[PATCH v5 2/3] i2c: iproc: Add Broadcom iProc I2C Driver

Ray Jui
2015-01-16T23:41:38Z

Add initial support to the Broadcom iProc I2C controller found in the
iProc family of SoCs.

The iProc I2C controller has separate internal TX and RX FIFOs, each has
a size of 64 bytes. The iProc I2C controller supports two bus speeds
including standard mode (100kHz) and fast mode (400kHz)

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
---
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-bcm-iproc.c | 493 ++++++++++++++++++++++++++++++++++++
3 files changed, 504 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-bcm-iproc.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 31e8308..af76d23 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -372,6 +372,16 @@ config I2C_BCM2835
This support is also available as a module. If so, the module
will be called i2c-bcm2835.

+config I2C_BCM_IPROC
+ tristate "Broadcom iProc I2C controller"
+ depends on ARCH_BCM_IPROC || COMPILE_TEST
+ default ARCH_BCM_IPROC
+ help
+ If you say yes to this option, support will be included for the
+ Broadcom iProc I2C controller.
+
+ If you don't know what to do here, say N.
+
config I2C_BCM_KONA
tristate "BCM Kona I2C adapter"
depends on ARCH_BCM_MOBILE
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 56388f6..d93b509 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_I2C_AT91) += i2c-at91.o
obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
obj-$(CONFIG_I2C_BCM2835) += i2c-bcm2835.o
+obj-$(CONFIG_I2C_BCM_IPROC) += i2c-bcm-iproc.o
obj-$(CONFIG_I2C_BLACKFIN_TWI) += i2c-bfin-twi.o
obj-$(CONFIG_I2C_CADENCE) += i2c-cadence.o
obj-$(CONFIG_I2C_CBUS_GPIO) += i2c-cbus-gpio.o
diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
new file mode 100644
index 0000000..a92d8f5
--- /dev/null
+++ b/drivers/i2c/busses/i2c-bcm-iproc.c
@@ -0,0 +1,493 @@
+/*
+ * Copyright (C) 2014 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+
+#define CFG_OFFSET 0x00
+#define CFG_RESET_SHIFT 31
+#define CFG_EN_SHIFT 30
+#define CFG_M_RETRY_CNT_SHIFT 16
+#define CFG_M_RETRY_CNT_MASK 0x0f
+
+#define TIM_CFG_OFFSET 0x04
+#define TIM_CFG_MODE_400_SHIFT 31
+
+#define M_FIFO_CTRL_OFFSET 0x0c
+#define M_FIFO_RX_FLUSH_SHIFT 31
+#define M_FIFO_TX_FLUSH_SHIFT 30
+#define M_FIFO_RX_CNT_SHIFT 16
+#define M_FIFO_RX_CNT_MASK 0x7f
+#define M_FIFO_RX_THLD_SHIFT 8
+#define M_FIFO_RX_THLD_MASK 0x3f
+
+#define M_CMD_OFFSET 0x30
+#define M_CMD_START_BUSY_SHIFT 31
+#define M_CMD_STATUS_SHIFT 25
+#define M_CMD_STATUS_MASK 0x07
+#define M_CMD_STATUS_SUCCESS 0x0
+#define M_CMD_STATUS_LOST_ARB 0x1
+#define M_CMD_STATUS_NACK_ADDR 0x2
+#define M_CMD_STATUS_NACK_DATA 0x3
+#define M_CMD_STATUS_TIMEOUT 0x4
+#define M_CMD_PROTOCOL_SHIFT 9
+#define M_CMD_PROTOCOL_MASK 0xf
+#define M_CMD_PROTOCOL_BLK_WR 0x7
+#define M_CMD_PROTOCOL_BLK_RD 0x8
+#define M_CMD_PEC_SHIFT 8
+#define M_CMD_RD_CNT_SHIFT 0
+#define M_CMD_RD_CNT_MASK 0xff
+
+#define IE_OFFSET 0x38
+#define IE_M_RX_FIFO_FULL_SHIFT 31
+#define IE_M_RX_THLD_SHIFT 30
+#define IE_M_START_BUSY_SHIFT 28
+
+#define IS_OFFSET 0x3c
+#define IS_M_RX_FIFO_FULL_SHIFT 31
+#define IS_M_RX_THLD_SHIFT 30
+#define IS_M_START_BUSY_SHIFT 28
+
+#define M_TX_OFFSET 0x40
+#define M_TX_WR_STATUS_SHIFT 31
+#define M_TX_DATA_SHIFT 0
+#define M_TX_DATA_MASK 0xff
+
+#define M_RX_OFFSET 0x44
+#define M_RX_STATUS_SHIFT 30
+#define M_RX_STATUS_MASK 0x03
+#define M_RX_PEC_ERR_SHIFT 29
