ARM: I2C: I2C Multi byte address support

Existing OMAP I2C driver does not support address
length greater than one. Hence this patch is to
add support for 2 byte address read/write.

Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Signed-off-by: Hebbar, Gururaja <gururaja.hebbar@ti.com>
Signed-off-by: Patil, Rachna <rachna@ti.com>

2 files changed, 296 insertions, 173 deletions

diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c
index a7ffd95..80932ef 100644
--- a/drivers/i2c/omap24xx_i2c.c
+++ b/drivers/i2c/omap24xx_i2c.c
@@ -29,10 +29,11 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#define I2C_TIMEOUT	1000
+#define I2C_STAT_TIMEO	(1 << 31)
+#define I2C_TIMEOUT	10
 
-static void wait_for_bb(void);
-static u16 wait_for_pin(void);
+static u32 wait_for_bb(void);
+static u32 wait_for_status_mask(u16 mask);
 static void flush_fifo(void);
 
 /*
@@ -50,7 +51,6 @@ void i2c_init(int speed, int slaveadd)
 	int psc, fsscll, fssclh;
 	int hsscll = 0, hssclh = 0;
 	u32 scll, sclh;
-	int timeout = I2C_TIMEOUT;
 
 	/* Only handle standard, fast and high speeds */
 	if ((speed != OMAP_I2C_STANDARD) &&
@@ -112,24 +112,14 @@ void i2c_init(int speed, int slaveadd)
 		sclh = (unsigned int)fssclh;
 	}
 
+	if (gd->flags & GD_FLG_RELOC)
+		bus_initialized[current_bus] = 1;
+
 	if (readw(&i2c_base->con) & I2C_CON_EN) {
 		writew(0, &i2c_base->con);
 		udelay(50000);
 	}
 
-	writew(0x2, &i2c_base->sysc); /* for ES2 after soft reset */
-	udelay(1000);
-
-	writew(I2C_CON_EN, &i2c_base->con);
-	while (!(readw(&i2c_base->syss) & I2C_SYSS_RDONE) && timeout--) {
-		if (timeout <= 0) {
-			puts("ERROR: Timeout in soft-reset\n");
-			return;
-		}
-		udelay(1000);
-	}
-
-	writew(0, &i2c_base->con);
 	writew(psc, &i2c_base->psc);
 	writew(scll, &i2c_base->scll);
 	writew(sclh, &i2c_base->sclh);
@@ -145,81 +135,6 @@ void i2c_init(int speed, int slaveadd)
 	flush_fifo();
 	writew(0xFFFF, &i2c_base->stat);
 	writew(0, &i2c_base->cnt);
-
-	if (gd->flags & GD_FLG_RELOC)
-		bus_initialized[current_bus] = 1;
-}
-
-static int i2c_read_byte(u8 devaddr, u8 regoffset, u8 *value)
-{
-	int i2c_error = 0;
-	u16 status;
-
-	/* wait until bus not busy */
-	wait_for_bb();
-
-	/* one byte only */
-	writew(1, &i2c_base->cnt);
-	/* set slave address */
-	writew(devaddr, &i2c_base->sa);
-	/* no stop bit needed here */
-	writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
-	      I2C_CON_TRX, &i2c_base->con);
-
-	/* send register offset */
-	while (1) {
-		status = wait_for_pin();
-		if (status == 0 || status & I2C_STAT_NACK) {
-			i2c_error = 1;
-			goto read_exit;
-		}
-		if (status & I2C_STAT_XRDY) {
-			/* Important: have to use byte access */
-			writeb(regoffset, &i2c_base->data);
-			writew(I2C_STAT_XRDY, &i2c_base->stat);
-		}
-		if (status & I2C_STAT_ARDY) {
-			writew(I2C_STAT_ARDY, &i2c_base->stat);
-			break;
-		}
-	}
-
-	/* set slave address */
-	writew(devaddr, &i2c_base->sa);
-	/* read one byte from slave */
-	writew(1, &i2c_base->cnt);
-	/* need stop bit here */
-	writew(I2C_CON_EN | I2C_CON_MST |
-		I2C_CON_STT | I2C_CON_STP,
-		&i2c_base->con);
-
-	/* receive data */
-	while (1) {
-		status = wait_for_pin();
-		if (status == 0 || status & I2C_STAT_NACK) {
-			i2c_error = 1;
-			goto read_exit;
-		}
-		if (status & I2C_STAT_RRDY) {
-#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
-	defined(CONFIG_OMAP44XX)
-			*value = readb(&i2c_base->data);
-#else
-			*value = readw(&i2c_base->data);
-#endif
-			writew(I2C_STAT_RRDY, &i2c_base->stat);
-		}
-		if (status & I2C_STAT_ARDY) {
-			writew(I2C_STAT_ARDY, &i2c_base->stat);
-			break;
-		}
-	}
-
-read_exit:
-	flush_fifo();
-	writew(0xFFFF, &i2c_base->stat);
-	writew(0, &i2c_base->cnt);
-	return i2c_error;
 }
 
