[PATCH 1/2] i2c: aspeed: added driver for Aspeed I2C

Brendan Higgins
2016-09-09T19:56:00Z

Added initial master and slave support for Aspeed I2C controller.
Supports fourteen busses present in ast24xx and ast25xx BMC SoCs by
Aspeed.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
---
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-aspeed.c | 816 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 827 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-aspeed.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 5c3993b..0178c6c 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -998,6 +998,16 @@ config I2C_RCAR
This driver can also be built as a module. If so, the module
will be called i2c-rcar.

+config I2C_ASPEED
+ tristate "Aspeed AST2xxx SoC I2C Controller"
+ depends on (ARCH_ASPEED || COMPILE_TEST) && OF
+ help
+ If you say yes to this option, support will be included for the
+ Aspeed AST2xxx SoC I2C controller.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-aspeed.
+
comment "External I2C/SMBus adapter drivers"

config I2C_DIOLAN_U2C
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 37f2819..49631cd 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -96,6 +96,7 @@ obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o
obj-$(CONFIG_I2C_XLR) += i2c-xlr.o
obj-$(CONFIG_I2C_XLP9XX) += i2c-xlp9xx.o
obj-$(CONFIG_I2C_RCAR) += i2c-rcar.o
+obj-$(CONFIG_I2C_ASPEED) += i2c-aspeed.o

# External I2C/SMBus adapter drivers
obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
new file mode 100644
index 0000000..9a5ca04
--- /dev/null
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -0,0 +1,816 @@
+/*
+ * I2C adapter for the ASPEED I2C bus.
+ *
+ * Copyright (C) 2012-2020 ASPEED Technology Inc.
+ * Copyright 2016 IBM Corporation
+ * Copyright 2016 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/slab.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+
+/* I2C Register */
+#define ASPEED_I2C_FUN_CTRL_REG 0x00
+#define ASPEED_I2C_AC_TIMING_REG1 0x04
+#define ASPEED_I2C_AC_TIMING_REG2 0x08
+#define ASPEED_I2C_INTR_CTRL_REG 0x0c
+#define ASPEED_I2C_INTR_STS_REG 0x10
+#define ASPEED_I2C_CMD_REG 0x14
+#define ASPEED_I2C_DEV_ADDR_REG 0x18
+#define ASPEED_I2C_BYTE_BUF_REG 0x20
+
+#define ASPEED_I2C_NUM_BUS 14
+
+/* Global Register Definition */
+/* 0x00 : I2C Interrupt Status Register */
+/* 0x08 : I2C Interrupt Target Assignment */
+
+/* Device Register Definition */
+/* 0x00 : I2CD Function Control Register */
+#define ASPEED_I2CD_MULTI_MASTER_DIS BIT(15)
+#define ASPEED_I2CD_SDA_DRIVE_1T_EN BIT(8)
+#define ASPEED_I2CD_M_SDA_DRIVE_1T_EN BIT(7)
+#define ASPEED_I2CD_M_HIGH_SPEED_EN BIT(6)
+#define ASPEED_I2CD_SLAVE_EN BIT(1)
+#define ASPEED_I2CD_MASTER_EN BIT(0)
+
+/* 0x08 : I2CD Clock and AC Timing Control Register #2 */
+#define ASPEED_NO_TIMEOUT_CTRL 0
+
+
+/* 0x0c : I2CD Interrupt Control Register &
+ * 0x10 : I2CD Interrupt Status Register
+ *
+ * These share bit definitions, so use the same values for the enable &
+ * status bits.
