[PATCH v6 4/5] i2c: aspeed: added driver for Aspeed I2C
From: Brendan Higgins
Date: Tue Mar 28 2017 - 01:13:59 EST
Added initial master support for Aspeed I2C controller. Supports
fourteen busses present in AST24XX and AST25XX BMC SoCs by Aspeed.
Signed-off-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
---
Changes for v2:
- Added single module_init (multiple was breaking some builds).
Changes for v3:
- Removed "bus" device tree param; now extracted from bus address offset
Changes for v4:
- I2C adapter number is now generated dynamically unless specified in alias.
Changes for v5:
- Removed irq_chip used to multiplex IRQ and replaced it with dummy_irq_chip
along with some other IRQ cleanup.
- Addressed comments from Cedric, and Vladimir, mostly stylistic things and
using devm managed resources.
- Increased max clock frequency before the bus is put in HighSpeed mode, as
per Kachalov's comment.
Changes for v6:
- No longer arbitrarily restrict bus to be slave xor master.
- Pulled out "struct aspeed_i2c_controller" as a interrupt controller.
- Pulled out slave support into its own commit.
- Rewrote code that sets clock divider register because the original version
set it incorrectly.
- Rewrote the aspeed_i2c_master_irq handler because the old method of
completing a completion in between restarts was too slow causing devices to
misbehave.
- Added support for I2C_M_RECV_LEN which I had incorrectly said was supported
before.
- Addressed other comments from Vladimir.
---
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-aspeed.c | 610 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 621 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-aspeed.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 8adc0f1d7ad0..e5ea5641a874 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -326,6 +326,16 @@ config I2C_POWERMAC
comment "I2C system bus drivers (mostly embedded / system-on-chip)"
+config I2C_ASPEED
+ tristate "Aspeed AST2xxx SoC I2C Controller"
+ depends on ARCH_ASPEED
+ 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.
+
config I2C_AT91
tristate "Atmel AT91 I2C Two-Wire interface (TWI)"
depends on ARCH_AT91
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 30b60855fbcd..e84604b9bf3b 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_I2C_HYDRA) += i2c-hydra.o
obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o
# Embedded system I2C/SMBus host controller drivers
+obj-$(CONFIG_I2C_ASPEED) += i2c-aspeed.o
obj-$(CONFIG_I2C_AT91) += i2c-at91.o
obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
new file mode 100644
index 000000000000..04266acc6c46
--- /dev/null
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -0,0 +1,610 @@
+/*
+ * Aspeed 24XX/25XX I2C Interrupt Controller.
+ *
+ * Copyright (C) 2012-2017 ASPEED Technology Inc.
+ * Copyright 2017 IBM Corporation
+ * Copyright 2017 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/clk.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.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
+
+/* 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_MASTER_EN BIT(0)
+
+/* 0x04 : I2CD Clock and AC Timing Control Register #1 */
+#define ASPEED_I2CD_TIME_SCL_HIGH_SHIFT 16
+#define ASPEED_I2CD_TIME_SCL_HIGH_MASK GENMASK(19, 16)
+#define ASPEED_I2CD_TIME_SCL_LOW_SHIFT 12
+#define ASPEED_I2CD_TIME_SCL_LOW_MASK GENMASK(15, 12)
+#define ASPEED_I2CD_TIME_BASE_DIVISOR_MASK GENMASK(3, 0)
+#define ASPEED_I2CD_TIME_SCL_REG_MAX GENMASK(3, 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_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)
+#define ASPEED_I2CD_INTR_ERROR \
+ (ASPEED_I2CD_INTR_ARBIT_LOSS | \
+ ASPEED_I2CD_INTR_ABNORMAL | \
+ ASPEED_I2CD_INTR_SCL_TIMEOUT | \
+ ASPEED_I2CD_INTR_SDA_DL_TIMEOUT)
+#define ASPEED_I2CD_INTR_ALL \
+ (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)
+
+/* 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)
+
+enum aspeed_i2c_master_state {
+ ASPEED_I2C_MASTER_START,
