Add a driver for the EMMA mobile I2C block.
The driver supports low and high-speed interrupt driven PIO transfers.
Signed-off-by: Ian Molton <ian.mol...@codethink.co.uk>
---
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-em.c | 501 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 512 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-em.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index dc6dea6..d66d4b4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -777,6 +777,16 @@ config I2C_RCAR
This driver can also be built as a module. If so, the module
will be called i2c-rcar.
+config I2C_EM
+ tristate "EMMA Mobile series I2C adapter"
+ depends on I2C && HAVE_CLK
+ help
+ If you say yes to this option, support will be included for the
+ I2C interface on the Renesas Electronics EM/EV family of processors.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-em
+
comment "External I2C/SMBus adapter drivers"
config I2C_DIOLAN_U2C
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index d00997f..d330706 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -42,6 +42,7 @@ i2c-designware-platform-objs := i2c-designware-platdrv.o
obj-$(CONFIG_I2C_DESIGNWARE_PCI) += i2c-designware-pci.o
i2c-designware-pci-objs := i2c-designware-pcidrv.o
obj-$(CONFIG_I2C_EG20T) += i2c-eg20t.o
+obj-$(CONFIG_I2C_EM) += i2c-em.o
obj-$(CONFIG_I2C_GPIO) += i2c-gpio.o
obj-$(CONFIG_I2C_HIGHLANDER) += i2c-highlander.o
obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o
diff --git a/drivers/i2c/busses/i2c-em.c b/drivers/i2c/busses/i2c-em.c
new file mode 100644
index 0000000..d7e91b4
--- /dev/null
+++ b/drivers/i2c/busses/i2c-em.c
@@ -0,0 +1,501 @@
+/*
+ * Copyright 2013 Codethink Ltd.
+ * Parts Copyright 2010 Renesas Electronics Corporation
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/of_i2c.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/sched.h>
+
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+/* I2C Registers */
+#define I2C_OFS_IICACT0 0x00 /* start */
+#define I2C_OFS_IIC0 0x04 /* shift */
+#define I2C_OFS_IICC0 0x08 /* control */
+#define I2C_OFS_SVA0 0x0c /* slave address */
+#define I2C_OFS_IICCL0 0x10 /* clock select */
+#define I2C_OFS_IICX0 0x14 /* extention */
+#define I2C_OFS_IICS0 0x18 /* status */
+#define I2C_OFS_IICSE0 0x1c /* status For emulation */
+#define I2C_OFS_IICF0 0x20 /* IIC flag */
+
+/* I2C IICACT0 Masks */
+#define I2C_BIT_IICE0 0x0001
+
+/* I2C IICC0 Masks */
+#define I2C_BIT_LREL0 0x0040
+#define I2C_BIT_WREL0 0x0020
+#define I2C_BIT_SPIE0 0x0010
+#define I2C_BIT_WTIM0 0x0008
+#define I2C_BIT_ACKE0 0x0004
+#define I2C_BIT_STT0 0x0002
+#define I2C_BIT_SPT0 0x0001
+
+/* I2C IICCL0 Masks */
+#define I2C_BIT_SMC0 0x0008
+#define I2C_BIT_DFC0 0x0004
+
+/* I2C IICSE0 Masks */
+#define I2C_BIT_MSTS0 0x0080
+#define I2C_BIT_ALD0 0x0040
+#define I2C_BIT_EXC0 0x0020
+#define I2C_BIT_COI0 0x0010
+#define I2C_BIT_TRC0 0x0008
+#define I2C_BIT_ACKD0 0x0004
+#define I2C_BIT_STD0 0x0002
+#define I2C_BIT_SPD0 0x0001
+
+/* I2C IICF0 Masks */
+#define I2C_BIT_STCF 0x0080
+#define I2C_BIT_IICBSY 0x0040
+#define I2C_BIT_STCEN 0x0002
+#define I2C_BIT_IICRSV 0x0001
+
+static int em_i2c_xfer(struct i2c_adapter *, struct i2c_msg[], int);
