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From: Addy Ke <addy.ke@rock-chips.com>
To: wsa@the-dreams.de, max.schwarz@online.de, heiko@sntech.de,
	olof@lixom.net, dianders@chromium.org
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, cf@rock-chips.com,
	xjq@rock-chips.com, huangtao@rock-chips.com, zyw@rock-chips.com,
	yzq@rock-chips.com, hj@rock-chips.com, kever.yang@rock-chips.com,
	hl@rock-chips.com, caesar.wang@rock-chips.com,
	zhengsq@rock-chips.com, Addy Ke <addy.ke@rock-chips.com>
Subject: [PATCH] i2c: rk3x: fix bug that cause transfer fails in master receive mode
Date: Fri, 22 Aug 2014 01:50:57 +0800	[thread overview]
Message-ID: <1408643457-7126-1-git-send-email-addy.ke@rock-chips.com> (raw)

In rk3x SOC, the I2C controller can receive/transmit up to 32 bytes data
in one transaction, so the size of data to be write/read to/from
TXDATAx/RXDATAx must be less than or equal 32 bytes at a time.

Test on pinky board, elan receive 158 bytes data.

Signed-off-by: Addy Ke <addy.ke@rock-chips.com>
---
 drivers/i2c/busses/i2c-rk3x.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index 69e1185..dc0aa64 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -323,6 +323,9 @@ static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd)
 	/* ack interrupt */
 	i2c_writel(i2c, REG_INT_MBRF, REG_IPD);
 
+	/* Can only handle a maximum of 32 bytes at a time */
+	len = (len > 32) ? 32 : len;
+
 	/* read the data from receive buffer */
 	for (i = 0; i < len; ++i) {
 		if (i % 4 == 0)
-- 
1.8.3.2

             reply	other threads:[~2014-08-21 17:50 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-21 17:50 Addy Ke [this message]
2014-08-21 18:04 ` [PATCH] i2c: rk3x: fix bug that cause transfer fails in master receive mode Sergei Shtylyov
     [not found]   ` <53F634AF.1010303-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org>
2014-08-21 18:17     ` Wolfram Sang
2014-08-21 18:54       ` Max Schwarz
2014-08-21 20:12         ` Wolfram Sang

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