--- /dev/null
+/*
+ * Renesas Solutions Highlander FPGA I2C/SMBus support.
+ *
+ * Supported devices: R0P7780LC0011RL, R0P7785LC0011RL
+ *
+ * Copyright (C) 2008 Paul Mundt
+ * Copyright (C) 2008 Renesas Solutions Corp.
+ * Copyright (C) 2008 Atom Create Engineering Co., Ltd.
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License version 2. See the file "COPYING" in the main directory
+ * of this archive for more details.
+ */
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/completion.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+
+#define SMCR 0x00
+#define SMCR_START (1 << 0)
+#define SMCR_IRIC (1 << 1)
+#define SMCR_BBSY (1 << 2)
+#define SMCR_ACKE (1 << 3)
+#define SMCR_RST (1 << 4)
+#define SMCR_IEIC (1 << 6)
+
+#define SMSMADR 0x02
+
+#define SMMR 0x04
+#define SMMR_MODE0 (1 << 0)
+#define SMMR_MODE1 (1 << 1)
+#define SMMR_CAP (1 << 3)
+#define SMMR_TMMD (1 << 4)
+#define SMMR_SP (1 << 7)
+
+#define SMSADR 0x06
+#define SMTRDR 0x46
+
+struct highlander_i2c_dev {
+ struct device *dev;
+ void __iomem *base;
+ struct i2c_adapter adapter;
+ struct completion cmd_complete;
+ unsigned long last_read_time;
+ int irq;
+ u8 *buf;
+ size_t buf_len;
+};
+
+static bool iic_force_poll, iic_force_normal;
+static int iic_timeout = 1000, iic_read_delay;
+
+static inline void highlander_i2c_irq_enable(struct highlander_i2c_dev *dev)
+{
+ iowrite16(ioread16(dev->base + SMCR) | SMCR_IEIC, dev->base + SMCR);
+}
+
+static inline void highlander_i2c_irq_disable(struct highlander_i2c_dev *dev)
+{
+ iowrite16(ioread16(dev->base + SMCR) & ~SMCR_IEIC, dev->base + SMCR);
+}
+
+static inline void highlander_i2c_start(struct highlander_i2c_dev *dev)
+{
+ iowrite16(ioread16(dev->base + SMCR) | SMCR_START, dev->base + SMCR);
+}
+
+static inline void highlander_i2c_done(struct highlander_i2c_dev *dev)
+{
+ iowrite16(ioread16(dev->base + SMCR) | SMCR_IRIC, dev->base + SMCR);
+}
+
+static void highlander_i2c_setup(struct highlander_i2c_dev *dev)
+{
+ u16 smmr;
+
+ smmr = ioread16(dev->base + SMMR);
+ smmr |= SMMR_TMMD;
+
+ if (iic_force_normal)
+ smmr &= ~SMMR_SP;
+ else
+ smmr |= SMMR_SP;
+
+ iowrite16(smmr, dev->base + SMMR);
+}
+
+static void smbus_write_data(u8 *src, u16 *dst, int len)
+{
+ for (; len > 1; len -= 2) {
+ *dst++ = be16_to_cpup((__be16 *)src);
+ src += 2;
+ }
+
+ if (len)
+ *dst = *src << 8;
+}
+
+static void smbus_read_data(u16 *src, u8 *dst, int len)
+{
+ for (; len > 1; len -= 2) {
+ *(__be16 *)dst = cpu_to_be16p(src++);
+ dst += 2;
+ }
+
+ if (len)
+ *dst = *src >> 8;
+}
+
+static void highlander_i2c_command(struct highlander_i2c_dev *dev,
+ u8 command, int len)
+{
+ unsigned int i;
+ u16 cmd = (command << 8) | command;
+
+ for (i = 0; i < len; i += 2) {
+ if (len - i == 1)
+ cmd = command << 8;
