--- /dev/null
+/*
+ * I2C driver for the Renesas EMEV2 SoC
+ *
+ * Copyright (C) 2015 Wolfram Sang <wsa@sang-engineering.com>
+ * Copyright 2013 Codethink Ltd.
+ * Copyright 2010-2015 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/sched.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 /* extension */
+#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
+
+struct em_i2c_device {
+ void __iomem *base;
+ struct i2c_adapter adap;
+ struct completion msg_done;
+ struct clk *sclk;
+};
+
+static inline void em_clear_set_bit(struct em_i2c_device *priv, u8 clear, u8 set, u8 reg)
+{
+ writeb((readb(priv->base + reg) & ~clear) | set, priv->base + reg);
+}
+
+static int em_i2c_wait_for_event(struct em_i2c_device *priv)
+{
+ unsigned long time_left;
+ int status;
+
+ reinit_completion(&priv->msg_done);
+
+ time_left = wait_for_completion_timeout(&priv->msg_done, priv->adap.timeout);
+
+ if (!time_left)
+ return -ETIMEDOUT;
+
+ status = readb(priv->base + I2C_OFS_IICSE0);
+ return status & I2C_BIT_ALD0 ? -EAGAIN : status;
+}
+
+static void em_i2c_stop(struct em_i2c_device *priv)
+{
+ /* Send Stop condition */
+ em_clear_set_bit(priv, 0, I2C_BIT_SPT0 | I2C_BIT_SPIE0, I2C_OFS_IICC0);
+
+ /* Wait for stop condition */
+ em_i2c_wait_for_event(priv);
+}
+
+static void em_i2c_reset(struct i2c_adapter *adap)
+{
+ struct em_i2c_device *priv = i2c_get_adapdata(adap);
+ int retr;
+
+ /* If I2C active */
+ if (readb(priv->base + I2C_OFS_IICACT0) & I2C_BIT_IICE0) {
+ /* Disable I2C operation */
+ writeb(0, priv->base + I2C_OFS_IICACT0);
+
+ retr = 1000;
+ while (readb(priv->base + I2C_OFS_IICACT0) == 1 && retr)
+ retr--;
+ WARN_ON(retr == 0);
+ }
+
+ /* Transfer mode set */
+ writeb(I2C_BIT_DFC0, priv->base + I2C_OFS_IICCL0);
+
+ /* Can Issue start without detecting a stop, Reservation disabled. */
+ writeb(I2C_BIT_STCEN | I2C_BIT_IICRSV, priv->base + I2C_OFS_IICF0);
+
+ /* I2C enable, 9 bit interrupt mode */
+ writeb(I2C_BIT_WTIM0, priv->base + I2C_OFS_IICC0);
+
+ /* Enable I2C operation */
+ writeb(I2C_BIT_IICE0, priv->base + I2C_OFS_IICACT0);
+
+ retr = 1000;
+ while (readb(priv->base + 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 *priv = i2c_get_adapdata(adap);
+ int count, status, read = !!(msg->flags & I2C_M_RD);
+
+ /* Send start condition */
+ em_clear_set_bit(priv, 0, I2C_BIT_ACKE0 | I2C_BIT_WTIM0, I2C_OFS_IICC0);
+ em_clear_set_bit(priv, 0, I2C_BIT_STT0, I2C_OFS_IICC0);
+
+ /* Send slave address and R/W type */
+ writeb((msg->addr << 1) | read, priv->base + I2C_OFS_IIC0);
+
+ /* Wait for transaction */
+ status = em_i2c_wait_for_event(priv);
+ if (status < 0)
+ goto out_reset;
+
+ /* Received NACK (result of setting slave address and R/W) */
+ if (!(status & I2C_BIT_ACKD0)) {
+ em_i2c_stop(priv);
+ goto out;
+ }
+
+ /* Extra setup for read transactions */
+ if (read) {
+ /* 8 bit interrupt mode */
+ em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_ACKE0, I2C_OFS_IICC0);
+ em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_WREL0, I2C_OFS_IICC0);
+
+ /* Wait for transaction */
+ status = em_i2c_wait_for_event(priv);
+ if (status < 0)
+ goto out_reset;
+ }
+
+ /* Send / receive data */
+ for (count = 0; count < msg->len; count++) {
+ if (read) { /* Read transaction */
