diff mbox

[U-Boot,13/20] keymile, common; fix i2c deblocking support

Message ID 1299591018-8944-14-git-send-email-hs@denx.de
State Changes Requested
Headers show

Commit Message

Heiko Schocher March 8, 2011, 1:30 p.m. UTC
This patch fix the i2c deblocking facility with the i2c HW-Controller.
The required delays for byte reading, the enhanced criteria for stop
the dummy read and required 5 start/stop sequences are added.

Add i2c deblocking before ivm eeprom read.

Improve i2c deblocking sequence by respecting stop hold time.

Cleaned function for deblocking. Have now one function i2c_make_abort()
available for bitbang, mpc82xx and mpc83xx harware controller.

Signed-off-by: Stefan Bigler <stefan.bigler@keymile.com>
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Heiko Schocher <hs@denx.de>
cc: Valentin Longchamp <valentin.longchamp@keymile.com>
---
 board/keymile/common/common.c |  109 ++++++++++++++++++++++++++++++-----------
 1 files changed, 80 insertions(+), 29 deletions(-)
diff mbox

Patch

diff --git a/board/keymile/common/common.c b/board/keymile/common/common.c
index 5b54e35..03d63c1 100644
--- a/board/keymile/common/common.c
+++ b/board/keymile/common/common.c
@@ -41,6 +41,7 @@ 
 #include <i2c.h>
 
 extern int i2c_soft_read_pin (void);
+extern int i2c_make_abort (void);
 
 int ivm_calc_crc (unsigned char *buf, int len)
 {
@@ -325,6 +326,9 @@  int ivm_read_eeprom (void)
 	if (buf != NULL)
 		dev_addr = simple_strtoul ((char *)buf, NULL, 16);
 
+	/* add deblocking here */
+	i2c_make_abort();
+
 	if (i2c_read(dev_addr, 0, 1, i2c_buffer, CONFIG_SYS_IVM_EEPROM_MAX_LEN) != 0) {
 		printf ("Error reading EEprom\n");
 		return -2;
@@ -334,7 +338,7 @@  int ivm_read_eeprom (void)
 }
 
 #if defined(CONFIG_SYS_I2C_INIT_BOARD)
-#define DELAY_ABORT_SEQ		62
+#define DELAY_ABORT_SEQ		62  /* @200kHz 9 clocks = 44us, 62us is ok */
 #define DELAY_HALF_PERIOD	(500 / (CONFIG_SYS_I2C_SPEED / 1000))
 
 #if defined(CONFIG_MGCOGE) || defined(CONFIG_MGCOGE2NE)
@@ -445,8 +449,21 @@  static void writeStartSeq (void)
    This I2C Deblocking mechanism was developed by Keymile in association
    with Anatech and Atmel in 1998.
  */
-static int i2c_make_abort (void)
+int i2c_make_abort (void)
 {
+
+#if defined(CONFIG_HARD_I2C) && !defined(CONFIG_MACH_SUEN3)
+	volatile immap_t *immap = (immap_t *)CONFIG_SYS_IMMR ;
+	volatile i2c8260_t *i2c	= (i2c8260_t *)&immap->im_i2c;
+
+	/* disable I2C controller first, otherwhise it thinks we want to    */
+	/* talk to the slave port...                                        */
+	i2c->i2c_i2mod &= ~0x01;
+
+	/* Set the PortPins to GPIO */
+	setports (1);
+#endif
+
 	int	scl_state = 0;
 	int	sda_state = 0;
 	int	i = 0;
@@ -473,54 +490,88 @@  static int i2c_make_abort (void)
 			writeStartSeq ();
 		}
 	}
+
+	/* respect stop setup time */
+	udelay (DELAY_ABORT_SEQ);
+	set_scl(1);
+	udelay (DELAY_ABORT_SEQ);
+	set_sda(1);
 	get_sda ();
+
+#if defined(CONFIG_HARD_I2C)
+	/* Set the PortPins back to use for I2C */
+	setports (0);
+#endif
 	return ret;
 }
 #endif
 