+ iowrite16(cmd, dev->base + SMSADR + i);
+ dev_dbg(dev->dev, "command data[%x] 0x%04x\n", i/2, cmd);
+ }
+}
+
+static int highlander_i2c_wait_for_bbsy(struct highlander_i2c_dev *dev)
+{
+ unsigned long timeout;
+
+ timeout = jiffies + msecs_to_jiffies(iic_timeout);
+ while (ioread16(dev->base + SMCR) & SMCR_BBSY) {
+ if (time_after(jiffies, timeout)) {
+ dev_warn(dev->dev, "timeout waiting for bus ready\n");
+ return -ETIMEDOUT;
+ }
+
+ msleep(1);
+ }
+
+ return 0;
+}
+
+static int highlander_i2c_reset(struct highlander_i2c_dev *dev)
+{
+ iowrite16(ioread16(dev->base + SMCR) | SMCR_RST, dev->base + SMCR);
+ return highlander_i2c_wait_for_bbsy(dev);
+}
+
+static int highlander_i2c_wait_for_ack(struct highlander_i2c_dev *dev)
+{
+ u16 tmp = ioread16(dev->base + SMCR);
+
+ if ((tmp & (SMCR_IRIC | SMCR_ACKE)) == SMCR_ACKE) {
+ dev_warn(dev->dev, "ack abnormality\n");
+ return highlander_i2c_reset(dev);
+ }
+
+ return 0;
+}
+
+static irqreturn_t highlander_i2c_irq(int irq, void *dev_id)
+{
+ struct highlander_i2c_dev *dev = dev_id;
+
+ highlander_i2c_done(dev);
+ complete(&dev->cmd_complete);
+
+ return IRQ_HANDLED;
+}
+
+static void highlander_i2c_poll(struct highlander_i2c_dev *dev)
+{
+ unsigned long timeout;
+ u16 smcr;
+
+ timeout = jiffies + msecs_to_jiffies(iic_timeout);
+ for (;;) {
+ smcr = ioread16(dev->base + SMCR);
+
+ /*
+ * Don't bother checking ACKE here, this and the reset
+ * are handled in highlander_i2c_wait_xfer_done() when
+ * waiting for the ACK.
+ */
+
+ if (smcr & SMCR_IRIC)
+ return;
+ if (time_after(jiffies, timeout))
+ break;
+
+ cpu_relax();
+ cond_resched();
+ }
+
+ dev_err(dev->dev, "polling timed out\n");
+}
+
+static inline int highlander_i2c_wait_xfer_done(struct highlander_i2c_dev *dev)
+{
+ if (dev->irq)
+ wait_for_completion_timeout(&dev->cmd_complete,
+ msecs_to_jiffies(iic_timeout));
+ else
+ /* busy looping, the IRQ of champions */
+ highlander_i2c_poll(dev);
+
+ return highlander_i2c_wait_for_ack(dev);
+}
+
+static int highlander_i2c_read(struct highlander_i2c_dev *dev)
+{
+ int i, cnt;
+ u16 data[16];
+
+ if (highlander_i2c_wait_for_bbsy(dev))
+ return -EAGAIN;
+
+ highlander_i2c_start(dev);
+
+ if (highlander_i2c_wait_xfer_done(dev)) {
+ dev_err(dev->dev, "Arbitration loss\n");
+ return -EAGAIN;
+ }
+
+ /*
+ * The R0P7780LC0011RL FPGA needs a significant delay between
+ * data read cycles, otherwise the transceiver gets confused and
+ * garbage is returned when the read is subsequently aborted.
+ *
+ * It is not sufficient to wait for BBSY.
+ *
+ * While this generally only applies to the older SH7780-based
+ * Highlanders, the same issue can be observed on SH7785 ones,
+ * albeit less frequently. SH7780-based Highlanders may need
+ * this to be as high as 1000 ms.
