ((core freq) / (10 x (TWSI freq) x 2 * (thp+1) x 2^N)) - 1
+	 *
+	 * For OcteonTX2 -
+	 * TWSI freq = (core freq) / (10 x (M+1) x (thp+2) x 2^N)
+	 * M = ((core freq) / (10 x (TWSI freq) x (thp+2) x 2^N)) - 1
+	 */
+	for (ndiv = 0; ndiv < 8; ndiv++) {
+		fsamp = tclk / (1 << ndiv);
+		mdiv = fsamp / speed / 10;
+		mdiv -= 1;
+		if (mdiv < 16)
+			break;
+	}
+
+	*m_div = mdiv;
+	*n_div = ndiv;
+}
+
+/**
+ * Init I2C controller
+ *
+ * @base	Base address of twsi registers
+ * @slave_addr	I2C slave address to configure this controller to
+ * @return	0 for success, otherwise error
+ */
+static int twsi_init(void __iomem *base, int slaveaddr)
+{
+	u64 val;
+
+	debug("%s (%p, 0x%x)\n", __func__, base, slaveaddr);
+
+	val = slaveaddr << 1 |
+		FIELD_PREP(TWSI_SW_EOP_IA_MASK, 0) |
+		FIELD_PREP(TWSI_SW_OP_MASK, TWSI_SW_EOP_IA) |
+		TWSI_SW_V;
+	twsi_write_sw(base, val);
+
+	/* Set slave address */
+	val = slaveaddr |
+		FIELD_PREP(TWSI_SW_EOP_IA_MASK, TWSI_EOP_SLAVE_ADDR) |
+		FIELD_PREP(TWSI_SW_OP_MASK, TWSI_SW_EOP_IA) |
+		TWSI_SW_V;
+	twsi_write_sw(base, val);
+
+	return 0;
+}
+
+/**
+ * Transfers data over the i2c bus
+ *
+ * @bus		i2c bus to transfer data over
+ * @msg		Array of i2c messages
+ * @nmsgs	Number of messages to send/receive
+ * @return	0 for success, otherwise error
+ */
+static int octeon_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
+			   int nmsgs)
+{
+	struct octeon_twsi *twsi = dev_get_priv(bus);
+	int ret;
+	int i;
+
+	debug("%s: %d messages\n", __func__, nmsgs);
+	for (i = 0; i < nmsgs; i++, msg++) {
+		debug("%s: chip=0x%x, len=0x%x\n", __func__, msg->addr,
+		      msg->len);
+
+		if (msg->flags & I2C_M_RD) {
+			debug("%s: Reading data\n", __func__);
+			ret = twsi_read_data(twsi->base, msg->addr,
+					     msg->buf, msg->len);
+		} else {
+			debug("%s: Writing data\n", __func__);
+			ret = twsi_write_data(twsi->base, msg->addr,
+					      msg->buf, msg->len);
+		}
+		if (ret) {
+			debug("%s: error sending\n", __func__);
+			return -EREMOTEIO;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * Set I2C bus speed
+ *
+ * @bus		i2c bus to transfer data over
+ * @speed	Speed in Hz to set
+ * @return	0 for success, otherwise error
+ */
+static int octeon_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
+{
+	struct octeon_twsi *twsi = dev_get_priv(bus);
+	int m_div, n_div;
+	ulong clk_rate;
+	u64 val;
+
+	debug("%s(%p, %u)\n", __func__, bus, speed);
+
+	clk_rate = clk_get_rate(&twsi->clk);
+	if (IS_ERR_VALUE(clk_rate))
+		return -EINVAL;
+
+	twsi_calc_div(bus, clk_rate, speed, &m_div, &n_div);
+	if (m_div >= 16)
+		return -1;
+
+	val = (u32)(((m_div & 0xf) << 3) | ((n_div & 0x7) << 0)) |
+		FIELD_PREP(TWSI_SW_EOP_IA_MASK, TWSI_CLKCTL) |