+ */
+#define ASPEED_I2CD_INTR_SDA_DL_TIMEOUT BIT(14)
+#define ASPEED_I2CD_INTR_BUS_RECOVER_DONE BIT(13)
+#define ASPEED_I2CD_INTR_SLAVE_MATCH BIT(7)
+#define ASPEED_I2CD_INTR_SCL_TIMEOUT BIT(6)
+#define ASPEED_I2CD_INTR_ABNORMAL BIT(5)
+#define ASPEED_I2CD_INTR_NORMAL_STOP BIT(4)
+#define ASPEED_I2CD_INTR_ARBIT_LOSS BIT(3)
+#define ASPEED_I2CD_INTR_RX_DONE BIT(2)
+#define ASPEED_I2CD_INTR_TX_NAK BIT(1)
+#define ASPEED_I2CD_INTR_TX_ACK BIT(0)
+
+/* 0x14 : I2CD Command/Status Register */
+#define ASPEED_I2CD_SCL_LINE_STS BIT(18)
+#define ASPEED_I2CD_SDA_LINE_STS BIT(17)
+#define ASPEED_I2CD_BUS_BUSY_STS BIT(16)
+#define ASPEED_I2CD_BUS_RECOVER_CMD BIT(11)
+
+/* Command Bit */
+#define ASPEED_I2CD_M_STOP_CMD BIT(5)
+#define ASPEED_I2CD_M_S_RX_CMD_LAST BIT(4)
+#define ASPEED_I2CD_M_RX_CMD BIT(3)
+#define ASPEED_I2CD_S_TX_CMD BIT(2)
+#define ASPEED_I2CD_M_TX_CMD BIT(1)
+#define ASPEED_I2CD_M_START_CMD BIT(0)
+
+/* 0x18 : I2CD Slave Device Address Register */
+#define ASPEED_I2CD_DEV_ADDR_MASK GENMASK(6, 0)
+
+enum aspeed_i2c_slave_state {
+ ASPEED_I2C_SLAVE_START,
+ ASPEED_I2C_SLAVE_READ_REQUESTED,
+ ASPEED_I2C_SLAVE_READ_PROCESSED,
+ ASPEED_I2C_SLAVE_WRITE_REQUESTED,
+ ASPEED_I2C_SLAVE_WRITE_RECEIVED,
+ ASPEED_I2C_SLAVE_STOP,
+};
+
+struct aspeed_i2c_bus {
+ struct i2c_adapter adap;
+ struct device *dev;
+ void __iomem *base;
+ spinlock_t lock;
+ struct completion cmd_complete;
+ int irq;
+ /* Transaction state. */
+ struct i2c_msg *msg;
+ int msg_pos;
+ u32 cmd_err;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ struct i2c_client *slave;
+ enum aspeed_i2c_slave_state slave_state;
+#endif
+};
+
+struct aspeed_i2c_controller {
+ struct device *dev;
+ void __iomem *base;
+ int irq;
+ struct irq_domain *irq_domain;
+};
+
+static inline void aspeed_i2c_write(struct aspeed_i2c_bus *bus, u32 val,
+ u32 reg)
+{
+ writel(val, bus->base + reg);
+}
+
+static inline u32 aspeed_i2c_read(struct aspeed_i2c_bus *bus, u32 reg)
+{
+ return readl(bus->base + reg);
+}
+
+static u8 aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus)
+{
+ u32 command;
+ unsigned long time_left;
+ unsigned long flags;
+ int ret = 0;
+
+ spin_lock_irqsave(&bus->lock, flags);
+ command = aspeed_i2c_read(bus, ASPEED_I2C_CMD_REG);
+ /* Bus is idle: no recovery needed. */
+ if ((command & ASPEED_I2CD_SDA_LINE_STS) &&
+ (command & ASPEED_I2CD_SCL_LINE_STS))
+ goto out;
+
+ dev_dbg(bus->dev, "bus hung (state %x), attempting recovery\n",
+ command);
+
+ /* Bus held: put bus in stop state. */
+ if ((command & ASPEED_I2CD_SDA_LINE_STS) &&
+ !(command & ASPEED_I2CD_SCL_LINE_STS)) {
+ aspeed_i2c_write(bus, ASPEED_I2CD_M_STOP_CMD,
+ ASPEED_I2C_CMD_REG);
+ reinit_completion(&bus->cmd_complete);
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ time_left = wait_for_completion_interruptible_timeout(
+ &bus->cmd_complete, bus->adap.timeout * HZ);
+
+ spin_lock_irqsave(&bus->lock, flags);
+ if (time_left == 0)
+ ret = -ETIMEDOUT;
+ else if (bus->cmd_err)
+ ret = -EIO;
+ /* Bus error. */
+ } else if (!(command & ASPEED_I2CD_SDA_LINE_STS)) {
+ aspeed_i2c_write(bus, ASPEED_I2CD_BUS_RECOVER_CMD,
+ ASPEED_I2C_CMD_REG);
+ reinit_completion(&bus->cmd_complete);
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ time_left = wait_for_completion_interruptible_timeout(
+ &bus->cmd_complete, bus->adap.timeout * HZ);
+
+ spin_lock_irqsave(&bus->lock, flags);
+ if (time_left == 0)
+ ret = -ETIMEDOUT;
+ else if (bus->cmd_err)
+ ret = -EIO;
