--- /dev/null
+/*
+ * Freescale MXS I2C bus driver
+ *
+ * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
+ *
+ * based on a (non-working) driver which was:
+ *
+ * Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * TODO: add dma-support if platform-support for it is available
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/platform_device.h>
+#include <linux/jiffies.h>
+#include <linux/io.h>
+
+#include <mach/common.h>
+
+#define DRIVER_NAME "mxs-i2c"
+
+#define MXS_I2C_CTRL0 (0x00)
+#define MXS_I2C_CTRL0_SET (0x04)
+
+#define MXS_I2C_CTRL0_SFTRST 0x80000000
+#define MXS_I2C_CTRL0_SEND_NAK_ON_LAST 0x02000000
+#define MXS_I2C_CTRL0_RETAIN_CLOCK 0x00200000
+#define MXS_I2C_CTRL0_POST_SEND_STOP 0x00100000
+#define MXS_I2C_CTRL0_PRE_SEND_START 0x00080000
+#define MXS_I2C_CTRL0_MASTER_MODE 0x00020000
+#define MXS_I2C_CTRL0_DIRECTION 0x00010000
+#define MXS_I2C_CTRL0_XFER_COUNT(v) ((v) & 0x0000FFFF)
+
+#define MXS_I2C_CTRL1 (0x40)
+#define MXS_I2C_CTRL1_SET (0x44)
+#define MXS_I2C_CTRL1_CLR (0x48)
+
+#define MXS_I2C_CTRL1_BUS_FREE_IRQ 0x80
+#define MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ 0x40
+#define MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ 0x20
+#define MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ 0x10
+#define MXS_I2C_CTRL1_EARLY_TERM_IRQ 0x08
+#define MXS_I2C_CTRL1_MASTER_LOSS_IRQ 0x04
+#define MXS_I2C_CTRL1_SLAVE_STOP_IRQ 0x02
+#define MXS_I2C_CTRL1_SLAVE_IRQ 0x01
+
+#define MXS_I2C_IRQ_MASK (MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ | \
+ MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ | \
+ MXS_I2C_CTRL1_EARLY_TERM_IRQ | \
+ MXS_I2C_CTRL1_MASTER_LOSS_IRQ | \
+ MXS_I2C_CTRL1_SLAVE_STOP_IRQ | \
+ MXS_I2C_CTRL1_SLAVE_IRQ)
+
+#define MXS_I2C_QUEUECTRL (0x60)
+#define MXS_I2C_QUEUECTRL_SET (0x64)
+#define MXS_I2C_QUEUECTRL_CLR (0x68)
+
+#define MXS_I2C_QUEUECTRL_QUEUE_RUN 0x20
+#define MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE 0x04
+
+#define MXS_I2C_QUEUESTAT (0x70)
+#define MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY 0x00002000
+
+#define MXS_I2C_QUEUECMD (0x80)
+
+#define MXS_I2C_QUEUEDATA (0x90)
+
+#define MXS_I2C_DATA (0xa0)
+
+
+#define MXS_CMD_I2C_SELECT (MXS_I2C_CTRL0_RETAIN_CLOCK | \
+ MXS_I2C_CTRL0_PRE_SEND_START | \
+ MXS_I2C_CTRL0_MASTER_MODE | \
+ MXS_I2C_CTRL0_DIRECTION | \
+ MXS_I2C_CTRL0_XFER_COUNT(1))
+
+#define MXS_CMD_I2C_WRITE (MXS_I2C_CTRL0_PRE_SEND_START | \
+ MXS_I2C_CTRL0_MASTER_MODE | \
+ MXS_I2C_CTRL0_DIRECTION)
+
+#define MXS_CMD_I2C_READ (MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
+ MXS_I2C_CTRL0_MASTER_MODE)
+
+/**
+ * struct mxs_i2c_dev - per device, private MXS-I2C data
+ *
+ * @dev: driver model device node
+ * @regs: IO registers pointer
+ * @cmd_complete: completion object for transaction wait
+ * @cmd_err: error code for last transaction
+ * @adapter: i2c subsystem adapter node
+ */
+struct mxs_i2c_dev {
+ struct device *dev;
+ void __iomem *regs;
+ struct completion cmd_complete;
+ u32 cmd_err;
+ struct i2c_adapter adapter;
+};
+
+/*
+ * TODO: check if calls to here are really needed. If not, we could get rid of
+ * mxs_reset_block and the mach-dependency. Needs an I2C analyzer, probably.
