From: Esben Haabendal <eha-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org> To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linuxppc-dev-mnsaURCQ41sdnm+yROfE0A@public.gmane.org Subject: [PATCH v2] i2c-mpc: generate START condition after STOP caused by read i2c_msg Date: Tue, 19 May 2009 07:22:10 +0200 [thread overview] Message-ID: <4A124202.4010201@doredevelopment.dk> (raw) This fixes MAL (arbitration lost) bug caused by illegal use of RSTA (repeated START) after STOP condition generated after last byte of reads. With this patch, it is possible to do an i2c_transfer() with additional i2c_msg's following the I2C_M_RD messages. It still needs to be resolved if it is possible to fix this issue by removing the STOP condition after reads in a robust way. Signed-off-by: Esben Haabendal <eha-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org> --- drivers/i2c/busses/i2c-mpc.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c index 4af5c09..0199f9a 100644 --- a/drivers/i2c/busses/i2c-mpc.c +++ b/drivers/i2c/busses/i2c-mpc.c @@ -456,17 +456,22 @@ static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) } for (i = 0; ret >= 0 && i < num; i++) { + int restart = i; pmsg = &msgs[i]; dev_dbg(i2c->dev, "Doing %s %d bytes to 0x%02x - %d of %d messages\n", pmsg->flags & I2C_M_RD ? "read" : "write", pmsg->len, pmsg->addr, i + 1, num); + if (i > 0 && ((pmsg - 1)->flags & I2C_M_RD)) + restart = 0; if (pmsg->flags & I2C_M_RD) ret = - mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i); + mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, + restart); else ret = - mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i); + mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, + restart); } mpc_i2c_stop(i2c); return (ret < 0) ? ret : num; -- 1.6.3.1
WARNING: multiple messages have this Message-ID (diff)
From: Esben Haabendal <eha@doredevelopment.dk> To: linux-i2c@vger.kernel.org, linuxppc-dev@ozlabs.org Subject: [PATCH v2] i2c-mpc: generate START condition after STOP caused by read i2c_msg Date: Tue, 19 May 2009 07:22:10 +0200 [thread overview] Message-ID: <4A124202.4010201@doredevelopment.dk> (raw) This fixes MAL (arbitration lost) bug caused by illegal use of RSTA (repeated START) after STOP condition generated after last byte of reads. With this patch, it is possible to do an i2c_transfer() with additional i2c_msg's following the I2C_M_RD messages. It still needs to be resolved if it is possible to fix this issue by removing the STOP condition after reads in a robust way. Signed-off-by: Esben Haabendal <eha@doredevelopment.dk> --- drivers/i2c/busses/i2c-mpc.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c index 4af5c09..0199f9a 100644 --- a/drivers/i2c/busses/i2c-mpc.c +++ b/drivers/i2c/busses/i2c-mpc.c @@ -456,17 +456,22 @@ static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) } for (i = 0; ret >= 0 && i < num; i++) { + int restart = i; pmsg = &msgs[i]; dev_dbg(i2c->dev, "Doing %s %d bytes to 0x%02x - %d of %d messages\n", pmsg->flags & I2C_M_RD ? "read" : "write", pmsg->len, pmsg->addr, i + 1, num); + if (i > 0 && ((pmsg - 1)->flags & I2C_M_RD)) + restart = 0; if (pmsg->flags & I2C_M_RD) ret = - mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i); + mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, + restart); else ret = - mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i); + mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, + restart); } mpc_i2c_stop(i2c); return (ret < 0) ? ret : num; -- 1.6.3.1
next reply other threads:[~2009-05-19 5:22 UTC|newest] Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-05-19 5:22 Esben Haabendal [this message] 2009-05-19 5:22 ` [PATCH v2] i2c-mpc: generate START condition after STOP caused by read i2c_msg Esben Haabendal 2009-05-26 11:30 ` Esben Haabendal 2009-05-26 11:30 ` Esben Haabendal [not found] ` <d2b9ea600905260430i72290901p9266de4cade049c1-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2009-05-26 21:33 ` Ben Dooks 2009-05-26 21:33 ` Ben Dooks [not found] ` <20090526213351.GG23114-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org> 2009-05-28 17:17 ` Wolfram Sang 2009-05-28 17:17 ` Wolfram Sang [not found] ` <20090528171726.GE3112-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> 2009-05-28 18:43 ` Joakim Tjernlund 2009-05-28 18:43 ` Joakim Tjernlund 2009-05-28 20:10 ` Esben Haabendal [not found] ` <d2b9ea600905281310p16f47ed0i454e25bf256d3010-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2009-05-28 20:34 ` Peter Korsgaard 2009-05-28 20:34 ` Peter Korsgaard [not found] ` <87ws8155md.fsf-uXGAPMMVk8amE9MCos8gUmSdvHPH+/yF@public.gmane.org> 2009-05-28 20:41 ` Esben Haabendal 2009-05-28 20:41 ` Esben Haabendal [not found] ` <d2b9ea600905281341s24efa4e3l6277a8aa5dec5bd-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2009-05-28 21:08 ` Peter Korsgaard 2009-05-28 21:08 ` Peter Korsgaard [not found] ` <87octd5415.fsf-uXGAPMMVk8amE9MCos8gUmSdvHPH+/yF@public.gmane.org> 2009-05-28 21:22 ` Esben Haabendal 2009-05-28 21:22 ` Esben Haabendal 2009-12-03 15:09 ` Michael Lawnick 2009-12-03 15:09 ` Michael Lawnick [not found] ` <4B17D4C5.3070100-Mmb7MZpHnFY@public.gmane.org> 2009-12-03 15:29 ` Ben Dooks 2009-12-03 15:29 ` Ben Dooks [not found] ` <20091203152916.GC23152-SMNkleLxa3Z6Wcw2j4pizdi2O/JbrIOy@public.gmane.org> 2009-12-03 15:49 ` Joakim Tjernlund 2009-12-03 15:49 ` Joakim Tjernlund 2009-12-04 6:58 ` Michael Lawnick 2009-12-04 6:58 ` Michael Lawnick 2009-12-03 15:42 ` Joakim Tjernlund 2009-05-28 19:31 ` Grant Likely 2009-05-28 19:31 ` Grant Likely [not found] ` <fa686aa40905281231o26c74a13v250bcedbd066e77b-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2009-05-28 20:15 ` Esben Haabendal 2009-05-28 20:15 ` Esben Haabendal 2009-06-02 22:25 ` Ben Dooks 2009-06-02 23:12 ` Grant Likely 2009-06-02 23:12 ` Grant Likely 2009-06-03 6:01 ` Grant Likely 2009-06-03 6:01 ` Grant Likely [not found] ` <4A124202.4010201-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org> 2009-06-14 13:16 ` Ben Dooks 2009-06-14 13:16 ` Ben Dooks [not found] ` <20090614131605.GK20446-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org> 2009-06-14 14:04 ` Esben Haabendal 2009-06-14 14:04 ` Esben Haabendal
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