+ /* Recovery failed. */
+ else if (!(aspeed_i2c_read(bus, ASPEED_I2C_CMD_REG) &
+ ASPEED_I2CD_SDA_LINE_STS))
+ ret = -EIO;
+ }
+
+out:
+ spin_unlock_irqrestore(&bus->lock, flags);
+ return ret;
+}
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+static bool aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus)
+{
+ bool irq_handled = true;
+ u32 command;
+ u32 irq_status;
+ u32 status_ack = 0;
+ u8 value;
+ struct i2c_client *slave = bus->slave;
+
+ spin_lock(&bus->lock);
+ if (!slave) {
+ irq_handled = false;
+ goto out;
+ }
+ command = aspeed_i2c_read(bus, ASPEED_I2C_CMD_REG);
+ irq_status = aspeed_i2c_read(bus, ASPEED_I2C_INTR_STS_REG);
+
+ /* Slave was requested, restart state machine. */
+ if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
+ status_ack |= ASPEED_I2CD_INTR_SLAVE_MATCH;
+ bus->slave_state = ASPEED_I2C_SLAVE_START;
+ }
+ /* Slave is not currently active, irq was for someone else. */
+ if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
+ irq_handled = false;
+ goto out;
+ }
+
+ dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
+ irq_status, command);
+
+ /* Slave was sent something. */
+ if (irq_status & ASPEED_I2CD_INTR_RX_DONE) {
+ value = aspeed_i2c_read(bus, ASPEED_I2C_BYTE_BUF_REG) >> 8;
+ /* Handle address frame. */
+ if (bus->slave_state == ASPEED_I2C_SLAVE_START) {
+ if (value & 0x1)
+ bus->slave_state =
+ ASPEED_I2C_SLAVE_READ_REQUESTED;
+ else
+ bus->slave_state =
+ ASPEED_I2C_SLAVE_WRITE_REQUESTED;
+ }
+ status_ack |= ASPEED_I2CD_INTR_RX_DONE;
+ }
+
+ /* Slave was asked to stop. */
+ if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
+ status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
+ bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+ }
+ if (irq_status & ASPEED_I2CD_INTR_TX_NAK) {
+ status_ack |= ASPEED_I2CD_INTR_TX_NAK;
+ bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+ }
+
+ if (bus->slave_state == ASPEED_I2C_SLAVE_READ_REQUESTED) {
+ if (irq_status & ASPEED_I2CD_INTR_TX_ACK)
+ dev_err(bus->dev, "Unexpected ACK on read request.\n");
+ bus->slave_state = ASPEED_I2C_SLAVE_READ_PROCESSED;
+
+ i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);
+ aspeed_i2c_write(bus, value, ASPEED_I2C_BYTE_BUF_REG);
+ aspeed_i2c_write(bus, ASPEED_I2CD_S_TX_CMD, ASPEED_I2C_CMD_REG);
+ } else if (bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
+ status_ack |= ASPEED_I2CD_INTR_TX_ACK;
+ if (!(irq_status & ASPEED_I2CD_INTR_TX_ACK))
+ dev_err(bus->dev,
+ "Expected ACK after processed read.\n");
+ i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value);
+ aspeed_i2c_write(bus, value, ASPEED_I2C_BYTE_BUF_REG);
+ aspeed_i2c_write(bus, ASPEED_I2CD_S_TX_CMD, ASPEED_I2C_CMD_REG);
+ } else if (bus->slave_state == ASPEED_I2C_SLAVE_WRITE_REQUESTED) {
+ bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
+ i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+ } else if (bus->slave_state == ASPEED_I2C_SLAVE_WRITE_RECEIVED) {
+ i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+ } else if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
+ i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
+ }
+
+ if (status_ack != irq_status)
+ dev_err(bus->dev,
+ "irq handled != irq. expected %x, but was %x\n",
+ irq_status, status_ack);
+ aspeed_i2c_write(bus, status_ack, ASPEED_I2C_INTR_STS_REG);
+
+out:
+ spin_unlock(&bus->lock);
+ return irq_handled;
+}
+#endif
+
+static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus)