+ */
+static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
+{
+ mxs_reset_block(i2c->regs);
+ writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
+}
+
+static void mxs_i2c_pioq_setup_read(struct mxs_i2c_dev *i2c, u8 addr, int len,
+ int flags)
+{
+ u32 data;
+
+ writel(MXS_CMD_I2C_SELECT, i2c->regs + MXS_I2C_QUEUECMD);
+
+ data = (addr << 1) | I2C_SMBUS_READ;
+ writel(data, i2c->regs + MXS_I2C_DATA);
+
+ data = MXS_CMD_I2C_READ | MXS_I2C_CTRL0_XFER_COUNT(len) | flags;
+ writel(data, i2c->regs + MXS_I2C_QUEUECMD);
+}
+
+static void mxs_i2c_pioq_setup_write(struct mxs_i2c_dev *i2c,
+ u8 addr, u8 *buf, int len, int flags)
+{
+ u32 data;
+ int i, shifts_left;
+
+ data = MXS_CMD_I2C_WRITE | MXS_I2C_CTRL0_XFER_COUNT(len + 1) | flags;
+ writel(data, i2c->regs + MXS_I2C_QUEUECMD);
+
+ /*
+ * We have to copy the slave address (u8) and buffer (arbitrary number
+ * of u8) into the data register (u32). To achieve that, the u8 are put
+ * into the MSBs of 'data' which is then shifted for the next u8. When
+ * apropriate, 'data' is written to MXS_I2C_DATA. So, the first u32
+ * looks like this:
+ *
+ * 3 2 1 0
+ * 10987654|32109876|54321098|76543210
+ * --------+--------+--------+--------
+ * buffer+2|buffer+1|buffer+0|slave_addr
+ */
+
+ data = ((addr << 1) | I2C_SMBUS_WRITE) << 24;
+
+ for (i = 0; i < len; i++) {
+ data >>= 8;
+ data |= buf[i] << 24;
+ if ((i & 3) == 2)
+ writel(data, i2c->regs + MXS_I2C_DATA);
+ }
+
+ /* Write out the remaining bytes if any */
+ shifts_left = 24 - (i & 3) * 8;
+ if (shifts_left)
+ writel(data >> shifts_left, i2c->regs + MXS_I2C_DATA);
+}
+
+/*
+ * TODO: should be replaceable with a waitqueue and RD_QUEUE_IRQ (setting the
+ * rd_threshold to 1). Couldn't get this to work, though.
+ */
+static int mxs_i2c_wait_for_data(struct mxs_i2c_dev *i2c)
+{
+ unsigned long timeout = jiffies + msecs_to_jiffies(1000);
+
+ while (readl(i2c->regs + MXS_I2C_QUEUESTAT)
+ & MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY) {
+ if (time_after(jiffies, timeout))
+ return -ETIMEDOUT;
+ cond_resched();
+ }
+
+ return 0;
+}
+
+static int mxs_i2c_finish_read(struct mxs_i2c_dev *i2c, u8 *buf, int len)
+{
+ u32 data;
+ int i;
+
+ for (i = 0; i < len; i++) {
+ if ((i & 3) == 0) {
+ if (mxs_i2c_wait_for_data(i2c))
+ return -ETIMEDOUT;
+ data = readl(i2c->regs + MXS_I2C_QUEUEDATA);
+ }
+ buf[i] = data & 0xff;
+ data >>= 8;
+ }
+
+ return 0;
+}
+
+/*
+ * Low level master read/write transaction.
