--- /dev/null
+/*
+ * drivers/i2c/busses/i2c-bfin-twi.c
+ *
+ * Description: Driver for Blackfin Two Wire Interface
+ *
+ * Author: sonicz <sonic.zhang@analog.com>
+ *
+ * Copyright (c) 2005-2007 Analog Devices, Inc.
+ *
+ * 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.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/mm.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+
+#include <asm/blackfin.h>
+#include <asm/irq.h>
+
+#define POLL_TIMEOUT (2 * HZ)
+
+/* SMBus mode*/
+#define TWI_I2C_MODE_STANDARD 0x01
+#define TWI_I2C_MODE_STANDARDSUB 0x02
+#define TWI_I2C_MODE_COMBINED 0x04
+
+struct bfin_twi_iface {
+ struct mutex twi_lock;
+ int irq;
+ spinlock_t lock;
+ char read_write;
+ u8 command;
+ u8 *transPtr;
+ int readNum;
+ int writeNum;
+ int cur_mode;
+ int manual_stop;
+ int result;
+ int timeout_count;
+ struct timer_list timeout_timer;
+ struct i2c_adapter adap;
+ struct completion complete;
+};
+
+static struct bfin_twi_iface twi_iface;
+
+static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface)
+{
+ unsigned short twi_int_status = bfin_read_TWI_INT_STAT();
+ unsigned short mast_stat = bfin_read_TWI_MASTER_STAT();
+
+ if (twi_int_status & XMTSERV) {
+ /* Transmit next data */
+ if (iface->writeNum > 0) {
+ bfin_write_TWI_XMT_DATA8(*(iface->transPtr++));
+ iface->writeNum--;
+ }
+ /* start receive immediately after complete sending in
+ * combine mode.
+ */
+ else if (iface->cur_mode == TWI_I2C_MODE_COMBINED) {
+ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL()
+ | MDIR | RSTART);
+ } else if (iface->manual_stop)
+ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL()
+ | STOP);
+ SSYNC();
+ /* Clear status */
+ bfin_write_TWI_INT_STAT(XMTSERV);
+ SSYNC();
+ }
+ if (twi_int_status & RCVSERV) {
+ if (iface->readNum > 0) {
+ /* Receive next data */
+ *(iface->transPtr) = bfin_read_TWI_RCV_DATA8();
+ if (iface->cur_mode == TWI_I2C_MODE_COMBINED) {
+ /* Change combine mode into sub mode after
+ * read first data.
+ */
+ iface->cur_mode = TWI_I2C_MODE_STANDARDSUB;
+ /* Get read number from first byte in block
+ * combine mode.
+ */
+ if (iface->readNum == 1 && iface->manual_stop)
+ iface->readNum = *iface->transPtr + 1;
+ }
+ iface->transPtr++;
+ iface->readNum--;
+ } else if (iface->manual_stop) {
+ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL()
+ | STOP);
+ SSYNC();
+ }
+ /* Clear interrupt source */
+ bfin_write_TWI_INT_STAT(RCVSERV);
+ SSYNC();
+ }
+ if (twi_int_status & MERR) {
+ bfin_write_TWI_INT_STAT(MERR);
+ bfin_write_TWI_INT_MASK(0);
+ bfin_write_TWI_MASTER_STAT(0x3e);
+ bfin_write_TWI_MASTER_CTL(0);
+ SSYNC();
+ iface->result = -1;
+ /* if both err and complete int stats are set, return proper
+ * results.
+ */
+ if (twi_int_status & MCOMP) {
+ bfin_write_TWI_INT_STAT(MCOMP);
+ bfin_write_TWI_INT_MASK(0);
+ bfin_write_TWI_MASTER_CTL(0);
+ SSYNC();
+ /* If it is a quick transfer, only address bug no data,
+ * not an err, return 1.
+ */
+ if (iface->writeNum == 0 && (mast_stat & BUFRDERR))
+ iface->result = 1;
+ /* If address not acknowledged return -1,
+ * else return 0.
