Commit b6ee52c3 authored by Nishanth Menon's avatar Nishanth Menon Committed by Tony Lindgren
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i2c-omap: FIFO handling support and broken hw workaround for i2c-omap 



Based on an earlier patch from Nishant Menon:

- Transfers can use FIFO on FIFO capable devices
- Prevents errors for HSI2C if FIFO is not used
- Implemented errenous handling of STT-STP handling on SDP2430

Also merged in is a fix from Jaron Marini to fix occasional i2c
hang if OMAP_I2C_CON_STT remains asserted.

Signed-off-by: default avatarJason P Marini <jason.marini@gmail.com>
Signed-off-by: default avatarNishanth Menon <nm@ti.com>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent 4574eb68

drivers/i2c/busses/i2c-omap.c

+150 −40
Original line number Diff line number Diff line
@@ -55,8 +55,11 @@ 
#define OMAP_I2C_SCLL_REG		0x34

#define OMAP_I2C_SCLH_REG		0x38

#define OMAP_I2C_SYSTEST_REG		0x3c

#define OMAP_I2C_BUFSTAT_REG		0x40



/* I2C Interrupt Enable Register (OMAP_I2C_IE): */

#define OMAP_I2C_IE_XDR		(1 << 14)	/* TX Buffer drain int enable */

#define OMAP_I2C_IE_RDR		(1 << 13)	/* RX Buffer drain int enable */

#define OMAP_I2C_IE_XRDY	(1 << 4)	/* TX data ready int enable */

#define OMAP_I2C_IE_RRDY	(1 << 3)	/* RX data ready int enable */

#define OMAP_I2C_IE_ARDY	(1 << 2)	/* Access ready int enable */
@@ -64,7 +67,8 @@ 
#define OMAP_I2C_IE_AL		(1 << 0)	/* Arbitration lost int ena */



/* I2C Status Register (OMAP_I2C_STAT): */

#define OMAP_I2C_STAT_SBD	(1 << 15)	/* Single byte data */

#define OMAP_I2C_STAT_XDR	(1 << 14)	/* TX Buffer draining */

#define OMAP_I2C_STAT_RDR	(1 << 13)	/* RX Buffer draining */

#define OMAP_I2C_STAT_BB	(1 << 12)	/* Bus busy */

#define OMAP_I2C_STAT_ROVR	(1 << 11)	/* Receive overrun */

#define OMAP_I2C_STAT_XUDF	(1 << 10)	/* Transmit underflow */
@@ -78,12 +82,14 @@ 


/* I2C Buffer Configuration Register (OMAP_I2C_BUF): */

#define OMAP_I2C_BUF_RDMA_EN	(1 << 15)	/* RX DMA channel enable */

#define OMAP_I2C_BUF_RXFIF_CLR	(1 << 14)	/* RX FIFO Clear */

#define OMAP_I2C_BUF_XDMA_EN	(1 << 7)	/* TX DMA channel enable */

#define OMAP_I2C_BUF_TXFIF_CLR	(1 << 6)	/* TX FIFO Clear */



/* I2C Configuration Register (OMAP_I2C_CON): */

#define OMAP_I2C_CON_EN		(1 << 15)	/* I2C module enable */

#define OMAP_I2C_CON_BE		(1 << 14)	/* Big endian mode */

#define OMAP_I2C_CON_OPMODE	(1 << 12)	/* High Speed support */

#define OMAP_I2C_CON_OPMODE_HS	(1 << 12)	/* High Speed support */

#define OMAP_I2C_CON_STB	(1 << 11)	/* Start byte mode (master) */

#define OMAP_I2C_CON_MST	(1 << 10)	/* Master/slave mode */

#define OMAP_I2C_CON_TRX	(1 << 9)	/* TX/RX mode (master only) */
@@ -127,7 +133,12 @@ struct omap_i2c_dev { 
	u8			*buf;

	size_t			buf_len;

	struct i2c_adapter	adapter;

	u8			fifo_size;	/* use as flag and value

						 * fifo_size==0 implies no fifo

						 * if set, should be trsh+1

						 */

	unsigned		rev1:1;

	unsigned		b_hw:1;		/* bad h/w fixes */

	unsigned		idle:1;

	u16			iestate;	/* Saved interrupt register */

};
@@ -297,6 +308,14 @@ static int omap_i2c_init(struct omap_i2c_dev *dev) 
	omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);

	omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);



	if (dev->fifo_size)