+ */
+static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
+ int stop)
+{
+ struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
+ int ret;
+ int flags;
+
+ init_completion(&i2c->cmd_complete);
+
+ dev_dbg(i2c->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
+ msg->addr, msg->len, msg->flags, stop);
+
+ if (msg->len == 0)
+ return -EINVAL;
+
+ flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0;
+
+ if (msg->flags & I2C_M_RD)
+ mxs_i2c_pioq_setup_read(i2c, msg->addr, msg->len, flags);
+ else
+ mxs_i2c_pioq_setup_write(i2c, msg->addr, msg->buf, msg->len,
+ flags);
+
+ writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
+ i2c->regs + MXS_I2C_QUEUECTRL_SET);
+
+ ret = wait_for_completion_timeout(&i2c->cmd_complete,
+ msecs_to_jiffies(1000));
+ if (ret == 0)
+ goto timeout;
+
+ if ((!i2c->cmd_err) && (msg->flags & I2C_M_RD)) {
+ ret = mxs_i2c_finish_read(i2c, msg->buf, msg->len);
+ if (ret)
+ goto timeout;
+ }
+
+ if (i2c->cmd_err == -ENXIO)
+ mxs_i2c_reset(i2c);
+
+ dev_dbg(i2c->dev, "Done with err=%d\n", i2c->cmd_err);
+
+ return i2c->cmd_err;
+
+timeout:
+ dev_dbg(i2c->dev, "Timeout!\n");
+ mxs_i2c_reset(i2c);
+ return -ETIMEDOUT;
+}
+
+static int mxs_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
+ int num)
+{
+ int i;
+ int err;
+
+ for (i = 0; i < num; i++) {
+ err = mxs_i2c_xfer_msg(adap, &msgs[i], i == (num - 1));
+ if (err)
+ return err;
+ }
+
+ return num;
+}
+
+static u32 mxs_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
+{
+ struct mxs_i2c_dev *i2c = dev_id;
+ u32 stat = readl(i2c->regs + MXS_I2C_CTRL1) & MXS_I2C_IRQ_MASK;
+
+ if (!stat)
+ return IRQ_NONE;
+
+ if (stat & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
+ i2c->cmd_err = -ENXIO;
+ else if (stat & (MXS_I2C_CTRL1_EARLY_TERM_IRQ |
+ MXS_I2C_CTRL1_MASTER_LOSS_IRQ |
+ MXS_I2C_CTRL1_SLAVE_STOP_IRQ | MXS_I2C_CTRL1_SLAVE_IRQ))
+ /* MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ is only for slaves */
+ i2c->cmd_err = -EIO;
+ else
+ i2c->cmd_err = 0;
+
+ complete(&i2c->cmd_complete);
+
+ writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR);
+ return IRQ_HANDLED;
+}
+
+static const struct i2c_algorithm mxs_i2c_algo = {
+ .master_xfer = mxs_i2c_xfer,
+ .functionality = mxs_i2c_func,
+};
+
+static int __devinit mxs_i2c_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct mxs_i2c_dev *i2c;
+ struct i2c_adapter *adap;
+ struct resource *res;
+ resource_size_t res_size;
+ int err, irq;
+
+ i2c = devm_kzalloc(dev, sizeof(struct mxs_i2c_dev), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENOENT;
+
+ res_size = resource_size(res);
+ if (!devm_request_mem_region(dev, res->start, res_size, res->name))
+ return -EBUSY;
+
+ i2c->regs = devm_ioremap_nocache(dev, res->start, res_size);
+ if (!i2c->regs)
+ return -EBUSY;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ err = devm_request_irq(dev, irq, mxs_i2c_isr, 0, dev_name(dev), i2c);
+ if (err)
+ return err;
+
+ i2c->dev = dev;
+ platform_set_drvdata(pdev, i2c);
+
+ /* Do reset to enforce correct startup after pinmuxing */
+ mxs_i2c_reset(i2c);
+ writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
+ i2c->regs + MXS_I2C_QUEUECTRL_SET);
+
+ adap = &i2c->adapter;
+ strlcpy(adap->name, "MXS I2C adapter", sizeof(adap->name));
+ adap->owner = THIS_MODULE;
+ adap->algo = &mxs_i2c_algo;
+ adap->dev.parent = dev;
+ adap->nr = pdev->id;
+ i2c_set_adapdata(adap, i2c);
+ err = i2c_add_numbered_adapter(adap);
+ if (err) {
+ dev_err(dev, "Failed to add adapter (%d)\n", err);
+ writel(MXS_I2C_CTRL0_SFTRST,
+ i2c->regs + MXS_I2C_CTRL0_SET);
+ return err;
+ }
+
+ return 0;
+}
+
+static int __devexit mxs_i2c_remove(struct platform_device *pdev)
+{
+ struct mxs_i2c_dev *i2c = platform_get_drvdata(pdev);
+ int ret;
+
+ ret = i2c_del_adapter(&i2c->adapter);
+ if (ret)
+ return -EBUSY;
+
+ writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
+ i2c->regs + MXS_I2C_QUEUECTRL_CLR);
+ writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET);
+
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static struct platform_driver mxs_i2c_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ },
+ .remove = __devexit_p(mxs_i2c_remove),
+};
+
+static int __init mxs_i2c_init(void)
+{
+ return platform_driver_probe(&mxs_i2c_driver, mxs_i2c_probe);
+}
+subsys_initcall(mxs_i2c_init);
+
+static void __exit mxs_i2c_exit(void)
+{
+ platform_driver_unregister(&mxs_i2c_driver);
+}
+module_exit(mxs_i2c_exit);
+
+MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
+MODULE_DESCRIPTION("MXS I2C Bus Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);
projects / platform / kernel / kernel-mfld-blackbay.git / commitdiff