+ */
+ else if (!(mast_stat & ANAK))
+ iface->result = 0;
+ }
+ complete(&iface->complete);
+ return;
+ }
+ if (twi_int_status & MCOMP) {
+ bfin_write_TWI_INT_STAT(MCOMP);
+ SSYNC();
+ if (iface->cur_mode == TWI_I2C_MODE_COMBINED) {
+ if (iface->readNum == 0) {
+ /* set the read number to 1 and ask for manual
+ * stop in block combine mode
+ */
+ iface->readNum = 1;
+ iface->manual_stop = 1;
+ bfin_write_TWI_MASTER_CTL(
+ bfin_read_TWI_MASTER_CTL()
+ | (0xff << 6));
+ } else {
+ /* set the readd number in other
+ * combine mode.
+ */
+ bfin_write_TWI_MASTER_CTL(
+ (bfin_read_TWI_MASTER_CTL() &
+ (~(0xff << 6))) |
+ ( iface->readNum << 6));
+ }
+ /* remove restart bit and enable master receive */
+ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() &
+ ~RSTART);
+ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() |
+ MEN | MDIR);
+ SSYNC();
+ } else {
+ iface->result = 1;
+ bfin_write_TWI_INT_MASK(0);
+ bfin_write_TWI_MASTER_CTL(0);
+ SSYNC();
+ complete(&iface->complete);
+ }
+ }
+}
+
+/* Interrupt handler */
+static irqreturn_t bfin_twi_interrupt_entry(int irq, void *dev_id)
+{
+ struct bfin_twi_iface *iface = dev_id;
+ unsigned long flags;
+
+ spin_lock_irqsave(&iface->lock, flags);
+ del_timer(&iface->timeout_timer);
+ bfin_twi_handle_interrupt(iface);
+ spin_unlock_irqrestore(&iface->lock, flags);
+ return IRQ_HANDLED;
+}
+
+static void bfin_twi_timeout(unsigned long data)
+{
+ struct bfin_twi_iface *iface = (struct bfin_twi_iface *)data;
+ unsigned long flags;
+
+ spin_lock_irqsave(&iface->lock, flags);
+ bfin_twi_handle_interrupt(iface);
+ if (iface->result == 0) {
+ iface->timeout_count--;
+ if (iface->timeout_count > 0) {
+ iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
+ add_timer(&iface->timeout_timer);
+ } else {
+ iface->result = -1;
+ complete(&iface->complete);
+ }
+ }
+ spin_unlock_irqrestore(&iface->lock, flags);
+}
+
+/*
+ * Generic i2c master transfer entrypoint
+ */
+static int bfin_twi_master_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ struct bfin_twi_iface *iface = adap->algo_data;
+ struct i2c_msg *pmsg;
+ int i, ret;
+ int rc = 0;
+
+ if (!(bfin_read_TWI_CONTROL() & TWI_ENA))
+ return -ENXIO;
+
+ mutex_lock(&iface->twi_lock);
+
+ while (bfin_read_TWI_MASTER_STAT() & BUSBUSY) {
+ mutex_unlock(&iface->twi_lock);
+ yield();
+ mutex_lock(&iface->twi_lock);
+ }
+
+ ret = 0;
+ for (i = 0; rc >= 0 && i < num; i++) {
+ pmsg = &msgs[i];
+ if (pmsg->flags & I2C_M_TEN) {
+ dev_err(&(adap->dev), "i2c-bfin-twi: 10 bits addr "
+ "not supported !\n");
+ rc = -EINVAL;
+ break;
+ }
+
+ iface->cur_mode = TWI_I2C_MODE_STANDARD;
+ iface->manual_stop = 0;
+ iface->transPtr = pmsg->buf;
+ iface->writeNum = iface->readNum = pmsg->len;
+ iface->result = 0;
+ iface->timeout_count = 10;
+ /* Set Transmit device address */
+ bfin_write_TWI_MASTER_ADDR(pmsg->addr);
+
+ /* FIFO Initiation. Data in FIFO should be
+ * discarded before start a new operation.
+ */
+ bfin_write_TWI_FIFO_CTL(0x3);
+ SSYNC();
+ bfin_write_TWI_FIFO_CTL(0);
+ SSYNC();
+
+ if (pmsg->flags & I2C_M_RD)
+ iface->read_write = I2C_SMBUS_READ;
+ else {
+ iface->read_write = I2C_SMBUS_WRITE;
+ /* Transmit first data */
+ if (iface->writeNum > 0) {
+ bfin_write_TWI_XMT_DATA8(*(iface->transPtr++));
+ iface->writeNum--;
+ SSYNC();
+ }
+ }
+
+ /* clear int stat */
+ bfin_write_TWI_INT_STAT(MERR|MCOMP|XMTSERV|RCVSERV);
+
+ /* Interrupt mask . Enable XMT, RCV interrupt */
+ bfin_write_TWI_INT_MASK(MCOMP | MERR |
+ ((iface->read_write == I2C_SMBUS_READ)?