+ */
+ if (iic_read_delay && time_before(jiffies, dev->last_read_time +
+ msecs_to_jiffies(iic_read_delay)))
+ msleep(jiffies_to_msecs((dev->last_read_time +
+ msecs_to_jiffies(iic_read_delay)) - jiffies));
+
+ cnt = (dev->buf_len + 1) >> 1;
+ for (i = 0; i < cnt; i++) {
+ data[i] = ioread16(dev->base + SMTRDR + (i * sizeof(u16)));
+ dev_dbg(dev->dev, "read data[%x] 0x%04x\n", i, data[i]);
+ }
+
+ smbus_read_data(data, dev->buf, dev->buf_len);
+
+ dev->last_read_time = jiffies;
+
+ return 0;
+}
+
+static int highlander_i2c_write(struct highlander_i2c_dev *dev)
+{
+ int i, cnt;
+ u16 data[16];
+
+ smbus_write_data(dev->buf, data, dev->buf_len);
+
+ cnt = (dev->buf_len + 1) >> 1;
+ for (i = 0; i < cnt; i++) {
+ iowrite16(data[i], dev->base + SMTRDR + (i * sizeof(u16)));
+ dev_dbg(dev->dev, "write data[%x] 0x%04x\n", i, data[i]);
+ }
+
+ if (highlander_i2c_wait_for_bbsy(dev))
+ return -EAGAIN;
+
+ highlander_i2c_start(dev);
+
+ return highlander_i2c_wait_xfer_done(dev);
+}
+
+static int highlander_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr,
+ unsigned short flags, char read_write,
+ u8 command, int size,
+ union i2c_smbus_data *data)
+{
+ struct highlander_i2c_dev *dev = i2c_get_adapdata(adap);
+ u16 tmp;
+
+ init_completion(&dev->cmd_complete);
+
+ dev_dbg(dev->dev, "addr %04x, command %02x, read_write %d, size %d\n",
+ addr, command, read_write, size);
+
+ /*
+ * Set up the buffer and transfer size
+ */
+ switch (size) {
+ case I2C_SMBUS_BYTE_DATA:
+ dev->buf = &data->byte;
+ dev->buf_len = 1;
+ break;
+ case I2C_SMBUS_I2C_BLOCK_DATA:
+ dev->buf = &data->block[1];
+ dev->buf_len = data->block[0];
+ break;
+ default:
+ dev_err(dev->dev, "unsupported command %d\n", size);
+ return -EINVAL;
+ }
+
+ /*
+ * Encode the mode setting
+ */
+ tmp = ioread16(dev->base + SMMR);
+ tmp &= ~(SMMR_MODE0 | SMMR_MODE1);
+
+ switch (dev->buf_len) {
+ case 1:
+ /* default */
+ break;
+ case 8:
+ tmp |= SMMR_MODE0;
+ break;
+ case 16:
+ tmp |= SMMR_MODE1;
+ break;
+ case 32:
+ tmp |= (SMMR_MODE0 | SMMR_MODE1);
+ break;
+ default:
+ dev_err(dev->dev, "unsupported xfer size %d\n", dev->buf_len);
+ return -EINVAL;
+ }
+
+ iowrite16(tmp, dev->base + SMMR);
+
+ /* Ensure we're in a sane state */
+ highlander_i2c_done(dev);
+
+ /* Set slave address */
+ iowrite16((addr << 1) | read_write, dev->base + SMSMADR);
+
+ highlander_i2c_command(dev, command, dev->buf_len);
+
+ if (read_write == I2C_SMBUS_READ)
+ return highlander_i2c_read(dev);
+ else
+ return highlander_i2c_write(dev);
+}
+
+static u32 highlander_i2c_func(struct i2c_adapter *adapter)
+{
+ return I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK;
+}
+
+static const struct i2c_algorithm highlander_i2c_algo = {
+ .smbus_xfer = highlander_i2c_smbus_xfer,
+ .functionality = highlander_i2c_func,
+};
+
+static int highlander_i2c_probe(struct platform_device *pdev)
+{