+{
+ const u32 errs = ASPEED_I2CD_INTR_ARBIT_LOSS |
+ ASPEED_I2CD_INTR_ABNORMAL |
+ ASPEED_I2CD_INTR_SCL_TIMEOUT |
+ ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |
+ ASPEED_I2CD_INTR_TX_NAK;
+ u32 irq_status;
+
+ spin_lock(&bus->lock);
+ irq_status = aspeed_i2c_read(bus, ASPEED_I2C_INTR_STS_REG);
+ bus->cmd_err = irq_status & errs;
+
+ dev_dbg(bus->dev, "master irq status 0x%08x\n", irq_status);
+
+ /* No message to transfer. */
+ if (bus->cmd_err ||
+ (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) ||
+ (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE)) {
+ complete(&bus->cmd_complete);
+ goto out;
+ } else if (!bus->msg || bus->msg_pos >= bus->msg->len)
+ goto out;
+
+ if ((bus->msg->flags & I2C_M_RD) &&
+ (irq_status & ASPEED_I2CD_INTR_RX_DONE)) {
+ bus->msg->buf[bus->msg_pos++] = aspeed_i2c_read(
+ bus, ASPEED_I2C_BYTE_BUF_REG) >> 8;
+ if (bus->msg_pos + 1 < bus->msg->len)
+ aspeed_i2c_write(bus, ASPEED_I2CD_M_RX_CMD,
+ ASPEED_I2C_CMD_REG);
+ else if (bus->msg_pos < bus->msg->len)
+ aspeed_i2c_write(bus, ASPEED_I2CD_M_RX_CMD |
+ ASPEED_I2CD_M_S_RX_CMD_LAST,
+ ASPEED_I2C_CMD_REG);
+ } else if (!(bus->msg->flags & I2C_M_RD) &&
+ (irq_status & ASPEED_I2CD_INTR_TX_ACK)) {
+ aspeed_i2c_write(bus, bus->msg->buf[bus->msg_pos++],
+ ASPEED_I2C_BYTE_BUF_REG);
+ aspeed_i2c_write(bus, ASPEED_I2CD_M_TX_CMD, ASPEED_I2C_CMD_REG);
+ }
+
+ /* Transmission complete: notify caller. */
+ if (bus->msg_pos >= bus->msg->len)
+ complete(&bus->cmd_complete);
+out:
+ aspeed_i2c_write(bus, irq_status, ASPEED_I2C_INTR_STS_REG);
+ spin_unlock(&bus->lock);
+ return true;
+}
+
+static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
+{
+ struct aspeed_i2c_bus *bus = dev_id;
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ if (aspeed_i2c_slave_irq(bus)) {
+ dev_dbg(bus->dev, "irq handled by slave.\n");
+ return IRQ_HANDLED;
+ }
+#endif
+ if (aspeed_i2c_master_irq(bus)) {
+ dev_dbg(bus->dev, "irq handled by master.\n");
+ return IRQ_HANDLED;
+ }
+ dev_err(bus->dev, "irq not handled properly!\n");
+ return IRQ_HANDLED;
+}
+
+static int aspeed_i2c_master_single_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msg)
+{
+ struct aspeed_i2c_bus *bus = adap->algo_data;
+ unsigned long flags;
+ u8 slave_addr;
+ u32 command = ASPEED_I2CD_M_START_CMD | ASPEED_I2CD_M_TX_CMD;
+ int ret = msg->len;
+ unsigned long time_left;
+
+ spin_lock_irqsave(&bus->lock, flags);
+ bus->msg = msg;
+ bus->msg_pos = 0;
+ slave_addr = msg->addr << 1;
+ if (msg->flags & I2C_M_RD) {
+ slave_addr |= 1;
+ command |= ASPEED_I2CD_M_RX_CMD;
+ if (msg->len == 1)
+ command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+ }
+ aspeed_i2c_write(bus, slave_addr, ASPEED_I2C_BYTE_BUF_REG);
+ aspeed_i2c_write(bus, command, ASPEED_I2C_CMD_REG);
+ reinit_completion(&bus->cmd_complete);
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ time_left = wait_for_completion_interruptible_timeout(
+ &bus->cmd_complete, bus->adap.timeout * HZ * msg->len);
+ if (time_left == 0)
+ return -ETIMEDOUT;
+
+ spin_lock_irqsave(&bus->lock, flags);
+ if (bus->cmd_err)
+ ret = -EIO;
+ bus->msg = NULL;
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ return ret;
+}
+
+static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ struct aspeed_i2c_bus *bus = adap->algo_data;
+ int ret;
+ int i;
+ unsigned long flags;
+ unsigned long time_left;
+
+ /* If bus is busy, attempt recovery. We assume a single master
+ * environment.