+#define M_RX_DATA_SHIFT 0
+#define M_RX_DATA_MASK 0xff
+
+#define I2C_TIMEOUT_MESC 100
+#define M_TX_RX_FIFO_SIZE 64
+
+enum bus_speed_index {
+ I2C_SPD_100K = 0,
+ I2C_SPD_400K,
+};
+
+struct bcm_iproc_i2c_dev {
+ struct device *device;
+ int irq;
+
+ void __iomem *base;
+
+ struct i2c_adapter adapter;
+
+ struct completion done;
+};
+
+/*
+ * Can be expanded in the future if more interrupt status bits are utilized
+ */
+#define ISR_MASK (1 << IS_M_START_BUSY_SHIFT)
+
+static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data)
+{
+ struct bcm_iproc_i2c_dev *iproc_i2c = data;
+ u32 status = readl(iproc_i2c->base + IS_OFFSET);
+
+ status &= ISR_MASK;
+
+ if (!status)
+ return IRQ_NONE;
+
+ writel(status, iproc_i2c->base + IS_OFFSET);
+ complete_all(&iproc_i2c->done);
+
+ return IRQ_HANDLED;
+}
+
+static bool bcm_iproc_i2c_bus_busy(struct bcm_iproc_i2c_dev *iproc_i2c)
+{
+ if (readl(iproc_i2c->base + M_CMD_OFFSET) &
+ (1 << M_CMD_START_BUSY_SHIFT))
+ return true;
+ else
+ return false;
+}
+
+static int bcm_iproc_i2c_format_addr(struct bcm_iproc_i2c_dev *iproc_i2c,
+ struct i2c_msg *msg, u8 *addr)
+{
+
+ if (msg->flags & I2C_M_TEN) {
+ dev_err(iproc_i2c->device, "no support for 10-bit address\n");
+ return -EINVAL;
+ }
+
+ *addr = msg->addr << 1;
+
+ if (msg->flags & I2C_M_RD)
+ *addr |= 1;
+
+ return 0;
+}
+
+static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *iproc_i2c,
+ struct i2c_msg *msg)
+{
+ u32 val;
+
+ val = readl(iproc_i2c->base + M_CMD_OFFSET);
+ val = (val >> M_CMD_STATUS_SHIFT) & M_CMD_STATUS_MASK;
+
+ switch (val) {
+ case M_CMD_STATUS_SUCCESS:
+ return 0;
+
+ case M_CMD_STATUS_LOST_ARB:
+ dev_dbg(iproc_i2c->device, "lost bus arbitration\n");
+ return -EAGAIN;
+
+ case M_CMD_STATUS_NACK_ADDR:
+ dev_dbg(iproc_i2c->device, "NAK addr:0x%02x\n", msg->addr);
+ return -ENXIO;
+
+ case M_CMD_STATUS_NACK_DATA:
+ dev_dbg(iproc_i2c->device, "NAK data\n");
+ return -ENXIO;
+
+ case M_CMD_STATUS_TIMEOUT:
+ dev_dbg(iproc_i2c->device, "bus timeout\n");
+ return -ETIMEDOUT;
+
+ default:
+ dev_dbg(iproc_i2c->device, "unknown error code=%d\n", val);
+ return -EIO;
+ }
+}
+
+static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
+ struct i2c_msg *msg)
+{
+ int ret, i;
+ u8 addr;
+ u32 val;
+ unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MESC);
+
+ if (msg->len > M_TX_RX_FIFO_SIZE - 1) {
+ dev_err(iproc_i2c->device,
+ "only support data length up to %u bytes\n",
+ M_TX_RX_FIFO_SIZE - 1);
+ return -EINVAL;
+ }
+
+ if (bcm_iproc_i2c_bus_busy(iproc_i2c)) {
+ dev_warn(iproc_i2c->device, "bus is busy\n");
+ return -EBUSY;
+ }
+
+ ret = bcm_iproc_i2c_format_addr(iproc_i2c, msg, &addr);
+ if (ret)
+ return ret;
+
+ /* load slave address into the TX FIFO */
+ writel(addr, iproc_i2c->base + M_TX_OFFSET);
+
+ /* for a write transaction, load data into the TX FIFO */
+ if (!(msg->flags & I2C_M_RD)) {
+ for (i = 0; i < msg->len; i++) {
+ val = msg->buf[i];
+
+ /* mark the last byte */
+ if (i == msg->len - 1)
+ val |= 1 << M_TX_WR_STATUS_SHIFT;
+
+ writel(val, iproc_i2c->base + M_TX_OFFSET);
+ }
+
+ if (msg->len == 0)
+ writel(1 << M_TX_WR_STATUS_SHIFT,
+ iproc_i2c->base + M_TX_OFFSET);
+ }
+
+ /* mark as incomplete before starting the transaction */
+ reinit_completion(&iproc_i2c->done);
+
+ /*
+ * Enable the "start busy" interrupt, which will be triggered after the
+ * transaction is done, i.e., the internal start_busy bit, transitions
+ * from 1 to 0.