 static void flush_fifo(void)
@@ -246,32 +161,42 @@ static void flush_fifo(void)
 
 int i2c_probe(uchar chip)
 {
-	u16 status;
+	u32 status;
 	int res = 1; /* default = fail */
 
 	if (chip == readw(&i2c_base->oa))
 		return res;
 
 	/* wait until bus not busy */
-	wait_for_bb();
+	status = wait_for_bb();
+	/* exit on BUS busy */
+	if (status & I2C_STAT_TIMEO)
+		return res;
 
 	/* try to write one byte */
 	writew(1, &i2c_base->cnt);
 	/* set slave address */
 	writew(chip, &i2c_base->sa);
 	/* stop bit needed here */
-	writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
-	       I2C_CON_STP, &i2c_base->con);
-
-	status = wait_for_pin();
-
-	/* check for ACK (!NAK) */
-	if (!(status & I2C_STAT_NACK))
-		res = 0;
-
-	/* abort transfer (force idle state) */
-	writew(0, &i2c_base->con);
-
+	writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT
+			| I2C_CON_STP, &i2c_base->con);
+	/* enough delay for the NACK bit set */
+	udelay(9000);
+
+	if (!(readw(&i2c_base->stat) & I2C_STAT_NACK)) {
+		res = 0;      /* success case */
+		flush_fifo();
+		writew(0xFFFF, &i2c_base->stat);
+	} else {
+		/* failure, clear sources*/
+		writew(0xFFFF, &i2c_base->stat);
+		/* finish up xfer */
+		writew(readw(&i2c_base->con) | I2C_CON_STP, &i2c_base->con);
+		status = wait_for_bb();
+		/* exit on BUS busy */
+		if (status & I2C_STAT_TIMEO)
+			return res;
+	}
 	flush_fifo();
 	/* don't allow any more data in... we don't want it. */
 	writew(0, &i2c_base->cnt);
@@ -281,111 +206,309 @@ int i2c_probe(uchar chip)
 
 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 {
-	int i;
+	int i2c_error = 0, i;
+	u32 status;
+
+	if ((alen > 2) || (alen < 0))
+		return 1;
 
-	if (alen > 1) {
-		printf("I2C read: addr len %d not supported\n", alen);
+	if (alen < 2) {
+		if (addr + len > 256)
+			return 1;
+	} else if (addr + len > 0xFFFF) {
 		return 1;
 	}
 
