i2c-designware: split of i2c-designware.c into core and bus specific parts
This patch splits i2c-designware.c into three pieces:
i2c-designware-core.c, contains the code that interacts directly
with the core.
i2c-designware-platdrv.c, contains the code specific to the
platform driver using the core.
i2c-designware-core.h contains the definitions and declareations
shared by i2c-designware-core.c and i2c-designware-platdrv.c.
This patch is the first in a set to allow multiple instances of the
designware I2C core in the system.
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
new file mode 100644
index 0000000..38d5a6b
--- /dev/null
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -0,0 +1,562 @@
+/*
+ * Synopsys DesignWare I2C adapter driver (master only).
+ *
+ * Based on the TI DAVINCI I2C adapter driver.
+ *
+ * Copyright (C) 2006 Texas Instruments.
+ * Copyright (C) 2007 MontaVista Software Inc.
+ * Copyright (C) 2009 Provigent Ltd.
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * ----------------------------------------------------------------------------
+ *
+ */
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include "i2c-designware-core.h"
+
+static char *abort_sources[] = {
+ [ABRT_7B_ADDR_NOACK] =
+ "slave address not acknowledged (7bit mode)",
+ [ABRT_10ADDR1_NOACK] =
+ "first address byte not acknowledged (10bit mode)",
+ [ABRT_10ADDR2_NOACK] =
+ "second address byte not acknowledged (10bit mode)",
+ [ABRT_TXDATA_NOACK] =
+ "data not acknowledged",
+ [ABRT_GCALL_NOACK] =
+ "no acknowledgement for a general call",
+ [ABRT_GCALL_READ] =
+ "read after general call",
+ [ABRT_SBYTE_ACKDET] =
+ "start byte acknowledged",
+ [ABRT_SBYTE_NORSTRT] =
+ "trying to send start byte when restart is disabled",
+ [ABRT_10B_RD_NORSTRT] =
+ "trying to read when restart is disabled (10bit mode)",
+ [ABRT_MASTER_DIS] =
+ "trying to use disabled adapter",
+ [ARB_LOST] =
+ "lost arbitration",
+};
+
+u32 dw_readl(struct dw_i2c_dev *dev, int offset)
+{
+ u32 value = readl(dev->base + offset);
+
+ if (dev->swab)
+ return swab32(value);
+ else
+ return value;
+}
+
+void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)
+{
+ if (dev->swab)
+ b = swab32(b);
+
+ writel(b, dev->base + offset);
+}
+
+static u32
+i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
+{
+ /*
+ * DesignWare I2C core doesn't seem to have solid strategy to meet
+ * the tHD;STA timing spec. Configuring _HCNT based on tHIGH spec
+ * will result in violation of the tHD;STA spec.
+ */
+ if (cond)
+ /*
+ * Conditional expression:
+ *
+ * IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH
+ *
+ * This is based on the DW manuals, and represents an ideal
+ * configuration. The resulting I2C bus speed will be
+ * faster than any of the others.
+ *
+ * If your hardware is free from tHD;STA issue, try this one.
+ */
+ return (ic_clk * tSYMBOL + 5000) / 10000 - 8 + offset;
+ else
+ /*
+ * Conditional expression:
+ *
+ * IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf)
+ *
+ * This is just experimental rule; the tHD;STA period turned
+ * out to be proportinal to (_HCNT + 3). With this setting,
+ * we could meet both tHIGH and tHD;STA timing specs.
+ *
+ * If unsure, you'd better to take this alternative.
+ *
+ * The reason why we need to take into account "tf" here,
+ * is the same as described in i2c_dw_scl_lcnt().
+ */
+ return (ic_clk * (tSYMBOL + tf) + 5000) / 10000 - 3 + offset;
+}
+
+static u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
+{
+ /*
+ * Conditional expression:
+ *
+ * IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf)
+ *
+ * DW I2C core starts counting the SCL CNTs for the LOW period
+ * of the SCL clock (tLOW) as soon as it pulls the SCL line.
+ * In order to meet the tLOW timing spec, we need to take into
+ * account the fall time of SCL signal (tf). Default tf value
+ * should be 0.3 us, for safety.
+ */
+ return ((ic_clk * (tLOW + tf) + 5000) / 10000) - 1 + offset;
+}
+
+/**
+ * i2c_dw_init() - initialize the designware i2c master hardware
+ * @dev: device private data
+ *
+ * This functions configures and enables the I2C master.
+ * This function is called during I2C init function, and in case of timeout at
+ * run time.