		/* Note: setup required fifo size - 1 */

		omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG,

					(dev->fifo_size - 1) << 8 | /* RTRSH */

					OMAP_I2C_BUF_RXFIF_CLR |

					(dev->fifo_size - 1) | /* XTRSH */

					OMAP_I2C_BUF_TXFIF_CLR);



	/* Take the I2C module out of reset: */

	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
@@ -304,7 +323,8 @@ static int omap_i2c_init(struct omap_i2c_dev *dev) 
	omap_i2c_write_reg(dev, OMAP_I2C_IE_REG,

			   (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |

			    OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |

			    OMAP_I2C_IE_AL));

			    OMAP_I2C_IE_AL)  | ((dev->fifo_size) ?

				(OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0));

	return 0;

}
@@ -351,6 +371,11 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, 


	omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);



	/* Clear the FIFO Buffers */

	w = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);

	w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;

	omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, w);



	init_completion(&dev->cmd_complete);

	dev->cmd_err = 0;
@@ -358,15 +383,38 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, 


	/* High speed configuration */

	if (dev->speed > 400)

		w |= OMAP_I2C_CON_OPMODE;

		w |= OMAP_I2C_CON_OPMODE_HS;



	if (msg->flags & I2C_M_TEN)

		w |= OMAP_I2C_CON_XA;

	if (!(msg->flags & I2C_M_RD))

		w |= OMAP_I2C_CON_TRX;

	if (stop)

	if (!dev->b_hw && stop)

		w |= OMAP_I2C_CON_STP;

	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);



	/*

	 * Don't write stt and stp together on some hardware.

	 */

	if (dev->b_hw && stop) {

		unsigned long delay = jiffies + OMAP_I2C_TIMEOUT;

		u16 con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);

		while (con & OMAP_I2C_CON_STT) {

			con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);



			/* Let the user know if i2c is in a bad state */

			if (time_after(jiffies, delay)) {

				dev_err(dev->dev, "controller timed out "

				"waiting for start condition to finish\n");

				return -ETIMEDOUT;

			}

			cpu_relax();

		}



		w |= OMAP_I2C_CON_STP;

		w &= ~OMAP_I2C_CON_STT;

		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);

	}



	/*

	 * REVISIT: We should abort the transfer on signals, but the bus goes
@@ -516,7 +564,7 @@ omap_i2c_isr(int this_irq, void *dev_id) 
	struct omap_i2c_dev *dev = dev_id;

	u16 bits;

	u16 stat, w;

	int count = 0;

	int err, count = 0;



	if (dev->idle)

		return IRQ_NONE;
@@ -531,39 +579,94 @@ omap_i2c_isr(int this_irq, void *dev_id) 


		omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);



		if (stat & OMAP_I2C_STAT_ARDY) {

			omap_i2c_complete_cmd(dev, 0);

			continue;

		err = 0;

		if (stat & OMAP_I2C_STAT_NACK) {

			err |= OMAP_I2C_STAT_NACK;

			omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,

					   OMAP_I2C_CON_STP);

		}

		if (stat & OMAP_I2C_STAT_RRDY) {

		if (stat & OMAP_I2C_STAT_AL) {

			dev_err(dev->dev, "Arbitration lost\n");

			err |= OMAP_I2C_STAT_AL;

		}

		if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |

					OMAP_I2C_STAT_AL))

			omap_i2c_complete_cmd(dev, err);

		if (stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR)) {

			u8 num_bytes = 1;

			if (dev->fifo_size) {

				if (stat & OMAP_I2C_STAT_RRDY)

					num_bytes = dev->fifo_size;

				else

					num_bytes = omap_i2c_read_reg(dev,

							OMAP_I2C_BUFSTAT_REG);

