linux-kernel - [PATCH v2 06/17] i2c: omap: improve 1p153 errata handling

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Message-Id: <1339691067-919-7-git-send-email-balbi@ti.com>
Date:	Thu, 14 Jun 2012 19:24:16 +0300
From:	Felipe Balbi <balbi@...com>
To:	ben-linux@...ff.org
Cc:	Tony Lindgren <tony@...mide.com>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	Russell King <linux@....linux.org.uk>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	Linux ARM Kernel Mailing List 
	<linux-arm-kernel@...ts.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	w.sang@...gutronix.de, Shubhrajyoti Datta <shubhrajyoti@...com>,
	Felipe Balbi <balbi@...com>
Subject: [PATCH v2 06/17] i2c: omap: improve 1p153 errata handling

Make it not depend on ISR's local variables
in order to make it easier to re-factor the
transmit data loop.

Signed-off-by: Felipe Balbi <balbi@...com>
---
 drivers/i2c/busses/i2c-omap.c |   45 ++++++++++++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 12 deletions(-)

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 0661ca1..41cec32 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -768,21 +768,24 @@ omap_i2c_omap1_isr(int this_irq, void *dev_id)
  * data to DATA_REG. Otherwise some data bytes can be lost while transferring
  * them from the memory to the I2C interface.
  */
-static int errata_omap3_1p153(struct omap_i2c_dev *dev, u16 *stat, int *err)
+static int errata_omap3_1p153(struct omap_i2c_dev *dev)
 {
 	unsigned long timeout = 10000;
+	u16 stat;
 
-	while (--timeout && !(*stat & OMAP_I2C_STAT_XUDF)) {
-		if (*stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
+	do {
+		stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
+		if (stat & OMAP_I2C_STAT_XUDF)
+			break;
+
+		if (stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
 			omap_i2c_ack_stat(dev, (OMAP_I2C_STAT_XRDY |
 					OMAP_I2C_STAT_XDR));
-			*err |= OMAP_I2C_STAT_XUDF;
 			return -ETIMEDOUT;
 		}
 
 		cpu_relax();
-		*stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
-	}
+	} while (--timeout);
 
 	if (!timeout) {
 		dev_err(dev->dev, "timeout waiting on XUDF bit\n");
@@ -946,9 +949,18 @@ complete:
 					}
 				}
 
-				if ((dev->errata & I2C_OMAP3_1P153) &&
-				    errata_omap3_1p153(dev, &stat, &err))
-					goto complete;
+				if (dev->errata & I2C_OMAP3_1P153) {
+					int ret;
+
+					ret = errata_omap3_1p153(dev);
+					stat = omap_i2c_read_reg(dev,
+							OMAP_I2C_STAT_REG);
+
+					if (ret < 0) {
+						err |= OMAP_I2C_STAT_XUDF;
+						goto complete;
+					}
+				}
 
 				omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
 			}
@@ -986,9 +998,18 @@ complete:
 					}
 				}
 
-				if ((dev->errata & I2C_OMAP3_1P153) &&
-				    errata_omap3_1p153(dev, &stat, &err))
-					goto complete;
+				if (dev->errata & I2C_OMAP3_1P153) {
+					int ret;
+
+					ret = errata_omap3_1p153(dev);
+					stat = omap_i2c_read_reg(dev,
+							OMAP_I2C_STAT_REG);
+
+					if (ret < 0) {
+						err |= OMAP_I2C_STAT_XUDF;
+						goto complete;
+					}
+				}
 
 				omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
 			}
-- 
1.7.10.4

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