-	if (addr + len > 256) {
-		puts("I2C read: address out of range\n");
+	/* wait until bus not busy */
+	status = wait_for_bb();
+
+	/* exit on BUS busy */
+	if (status & I2C_STAT_TIMEO)
 		return 1;
+
+	writew((alen & 0xFF), &i2c_base->cnt);
+	/* set slave address */
+	writew(chip, &i2c_base->sa);
+	/* Clear the Tx & Rx FIFOs */
+	writew((readw(&i2c_base->buf) | I2C_RXFIFO_CLEAR |
+		I2C_TXFIFO_CLEAR), &i2c_base->buf);
+	/* no stop bit needed here */
+	writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_TRX |
+		I2C_CON_STT, &i2c_base->con);
+
+	/* wait for Transmit ready condition */
+	status = wait_for_status_mask(I2C_STAT_XRDY | I2C_STAT_NACK);
+
+	if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO))
+		i2c_error = 1;
+
+	if (!i2c_error) {
+		if (status & I2C_STAT_XRDY) {
+			switch (alen) {
+			case 2:
+				/* Send address MSByte */
+#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX)
+				writew(((addr >> 8) & 0xFF), &i2c_base->data);
+
+				/* Clearing XRDY event */
+				writew((status & I2C_STAT_XRDY),
+						&i2c_base->stat);
+				/* wait for Transmit ready condition */
+				status = wait_for_status_mask(I2C_STAT_XRDY |
+						I2C_STAT_NACK);
+
+				if (status & (I2C_STAT_NACK |
+						I2C_STAT_TIMEO)) {
+					i2c_error = 1;
+					break;
+				}
+#endif
+			case 1:
+#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX)
+				/* Send address LSByte */
+				writew((addr & 0xFF), &i2c_base->data);
+#else
+				/* Send address Short word */
+				writew((addr & 0xFFFF), &i2c_base->data);
+#endif
+				/* Clearing XRDY event */
+				writew((status & I2C_STAT_XRDY),
+					&i2c_base->stat);
+				/*wait for Transmit ready condition */
+				status = wait_for_status_mask(I2C_STAT_ARDY |
+						I2C_STAT_NACK);
+
+				if (status & (I2C_STAT_NACK |
+					I2C_STAT_TIMEO)) {
+					i2c_error = 1;
+					break;
+				}
+			}
+		} else
+			i2c_error = 1;
 	}
 
-	for (i = 0; i < len; i++) {
-		if (i2c_read_byte(chip, addr + i, &buffer[i])) {
-			puts("I2C read: I/O error\n");
-			i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
-			return 1;
+	/* Wait for ARDY to set */
+	status = wait_for_status_mask(I2C_STAT_ARDY | I2C_STAT_NACK
+			| I2C_STAT_AL);
+
+	if (!i2c_error) {
+		/* set slave address */
+		writew(chip, &i2c_base->sa);
+		writew((len & 0xFF), &i2c_base->cnt);
+		/* Clear the Tx & Rx FIFOs */
+		writew((readw(&i2c_base->buf) | I2C_RXFIFO_CLEAR |
+			I2C_TXFIFO_CLEAR), &i2c_base->buf);
+		/* need stop bit here */
+		writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP,
+			&i2c_base->con);
+
+		for (i = 0; i < len; i++) {
+			/* wait for Receive condition */
+			status = wait_for_status_mask(I2C_STAT_RRDY |
+				I2C_STAT_NACK);
+			if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO)) {
+				i2c_error = 1;
+				break;
+			}
+
+			if (status & I2C_STAT_RRDY) {
+#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX)
+				buffer[i] = readb(&i2c_base->data);
+#else
+				*((u16 *)&buffer[i]) =
+					readw(&i2c_base->data) & 0xFFFF;
+				i++;
+#endif
+				writew((status & I2C_STAT_RRDY),
+					&i2c_base->stat);
+				udelay(1000);
+			} else {
+				i2c_error = 1;
+			}
 		}
 	}
 
+	/* Wait for ARDY to set */
+	status = wait_for_status_mask(I2C_STAT_ARDY | I2C_STAT_NACK
+			| I2C_STAT_AL);
+
+	if (i2c_error) {
+		writew(0, &i2c_base->con);
+		return 1;
+	}
+
+	writew(I2C_CON_EN, &i2c_base->con);
+
+	while (readw(&i2c_base->stat)
+		|| (readw(&i2c_base->con) & I2C_CON_MST)) {
+		udelay(10000);
+		writew(0xFFFF, &i2c_base->stat);
+	}
+
+	writew(I2C_CON_EN, &i2c_base->con);
+	flush_fifo();
+	writew(0xFFFF, &i2c_base->stat);
+	writew(0, &i2c_base->cnt);
+
 	return 0;
 }
 
 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 {
-	int i;
-	u16 status;
-	int i2c_error = 0;
 
-	if (alen > 1) {
-		printf("I2C write: addr len %d not supported\n", alen);
+	int i, i2c_error = 0;
+	u32 status;
+	u16 writelen;
+
+	if (alen > 2)
 		return 1;
-	}
 
-	if (addr + len > 256) {
-		printf("I2C write: address 0x%x + 0x%x out of range\n",
-				addr, len);
+	if (alen < 2) {
+		if (addr + len > 256)
+			return 1;
+	} else if (addr + len > 0xFFFF) {
 		return 1;
 	}
 