+
+struct em_i2c_device {
+ struct i2c_adapter adap;
+ wait_queue_head_t i2c_wait;
+ void __iomem *membase;
+ struct clk *clk;
+ struct clk *sclk;
+ int irq;
+ int flags;
+ int pending;
+ spinlock_t irq_lock;
+};
+
+#define to_em_i2c(adap) (struct em_i2c_device *)i2c_get_adapdata(adap)
+
+static u32 em_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm em_i2c_algo = {
+ .master_xfer = em_i2c_xfer,
+ .smbus_xfer = NULL,
+ .functionality = em_i2c_func,
+};
+
+static void em_i2c_enable_clock(struct em_i2c_device *i2c_dev)
+{
+ clk_enable(i2c_dev->clk);
+ clk_enable(i2c_dev->sclk);
+}
+
+static void em_i2c_disable_clock(struct em_i2c_device *i2c_dev)
+{
+ clk_disable(i2c_dev->sclk);
+ clk_disable(i2c_dev->clk);
+}
+
+static int em_i2c_wait_for_event(struct em_i2c_device *i2c_dev, u16 *status)
+{
+ int interrupted;
+
+ do {
+ interrupted = wait_event_interruptible_timeout(
+ i2c_dev->i2c_wait, i2c_dev->pending,
+ i2c_dev->adap.timeout);
+
+ if (i2c_dev->pending) {
+ spin_lock_irq(&i2c_dev->irq_lock);
+ i2c_dev->pending = 0;
+ spin_unlock_irq(&i2c_dev->irq_lock);
+ *status = readl(i2c_dev->membase + I2C_OFS_IICSE0);
+ return 0;
+ }
+
+ } while (interrupted);
+
+ *status = 0;
+
+ return -ETIMEDOUT;
+}
+
+static int em_i2c_stop(struct em_i2c_device *i2c_dev)
+{
+ u16 status;
+
+ /* Send Stop condition */
+ writel((readl(i2c_dev->membase + I2C_OFS_IICC0) | I2C_BIT_SPT0 |
+ I2C_BIT_SPIE0), i2c_dev->membase + I2C_OFS_IICC0);
+
+ /* Wait for stop condition */
+ em_i2c_wait_for_event(i2c_dev, &status);
+ /* FIXME - check status? */
+
+ if ((readl(i2c_dev->membase + I2C_OFS_IICSE0) & I2C_BIT_SPD0) != 0)
+ return 0;
+
+ return -EBUSY;
+}
+
+static int em_i2c_start(struct em_i2c_device *i2c_dev)
+{
+ /* Send start condition */
+ writel((readl(i2c_dev->membase + I2C_OFS_IICC0)) | I2C_BIT_ACKE0 |
+ I2C_BIT_WTIM0, i2c_dev->membase + I2C_OFS_IICC0);
+
+ writel((readl(i2c_dev->membase + I2C_OFS_IICC0) | I2C_BIT_STT0),
+ i2c_dev->membase + I2C_OFS_IICC0);
+
+ return -EBUSY;
+}
+
+static void em_i2c_reset(struct i2c_adapter *adap)
+{
+ struct em_i2c_device *i2c_dev = to_em_i2c(adap);
+ int retr;
+
+ /* If I2C active */
+ if (readl(i2c_dev->membase + I2C_OFS_IICACT0) & I2C_BIT_IICE0) {
+
+ /* Disable I2C operation */
+ writel(0, i2c_dev->membase + I2C_OFS_IICACT0);
+
+ retr = 1000;
+ while (readl(i2c_dev->membase + I2C_OFS_IICACT0) == 1 && retr)
+ retr--;
+ WARN_ON(retr == 0);
+ }
+
+ /* Transfer mode set */
+ writel(i2c_dev->flags, i2c_dev->membase + I2C_OFS_IICCL0);
+
+ /* Can Issue start without detecting a stop, Reservation disabled. */
+ writel(I2C_BIT_STCEN | I2C_BIT_IICRSV,
+ i2c_dev->membase + I2C_OFS_IICF0);
+
+ /* I2C enable, 9 bit interrupt mode */
+ writel(I2C_BIT_WTIM0, i2c_dev->membase + I2C_OFS_IICC0);
+
+ /* Enable I2C operation */
+ writel(I2C_BIT_IICE0, i2c_dev->membase + I2C_OFS_IICACT0);
+
+ retr = 1000;
+ while (readl(i2c_dev->membase + I2C_OFS_IICACT0) == 0 && retr)
+ retr--;
+ WARN_ON(retr == 0);
+}
+
+static int __em_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msg,
+ int stop)
+{
+ struct em_i2c_device *i2c_dev = to_em_i2c(adap);
+ int count = 0;
+ u16 status;
+
+ /* Start transfer */
+ em_i2c_start(i2c_dev);