+ */
+ if (aspeed_i2c_read(bus, ASPEED_I2C_CMD_REG) &
+ ASPEED_I2CD_BUS_BUSY_STS) {
+ ret = aspeed_i2c_recover_bus(bus);
+ if (ret)
+ return ret;
+ }
+
+ for (i = 0; i < num; i++) {
+ ret = aspeed_i2c_master_single_xfer(adap, &msgs[i]);
+ if (ret < 0)
+ break;
+ /* TODO: Support other forms of I2C protocol mangling. */
+ if (msgs[i].flags & I2C_M_STOP) {
+ spin_lock_irqsave(&bus->lock, flags);
+ aspeed_i2c_write(bus, ASPEED_I2CD_M_STOP_CMD,
+ ASPEED_I2C_CMD_REG);
+ reinit_completion(&bus->cmd_complete);
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ time_left = wait_for_completion_interruptible_timeout(
+ &bus->cmd_complete,
+ bus->adap.timeout * HZ);
+ if (time_left == 0)
+ return -ETIMEDOUT;
+ }
+ }
+
+ spin_lock_irqsave(&bus->lock, flags);
+ aspeed_i2c_write(bus, ASPEED_I2CD_M_STOP_CMD, ASPEED_I2C_CMD_REG);
+ reinit_completion(&bus->cmd_complete);
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ time_left = wait_for_completion_interruptible_timeout(
+ &bus->cmd_complete, bus->adap.timeout * HZ);
+ if (time_left == 0)
+ return -ETIMEDOUT;
+
+ /* If nothing went wrong, return number of messages transferred. */
+ if (ret < 0)
+ return ret;
+ else
+ return i;
+}
+
+static u32 aspeed_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+static int aspeed_i2c_reg_slave(struct i2c_client *client)
+{
+ struct aspeed_i2c_bus *bus;
+ unsigned long flags;
+ u32 addr_reg_val;
+ u32 func_ctrl_reg_val;
+
+ bus = client->adapter->algo_data;
+ spin_lock_irqsave(&bus->lock, flags);
+ if (bus->slave) {
+ spin_unlock_irqrestore(&bus->lock, flags);
+ return -EINVAL;
+ }
+
+ /* Set slave addr. */
+ addr_reg_val = aspeed_i2c_read(bus, ASPEED_I2C_DEV_ADDR_REG);
+ addr_reg_val &= ~ASPEED_I2CD_DEV_ADDR_MASK;
+ addr_reg_val |= client->addr & ASPEED_I2CD_DEV_ADDR_MASK;
+ aspeed_i2c_write(bus, addr_reg_val, ASPEED_I2C_DEV_ADDR_REG);
+
+ /* Switch from master mode to slave mode. */
+ func_ctrl_reg_val = aspeed_i2c_read(bus, ASPEED_I2C_FUN_CTRL_REG);
+ func_ctrl_reg_val &= ~ASPEED_I2CD_MASTER_EN;
+ func_ctrl_reg_val |= ASPEED_I2CD_SLAVE_EN;
+ aspeed_i2c_write(bus, func_ctrl_reg_val, ASPEED_I2C_FUN_CTRL_REG);
+
+ bus->slave = client;
+ bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+ spin_unlock_irqrestore(&bus->lock, flags);
+ return 0;
+}
+
+static int aspeed_i2c_unreg_slave(struct i2c_client *client)
+{
+ struct aspeed_i2c_bus *bus = client->adapter->algo_data;
+ unsigned long flags;
+ u32 func_ctrl_reg_val;
+
+ spin_lock_irqsave(&bus->lock, flags);
+ if (!bus->slave) {
+ spin_unlock_irqrestore(&bus->lock, flags);
+ return -EINVAL;
+ }
+
+ /* Switch from slave mode to master mode. */
+ func_ctrl_reg_val = aspeed_i2c_read(bus, ASPEED_I2C_FUN_CTRL_REG);
+ func_ctrl_reg_val &= ~ASPEED_I2CD_SLAVE_EN;
+ func_ctrl_reg_val |= ASPEED_I2CD_MASTER_EN;
+ aspeed_i2c_write(bus, func_ctrl_reg_val, ASPEED_I2C_FUN_CTRL_REG);