+ struct highlander_i2c_dev *dev;
+ struct i2c_adapter *adap;
+ struct resource *res;
+ int ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (unlikely(!res)) {
+ dev_err(&pdev->dev, "no mem resource\n");
+ return -ENODEV;
+ }
+
+ dev = kzalloc(sizeof(struct highlander_i2c_dev), GFP_KERNEL);
+ if (unlikely(!dev))
+ return -ENOMEM;
+
+ dev->base = ioremap_nocache(res->start, resource_size(res));
+ if (unlikely(!dev->base)) {
+ ret = -ENXIO;
+ goto err;
+ }
+
+ dev->dev = &pdev->dev;
+ platform_set_drvdata(pdev, dev);
+
+ dev->irq = platform_get_irq(pdev, 0);
+ if (iic_force_poll)
+ dev->irq = 0;
+
+ if (dev->irq) {
+ ret = request_irq(dev->irq, highlander_i2c_irq, 0,
+ pdev->name, dev);
+ if (unlikely(ret))
+ goto err_unmap;
+
+ highlander_i2c_irq_enable(dev);
+ } else {
+ dev_notice(&pdev->dev, "no IRQ, using polling mode\n");
+ highlander_i2c_irq_disable(dev);
+ }
+
+ dev->last_read_time = jiffies; /* initial read jiffies */
+
+ highlander_i2c_setup(dev);
+
+ adap = &dev->adapter;
+ i2c_set_adapdata(adap, dev);
+ adap->owner = THIS_MODULE;
+ adap->class = I2C_CLASS_HWMON;
+ strlcpy(adap->name, "HL FPGA I2C adapter", sizeof(adap->name));
+ adap->algo = &highlander_i2c_algo;
+ adap->dev.parent = &pdev->dev;
+ adap->nr = pdev->id;
+
+ /*
+ * Reset the adapter
+ */
+ ret = highlander_i2c_reset(dev);
+ if (unlikely(ret)) {
+ dev_err(&pdev->dev, "controller didn't come up\n");
+ goto err_free_irq;
+ }
+
+ ret = i2c_add_numbered_adapter(adap);
+ if (unlikely(ret)) {
+ dev_err(&pdev->dev, "failure adding adapter\n");
+ goto err_free_irq;
+ }
+
+ return 0;
+
+err_free_irq:
+ if (dev->irq)
+ free_irq(dev->irq, dev);
+err_unmap:
+ iounmap(dev->base);
+err:
+ kfree(dev);
+
+ return ret;
+}
+
+static int highlander_i2c_remove(struct platform_device *pdev)
+{
+ struct highlander_i2c_dev *dev = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&dev->adapter);
+
+ if (dev->irq)
+ free_irq(dev->irq, dev);
+
+ iounmap(dev->base);
+ kfree(dev);
+
+ return 0;
+}
+
+static struct platform_driver highlander_i2c_driver = {
+ .driver = {
+ .name = "i2c-highlander",
+ },
+
+ .probe = highlander_i2c_probe,
+ .remove = highlander_i2c_remove,
+};
+
+module_platform_driver(highlander_i2c_driver);
+
+MODULE_AUTHOR("Paul Mundt");
+MODULE_DESCRIPTION("Renesas Highlander FPGA I2C/SMBus adapter");
+MODULE_LICENSE("GPL v2");
+
+module_param(iic_force_poll, bool, 0);
+module_param(iic_force_normal, bool, 0);
+module_param(iic_timeout, int, 0);
+module_param(iic_read_delay, int, 0);
+
+MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
+MODULE_PARM_DESC(iic_force_normal,
+ "Force normal mode (100 kHz), default is fast mode (400 kHz)");
+MODULE_PARM_DESC(iic_timeout, "Set timeout value in msecs (default 1000 ms)");
+MODULE_PARM_DESC(iic_read_delay,
+ "Delay between data read cycles (default 0 ms)");
Code Review / kvmfornfv.git / blobdiff