 	/* wait until bus not busy */
-	wait_for_bb();
+	status = wait_for_bb();
+
+	/* exiting on BUS busy */
+	if (status & I2C_STAT_TIMEO)
+		return 1;
 
-	/* start address phase - will write regoffset + len bytes data */
-	/* TODO consider case when !CONFIG_OMAP243X/34XX/44XX */
-	writew(alen + len, &i2c_base->cnt);
+	writelen = (len & 0xFFFF) + alen;
+
+	/* two bytes */
+	writew((writelen & 0xFFFF), &i2c_base->cnt);
+	/* Clear the Tx & Rx FIFOs */
+	writew((readw(&i2c_base->buf) | I2C_RXFIFO_CLEAR |
+			I2C_TXFIFO_CLEAR), &i2c_base->buf);
 	/* set slave address */
 	writew(chip, &i2c_base->sa);
 	/* stop bit needed here */
 	writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
 		I2C_CON_STP, &i2c_base->con);
 
-	/* Send address byte */
-	status = wait_for_pin();
+	/* wait for Transmit ready condition */
+	status = wait_for_status_mask(I2C_STAT_XRDY | I2C_STAT_NACK);
 
-	if (status == 0 || status & I2C_STAT_NACK) {
+	if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO))
 		i2c_error = 1;
-		printf("error waiting for i2c address ACK (status=0x%x)\n",
-		      status);
-		goto write_exit;
-	}
 
-	if (status & I2C_STAT_XRDY) {
-		writeb(addr & 0xFF, &i2c_base->data);
-		writew(I2C_STAT_XRDY, &i2c_base->stat);
-	} else {
-		i2c_error = 1;
-		printf("i2c bus not ready for transmit (status=0x%x)\n",
-		      status);
-		goto write_exit;
-	}
+	if (!i2c_error) {
+		if (status & I2C_STAT_XRDY) {
+			switch (alen) {
+#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX)
+			case 2:
+				/* send out MSB byte */
+				writeb(((addr >> 8) & 0xFF), &i2c_base->data);
+#else
+				writeb((addr  & 0xFFFF), &i2c_base->data);
+				break;
+#endif
+				/* Clearing XRDY event */
+				writew((status & I2C_STAT_XRDY),
+					&i2c_base->stat);
+				/*waiting for Transmit ready * condition */
+				status = wait_for_status_mask(I2C_STAT_XRDY |
+						I2C_STAT_NACK);
+
+				if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO)) {
+					i2c_error = 1;
+					break;
+				}
+			case 1:
+#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX)
+				/* send out MSB byte */
+				writeb((addr  & 0xFF), &i2c_base->data);
+#else
+				writew(((buffer[0] << 8) | (addr & 0xFF)),
+					&i2c_base->data);
+#endif
+			}
 
-	/* address phase is over, now write data */
-	for (i = 0; i < len; i++) {
-		status = wait_for_pin();
+			/* Clearing XRDY event */
+			writew((status & I2C_STAT_XRDY), &i2c_base->stat);
+		}
+
+		/* waiting for Transmit ready condition */
+		status = wait_for_status_mask(I2C_STAT_XRDY | I2C_STAT_NACK);
 
-		if (status == 0 || status & I2C_STAT_NACK) {
+		if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO))
 			i2c_error = 1;
-			printf("i2c error waiting for data ACK (status=0x%x)\n",
-					status);
-			goto write_exit;
+
+		if (!i2c_error) {
+			for (i = ((alen > 1) ? 0 : 1); i < len; i++) {
+				if (status & I2C_STAT_XRDY) {
+#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX)
+					writeb((buffer[i] & 0xFF),
+						&i2c_base->data);
+#else
+					writew((((buffer[i] << 8) |
+					buffer[i + 1]) & 0xFFFF),
+						&i2c_base->data);
+					i++;
+#endif
+				} else
+					i2c_error = 1;
+					/* Clearing XRDY event */
+					writew((status & I2C_STAT_XRDY),
+						&i2c_base->stat);
+					/* waiting for XRDY condition */
+					status = wait_for_status_mask(
+						I2C_STAT_XRDY |
+						I2C_STAT_ARDY |
+						I2C_STAT_NACK);
+					if (status & (I2C_STAT_NACK |
+						I2C_STAT_TIMEO)) {
+						i2c_error = 1;
+						break;
+					}
+					if (status & I2C_STAT_ARDY)
+						break;
+			}
 		}
+	}
 