+		FIELD_PREP(TWSI_SW_OP_MASK, TWSI_SW_EOP_IA) |
+		TWSI_SW_V;
+	/* Only init non-slave ports */
+	writeq(val, twsi->base + TWSI_SW_TWSI);
+
+	debug("%s: Wrote 0x%llx to sw_twsi\n", __func__, val);
+	return 0;
+}
+
+/**
+ * Driver probe function
+ *
+ * @dev		I2C device to probe
+ * @return	0 for success, otherwise error
+ */
+static int octeon_i2c_probe(struct udevice *dev)
+{
+	struct octeon_twsi *twsi = dev_get_priv(dev);
+	u32 i2c_slave_addr;
+	int ret;
+
+	twsi->data = (const struct octeon_i2c_data *)dev_get_driver_data(dev);
+
+	if (twsi->data->probe == PROBE_PCI) {
+		pci_dev_t bdf = dm_pci_get_bdf(dev);
+
+		debug("TWSI PCI device: %x\n", bdf);
+		dev->req_seq = PCI_FUNC(bdf);
+
+		twsi->base = dm_pci_map_bar(dev, PCI_BASE_ADDRESS_0,
+					    PCI_REGION_MEM);
+	} else {
+		twsi->base = dev_remap_addr(dev);
+	}
+	twsi->base += twsi->data->reg_offs;
+
+	i2c_slave_addr = dev_read_u32_default(dev, "i2c-sda-hold-time-ns",
+					      CONFIG_SYS_I2C_OCTEON_SLAVE_ADDR);
+
+	ret = clk_get_by_index(dev, 0, &twsi->clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_enable(&twsi->clk);
+	if (ret)
+		return ret;
+
+	debug("TWSI bus %d at %p\n", dev->seq, twsi->base);
+
+	/* Start with standard speed, real speed set via DT or cmd */
+	return twsi_init(twsi->base, i2c_slave_addr);
+}
+
+static const struct dm_i2c_ops octeon_i2c_ops = {
+	.xfer		= octeon_i2c_xfer,
+	.set_bus_speed	= octeon_i2c_set_bus_speed,
+};
+
+static const struct octeon_i2c_data i2c_octeon_data = {
+	.probe = PROBE_DT,
+	.reg_offs = 0x0000,
+	.thp = 3,
+	.clk_method = CLK_METHOD_OCTEON,
+};
+
+static const struct octeon_i2c_data i2c_octeontx_data = {
+	.probe = PROBE_PCI,
+	.reg_offs = 0x8000,
+	.thp = 3,
+	.clk_method = CLK_METHOD_OCTEON,
+};
+
+static const struct octeon_i2c_data i2c_octeontx2_data = {
+	.probe = PROBE_PCI,
+	.reg_offs = 0x8000,
+	.thp = 24,
+	.clk_method = CLK_METHOD_OCTEONTX2,
+};
+
+static const struct udevice_id octeon_i2c_ids[] = {
+	{ .compatible = "cavium,octeon-7890-twsi",
+	  .data = (ulong)&i2c_octeon_data },
+	{ .compatible = "cavium,thunder-8890-twsi",
+	  .data = (ulong)&i2c_octeontx_data },
+	{ .compatible = "cavium,thunder2-99xx-twsi",
+	  .data = (ulong)&i2c_octeontx2_data },
+	{ }
+};
+
+U_BOOT_DRIVER(octeon_pci_twsi) = {
+	.name	= "i2c_octeon",
+	.id	= UCLASS_I2C,
+	.of_match = octeon_i2c_ids,
+	.probe	= octeon_i2c_probe,
+	.priv_auto_alloc_size = sizeof(struct octeon_twsi),
+	.ops	= &octeon_i2c_ops,
+};
+
+static struct pci_device_id octeon_twsi_supported[] = {
+	{ PCI_VDEVICE(CAVIUM, PCI_DEVICE_ID_CAVIUM_TWSI),
+	  .driver_data = (ulong)&i2c_octeontx2_data },
+	{ },
+};
+
+U_BOOT_PCI_DEVICE(octeon_pci_twsi, octeon_twsi_supported);
-- 
2.26.2

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