+
+ bus->slave = NULL;
+ spin_unlock_irqrestore(&bus->lock, flags);
+ return 0;
+}
+#endif
+
+static const struct i2c_algorithm aspeed_i2c_algo = {
+ .master_xfer = aspeed_i2c_master_xfer,
+ .functionality = aspeed_i2c_functionality,
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ .reg_slave = aspeed_i2c_reg_slave,
+ .unreg_slave = aspeed_i2c_unreg_slave,
+#endif
+};
+
+static u32 aspeed_i2c_get_clk_reg_val(u32 divider_ratio)
+{
+ unsigned int inc = 0, div;
+ u32 scl_low, scl_high, data;
+
+ for (div = 0; divider_ratio >= 16; div++) {
+ inc |= (divider_ratio & 1);
+ divider_ratio >>= 1;
+ }
+ divider_ratio += inc;
+ scl_low = (divider_ratio >> 1) - 1;
+ scl_high = divider_ratio - scl_low - 2;
+ data = 0x77700300 | (scl_high << 16) | (scl_low << 12) | div;
+ return data;
+}
+
+static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus,
+ struct platform_device *pdev)
+{
+ struct clk *pclk;
+ u32 clk_freq;
+ u32 divider_ratio;
+ int ret;
+
+ pclk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(pclk)) {
+ dev_err(&pdev->dev, "clk_get failed\n");
+ return PTR_ERR(pclk);
+ }
+ ret = of_property_read_u32(pdev->dev.of_node,
+ "clock-frequency", &clk_freq);
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "Could not read clock-frequency property\n");
+ clk_freq = 100000;
+ }
+ divider_ratio = clk_get_rate(pclk) / clk_freq;
+ /* We just need the clock rate, we don't actually use the clk object. */
+ devm_clk_put(&pdev->dev, pclk);
+
+ /* Set AC Timing */
+ if (clk_freq / 1000 > 400) {
+ aspeed_i2c_write(bus, aspeed_i2c_read(bus,
+ ASPEED_I2C_FUN_CTRL_REG) |
+ ASPEED_I2CD_M_HIGH_SPEED_EN |
+ ASPEED_I2CD_M_SDA_DRIVE_1T_EN |
+ ASPEED_I2CD_SDA_DRIVE_1T_EN,
+ ASPEED_I2C_FUN_CTRL_REG);
+
+ aspeed_i2c_write(bus, 0x3, ASPEED_I2C_AC_TIMING_REG2);
+ aspeed_i2c_write(bus, aspeed_i2c_get_clk_reg_val(divider_ratio),
+ ASPEED_I2C_AC_TIMING_REG1);
+ } else {
+ aspeed_i2c_write(bus, aspeed_i2c_get_clk_reg_val(divider_ratio),
+ ASPEED_I2C_AC_TIMING_REG1);
+ aspeed_i2c_write(bus, ASPEED_NO_TIMEOUT_CTRL,
+ ASPEED_I2C_AC_TIMING_REG2);
+ }
+
+ return 0;
+}
+
+static void noop(struct irq_data *data) { }
+
+static struct irq_chip aspeed_i2c_irqchip = {
+ .name = "ast-i2c",
+ .irq_unmask = noop,
+ .irq_mask = noop,
+};
+
+static int aspeed_i2c_probe_bus(struct platform_device *pdev)
+{
+ struct aspeed_i2c_bus *bus;
+ struct aspeed_i2c_controller *controller =
+ dev_get_drvdata(pdev->dev.parent);
+ struct resource *res;
+ int ret, bus_num, irq;
+
+ bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
+ if (!bus)
+ return -ENOMEM;
+
+ ret = of_property_read_u32(pdev->dev.of_node, "bus", &bus_num);
+ if (ret)
+ return -ENXIO;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ bus->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(bus->base))
+ return PTR_ERR(bus->base);