+ RCVSERV : XMTSERV));
+ SSYNC();
+
+ if (pmsg->len > 0 && pmsg->len <= 255)
+ bfin_write_TWI_MASTER_CTL(pmsg->len << 6);
+ else if (pmsg->len > 255) {
+ bfin_write_TWI_MASTER_CTL(0xff << 6);
+ iface->manual_stop = 1;
+ } else
+ break;
+
+ iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
+ add_timer(&iface->timeout_timer);
+
+ /* Master enable */
+ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN |
+ ((iface->read_write == I2C_SMBUS_READ) ? MDIR : 0) |
+ ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ>100) ? FAST : 0));
+ SSYNC();
+
+ wait_for_completion(&iface->complete);
+
+ rc = iface->result;
+ if (rc == 1)
+ ret++;
+ else if (rc == -1)
+ break;
+ }
+
+ /* Release mutex */
+ mutex_unlock(&iface->twi_lock);
+
+ return ret;
+}
+
+/*
+ * SMBus type transfer entrypoint
+ */
+
+int bfin_twi_smbus_xfer(struct i2c_adapter *adap, u16 addr,
+ unsigned short flags, char read_write,
+ u8 command, int size, union i2c_smbus_data *data)
+{
+ struct bfin_twi_iface *iface = adap->algo_data;
+ int rc = 0;
+
+ if (!(bfin_read_TWI_CONTROL() & TWI_ENA))
+ return -ENXIO;
+
+ mutex_lock(&iface->twi_lock);
+
+ while (bfin_read_TWI_MASTER_STAT() & BUSBUSY) {
+ mutex_unlock(&iface->twi_lock);
+ yield();
+ mutex_lock(&iface->twi_lock);
+ }
+
+ iface->writeNum = 0;
+ iface->readNum = 0;
+
+ /* Prepare datas & select mode */
+ switch (size) {
+ case I2C_SMBUS_QUICK:
+ iface->transPtr = NULL;
+ iface->cur_mode = TWI_I2C_MODE_STANDARD;
+ break;
+ case I2C_SMBUS_BYTE:
+ if (data == NULL)
+ iface->transPtr = NULL;
+ else {
+ if (read_write == I2C_SMBUS_READ)
+ iface->readNum = 1;
+ else
+ iface->writeNum = 1;
+ iface->transPtr = &data->byte;
+ }
+ iface->cur_mode = TWI_I2C_MODE_STANDARD;
+ break;
+ case I2C_SMBUS_BYTE_DATA:
+ if (read_write == I2C_SMBUS_READ) {
+ iface->readNum = 1;
+ iface->cur_mode = TWI_I2C_MODE_COMBINED;
+ } else {
+ iface->writeNum = 1;
+ iface->cur_mode = TWI_I2C_MODE_STANDARDSUB;
+ }
+ iface->transPtr = &data->byte;
+ break;
+ case I2C_SMBUS_WORD_DATA:
+ if (read_write == I2C_SMBUS_READ) {
+ iface->readNum = 2;
+ iface->cur_mode = TWI_I2C_MODE_COMBINED;
+ } else {
+ iface->writeNum = 2;
+ iface->cur_mode = TWI_I2C_MODE_STANDARDSUB;
+ }
+ iface->transPtr = (u8 *)&data->word;
+ break;
+ case I2C_SMBUS_PROC_CALL:
+ iface->writeNum = 2;
+ iface->readNum = 2;
+ iface->cur_mode = TWI_I2C_MODE_COMBINED;
+ iface->transPtr = (u8 *)&data->word;
+ break;
+ case I2C_SMBUS_BLOCK_DATA:
+ if (read_write == I2C_SMBUS_READ) {
+ iface->readNum = 0;
+ iface->cur_mode = TWI_I2C_MODE_COMBINED;
+ } else {
+ iface->writeNum = data->block[0] + 1;
+ iface->cur_mode = TWI_I2C_MODE_STANDARDSUB;
+ }
+ iface->transPtr = data->block;
+ break;
+ default:
+ return -1;
+ }
+
+ iface->result = 0;
+ iface->manual_stop = 0;
+ iface->read_write = read_write;
+ iface->command = command;
+ iface->timeout_count = 10;
+
+ /* FIFO Initiation. Data in FIFO should be discarded before
+ * start a new operation.