+ */
+int i2c_dw_init(struct dw_i2c_dev *dev)
+{
+ u32 input_clock_khz = clk_get_rate(dev->clk) / 1000;
+ u32 ic_con, hcnt, lcnt;
+ u32 reg;
+
+ /* Configure register endianess access */
+ reg = dw_readl(dev, DW_IC_COMP_TYPE);
+ if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
+ dev->swab = 1;
+ reg = DW_IC_COMP_TYPE_VALUE;
+ }
+
+ if (reg != DW_IC_COMP_TYPE_VALUE) {
+ dev_err(dev->dev, "Unknown Synopsys component type: "
+ "0x%08x\n", reg);
+ return -ENODEV;
+ }
+
+ /* Disable the adapter */
+ dw_writel(dev, 0, DW_IC_ENABLE);
+
+ /* set standard and fast speed deviders for high/low periods */
+
+ /* Standard-mode */
+ hcnt = i2c_dw_scl_hcnt(input_clock_khz,
+ 40, /* tHD;STA = tHIGH = 4.0 us */
+ 3, /* tf = 0.3 us */
+ 0, /* 0: DW default, 1: Ideal */
+ 0); /* No offset */
+ lcnt = i2c_dw_scl_lcnt(input_clock_khz,
+ 47, /* tLOW = 4.7 us */
+ 3, /* tf = 0.3 us */
+ 0); /* No offset */
+ dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT);
+ dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
+ dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
+
+ /* Fast-mode */
+ hcnt = i2c_dw_scl_hcnt(input_clock_khz,
+ 6, /* tHD;STA = tHIGH = 0.6 us */
+ 3, /* tf = 0.3 us */
+ 0, /* 0: DW default, 1: Ideal */
+ 0); /* No offset */
+ lcnt = i2c_dw_scl_lcnt(input_clock_khz,
+ 13, /* tLOW = 1.3 us */
+ 3, /* tf = 0.3 us */
+ 0); /* No offset */
+ dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT);
+ dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
+ dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
+
+ /* Configure Tx/Rx FIFO threshold levels */
+ dw_writel(dev, dev->tx_fifo_depth - 1, DW_IC_TX_TL);
+ dw_writel(dev, 0, DW_IC_RX_TL);
+
+ /* configure the i2c master */
+ ic_con = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
+ DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
+ dw_writel(dev, ic_con, DW_IC_CON);
+ return 0;
+}
+
+/*
+ * Waiting for bus not busy
+ */
+static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
+{
+ int timeout = TIMEOUT;
+
+ while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
+ if (timeout <= 0) {
+ dev_warn(dev->dev, "timeout waiting for bus ready\n");
+ return -ETIMEDOUT;
+ }
+ timeout--;
+ mdelay(1);
+ }
+
+ return 0;
+}
+
+static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
+{
+ struct i2c_msg *msgs = dev->msgs;
+ u32 ic_con;
+
+ /* Disable the adapter */
+ dw_writel(dev, 0, DW_IC_ENABLE);
+
+ /* set the slave (target) address */
+ dw_writel(dev, msgs[dev->msg_write_idx].addr, DW_IC_TAR);
+
+ /* if the slave address is ten bit address, enable 10BITADDR */
+ ic_con = dw_readl(dev, DW_IC_CON);
+ if (msgs[dev->msg_write_idx].flags & I2C_M_TEN)
+ ic_con |= DW_IC_CON_10BITADDR_MASTER;
+ else
+ ic_con &= ~DW_IC_CON_10BITADDR_MASTER;
+ dw_writel(dev, ic_con, DW_IC_CON);
+
+ /* Enable the adapter */
+ dw_writel(dev, 1, DW_IC_ENABLE);
+
+ /* Enable interrupts */
+ dw_writel(dev, DW_IC_INTR_DEFAULT_MASK, DW_IC_INTR_MASK);
+}
+
+/*
+ * Initiate (and continue) low level master read/write transaction.
+ * This function is only called from i2c_dw_isr, and pumping i2c_msg
+ * messages into the tx buffer. Even if the size of i2c_msg data is
+ * longer than the size of the tx buffer, it handles everything.