+ ASPEED_I2C_MASTER_TX_FIRST,
+ ASPEED_I2C_MASTER_TX,
+ ASPEED_I2C_MASTER_RX,
+ ASPEED_I2C_MASTER_STOP,
+ ASPEED_I2C_MASTER_INACTIVE,
+};
+
+struct aspeed_i2c_bus {
+ struct i2c_adapter adap;
+ struct device *dev;
+ void __iomem *base;
+ /* Synchronizes I/O mem access to base. */
+ spinlock_t lock;
+ struct completion cmd_complete;
+ int irq;
+ /* Transaction state. */
+ enum aspeed_i2c_master_state master_state;
+ struct i2c_msg *msgs;
+ size_t buf_index;
+ size_t msgs_index;
+ size_t msgs_size;
+ bool send_stop;
+ int cmd_err;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ struct i2c_client *slave;
+ enum aspeed_i2c_slave_state slave_state;
+#endif
+};
+
+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 int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus)
+{
+ unsigned long time_left, flags;
+ int ret = 0;
+ u32 command;
+
+ spin_lock_irqsave(&bus->lock, flags);
+ command = aspeed_i2c_read(bus, ASPEED_I2C_CMD_REG);
+
+ if (command & ASPEED_I2CD_SDA_LINE_STS) {
+ /* Bus is idle: no recovery needed. */
+ if (command & ASPEED_I2CD_SCL_LINE_STS)
+ goto out;
+ dev_dbg(bus->dev, "bus hung (state %x), attempting recovery\n",
+ command);
+
+ 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_timeout(
+ &bus->cmd_complete, bus->adap.timeout);
+
+ spin_lock_irqsave(&bus->lock, flags);
+ if (time_left == 0)
+ ret = -ETIMEDOUT;
+ else if (bus->cmd_err)
+ ret = -EIO;
+ /* Bus error. */
+ } else {
+ dev_dbg(bus->dev, "bus hung (state %x), attempting recovery\n",
+ command);
+
+ 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_timeout(
+ &bus->cmd_complete, bus->adap.timeout);
+
+ 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;
+}
+
+static void do_start(struct aspeed_i2c_bus *bus)
+{
+ u32 command = ASPEED_I2CD_M_START_CMD | ASPEED_I2CD_M_TX_CMD;
+ struct i2c_msg *msg = &bus->msgs[bus->msgs_index];
+ u8 slave_addr = msg->addr << 1;
+
+ bus->master_state = ASPEED_I2C_MASTER_START;
+ bus->buf_index = 0;
+
+ if (msg->flags & I2C_M_RD) {
+ slave_addr |= 1;
+ command |= ASPEED_I2CD_M_RX_CMD;
+ /* Need to let the hardware know to NACK after RX. */
+ if (msg->len == 1 && !(msg->flags & I2C_M_RECV_LEN))
+ 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);
+}
+
+static void do_stop(struct aspeed_i2c_bus *bus)
+{
+ bus->master_state = ASPEED_I2C_MASTER_STOP;
+ aspeed_i2c_write(bus, ASPEED_I2CD_M_STOP_CMD,
+ ASPEED_I2C_CMD_REG);
+}
+
+static void aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus)
+{
+ struct i2c_msg *msg = &bus->msgs[bus->msgs_index];
+ u32 irq_status, status_ack = 0, command = 0;
+ u8 recv_byte;
+
+ spin_lock(&bus->lock);
+ irq_status = aspeed_i2c_read(bus, ASPEED_I2C_INTR_STS_REG);
+
+ if (irq_status & ASPEED_I2CD_INTR_ERROR ||
+ (!bus->msgs && bus->master_state != ASPEED_I2C_MASTER_STOP)) {
+ dev_dbg(bus->dev, "received error interrupt: 0x%08x",
+ irq_status);
+ bus->cmd_err = -EIO;
+ do_stop(bus);
+ goto out_no_complete;
+ }
+
+ if (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE) {
+ bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
+ status_ack |= ASPEED_I2CD_INTR_BUS_RECOVER_DONE;
+ goto out_complete;
+ }
+
+ if (bus->master_state == ASPEED_I2C_MASTER_START) {
+ if (!(irq_status & ASPEED_I2CD_INTR_TX_ACK)) {
+ dev_dbg(bus->dev,
+ "no slave present at %02x", msg->addr);
+ status_ack |= ASPEED_I2CD_INTR_TX_NAK;
+ bus->cmd_err = -EIO;
+ do_stop(bus);
+ goto out_no_complete;
+ } else {
+ status_ack |= ASPEED_I2CD_INTR_TX_ACK;
+ if (msg->flags & I2C_M_RD)
+ bus->master_state = ASPEED_I2C_MASTER_RX;
+ else
+ bus->master_state = ASPEED_I2C_MASTER_TX_FIRST;
+ }
+ }
+
+ switch (bus->master_state) {
+ case ASPEED_I2C_MASTER_TX:
+ if (irq_status & ASPEED_I2CD_INTR_TX_NAK) {
+ dev_dbg(bus->dev, "slave NACKed TX");
+ status_ack |= ASPEED_I2CD_INTR_TX_NAK;
+ bus->cmd_err = -EIO;
+ do_stop(bus);
+ goto out_no_complete;
+ } else if (!(irq_status & ASPEED_I2CD_INTR_TX_ACK)) {
+ dev_err(bus->dev, "slave failed to ACK TX");
+ goto out_complete;
+ }
+ status_ack |= ASPEED_I2CD_INTR_TX_ACK;