+ msg->buf[count] = readb(priv->base + I2C_OFS_IIC0);
+ em_clear_set_bit(priv, 0, I2C_BIT_WREL0, I2C_OFS_IICC0);
+
+ } else { /* Write transaction */
+ /* Received NACK */
+ if (!(status & I2C_BIT_ACKD0)) {
+ em_i2c_stop(priv);
+ goto out;
+ }
+
+ /* Write data */
+ writeb(msg->buf[count], priv->base + I2C_OFS_IIC0);
+ }
+
+ /* Wait for R/W transaction */
+ status = em_i2c_wait_for_event(priv);
+ if (status < 0)
+ goto out_reset;
+ }
+
+ if (stop)
+ em_i2c_stop(priv);
+
+ return count;
+
+out_reset:
+ em_i2c_reset(adap);
+out:
+ return status < 0 ? status : -ENXIO;
+}
+
+static int em_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ struct em_i2c_device *priv = i2c_get_adapdata(adap);
+ int ret, i;
+
+ if (readb(priv->base + I2C_OFS_IICF0) & I2C_BIT_IICBSY)
+ return -EAGAIN;
+
+ for (i = 0; i < num; i++) {
+ ret = __em_i2c_xfer(adap, &msgs[i], (i == (num - 1)));
+ if (ret < 0)
+ return ret;
+ }
+
+ /* I2C transfer completed */
+ return num;
+}
+
+static irqreturn_t em_i2c_irq_handler(int this_irq, void *dev_id)
+{
+ struct em_i2c_device *priv = dev_id;
+
+ complete(&priv->msg_done);
+ return IRQ_HANDLED;
+}
+
+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,
+ .functionality = em_i2c_func,
+};
+
+static int em_i2c_probe(struct platform_device *pdev)
+{
+ struct em_i2c_device *priv;
+ struct resource *r;
+ int irq, ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ priv->base = devm_ioremap_resource(&pdev->dev, r);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ strlcpy(priv->adap.name, "EMEV2 I2C", sizeof(priv->adap.name));
+
+ priv->sclk = devm_clk_get(&pdev->dev, "sclk");
+ if (IS_ERR(priv->sclk))
+ return PTR_ERR(priv->sclk);
+
+ clk_prepare_enable(priv->sclk);
+
+ priv->adap.timeout = msecs_to_jiffies(100);
+ priv->adap.retries = 5;
+ priv->adap.dev.parent = &pdev->dev;
+ priv->adap.algo = &em_i2c_algo;
+ priv->adap.owner = THIS_MODULE;
+ priv->adap.dev.of_node = pdev->dev.of_node;
+
+ init_completion(&priv->msg_done);
+
+ platform_set_drvdata(pdev, priv);
+ i2c_set_adapdata(&priv->adap, priv);
+
+ em_i2c_reset(&priv->adap);
+
+ irq = platform_get_irq(pdev, 0);
+ ret = devm_request_irq(&pdev->dev, irq, em_i2c_irq_handler, 0,
+ "em_i2c", priv);
+ if (ret)
+ goto err_clk;
+
+ ret = i2c_add_adapter(&priv->adap);
+
+ if (ret)
+ goto err_clk;
+
+ dev_info(&pdev->dev, "Added i2c controller %d, irq %d\n", priv->adap.nr, irq);
+
+ return 0;
+
+err_clk:
+ clk_disable_unprepare(priv->sclk);
+ return ret;
+}
+
+static int em_i2c_remove(struct platform_device *dev)
+{
+ struct em_i2c_device *priv = platform_get_drvdata(dev);
+
+ i2c_del_adapter(&priv->adap);
+ clk_disable_unprepare(priv->sclk);
+
+ return 0;
+}
+
+static const struct of_device_id em_i2c_ids[] = {
+ { .compatible = "renesas,iic-emev2", },
+ { }
+};
+
+static struct platform_driver em_i2c_driver = {
+ .probe = em_i2c_probe,
+ .remove = em_i2c_remove,
+ .driver = {
+ .name = "em-i2c",
+ .of_match_table = em_i2c_ids,
+ }
+};
+module_platform_driver(em_i2c_driver);
+
+MODULE_DESCRIPTION("EMEV2 I2C bus driver");
+MODULE_AUTHOR("Ian Molton and Wolfram Sang <wsa@sang-engineering.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DEVICE_TABLE(of, em_i2c_ids);
Code Review / kvmfornfv.git / blobdiff