+
+ bus->irq = platform_get_irq(pdev, 0);
+ if (bus->irq < 0) {
+ dev_err(&pdev->dev, "platform_get_irq failed\n");
+ return -ENXIO;
+ }
+
+ irq = irq_create_mapping(controller->irq_domain, bus_num);
+ irq_set_chip_data(irq, controller);
+ irq_set_chip_and_handler(irq, &aspeed_i2c_irqchip, handle_simple_irq);
+ ret = devm_request_irq(&pdev->dev, bus->irq, aspeed_i2c_bus_irq,
+ 0, dev_name(&pdev->dev), bus);
+ if (ret) {
+ dev_err(&pdev->dev, "devm_request_irq failed\n");
+ return -ENXIO;
+ }
+
+ /* Initialize the I2C adapter */
+ spin_lock_init(&bus->lock);
+ init_completion(&bus->cmd_complete);
+ bus->adap.nr = bus_num;
+ bus->adap.owner = THIS_MODULE;
+ bus->adap.retries = 0;
+ bus->adap.timeout = 5;
+ bus->adap.algo = &aspeed_i2c_algo;
+ bus->adap.algo_data = bus;
+ bus->adap.dev.parent = &pdev->dev;
+ bus->adap.dev.of_node = pdev->dev.of_node;
+ snprintf(bus->adap.name, sizeof(bus->adap.name), "Aspeed i2c-%d",
+ bus_num);
+
+ bus->dev = &pdev->dev;
+
+ /* reset device: disable master & slave functions */
+ aspeed_i2c_write(bus, 0, ASPEED_I2C_FUN_CTRL_REG);
+
+ ret = aspeed_i2c_init_clk(bus, pdev);
+ if (ret < 0)
+ return ret;
+
+ /* Enable Master Mode */
+ aspeed_i2c_write(bus, aspeed_i2c_read(bus, ASPEED_I2C_FUN_CTRL_REG) |
+ ASPEED_I2CD_MASTER_EN |
+ ASPEED_I2CD_MULTI_MASTER_DIS, ASPEED_I2C_FUN_CTRL_REG);
+
+ /* Set interrupt generation of I2C controller */
+ aspeed_i2c_write(bus, ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |
+ ASPEED_I2CD_INTR_BUS_RECOVER_DONE |
+ ASPEED_I2CD_INTR_SCL_TIMEOUT |
+ ASPEED_I2CD_INTR_ABNORMAL |
+ ASPEED_I2CD_INTR_NORMAL_STOP |
+ ASPEED_I2CD_INTR_ARBIT_LOSS |
+ ASPEED_I2CD_INTR_RX_DONE |
+ ASPEED_I2CD_INTR_TX_NAK |
+ ASPEED_I2CD_INTR_TX_ACK,
+ ASPEED_I2C_INTR_CTRL_REG);
+
+ ret = i2c_add_numbered_adapter(&bus->adap);
+ if (ret < 0)
+ return -ENXIO;
+
+ platform_set_drvdata(pdev, bus);
+
+ dev_info(bus->dev, "i2c bus %d registered, irq %d\n",
+ bus->adap.nr, bus->irq);
+
+ return 0;
+}
+
+static int aspeed_i2c_remove_bus(struct platform_device *pdev)
+{
+ struct aspeed_i2c_bus *bus = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&bus->adap);
+ return 0;
+}
+
+static const struct of_device_id aspeed_i2c_bus_of_table[] = {
+ { .compatible = "aspeed,ast2400-i2c-bus", },
+ { .compatible = "aspeed,ast2500-i2c-bus", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, aspeed_i2c_of_table);
+
+static struct platform_driver aspeed_i2c_bus_driver = {
+ .probe = aspeed_i2c_probe_bus,
+ .remove = aspeed_i2c_remove_bus,
+ .driver = {
+ .name = "ast-i2c-bus",
+ .of_match_table = aspeed_i2c_bus_of_table,
+ },
+};
+module_platform_driver(aspeed_i2c_bus_driver);
+
+static void aspeed_i2c_controller_irq(struct irq_desc *desc)
+{
+ struct aspeed_i2c_controller *c = irq_desc_get_handler_data(desc);
+ unsigned long p, status;
+ unsigned int bus_irq;