+ */
+ writel(1 << IE_M_START_BUSY_SHIFT, iproc_i2c->base + IE_OFFSET);
+
+ /*
+ * Now we can activate the transfer. For a read operation, specify the
+ * number of bytes to read
+ */
+ val = 1 << M_CMD_START_BUSY_SHIFT;
+ if (msg->flags & I2C_M_RD) {
+ val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) |
+ (msg->len << M_CMD_RD_CNT_SHIFT);
+ } else {
+ val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT);
+ }
+ writel(val, iproc_i2c->base + M_CMD_OFFSET);
+
+ time_left = wait_for_completion_timeout(&iproc_i2c->done, time_left);
+
+ /* disable all interrupts */
+ writel(0, iproc_i2c->base + IE_OFFSET);
+
+ if (!time_left) {
+ dev_err(iproc_i2c->device, "transaction timed out\n");
+
+ /* flush FIFOs */
+ val = (1 << M_FIFO_RX_FLUSH_SHIFT) |
+ (1 << M_FIFO_TX_FLUSH_SHIFT);
+ writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET);
+ return -ETIMEDOUT;
+ }
+
+ ret = bcm_iproc_i2c_check_status(iproc_i2c, msg);
+ if (ret) {
+ /* flush both TX/RX FIFOs */
+ val = (1 << M_FIFO_RX_FLUSH_SHIFT) |
+ (1 << M_FIFO_TX_FLUSH_SHIFT);
+ writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET);
+ return ret;
+ }
+
+ /*
+ * For a read operation, we now need to load the data from FIFO
+ * into the memory buffer
+ */
+ if (msg->flags & I2C_M_RD) {
+ for (i = 0; i < msg->len; i++) {
+ msg->buf[i] = (readl(iproc_i2c->base + M_RX_OFFSET) >>
+ M_RX_DATA_SHIFT) & M_RX_DATA_MASK;
+ }
+ }
+
+ dev_dbg(iproc_i2c->device, "xfer %c, addr=0x%02x, len=%d\n",
+ (msg->flags & I2C_M_RD) ? 'R' : 'W', msg->addr,
+ msg->len);
+ dev_dbg(iproc_i2c->device, "**** data start ****\n");
+ for (i = 0; i < msg->len; i++)
+ dev_dbg(iproc_i2c->device, "0x%02x ", msg->buf[i]);
+ dev_dbg(iproc_i2c->device, "**** data end ****\n");
+
+ return 0;
+}
+
+static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter,
+ struct i2c_msg msgs[], int num)
+{
+ struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adapter);
+ int ret, i;
+
+ /* go through all messages */
+ for (i = 0; i < num; i++) {
+ ret = bcm_iproc_i2c_xfer_single_msg(iproc_i2c, &msgs[i]);
+ if (ret) {
+ dev_err(iproc_i2c->device, "xfer failed\n");
+ return ret;
+ }
+ }
+
+ return num;
+}
+
+static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm bcm_iproc_algo = {
+ .master_xfer = bcm_iproc_i2c_xfer,
+ .functionality = bcm_iproc_i2c_functionality,
+};
+
+static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c)
+{
+ unsigned int bus_speed, speed_bit;
+ u32 val;
+ int ret = of_property_read_u32(iproc_i2c->device->of_node,
+ "clock-frequency", &bus_speed);
+ if (ret < 0) {
+ dev_info(iproc_i2c->device,
+ "unable to interpret clock-frequency DT property\n");
+ bus_speed = 100000;
+ }
+
+ if (bus_speed < 100000) {
+ dev_err(iproc_i2c->device, "%d Hz bus speed not supported\n",
+ bus_speed);
+ dev_err(iproc_i2c->device,
+ "valid speeds are 100khz and 400khz\n");
+ return -EINVAL;
+ } else if (bus_speed < 400000) {
+ speed_bit = 0;
+ } else {
+ /* bus_speed >= 400000 */
+ speed_bit = 1;
+ }
+
+ val = readl(iproc_i2c->base + TIM_CFG_OFFSET);
+ val &= ~(1 << TIM_CFG_MODE_400_SHIFT);
+ val |= speed_bit << TIM_CFG_MODE_400_SHIFT;
+ writel(val, iproc_i2c->base + TIM_CFG_OFFSET);
+
+ dev_info(iproc_i2c->device, "bus set to %u Hz\n", bus_speed);
+
+ return 0;
+}
+
+static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *iproc_i2c)
+{
+ u32 val;
+
+ /* put controller in reset */
+ val = readl(iproc_i2c->base + CFG_OFFSET);
