From: Christian Eggers <ceggers@arri.de>
To: Oleksij Rempel <linux@rempel-privat.de>,
Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>,
NXP Linux Team <linux-imx@nxp.com>, <linux-i2c@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>,
Christian Eggers <ceggers@arri.de>, <stable@vger.kernel.org>
Subject: [PATCH 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost
Date: Thu, 17 Sep 2020 14:20:29 +0200 [thread overview]
Message-ID: <20200917122029.11121-4-ceggers@arri.de> (raw)
In-Reply-To: <20200917122029.11121-1-ceggers@arri.de>
If arbitration is lost, the master automatically changes to slave mode.
I2SR_IBB may or may not be reset by hardware. Raising a STOP condition
by resetting I2CR_MSTA has no effect and will not clear I2SR_IBB.
So calling i2c_imx_bus_busy() is not required and would busy-wait until
timeout.
Signed-off-by: Christian Eggers <ceggers@arri.de>
Cc: stable@vger.kernel.org # Requires trival backporting, simple remove the
# 3rd argument from the calls to i2c_imx_bus_busy().
---
drivers/i2c/busses/i2c-imx.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 9d9b668ec7f2..c52fe20d74c9 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -608,6 +608,8 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic)
/* Stop I2C transaction */
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
+ if (!(temp & I2CR_MSTA))
+ i2c_imx->stopped = 1;
temp &= ~(I2CR_MSTA | I2CR_MTX);
if (i2c_imx->dma)
temp &= ~I2CR_DMAEN;
@@ -773,9 +775,12 @@ static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx,
*/
dev_dbg(dev, "<%s> clear MSTA\n", __func__);
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
+ if (!(temp & I2CR_MSTA))
+ i2c_imx->stopped = 1;
temp &= ~(I2CR_MSTA | I2CR_MTX);
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
- i2c_imx_bus_busy(i2c_imx, 0, false);
+ if (!i2c_imx->stopped)
+ i2c_imx_bus_busy(i2c_imx, 0, false);
} else {
/*
* For i2c master receiver repeat restart operation like:
@@ -900,9 +905,12 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs,
dev_dbg(&i2c_imx->adapter.dev,
"<%s> clear MSTA\n", __func__);
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
+ if (!(temp & I2CR_MSTA))
+ i2c_imx->stopped = 1;
temp &= ~(I2CR_MSTA | I2CR_MTX);
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
- i2c_imx_bus_busy(i2c_imx, 0, atomic);
+ if (!i2c_imx->stopped)
+ i2c_imx_bus_busy(i2c_imx, 0, atomic);
} else {
/*
* For i2c master receiver repeat restart operation like:
--
Christian Eggers
Embedded software developer
Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918
Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477
Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler
next prev parent reply other threads:[~2020-09-17 12:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 12:20 [PATCH 0/3] i2c: imx: Fix handling of arbitration loss Christian Eggers
2020-09-17 12:20 ` [PATCH 1/3] i2c: imx: Fix reset of I2SR_IAL flag Christian Eggers
2020-09-17 14:02 ` Uwe Kleine-König
2020-09-17 14:13 ` Christian Eggers
2020-09-25 8:11 ` Uwe Kleine-König
2020-10-02 8:01 ` Christian Eggers
2020-10-02 10:21 ` Uwe Kleine-König
2020-09-17 12:20 ` [PATCH 2/3] i2c: imx: Check for I2SR_IAL after every byte Christian Eggers
2020-09-17 12:20 ` Christian Eggers [this message]
2020-09-25 7:03 ` [PATCH 0/3] i2c: imx: Fix handling of arbitration loss Oleksij Rempel
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