+
+ status = readl(c->base);
+ for_each_set_bit(p, &status, ASPEED_I2C_NUM_BUS) {
+ bus_irq = irq_find_mapping(c->irq_domain, p);
+ generic_handle_irq(bus_irq);
+ }
+}
+
+static int aspeed_i2c_probe_controller(struct platform_device *pdev)
+{
+ struct aspeed_i2c_controller *controller;
+ struct device_node *np;
+ struct resource *res;
+
+ controller = kzalloc(sizeof(*controller), GFP_KERNEL);
+ if (!controller)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ controller->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(controller->base))
+ return PTR_ERR(controller->base);
+
+ controller->irq = platform_get_irq(pdev, 0);
+ if (controller->irq < 0) {
+ dev_err(&pdev->dev, "no platform IRQ\n");
+ return -ENXIO;
+ }
+
+ controller->irq_domain = irq_domain_add_linear(pdev->dev.of_node,
+ ASPEED_I2C_NUM_BUS, &irq_domain_simple_ops, NULL);
+ if (!controller->irq_domain) {
+ dev_err(&pdev->dev, "no IRQ domain\n");
+ return -ENXIO;
+ }
+ controller->irq_domain->name = "ast-i2c-domain";
+
+ irq_set_chained_handler_and_data(controller->irq,
+ aspeed_i2c_controller_irq, controller);
+
+ controller->dev = &pdev->dev;
+
+ platform_set_drvdata(pdev, controller);
+
+ dev_info(controller->dev, "i2c controller registered, irq %d\n",
+ controller->irq);
+
+ for_each_child_of_node(pdev->dev.of_node, np) {
+ int ret;
+ u32 bus_num;
+ char bus_id[sizeof("i2c-12345")];
+
+ /*
+ * Set a useful name derived from the bus number; the device
+ * tree should provide us with one that corresponds to the
+ * hardware numbering. If the property is missing the
+ * probe would fail so just skip it here.
+ */
+
+ ret = of_property_read_u32(np, "bus", &bus_num);
+ if (ret)
+ continue;
+
+ ret = snprintf(bus_id, sizeof(bus_id), "i2c-%u", bus_num);
+ if (ret >= sizeof(bus_id))
+ continue;
+
+ of_platform_device_create(np, bus_id, &pdev->dev);
+ of_node_put(np);
+ }
+
+ return 0;
+}
+
+static int aspeed_i2c_remove_controller(struct platform_device *pdev)
+{
+ struct aspeed_i2c_controller *controller = platform_get_drvdata(pdev);
+
+ irq_domain_remove(controller->irq_domain);
+ return 0;
+}
+
+static const struct of_device_id aspeed_i2c_controller_of_table[] = {
+ { .compatible = "aspeed,ast2400-i2c-controller", },
+ { .compatible = "aspeed,ast2500-i2c-controller", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, aspeed_i2c_of_table);
+
+static struct platform_driver aspeed_i2c_controller_driver = {
+ .probe = aspeed_i2c_probe_controller,
+ .remove = aspeed_i2c_remove_controller,
+ .driver = {
+ .name = "ast-i2c-controller",
+ .of_match_table = aspeed_i2c_controller_of_table,
+ },
+};
+
+module_platform_driver(aspeed_i2c_controller_driver);
+
+MODULE_AUTHOR("Brendan Higgins <brendanhiggins@google.com>");
+MODULE_DESCRIPTION("Aspeed I2C Bus Driver");
+MODULE_LICENSE("GPL");
--
2.8.0.rc3.226.g39d4020