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path: root/drivers/i2c/busses/i2c-mxs.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-mxs.c')
-rw-r--r--drivers/i2c/busses/i2c-mxs.c186
1 files changed, 14 insertions, 172 deletions
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 1f58197..286ca19 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -1,7 +1,7 @@
/*
* Freescale MXS I2C bus driver
*
- * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
+ * Copyright (C) 2011-2012 Wolfram Sang, Pengutronix e.K.
*
* based on a (non-working) driver which was:
*
@@ -35,10 +35,6 @@
#define DRIVER_NAME "mxs-i2c"
-static bool use_pioqueue;
-module_param(use_pioqueue, bool, 0);
-MODULE_PARM_DESC(use_pioqueue, "Use PIOQUEUE mode for transfer instead of DMA");
-
#define MXS_I2C_CTRL0 (0x00)
#define MXS_I2C_CTRL0_SET (0x04)
@@ -75,23 +71,6 @@ MODULE_PARM_DESC(use_pioqueue, "Use PIOQUEUE mode for transfer instead of DMA");
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_QUEUESTAT_WRITE_QUEUE_CNT_MASK 0x0000001F
-
-#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 | \
@@ -153,7 +132,6 @@ struct mxs_i2c_dev {
const struct mxs_i2c_speed_config *speed;
/* DMA support components */
- bool dma_mode;
int dma_channel;
struct dma_chan *dmach;
struct mxs_dma_data dma_data;
@@ -172,99 +150,6 @@ static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
writel(i2c->speed->timing2, i2c->regs + MXS_I2C_TIMING2);
writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
- if (i2c->dma_mode)
- writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
- i2c->regs + MXS_I2C_QUEUECTRL_CLR);
- else
- writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
- i2c->regs + MXS_I2C_QUEUECTRL_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
- * appropriate, '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 uninitialized_var(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;
}
static void mxs_i2c_dma_finish(struct mxs_i2c_dev *i2c)
@@ -432,39 +317,17 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
init_completion(&i2c->cmd_complete);
i2c->cmd_err = 0;
- if (i2c->dma_mode) {
- ret = mxs_i2c_dma_setup_xfer(adap, msg, flags);
- if (ret)
- return ret;
- } else {
- 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 = mxs_i2c_dma_setup_xfer(adap, msg, flags);
+ if (ret)
+ return ret;
ret = wait_for_completion_timeout(&i2c->cmd_complete,
msecs_to_jiffies(1000));
if (ret == 0)
goto timeout;
- if (!i2c->dma_mode && !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);
- else
- writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
- i2c->regs + MXS_I2C_QUEUECTRL_CLR);
dev_dbg(i2c->dev, "Done with err=%d\n", i2c->cmd_err);
@@ -472,8 +335,7 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
timeout:
dev_dbg(i2c->dev, "Timeout!\n");
- if (i2c->dma_mode)
- mxs_i2c_dma_finish(i2c);
+ mxs_i2c_dma_finish(i2c);
mxs_i2c_reset(i2c);
return -ETIMEDOUT;
}
@@ -502,7 +364,6 @@ 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;
- bool is_last_cmd;
if (!stat)
return IRQ_NONE;
@@ -515,14 +376,6 @@ static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
/* MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ is only for slaves */
i2c->cmd_err = -EIO;
- if (!i2c->dma_mode) {
- is_last_cmd = (readl(i2c->regs + MXS_I2C_QUEUESTAT) &
- MXS_I2C_QUEUESTAT_WRITE_QUEUE_CNT_MASK) == 0;
-
- if (is_last_cmd || i2c->cmd_err)
- complete(&i2c->cmd_complete);
- }
-
writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR);
return IRQ_HANDLED;
@@ -556,23 +409,14 @@ static int mxs_i2c_get_ofdata(struct mxs_i2c_dev *i2c)
int ret;
/*
- * The MXS I2C DMA mode is prefered and enabled by default.
- * The PIO mode is still supported, but should be used only
- * for debuging purposes etc.
- */
- i2c->dma_mode = !use_pioqueue;
- if (!i2c->dma_mode)
- dev_info(dev, "Using PIOQUEUE mode for I2C transfers!\n");
-
- /*
* TODO: This is a temporary solution and should be changed
* to use generic DMA binding later when the helpers get in.
*/
ret = of_property_read_u32(node, "fsl,i2c-dma-channel",
&i2c->dma_channel);
if (ret) {
- dev_warn(dev, "Failed to get DMA channel, using PIOQUEUE!\n");
- i2c->dma_mode = 0;
+ dev_err(dev, "Failed to get DMA channel!\n");
+ return -ENODEV;
}
ret = of_property_read_u32(node, "clock-frequency", &speed);
@@ -634,15 +478,13 @@ static int __devinit mxs_i2c_probe(struct platform_device *pdev)
}
/* Setup the DMA */
- if (i2c->dma_mode) {
- dma_cap_zero(mask);
- dma_cap_set(DMA_SLAVE, mask);
- i2c->dma_data.chan_irq = dmairq;
- i2c->dmach = dma_request_channel(mask, mxs_i2c_dma_filter, i2c);
- if (!i2c->dmach) {
- dev_err(dev, "Failed to request dma\n");
- return -ENODEV;
- }
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+ i2c->dma_data.chan_irq = dmairq;
+ i2c->dmach = dma_request_channel(mask, mxs_i2c_dma_filter, i2c);
+ if (!i2c->dmach) {
+ dev_err(dev, "Failed to request dma\n");
+ return -ENODEV;
}
platform_set_drvdata(pdev, i2c);
generated by cgit v0.10.2 at 2024-11-11 22:34:30 (GMT)