+ val |= 1 << CFG_RESET_SHIFT;
+ val &= ~(1 << CFG_EN_SHIFT);
+ writel(val, iproc_i2c->base + CFG_OFFSET);
+
+ /* wait 100 usec per spec */
+ udelay(100);
+
+ /* bring controller out of reset */
+ val &= ~(1 << CFG_RESET_SHIFT);
+ writel(val, iproc_i2c->base + CFG_OFFSET);
+
+ /* flush TX/RX FIFOs and set RX FIFO threshold to zero */
+ val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT);
+ writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET);
+
+ /* disable all interrupts */
+ writel(0, iproc_i2c->base + IE_OFFSET);
+
+ /* clear all pending interrupts */
+ writel(0xffffffff, iproc_i2c->base + IS_OFFSET);
+
+ return 0;
+}
+
+static void bcm_iproc_i2c_enable(struct bcm_iproc_i2c_dev *iproc_i2c)
+{
+ u32 val;
+
+ val = readl(iproc_i2c->base + CFG_OFFSET);
+ val |= 1 << CFG_EN_SHIFT;
+ writel(val, iproc_i2c->base + CFG_OFFSET);
+}
+
+static void bcm_iproc_i2c_disable(struct bcm_iproc_i2c_dev *iproc_i2c)
+{
+ u32 val;
+
+ val = readl(iproc_i2c->base + CFG_OFFSET);
+ val &= ~(1 << CFG_EN_SHIFT);
+ writel(val, iproc_i2c->base + CFG_OFFSET);
+}
+
+static int bcm_iproc_i2c_probe(struct platform_device *pdev)
+{
+ int irq, ret = 0;
+ struct bcm_iproc_i2c_dev *iproc_i2c;
+ struct i2c_adapter *adap;
+ struct resource *res;
+
+ iproc_i2c = devm_kzalloc(&pdev->dev, sizeof(*iproc_i2c),
+ GFP_KERNEL);
+ if (!iproc_i2c)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, iproc_i2c);
+ iproc_i2c->device = &pdev->dev;
+ init_completion(&iproc_i2c->done);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ iproc_i2c->base = devm_ioremap_resource(iproc_i2c->device, res);
+ if (IS_ERR(iproc_i2c->base))
+ return PTR_ERR(iproc_i2c->base);
+
+ ret = bcm_iproc_i2c_init(iproc_i2c);
+ if (ret)
+ return ret;
+
+ ret = bcm_iproc_i2c_cfg_speed(iproc_i2c);
+ if (ret)
+ return ret;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq <= 0) {
+ dev_err(iproc_i2c->device, "no irq resource\n");
+ return irq;
+ }
+ iproc_i2c->irq = irq;
+
+ ret = devm_request_irq(iproc_i2c->device, irq, bcm_iproc_i2c_isr, 0,
+ pdev->name, iproc_i2c);
+ if (ret < 0) {
+ dev_err(iproc_i2c->device, "unable to request irq %i\n", irq);
+ return ret;
+ }
+
+ bcm_iproc_i2c_enable(iproc_i2c);
+
+ adap = &iproc_i2c->adapter;
+ i2c_set_adapdata(adap, iproc_i2c);
+ strlcpy(adap->name, "Broadcom iProc I2C adapter", sizeof(adap->name));
+ adap->algo = &bcm_iproc_algo;
+ adap->dev.parent = &pdev->dev;
+ adap->dev.of_node = pdev->dev.of_node;
+
+ ret = i2c_add_adapter(adap);
+ if (ret) {
+ dev_err(iproc_i2c->device, "failed to add adapter\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int bcm_iproc_i2c_remove(struct platform_device *pdev)
+{
+ struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev);
+
+ disable_irq(iproc_i2c->irq);
+ i2c_del_adapter(&iproc_i2c->adapter);
+ bcm_iproc_i2c_disable(iproc_i2c);
+
+ return 0;
+}
+
+static const struct of_device_id bcm_iproc_i2c_of_match[] = {
+ { .compatible = "brcm,iproc-i2c" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, bcm_iproc_i2c_of_match);
+
+static struct platform_driver bcm_iproc_i2c_driver = {
+ .driver = {
+ .name = "bcm-iproc-i2c",
+ .of_match_table = bcm_iproc_i2c_of_match,
+ },
+ .probe = bcm_iproc_i2c_probe,
+ .remove = bcm_iproc_i2c_remove,
+};
+module_platform_driver(bcm_iproc_i2c_driver);
+
+MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
+MODULE_DESCRIPTION("Broadcom iProc I2C Driver");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5