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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>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
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 v3 1/3] i2c: imx: Fix reset of I2SR_IAL flag
Date: Tue, 6 Oct 2020 12:51:33 +0200
Message-ID: <20201006105135.28985-2-ceggers@arri.de> (raw)
In-Reply-To: <20201006105135.28985-1-ceggers@arri.de>

According to the "VFxxx Controller Reference Manual" (and the comment
block starting at line 97), Vybrid requires writing a one for clearing
an interrupt flag. Syncing the method for clearing I2SR_IIF in
i2c_imx_isr().

Signed-off-by: Christian Eggers <ceggers@arri.de>
Cc: stable@vger.kernel.org
---
 drivers/i2c/busses/i2c-imx.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 0ab5381aa012..745f4071155a 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -412,6 +412,19 @@ static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx)
 	dma->chan_using = NULL;
 }
 
+static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx, unsigned int bits)
+{
+	unsigned int temp;
+
+	/*
+	 * i2sr_clr_opcode is the value to clear all interrupts.
+	 * Here we want to clear only <bits>, so we write
+	 * ~i2sr_clr_opcode with just <bits> toggled.
+	 */
+	temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits;
+	imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
+}
+
 static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy, bool atomic)
 {
 	unsigned long orig_jiffies = jiffies;
@@ -424,8 +437,7 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy, bool a
 
 		/* check for arbitration lost */
 		if (temp & I2SR_IAL) {
-			temp &= ~I2SR_IAL;
-			imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
+			i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
 			return -EAGAIN;
 		}
 
@@ -623,9 +635,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 	if (temp & I2SR_IIF) {
 		/* save status register */
 		i2c_imx->i2csr = temp;
-		temp &= ~I2SR_IIF;
-		temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
-		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
+		i2c_imx_clear_irq(i2c_imx, I2SR_IIF);
 		wake_up(&i2c_imx->queue);
 		return IRQ_HANDLED;
 	}
-- 
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


  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-02 15:23 [PATCH v2 0/3] i2c: imx: Fix handling of arbitration loss Christian Eggers
2020-10-02 15:23 ` [PATCH v2 1/3] i2c: imx: Fix reset of I2SR_IAL flag Christian Eggers
2020-10-05  8:05   ` Krzysztof Kozlowski
2020-10-06  6:05   ` Uwe Kleine-König
2020-10-06 10:51     ` [PATCH v3 0/3] i2c: imx: Fix handling of arbitration loss Christian Eggers
2020-10-06 10:51       ` Christian Eggers [this message]
2020-10-06 12:06         ` [PATCH v3 1/3] i2c: imx: Fix reset of I2SR_IAL flag David Laight
2020-10-06 12:30           ` Christian Eggers
2020-10-06 12:46           ` Uwe Kleine-König
2020-10-06 12:52             ` David Laight
2020-10-06 10:51       ` [PATCH v3 2/3] i2c: imx: Check for I2SR_IAL after every byte Christian Eggers
2020-10-06 10:51       ` [PATCH v3 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost Christian Eggers
2020-10-02 15:23 ` [PATCH v2 2/3] i2c: imx: Check for I2SR_IAL after every byte Christian Eggers
2020-10-05  8:07   ` Krzysztof Kozlowski
2020-10-05  9:25     ` Christian Eggers
2020-10-02 15:23 ` [PATCH v2 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost Christian Eggers
2020-10-05  8:16   ` Krzysztof Kozlowski

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