-		if (status & I2C_STAT_XRDY) {
-			writeb(buffer[i], &i2c_base->data);
-			writew(I2C_STAT_XRDY, &i2c_base->stat);
-		} else {
-			i2c_error = 1;
-			printf("i2c bus not ready for Tx (i=%d)\n", i);
-			goto write_exit;
+	status = wait_for_status_mask(I2C_STAT_ARDY | I2C_STAT_NACK |
+				I2C_STAT_AL);
+
+	if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO))
+		i2c_error = 1;
+
+	if (i2c_error) {
+		writew(0, &i2c_base->con);
+		return 1;
+	}
+
+	if (!i2c_error) {
+		int eout = 200;
+
+		writew(I2C_CON_EN, &i2c_base->con);
+		while ((status = readw(&i2c_base->stat)) ||
+				(readw(&i2c_base->con) & I2C_CON_MST)) {
+			udelay(1000);
+			/* have to read to clear intrrupt */
+			writew(0xFFFF, &i2c_base->stat);
+			if (--eout == 0)
+				/* better leave with error than hang */
+				break;
 		}
 	}
 
-write_exit:
 	flush_fifo();
 	writew(0xFFFF, &i2c_base->stat);
-	return i2c_error;
+	writew(0, &i2c_base->cnt);
+	return 0;
 }
 
-static void wait_for_bb(void)
+static u32 wait_for_bb(void)
 {
 	int timeout = I2C_TIMEOUT;
-	u16 stat;
+	u32 stat;
 
-	writew(0xFFFF, &i2c_base->stat);	/* clear current interrupts...*/
 	while ((stat = readw(&i2c_base->stat) & I2C_STAT_BB) && timeout--) {
 		writew(stat, &i2c_base->stat);
 		udelay(1000);
@@ -394,30 +517,28 @@ static void wait_for_bb(void)
 	if (timeout <= 0) {
 		printf("timed out in wait_for_bb: I2C_STAT=%x\n",
 			readw(&i2c_base->stat));
+		stat |= I2C_STAT_TIMEO;
 	}
 	writew(0xFFFF, &i2c_base->stat);	 /* clear delayed stuff*/
+	return stat;
 }
 
-static u16 wait_for_pin(void)
+static u32 wait_for_status_mask(u16 mask)
 {
-	u16 status;
+	u32 status;
 	int timeout = I2C_TIMEOUT;
 
 	do {
 		udelay(1000);
 		status = readw(&i2c_base->stat);
-	} while (!(status &
-		   (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
-		    I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
-		    I2C_STAT_AL)) && timeout--);
+	} while (!(status & mask) && timeout--);
 
 	if (timeout <= 0) {
-		printf("timed out in wait_for_pin: I2C_STAT=%x\n",
+		printf("timed out in wait_for_status_mask: I2C_STAT=%x\n",
 			readw(&i2c_base->stat));
 		writew(0xFFFF, &i2c_base->stat);
-		status = 0;
+		status |= I2C_STAT_TIMEO;
 	}
-
 	return status;
 }
 
diff --git a/drivers/i2c/omap24xx_i2c.h b/drivers/i2c/omap24xx_i2c.h
index 1f38c23..9a0b126 100644
--- a/drivers/i2c/omap24xx_i2c.h
+++ b/drivers/i2c/omap24xx_i2c.h
@@ -60,7 +60,9 @@
 /* I2C Buffer Configuration Register (I2C_BUF): */
 
 #define I2C_BUF_RDMA_EN		(1 << 15) /* Receive DMA channel enable */
+#define I2C_RXFIFO_CLEAR	(1 << 14) /* RX FIFO Clear */
 #define I2C_BUF_XDMA_EN		(1 << 7)  /* Transmit DMA channel enable */
+#define I2C_TXFIFO_CLEAR	(1 << 6)  /* TX FIFO clear */
 
 /* I2C Configuration Register (I2C_CON): */