+ */
+ bfin_write_TWI_FIFO_CTL(0x3);
+ SSYNC();
+ bfin_write_TWI_FIFO_CTL(0);
+
+ /* clear int stat */
+ bfin_write_TWI_INT_STAT(MERR|MCOMP|XMTSERV|RCVSERV);
+
+ /* Set Transmit device address */
+ bfin_write_TWI_MASTER_ADDR(addr);
+ SSYNC();
+
+ iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
+ add_timer(&iface->timeout_timer);
+
+ switch (iface->cur_mode) {
+ case TWI_I2C_MODE_STANDARDSUB:
+ bfin_write_TWI_XMT_DATA8(iface->command);
+ bfin_write_TWI_INT_MASK(MCOMP | MERR |
+ ((iface->read_write == I2C_SMBUS_READ) ?
+ RCVSERV : XMTSERV));
+ SSYNC();
+
+ if (iface->writeNum + 1 <= 255)
+ bfin_write_TWI_MASTER_CTL((iface->writeNum + 1) << 6);
+ else {
+ bfin_write_TWI_MASTER_CTL(0xff << 6);
+ iface->manual_stop = 1;
+ }
+ /* Master enable */
+ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN |
+ ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ>100) ? FAST : 0));
+ break;
+ case TWI_I2C_MODE_COMBINED:
+ bfin_write_TWI_XMT_DATA8(iface->command);
+ bfin_write_TWI_INT_MASK(MCOMP | MERR | RCVSERV | XMTSERV);
+ SSYNC();
+
+ if (iface->writeNum > 0)
+ bfin_write_TWI_MASTER_CTL((iface->writeNum + 1) << 6);
+ else
+ bfin_write_TWI_MASTER_CTL(0x1 << 6);
+ /* Master enable */
+ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN |
+ ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ>100) ? FAST : 0));
+ break;
+ default:
+ bfin_write_TWI_MASTER_CTL(0);
+ if (size != I2C_SMBUS_QUICK) {
+ /* Don't access xmit data register when this is a
+ * read operation.
+ */
+ if (iface->read_write != I2C_SMBUS_READ) {
+ if (iface->writeNum > 0) {
+ bfin_write_TWI_XMT_DATA8(*(iface->transPtr++));
+ if (iface->writeNum <= 255)
+ bfin_write_TWI_MASTER_CTL(iface->writeNum << 6);
+ else {
+ bfin_write_TWI_MASTER_CTL(0xff << 6);
+ iface->manual_stop = 1;
+ }
+ iface->writeNum--;
+ } else {
+ bfin_write_TWI_XMT_DATA8(iface->command);
+ bfin_write_TWI_MASTER_CTL(1 << 6);
+ }
+ } else {
+ if (iface->readNum > 0 && iface->readNum <= 255)
+ bfin_write_TWI_MASTER_CTL(iface->readNum << 6);
+ else if (iface->readNum > 255) {
+ bfin_write_TWI_MASTER_CTL(0xff << 6);
+ iface->manual_stop = 1;
+ } else {
+ del_timer(&iface->timeout_timer);
+ break;
+ }
+ }
+ }
+ bfin_write_TWI_INT_MASK(MCOMP | MERR |
+ ((iface->read_write == I2C_SMBUS_READ) ?