+ */
+void
+i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
+{
+ struct i2c_msg *msgs = dev->msgs;
+ u32 intr_mask;
+ int tx_limit, rx_limit;
+ u32 addr = msgs[dev->msg_write_idx].addr;
+ u32 buf_len = dev->tx_buf_len;
+ u8 *buf = dev->tx_buf;
+
+ intr_mask = DW_IC_INTR_DEFAULT_MASK;
+
+ for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) {
+ /*
+ * if target address has changed, we need to
+ * reprogram the target address in the i2c
+ * adapter when we are done with this transfer
+ */
+ if (msgs[dev->msg_write_idx].addr != addr) {
+ dev_err(dev->dev,
+ "%s: invalid target address\n", __func__);
+ dev->msg_err = -EINVAL;
+ break;
+ }
+
+ if (msgs[dev->msg_write_idx].len == 0) {
+ dev_err(dev->dev,
+ "%s: invalid message length\n", __func__);
+ dev->msg_err = -EINVAL;
+ break;
+ }
+
+ if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
+ /* new i2c_msg */
+ buf = msgs[dev->msg_write_idx].buf;
+ buf_len = msgs[dev->msg_write_idx].len;
+ }
+
+ tx_limit = dev->tx_fifo_depth - dw_readl(dev, DW_IC_TXFLR);
+ rx_limit = dev->rx_fifo_depth - dw_readl(dev, DW_IC_RXFLR);
+
+ while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
+ if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {
+ dw_writel(dev, 0x100, DW_IC_DATA_CMD);
+ rx_limit--;
+ } else
+ dw_writel(dev, *buf++, DW_IC_DATA_CMD);
+ tx_limit--; buf_len--;
+ }
+
+ dev->tx_buf = buf;
+ dev->tx_buf_len = buf_len;
+
+ if (buf_len > 0) {
+ /* more bytes to be written */
+ dev->status |= STATUS_WRITE_IN_PROGRESS;
+ break;
+ } else
+ dev->status &= ~STATUS_WRITE_IN_PROGRESS;
+ }
+
+ /*
+ * If i2c_msg index search is completed, we don't need TX_EMPTY
+ * interrupt any more.
+ */
+ if (dev->msg_write_idx == dev->msgs_num)
+ intr_mask &= ~DW_IC_INTR_TX_EMPTY;
+
+ if (dev->msg_err)
+ intr_mask = 0;
+
+ dw_writel(dev, intr_mask, DW_IC_INTR_MASK);
+}
+
+static void
+i2c_dw_read(struct dw_i2c_dev *dev)
+{
+ struct i2c_msg *msgs = dev->msgs;
+ int rx_valid;
+
+ for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) {
+ u32 len;
+ u8 *buf;
+
+ if (!(msgs[dev->msg_read_idx].flags & I2C_M_RD))
+ continue;
+
+ if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
+ len = msgs[dev->msg_read_idx].len;
+ buf = msgs[dev->msg_read_idx].buf;
+ } else {
+ len = dev->rx_buf_len;
+ buf = dev->rx_buf;
+ }
+
+ rx_valid = dw_readl(dev, DW_IC_RXFLR);
+
+ for (; len > 0 && rx_valid > 0; len--, rx_valid--)
+ *buf++ = dw_readl(dev, DW_IC_DATA_CMD);
+
+ if (len > 0) {
+ dev->status |= STATUS_READ_IN_PROGRESS;
+ dev->rx_buf_len = len;
+ dev->rx_buf = buf;
+ return;
+ } else
+ dev->status &= ~STATUS_READ_IN_PROGRESS;
+ }
+}
+
+static int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev)
+{
+ unsigned long abort_source = dev->abort_source;
+ int i;
+
+ if (abort_source & DW_IC_TX_ABRT_NOACK) {
+ for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
+ dev_dbg(dev->dev,
+ "%s: %s\n", __func__, abort_sources[i]);
+ return -EREMOTEIO;
+ }
+
+ for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
+ dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]);
+
+ if (abort_source & DW_IC_TX_ARB_LOST)
+ return -EAGAIN;
+ else if (abort_source & DW_IC_TX_ABRT_GCALL_READ)
+ return -EINVAL; /* wrong msgs[] data */
+ else
+ return -EIO;
+}
+
+/*
+ * Prepare controller for a transaction and call i2c_dw_xfer_msg
+ */
+int
+i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+ struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+ int ret;
+
+ dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
+
+ mutex_lock(&dev->lock);
+
+ INIT_COMPLETION(dev->cmd_complete);
+ dev->msgs = msgs;
+ dev->msgs_num = num;
+ dev->cmd_err = 0;
+ dev->msg_write_idx = 0;
+ dev->msg_read_idx = 0;
+ dev->msg_err = 0;
+ dev->status = STATUS_IDLE;
+ dev->abort_source = 0;
+
+ ret = i2c_dw_wait_bus_not_busy(dev);
+ if (ret < 0)
+ goto done;
+
+ /* start the transfers */
+ i2c_dw_xfer_init(dev);
+
+ /* wait for tx to complete */
+ ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, HZ);
+ if (ret == 0) {
+ dev_err(dev->dev, "controller timed out\n");
+ i2c_dw_init(dev);
+ ret = -ETIMEDOUT;
+ goto done;
+ } else if (ret < 0)
+ goto done;
+
+ if (dev->msg_err) {
+ ret = dev->msg_err;
+ goto done;
+ }
+
+ /* no error */
+ if (likely(!dev->cmd_err)) {
+ /* Disable the adapter */
+ dw_writel(dev, 0, DW_IC_ENABLE);
+ ret = num;
+ goto done;
+ }
+
+ /* We have an error */
+ if (dev->cmd_err == DW_IC_ERR_TX_ABRT) {
+ ret = i2c_dw_handle_tx_abort(dev);
+ goto done;
+ }
+ ret = -EIO;
+
+done:
+ mutex_unlock(&dev->lock);
+
+ return ret;
+}
+
+u32 i2c_dw_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C |
+ I2C_FUNC_10BIT_ADDR |
+ I2C_FUNC_SMBUS_BYTE |
+ I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_SMBUS_WORD_DATA |
+ I2C_FUNC_SMBUS_I2C_BLOCK;
+}
+
+static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
+{
+ u32 stat;
+
+ /*
+ * The IC_INTR_STAT register just indicates "enabled" interrupts.