+ /* fallthrough intended */
+ case ASPEED_I2C_MASTER_TX_FIRST:
+ if (bus->buf_index < msg->len) {
+ bus->master_state = ASPEED_I2C_MASTER_TX;
+ aspeed_i2c_write(bus, msg->buf[bus->buf_index++],
+ ASPEED_I2C_BYTE_BUF_REG);
+ aspeed_i2c_write(bus, ASPEED_I2CD_M_TX_CMD,
+ ASPEED_I2C_CMD_REG);
+ } else if (bus->msgs_index + 1 < bus->msgs_size) {
+ bus->msgs_index++;
+ do_start(bus);
+ } else {
+ do_stop(bus);
+ }
+ goto out_no_complete;
+ case ASPEED_I2C_MASTER_RX:
+ if (!(irq_status & ASPEED_I2CD_INTR_RX_DONE)) {
+ dev_err(bus->dev, "master failed to RX");
+ goto out_complete;
+ }
+ status_ack |= ASPEED_I2CD_INTR_RX_DONE;
+
+ recv_byte = aspeed_i2c_read(bus, ASPEED_I2C_BYTE_BUF_REG) >> 8;
+ msg->buf[bus->buf_index++] = recv_byte;
+
+ if (msg->flags & I2C_M_RECV_LEN &&
+ recv_byte <= I2C_SMBUS_BLOCK_MAX) {
+ msg->len = recv_byte +
+ ((msg->flags & I2C_CLIENT_PEC) ? 2 : 1);
+ msg->flags &= ~I2C_M_RECV_LEN;
+ }
+
+ if (bus->buf_index < msg->len) {
+ bus->master_state = ASPEED_I2C_MASTER_RX;
+ command = ASPEED_I2CD_M_RX_CMD;
+ if (bus->buf_index + 1 == msg->len)
+ command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+ aspeed_i2c_write(bus, command, ASPEED_I2C_CMD_REG);
+ } else if (bus->msgs_index + 1 < bus->msgs_size) {
+ bus->msgs_index++;
+ do_start(bus);
+ } else {
+ do_stop(bus);
+ }
+ goto out_no_complete;
+ case ASPEED_I2C_MASTER_STOP:
+ if (!(irq_status & ASPEED_I2CD_INTR_NORMAL_STOP)) {
+ dev_err(bus->dev, "master failed to STOP");
+ bus->cmd_err = -EIO;
+ }
+ status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
+
+ bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
+ goto out_complete;
+ case ASPEED_I2C_MASTER_INACTIVE:
+ dev_err(bus->dev,
+ "master received interrupt 0x%08x, but is inactive",
+ irq_status);
+ bus->cmd_err = -EIO;
+ goto out_complete;
+ default:
+ WARN(1, "unknown master state\n");
+ bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
+ bus->cmd_err = -EIO;
+ goto out_complete;
+ }
+
+out_complete:
+ complete(&bus->cmd_complete);
+out_no_complete:
+ if (irq_status != status_ack)
+ dev_err(bus->dev,
+ "irq handled != irq. expected 0x%08x, but was 0x%08x\n",
+ irq_status, status_ack);
+ aspeed_i2c_write(bus, irq_status, ASPEED_I2C_INTR_STS_REG);
+ spin_unlock(&bus->lock);
+}
+
+static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
+{
+ struct aspeed_i2c_bus *bus = dev_id;
+
+ aspeed_i2c_master_irq(bus);
+ return IRQ_HANDLED;
+}
+
+static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ struct aspeed_i2c_bus *bus = adap->algo_data;
+ unsigned long time_left, flags;
+ int ret = 0;
+
+ bus->cmd_err = 0;
+
+ /* 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;
+ }
+
+ spin_lock_irqsave(&bus->lock, flags);
+ bus->msgs = msgs;
+ bus->msgs_index = 0;
+ bus->msgs_size = num;
+
+ do_start(bus);
+ reinit_completion(&bus->cmd_complete);
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ time_left = wait_for_completion_timeout(&bus->cmd_complete,
+ bus->adap.timeout);
+
+ spin_lock_irqsave(&bus->lock, flags);
+ bus->msgs = NULL;
+ if (time_left == 0)
+ ret = -ETIMEDOUT;
+ else
+ ret = bus->cmd_err;
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ /* If nothing went wrong, return number of messages transferred. */
+ if (ret >= 0)
+ return bus->msgs_index + 1;
+ else
+ return ret;
+}
+
+static u32 aspeed_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm aspeed_i2c_algo = {
+ .master_xfer = aspeed_i2c_master_xfer,
+ .functionality = aspeed_i2c_functionality,
+};
+
+static u32 aspeed_i2c_get_clk_reg_val(u32 divisor)
+{
+ u32 base_clk, clk_high, clk_low, tmp;
+
+ /*
+ * The actual clock frequency of SCL is:
+ * SCL_freq = base_freq * (SCL_high + SCL_low)
+ * = APB_freq / divisor
+ * where base_freq is a programmable clock divider; its value is
+ * base_freq = 1 << base_clk
+ * SCL_high is the number of base_freq clock cycles that SCL stays high
+ * and SCL_low is the number of base_freq clock cycles that SCL stays
+ * low for a period of SCL.