			}

			while (num_bytes) {

				num_bytes--;

				w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);

				if (dev->buf_len) {

					*dev->buf++ = w;

					dev->buf_len--;

					/* Data reg from 2430 is 8 bit wide */

					if (!cpu_is_omap2430()) {

						if (dev->buf_len) {

							*dev->buf++ = w >> 8;

							dev->buf_len--;

						}

			} else

				dev_err(dev->dev, "RRDY IRQ while no data "

					}

				} else {

					if (stat & OMAP_I2C_STAT_RRDY)

						dev_err(dev->dev,

							"RRDY IRQ while no data"

								" requested\n");

					if (stat & OMAP_I2C_STAT_RDR)

						dev_err(dev->dev,

							"RDR IRQ while no data"

								" requested\n");

			omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RRDY);

					break;

				}

			}

			omap_i2c_ack_stat(dev,

				stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR));

			continue;

		}

		if (stat & OMAP_I2C_STAT_XRDY) {

		if (stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR)) {

			u8 num_bytes = 1;

			if (dev->fifo_size) {

				if (stat & OMAP_I2C_STAT_XRDY)

					num_bytes = dev->fifo_size;

				else

					num_bytes = omap_i2c_read_reg(dev,

							OMAP_I2C_BUFSTAT_REG);

			}

			while (num_bytes) {

				num_bytes--;

				w = 0;

				if (dev->buf_len) {

					w = *dev->buf++;

					dev->buf_len--;

					/* Data reg from  2430 is 8 bit wide */

					if (!cpu_is_omap2430()) {

						if (dev->buf_len) {

							w |= *dev->buf++ << 8;

							dev->buf_len--;

						}

			} else

				dev_err(dev->dev, "XRDY IRQ while no "

					}

				} else {

					if (stat & OMAP_I2C_STAT_XRDY)

						dev_err(dev->dev,

							"XRDY IRQ while no "

							"data to send\n");

					if (stat & OMAP_I2C_STAT_XDR)

						dev_err(dev->dev,

							"XDR IRQ while no "

							"data to send\n");

					break;

				}

				omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);

			omap_i2c_ack_stat(dev, OMAP_I2C_STAT_XRDY);

			}

			omap_i2c_ack_stat(dev,

				stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));

			continue;

		}

		if (stat & OMAP_I2C_STAT_ROVR) {
@@ -571,18 +674,9 @@ omap_i2c_isr(int this_irq, void *dev_id) 
			dev->cmd_err |= OMAP_I2C_STAT_ROVR;

		}

		if (stat & OMAP_I2C_STAT_XUDF) {

			dev_err(dev->dev, "Transmit overflow\n");

			dev_err(dev->dev, "Transmit underflow\n");

			dev->cmd_err |= OMAP_I2C_STAT_XUDF;

		}

		if (stat & OMAP_I2C_STAT_NACK) {

			omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);

			omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,

					   OMAP_I2C_CON_STP);

		}

		if (stat & OMAP_I2C_STAT_AL) {

			dev_err(dev->dev, "Arbitration lost\n");

			omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);

		}

	}



	return count ? IRQ_HANDLED : IRQ_NONE;
@@ -651,6 +745,22 @@ omap_i2c_probe(struct platform_device *pdev) 
	if (cpu_is_omap15xx())

		dev->rev1 = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) < 0x20;



	if (cpu_is_omap2430()) {

		u16 s;



		/* Set up the fifo size - Get total size */

		s = (omap_i2c_read_reg(dev, OMAP_I2C_BUFSTAT_REG) >> 14) & 0x3;

		dev->fifo_size = 0x8 << s;



		/*

		 * Set up notification threshold as half the total available

		 * size. This is to ensure that we can handle the status on int

		 * call back latencies.

		 */

		dev->fifo_size = (dev->fifo_size / 2);

		dev->b_hw = 1; /* Enable hardware fixes */

	}



	/* reset ASAP, clearing any IRQs */

	omap_i2c_init(dev);

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