From: Wolfram Sang <wsa+renesas@sang-engineering.com> To: linux-i2c@vger.kernel.org, cerg2010cerg2010@mail.ru Cc: linux-renesas-soc@vger.kernel.org, Wolfram Sang <wsa+renesas@sang-engineering.com>, dri-devel@lists.freedesktop.org Subject: [RFT] i2c: algos: bit: prepare/unprepare before sending initial STOP Date: Fri, 15 Jun 2018 14:17:23 +0900 [thread overview] Message-ID: <20180615051723.7193-1-wsa+renesas@sang-engineering.com> (raw) Some adapters need to be prepared/unprepared before bitbanging the bus. Do this for the initial STOP, too. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> --- Ok, another idea to fix the regression. I'm not 100% sure if the placement is perfect, but it should serve well enough as a proof of concept to see if this is the actual issue. It looks promising, though. drivers/i2c/algos/i2c-algo-bit.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index 4a34f311e1ff..fab4437ecbb5 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -648,10 +648,19 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap, adap->quirks = &i2c_bit_quirk_no_clk_stretch; /* Bring bus to a known state. Looks like STOP if bus is not free yet */ + if (bit_adap->pre_xfer) { + ret = bit_adap->pre_xfer(adap); + if (ret < 0) + return ret; + } + setscl(bit_adap, 1); udelay(bit_adap->udelay); setsda(bit_adap, 1); + if (bit_adap->post_xfer) + bit_adap->post_xfer(adap); + ret = add_adapter(adap); if (ret < 0) return ret; -- 2.11.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
WARNING: multiple messages have this Message-ID (diff)
From: Wolfram Sang <wsa+renesas@sang-engineering.com> To: linux-i2c@vger.kernel.org, cerg2010cerg2010@mail.ru Cc: linux-renesas-soc@vger.kernel.org, dri-devel@lists.freedesktop.org, Wolfram Sang <wsa+renesas@sang-engineering.com> Subject: [RFT] i2c: algos: bit: prepare/unprepare before sending initial STOP Date: Fri, 15 Jun 2018 14:17:23 +0900 [thread overview] Message-ID: <20180615051723.7193-1-wsa+renesas@sang-engineering.com> (raw) Some adapters need to be prepared/unprepared before bitbanging the bus. Do this for the initial STOP, too. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> --- Ok, another idea to fix the regression. I'm not 100% sure if the placement is perfect, but it should serve well enough as a proof of concept to see if this is the actual issue. It looks promising, though. drivers/i2c/algos/i2c-algo-bit.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index 4a34f311e1ff..fab4437ecbb5 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -648,10 +648,19 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap, adap->quirks = &i2c_bit_quirk_no_clk_stretch; /* Bring bus to a known state. Looks like STOP if bus is not free yet */ + if (bit_adap->pre_xfer) { + ret = bit_adap->pre_xfer(adap); + if (ret < 0) + return ret; + } + setscl(bit_adap, 1); udelay(bit_adap->udelay); setsda(bit_adap, 1); + if (bit_adap->post_xfer) + bit_adap->post_xfer(adap); + ret = add_adapter(adap); if (ret < 0) return ret; -- 2.11.0
next reply other threads:[~2018-06-15 5:17 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-06-15 5:17 Wolfram Sang [this message] 2018-06-15 5:17 ` [RFT] i2c: algos: bit: prepare/unprepare before sending initial STOP Wolfram Sang 2018-06-15 8:25 ` Sergei Shtylyov 2018-06-15 8:25 ` Sergei Shtylyov
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