+ * The actual register has a minimum SCL_high and SCL_low minimum of 1;
+ * thus, they start counting at zero. So
+ * SCL_high = clk_high + 1
+ * SCL_low = clk_low + 1
+ * Thus,
+ * SCL_freq = (1 << base_clk) * (clk_high + 1 + clk_low + 1)
+ * The documentation recommends clk_high >= 8 and clk_low >= 7 when
+ * possible; this last constraint gives us the following solution:
+ */
+ base_clk = divisor > 32 ? ilog2(divisor / 16 - 1) : 0;
+ tmp = divisor / (1 << base_clk);
+ clk_high = tmp / 2 + tmp % 2;
+ clk_low = tmp - clk_high;
+
+ clk_high -= 1;
+ clk_low -= 1;
+
+ return ((clk_high << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT)
+ & ASPEED_I2CD_TIME_SCL_HIGH_MASK)
+ | ((clk_low << ASPEED_I2CD_TIME_SCL_LOW_SHIFT)
+ & ASPEED_I2CD_TIME_SCL_LOW_MASK)
+ | (base_clk & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK);
+}
+
+static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus,
+ struct platform_device *pdev)
+{
+ u32 clk_freq, divisor;
+ struct clk *pclk;
+ 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;
+ }
+ divisor = 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 > 1000) {
+ 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(divisor),
+ ASPEED_I2C_AC_TIMING_REG1);
+ } else {
+ aspeed_i2c_write(bus, aspeed_i2c_get_clk_reg_val(divisor),
+ ASPEED_I2C_AC_TIMING_REG1);
+ aspeed_i2c_write(bus, ASPEED_NO_TIMEOUT_CTRL,
+ ASPEED_I2C_AC_TIMING_REG2);
+ }
+
+ return 0;
+}
+
+static int aspeed_i2c_probe_bus(struct platform_device *pdev)
+{
+ struct aspeed_i2c_bus *bus;
+ struct resource *res;
+ int ret;
+
+ bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
+ if (!bus)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ bus->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(bus->base)) {
+ dev_err(&pdev->dev, "failed to devm_ioremap_resource\n");
+ return PTR_ERR(bus->base);
+ }
+
+ bus->irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
+ ret = devm_request_irq(&pdev->dev, bus->irq, aspeed_i2c_bus_irq,
+ IRQF_SHARED, dev_name(&pdev->dev), bus);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to request interrupt\n");
+ return ret;
+ }
+
+ /* Initialize the I2C adapter */
+ spin_lock_init(&bus->lock);
+ init_completion(&bus->cmd_complete);
+ bus->adap.owner = THIS_MODULE;
+ bus->adap.retries = 0;
+ bus->adap.timeout = 5 * HZ;
+ 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");
+
+ 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_ALL, ASPEED_I2C_INTR_CTRL_REG);
+
+ ret = i2c_add_adapter(&bus->adap);
+ if (ret < 0)
+ return ret;
+
+ 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_bus_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);
+
+MODULE_AUTHOR("Brendan Higgins <brendanhiggins@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Aspeed I2C Bus Driver");
+MODULE_LICENSE("GPL v2");
--
2.12.2.564.g063fe858b8-goog