diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-mxs.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-mxs.c | 186 |
1 files changed, 14 insertions, 172 deletions
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c index 1f58197062cf..286ca1917820 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); |