+
+ /* Send slave address and R/W type */
+ writel((msg->addr << 1) | ((msg->flags & I2C_M_RD) ? 1 : 0),
+ i2c_dev->membase + I2C_OFS_IIC0);
+
+ /* Wait for transaction */
+ if (em_i2c_wait_for_event(i2c_dev, &status))
+ goto out_reset;
+
+ /* Arbitration, Extension mode or Slave mode are all errors */
+ if (status & (I2C_BIT_EXC0 | I2C_BIT_COI0 | I2C_BIT_ALD0)
+ || !(status & I2C_BIT_MSTS0))
+ goto out_reset;
+
+ /* Extra setup for read transactions */
+ if (!(status & I2C_BIT_TRC0)) {
+
+ /* msg->flags is Write type */
+ if (!(msg->flags & I2C_M_RD))
+ goto out_reset;
+
+ /* Recieved No ACK (result of setting slave address and R/W) */
+ if (!(status & I2C_BIT_ACKD0)) {
+ em_i2c_stop(i2c_dev);
+ goto out;
+ }
+
+ /* 8 bit interrupt mode */
+ writel((readl(i2c_dev->membase + I2C_OFS_IICC0)
+ & ~I2C_BIT_WTIM0) | I2C_BIT_ACKE0,
+ i2c_dev->membase + I2C_OFS_IICC0);
+ writel((readl(i2c_dev->membase + I2C_OFS_IICC0)
+ & ~I2C_BIT_WTIM0) | I2C_BIT_WREL0,
+ i2c_dev->membase + I2C_OFS_IICC0);
+
+ /* Wait for transaction */
+ if (em_i2c_wait_for_event(i2c_dev, &status))
+ goto out_reset;
+ }
+
+ /* Send / receive data */
+ do {
+ /* Arbitration, Extension mode or Slave mode are errors*/
+ if (status & (I2C_BIT_EXC0 | I2C_BIT_COI0 | I2C_BIT_ALD0)
+ || !(status & I2C_BIT_MSTS0))
+ goto out_reset;
+
+ if (!(status & I2C_BIT_TRC0)) { /* Read transaction */
+
+ /* msg->flags is Write type */
+ if (!(msg->flags & I2C_M_RD))
+ goto out_reset;
+
+ if (count == msg->len)
+ break;
+
+ msg->buf[count++] =
+ readl(i2c_dev->membase + I2C_OFS_IIC0);
+
+
+ writel((readl(i2c_dev->membase + I2C_OFS_IICC0)
+ | I2C_BIT_WREL0),
+ i2c_dev->membase + I2C_OFS_IICC0);
+
+ } else { /* Write transaction */
+
+ /* msg->flags is Read type */
+ if ((msg->flags & I2C_M_RD))
+ goto out_reset;
+
+ /* Recieved No ACK */
+ if (!(status & I2C_BIT_ACKD0)) {
+ em_i2c_stop(i2c_dev);
+ goto out;
+ }
+
+ if (count == msg->len)
+ break;
+
+ /* Write data */
+ writel(msg->buf[count++], i2c_dev->membase
+ + I2C_OFS_IIC0);
+ }
+
+ /* Wait for R/W transaction */
+ if (em_i2c_wait_for_event(i2c_dev, &status))
+ goto out_reset;
+
+ } while (1);
+
+ if (stop)
+ em_i2c_stop(i2c_dev);
+
+ return count;
+
+out_reset:
+ em_i2c_reset(adap);
+out:
+ return -EREMOTEIO;
+}
+
+static int em_i2c_wait_free(struct i2c_adapter *adap)
+{
+ struct em_i2c_device *i2c_dev = to_em_i2c(adap);
+ int timeout = adap->timeout;
+ int status;
+
+ /* wait until I2C bus free */
+ while ((readl(i2c_dev->membase + I2C_OFS_IICF0) & I2C_BIT_IICBSY)
+ && timeout--) {
+ schedule_timeout_uninterruptible(1);
+ }
+
+ status = (timeout <= 0);
+
+ if (status)
+ dev_info(&adap->dev, "I2C bus is busy\n");
+
+ return status;
+}
+
+static int em_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ struct em_i2c_device *i2c_dev = to_em_i2c(adap);
+ int ret = 0;
+ int i;
+
+ em_i2c_enable_clock(i2c_dev);
+ em_i2c_reset(adap);
+
+ /* Attempt to gain control of the adapter */
+ i = 0;
+ while (em_i2c_wait_free(adap)) {
+ switch (i) {
+ case 0:
+ if (!(readl(i2c_dev->membase + I2C_OFS_IICSE0)
+ & I2C_BIT_MSTS0)) {
+ /* Slave mode -> Error */
+ ret = -EBUSY;
+ goto out;
+ }
+
+ em_i2c_stop(i2c_dev);
+ break;
+ case 1:
+ em_i2c_reset(adap);