-/**
- * i2c_init_board - reset i2c bus. When the board is powercycled during a
- * bus transfer it might hang; for details see doc/I2C_Edge_Conditions.
- */
-void i2c_init_board(void)
-{
 #if defined(CONFIG_MPC83xx)
+static void writeStartSeq (void)
+{
+	struct fsl_i2c *dev;
+	dev = (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C_OFFSET);
+	udelay(DELAY_ABORT_SEQ);
+	out_8 (&dev->cr, (I2C_CR_MEN | I2C_CR_MSTA));
+	udelay(DELAY_ABORT_SEQ);
+	out_8 (&dev->cr, (I2C_CR_MEN));
+}
+
+int i2c_make_abort (void)
+{
 	struct fsl_i2c *dev;
 	dev = (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C_OFFSET);
 	uchar	dummy;
+	uchar   last;
+	int     nbr_read = 0;
+	int     i = 0;
+	int	    ret = 0;
 
+	/* wait after each operation to finsh with a delay */
 	out_8 (&dev->cr, (I2C_CR_MSTA));
+	udelay(DELAY_ABORT_SEQ);
 	out_8 (&dev->cr, (I2C_CR_MEN | I2C_CR_MSTA));
+	udelay(DELAY_ABORT_SEQ);
 	dummy = in_8(&dev->dr);
-	dummy = in_8(&dev->dr);
-	if (dummy != 0xff) {
-		dummy = in_8(&dev->dr);
+	udelay(DELAY_ABORT_SEQ);
+	last = in_8(&dev->dr);
+	nbr_read++;
+
+	/* do read until the last bit is 1, but stop if the full eeprom is read */
+	while (((last & 0x01) != 0x01) && (nbr_read < CONFIG_SYS_IVM_EEPROM_MAX_LEN)) {
+		udelay(DELAY_ABORT_SEQ);
+		last = in_8(&dev->dr);
+		nbr_read++;
 	}
+	if ((last & 0x01) != 0x01)
+		ret = -2;
+	if ((last != 0xff) || (nbr_read > 1))
+		printf("[INFO] i2c abort after %d bytes (0x%02x)\n", nbr_read, last);
+	udelay(DELAY_ABORT_SEQ);
 	out_8 (&dev->cr, (I2C_CR_MEN));
-	out_8 (&dev->cr, 0x00);
-	out_8 (&dev->cr, (I2C_CR_MEN));
+	udelay(DELAY_ABORT_SEQ);
+	/* clear status reg */
+	out_8 (&dev->sr, 0);
 
-#else
-#if defined(CONFIG_HARD_I2C) && !defined(MACH_TYPE_KM_KIRKWOOD)
-	volatile immap_t *immap = (immap_t *)CONFIG_SYS_IMMR ;
-	volatile i2c8260_t *i2c	= (i2c8260_t *)&immap->im_i2c;
-
-	/* disable I2C controller first, otherwhise it thinks we want to    */
-	/* talk to the slave port...                                        */
-	i2c->i2c_i2mod &= ~0x01;
+	for (i = 0; i < 5; i++) {
+		writeStartSeq ();
+	}
+	if (ret != 0) {
+		printf("[ERROR] i2c abort failed after %d bytes (0x%02x)\n", nbr_read, last);
+	}
+	return ret;
+}
 
-	/* Set the PortPins to GPIO */
-	setports (1);
 #endif
 
+/**
+ * i2c_init_board - reset i2c bus. When the board is powercycled during a
+ * bus transfer it might hang; for details see doc/I2C_Edge_Conditions.
+ */
+void i2c_init_board(void)
+{
 	/* Now run the AbortSequence() */
 	i2c_make_abort ();
-
-#if defined(CONFIG_HARD_I2C)
-	/* Set the PortPins back to use for I2C */
-	setports (0);
-#endif
-#endif
 }
 #endif
 #endif