+ * Ths unmasked raw version of interrupt status bits are available
+ * in the IC_RAW_INTR_STAT register.
+ *
+ * That is,
+ * stat = dw_readl(IC_INTR_STAT);
+ * equals to,
+ * stat = dw_readl(IC_RAW_INTR_STAT) & dw_readl(IC_INTR_MASK);
+ *
+ * The raw version might be useful for debugging purposes.
+ */
+ stat = dw_readl(dev, DW_IC_INTR_STAT);
+
+ /*
+ * Do not use the IC_CLR_INTR register to clear interrupts, or
+ * you'll miss some interrupts, triggered during the period from
+ * dw_readl(IC_INTR_STAT) to dw_readl(IC_CLR_INTR).
+ *
+ * Instead, use the separately-prepared IC_CLR_* registers.
+ */
+ if (stat & DW_IC_INTR_RX_UNDER)
+ dw_readl(dev, DW_IC_CLR_RX_UNDER);
+ if (stat & DW_IC_INTR_RX_OVER)
+ dw_readl(dev, DW_IC_CLR_RX_OVER);
+ if (stat & DW_IC_INTR_TX_OVER)
+ dw_readl(dev, DW_IC_CLR_TX_OVER);
+ if (stat & DW_IC_INTR_RD_REQ)
+ dw_readl(dev, DW_IC_CLR_RD_REQ);
+ if (stat & DW_IC_INTR_TX_ABRT) {
+ /*
+ * The IC_TX_ABRT_SOURCE register is cleared whenever
+ * the IC_CLR_TX_ABRT is read. Preserve it beforehand.
+ */
+ dev->abort_source = dw_readl(dev, DW_IC_TX_ABRT_SOURCE);
+ dw_readl(dev, DW_IC_CLR_TX_ABRT);
+ }
+ if (stat & DW_IC_INTR_RX_DONE)
+ dw_readl(dev, DW_IC_CLR_RX_DONE);
+ if (stat & DW_IC_INTR_ACTIVITY)
+ dw_readl(dev, DW_IC_CLR_ACTIVITY);
+ if (stat & DW_IC_INTR_STOP_DET)
+ dw_readl(dev, DW_IC_CLR_STOP_DET);
+ if (stat & DW_IC_INTR_START_DET)
+ dw_readl(dev, DW_IC_CLR_START_DET);
+ if (stat & DW_IC_INTR_GEN_CALL)
+ dw_readl(dev, DW_IC_CLR_GEN_CALL);
+
+ return stat;
+}
+
+/*
+ * Interrupt service routine. This gets called whenever an I2C interrupt
+ * occurs.
+ */
+irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
+{
+ struct dw_i2c_dev *dev = dev_id;
+ u32 stat;
+
+ stat = i2c_dw_read_clear_intrbits(dev);
+ dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
+
+ if (stat & DW_IC_INTR_TX_ABRT) {
+ dev->cmd_err |= DW_IC_ERR_TX_ABRT;
+ dev->status = STATUS_IDLE;
+
+ /*
+ * Anytime TX_ABRT is set, the contents of the tx/rx
+ * buffers are flushed. Make sure to skip them.
+ */
+ dw_writel(dev, 0, DW_IC_INTR_MASK);
+ goto tx_aborted;
+ }
+
+ if (stat & DW_IC_INTR_RX_FULL)
+ i2c_dw_read(dev);
+
+ if (stat & DW_IC_INTR_TX_EMPTY)
+ i2c_dw_xfer_msg(dev);
+
+ /*
+ * No need to modify or disable the interrupt mask here.
+ * i2c_dw_xfer_msg() will take care of it according to
+ * the current transmit status.
+ */
+
+tx_aborted:
+ if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
+ complete(&dev->cmd_complete);
+
+ return IRQ_HANDLED;
+}