Groups > linux.kernel > #1291901

[PATCH v3] i2c: mediatek: fix i2c multi transfer issue in high speed mode

Path	csiph.com!news.mixmin.net!weretis.net!feeder1.news.weretis.net!news.roellig-ltd.de!open-news-network.org!border2.nntp.ams1.giganews.com!nntp.giganews.com!news.panservice.it!diesel.cu.mi.it!bofh.it!news.nic.it!robomod
From	Liguo Zhang <liguo.zhang@mediatek.com>
Newsgroups	linux.kernel
Subject	[PATCH v3] i2c: mediatek: fix i2c multi transfer issue in high speed mode
Date	Tue, 15 Dec 2015 08:30:01 +0100
Message-ID	<qFSdz-U2-5@gated-at.bofh.it> (permalink)
X-Original-To	Wolfram Sang <wsa@the-dreams.de>
X-Listener-Flag	11101
X-Mailer	git-send-email 1.8.1.1.dirty
MIME-Version	1.0
Content-Type	text/plain
X-Mtk	N
Sender	robomod@news.nic.it
List-ID	<linux-kernel.vger.kernel.org>
X-Mailing-List	linux-kernel@vger.kernel.org
Approved	robomod@news.nic.it
Lines	72
Organization	linux.* mail to news gateway
X-Original-Cc	<srv_heupstream@mediatek.com>, Matthias Brugger <matthias.bgg@gmail.com>, Eddie Huang <eddie.huang@mediatek.com>, Xudong Chen <xudong.chen@mediatek.com>, Sascha Hauer <s.hauer@pengutronix.de>, <linux-i2c@vger.kernel.org>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-mediatek@lists.infradead.org>, Liguo Zhang <liguo.zhang@mediatek.com>
X-Original-Date	Tue, 15 Dec 2015 15:22:26 +0800
X-Original-Message-ID	<1450164146-28995-1-git-send-email-liguo.zhang@mediatek.com>
X-Original-Sender	linux-kernel-owner@vger.kernel.org
Xref	csiph.com linux.kernel:1291901

Show key headers only | View raw

For mt8173 platform with auto restart support, when doing i2c multi
transfer in high speed, we should ignore the first restart irq after
the master code, otherwise the first transfer will be discarded.

Signed-off-by: Liguo Zhang <liguo.zhang@mediatek.com>
Reviewed-by: Eddie Huang <eddie.huang@mediatek.com>
---
Change in v3:
ignore the first restart irq after the master code when doing
i2c multi transfer in high speed.

change in v2:
fix i2c checkpatch error.

---
 drivers/i2c/busses/i2c-mt65xx.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index dc4aac6..aec8e6c 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -155,6 +155,7 @@ struct mtk_i2c {
 	u16 timing_reg;
 	u16 high_speed_reg;
 	unsigned char auto_restart;
+	bool ignore_restart_irq;
 	const struct mtk_i2c_compatible *dev_comp;
 };
 
@@ -539,6 +540,14 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap,
 		}
 	}
 
+	if (i2c->auto_restart && num >= 2 && i2c->speed_hz > MAX_FS_MODE_SPEED)
+		/* ignore the first restart irq after the master code,
+		 * otherwise the first transfer will be discarded.
+		 */
+		i2c->ignore_restart_irq = true;
+	else
+		i2c->ignore_restart_irq = false;
+
 	while (left_num--) {
 		if (!msgs->buf) {
 			dev_dbg(i2c->dev, "data buffer is NULL.\n");
@@ -592,8 +601,16 @@ static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
 	 * i2c->irq_stat need keep the two interrupt value.
 	 */
 	i2c->irq_stat |= intr_stat;
-	if (i2c->irq_stat & (I2C_TRANSAC_COMP | restart_flag))
-		complete(&i2c->msg_complete);
+
+	if (i2c->ignore_restart_irq && (i2c->irq_stat & restart_flag)) {
+		i2c->ignore_restart_irq = false;
+		i2c->irq_stat = 0;
+		writew(I2C_RS_MUL_CNFG | I2C_RS_MUL_TRIG | I2C_TRANSAC_START,
+		       i2c->base + OFFSET_START);
+	} else {
+		if (i2c->irq_stat & (I2C_TRANSAC_COMP | restart_flag))
+			complete(&i2c->msg_complete);
+	}
 
 	return IRQ_HANDLED;
 }
-- 
1.8.1.1.dirty

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

[PATCH v3] i2c: mediatek: fix i2c multi transfer issue in high speed mode Liguo Zhang <liguo.zhang@mediatek.com> - 2015-12-15 08:30 +0100

csiph-web