+ break;
+ case 2:
+ ret = -EREMOTEIO;
+ goto out;
+ }
+ i++;
+ }
+
+ /* Send messages */
+ for (i = 0; i < num; i++) {
+ ret = __em_i2c_xfer(adap, &msgs[i], (i == (num - 1)));
+ if (ret < 0)
+ goto out;
+ }
+
+ /* I2C transfer completed */
+ ret = i;
+
+out:
+ em_i2c_disable_clock(i2c_dev);
+
+ return ret;
+}
+
+static irqreturn_t em_i2c_irq_handler(int this_irq, void *dev_id)
+{
+ struct em_i2c_device *i2c_dev = dev_id;
+
+ i2c_dev->pending = 1;
+
+ wake_up_interruptible(&i2c_dev->i2c_wait);
+
+ return IRQ_HANDLED;
+}
+
+static int em_i2c_probe(struct platform_device *pdev)
+{
+ struct em_i2c_device *i2c_dev;
+ struct resource *r;
+ int ret;
+
+ i2c_dev = devm_kzalloc(&pdev->dev, sizeof(struct em_i2c_device),
+ GFP_KERNEL);
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ i2c_dev->membase = devm_ioremap_resource(&pdev->dev, r);
+ if (IS_ERR(i2c_dev->membase))
+ return PTR_ERR(i2c_dev->membase);
+
+ strlcpy(i2c_dev->adap.name, "em_i2c", sizeof(i2c_dev->adap.name));
+
+ i2c_dev->clk = devm_clk_get(&pdev->dev, NULL);
+ if (!IS_ERR(i2c_dev->clk))
+ clk_prepare(i2c_dev->clk);
+
+ i2c_dev->sclk = devm_clk_get(&pdev->dev, "sclk");
+ if (!IS_ERR(i2c_dev->sclk))
+ clk_prepare(i2c_dev->sclk);
+
+ i2c_dev->irq = platform_get_irq(pdev, 0);
+ i2c_dev->adap.timeout = msecs_to_jiffies(100);
+ i2c_dev->adap.dev.parent = &pdev->dev;
+ i2c_dev->adap.algo = &em_i2c_algo;
+ i2c_dev->adap.owner = THIS_MODULE;
+ i2c_dev->adap.nr = pdev->id;
+ i2c_dev->adap.dev.of_node = pdev->dev.of_node;
+
+ init_waitqueue_head(&i2c_dev->i2c_wait);
+
+ spin_lock_init(&i2c_dev->irq_lock);
+
+ i2c_dev->flags = I2C_BIT_DFC0;
+
+ if (of_find_property(pdev->dev.of_node, "high-speed", NULL))
+ i2c_dev->flags |= I2C_BIT_SMC0;
+
+ platform_set_drvdata(pdev, i2c_dev);
+ i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
+
+ em_i2c_enable_clock(i2c_dev);
+ em_i2c_reset(&i2c_dev->adap);
+ em_i2c_disable_clock(i2c_dev);
+
+ ret = devm_request_irq(&pdev->dev, i2c_dev->irq, em_i2c_irq_handler, 0,
+ "em_i2c", i2c_dev);
+
+ if (ret)
+ goto exit_clk;
+
+ ret = i2c_add_numbered_adapter(&i2c_dev->adap);
+
+ if (ret != 0)
+ goto exit_clk;
+
+ of_i2c_register_devices(&i2c_dev->adap);
+
+ dev_info(&pdev->dev, "Added i2c controller %d irq %d @ 0x%p\n",
+ i2c_dev->adap.nr, i2c_dev->irq, i2c_dev->membase);
+
+ return 0;
+
+exit_clk:
+ clk_disable(i2c_dev->clk);
+ clk_unprepare(i2c_dev->clk);
+ return ret;
+}
+
+static int em_i2c_remove(struct platform_device *dev)
+{
+ struct em_i2c_device *i2c_dev = platform_get_drvdata(dev);
+
+ i2c_del_adapter(&i2c_dev->adap);
+
+ clk_disable(i2c_dev->clk);
+ clk_unprepare(i2c_dev->clk);
+
+ return 0;
+}
+
+static struct of_device_id em_i2c_ids[] = {
+ { .compatible = "renesas,em-i2c", },
+ { }
+};
+
+static struct platform_driver em_i2c_driver = {
+ .probe = em_i2c_probe,
+ .remove = em_i2c_remove,
+ .driver = {
+ .name = "em-i2c",
+ .owner = THIS_MODULE,
+ .of_match_table = em_i2c_ids,
+ }
+};
+
+module_platform_driver(em_i2c_driver);
+MODULE_DEVICE_TABLE(of, em_i2c_ids);
+
+MODULE_LICENSE("GPLv2");
+MODULE_DESCRIPTION("EMEV2 I2C bus driver");
+MODULE_AUTHOR("Ian Molton");
+
--
1.7.10.4
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