+ RCVSERV : XMTSERV));
+ SSYNC();
+
+ /* Master enable */
+ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN |
+ ((iface->read_write == I2C_SMBUS_READ) ? MDIR : 0) |
+ ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ > 100) ? FAST : 0));
+ break;
+ }
+ SSYNC();
+
+ wait_for_completion(&iface->complete);
+
+ rc = (iface->result >= 0) ? 0 : -1;
+
+ /* Release mutex */
+ mutex_unlock(&iface->twi_lock);
+
+ return rc;
+}
+
+/*
+ * Return what the adapter supports
+ */
+static u32 bfin_twi_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+ I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+ I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_PROC_CALL |
+ I2C_FUNC_I2C;
+}
+
+
+static struct i2c_algorithm bfin_twi_algorithm = {
+ .master_xfer = bfin_twi_master_xfer,
+ .smbus_xfer = bfin_twi_smbus_xfer,
+ .functionality = bfin_twi_functionality,
+};
+
+
+static int i2c_bfin_twi_suspend(struct platform_device *dev, pm_message_t state)
+{
+/* struct bfin_twi_iface *iface = platform_get_drvdata(dev);*/
+
+ /* Disable TWI */
+ bfin_write_TWI_CONTROL(bfin_read_TWI_CONTROL() & ~TWI_ENA);
+ SSYNC();
+
+ return 0;
+}
+
+static int i2c_bfin_twi_resume(struct platform_device *dev)
+{
+/* struct bfin_twi_iface *iface = platform_get_drvdata(dev);*/
+
+ /* Enable TWI */
+ bfin_write_TWI_CONTROL(bfin_read_TWI_CONTROL() | TWI_ENA);
+ SSYNC();
+
+ return 0;
+}
+
+static int i2c_bfin_twi_probe(struct platform_device *dev)
+{
+ struct bfin_twi_iface *iface = &twi_iface;
+ struct i2c_adapter *p_adap;
+ int rc;
+
+ mutex_init(&(iface->twi_lock));
+ spin_lock_init(&(iface->lock));
+ init_completion(&(iface->complete));
+ iface->irq = IRQ_TWI;
+
+ init_timer(&(iface->timeout_timer));
+ iface->timeout_timer.function = bfin_twi_timeout;
+ iface->timeout_timer.data = (unsigned long)iface;
+
+ p_adap = &iface->adap;
+ p_adap->id = I2C_HW_BLACKFIN;
+ strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
+ p_adap->algo = &bfin_twi_algorithm;
+ p_adap->algo_data = iface;
+ p_adap->class = I2C_CLASS_ALL;
+ p_adap->dev.parent = &dev->dev;
+
+ rc = request_irq(iface->irq, bfin_twi_interrupt_entry,
+ IRQF_DISABLED, dev->name, iface);
+ if (rc) {
+ dev_err(&(p_adap->dev), "i2c-bfin-twi: can't get IRQ %d !\n",
+ iface->irq);
+ return -ENODEV;
+ }
+
+ /* Set TWI internal clock as 10MHz */
+ bfin_write_TWI_CONTROL(((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F);
+
+ /* Set Twi interface clock as specified */
+ bfin_write_TWI_CLKDIV((( 5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ )
+ << 8) | (( 5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ )
+ & 0xFF));
+
+ /* Enable TWI */
+ bfin_write_TWI_CONTROL(bfin_read_TWI_CONTROL() | TWI_ENA);
+ SSYNC();
+
+ rc = i2c_add_adapter(p_adap);
+ if (rc < 0)
+ free_irq(iface->irq, iface);
+ else
+ platform_set_drvdata(dev, iface);
+
+ return rc;
+}
+
+static int i2c_bfin_twi_remove(struct platform_device *pdev)
+{
+ struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
+
+ platform_set_drvdata(pdev, NULL);
+
+ i2c_del_adapter(&(iface->adap));
+ free_irq(iface->irq, iface);
+
+ return 0;
+}
+
+static struct platform_driver i2c_bfin_twi_driver = {
+ .probe = i2c_bfin_twi_probe,
+ .remove = i2c_bfin_twi_remove,
+ .suspend = i2c_bfin_twi_suspend,
+ .resume = i2c_bfin_twi_resume,
+ .driver = {
+ .name = "i2c-bfin-twi",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init i2c_bfin_twi_init(void)
+{
+ pr_info("I2C: Blackfin I2C TWI driver\n");
+
+ return platform_driver_register(&i2c_bfin_twi_driver);
+}
+
+static void __exit i2c_bfin_twi_exit(void)
+{
+ platform_driver_unregister(&i2c_bfin_twi_driver);
+}
+
+MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
+MODULE_DESCRIPTION("I2C-Bus adapter routines for Blackfin TWI");
+MODULE_LICENSE("GPL");
+
+module_init(i2c_bfin_twi_init);
+module_exit(i2c_bfin_twi_exit);
projects / openwrt / staging / blogic.git / commitdiff