The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 384a9565f70a876c2e78e58c5ca0bbf0547e4f6d Mon Sep 17 00:00:00 2001

From: Christian Eggers ceggers@arri.de Date: Fri, 9 Oct 2020 13:03:18 +0200 Subject: [PATCH] i2c: imx: Fix reset of I2SR_IAL flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

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 Fixes: 4b775022f6fd ("i2c: imx: add struct to hold more configurable quirks") Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Acked-by: Oleksij Rempel o.rempel@pengutronix.de Cc: stable@vger.kernel.org Signed-off-by: Wolfram Sang wsa@kernel.org

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index c98529c76348..39e98d216016 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. This is required because i.MX needs W0C and Vybrid uses W1C. + */ + 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; }

@@ -469,7 +481,7 @@ static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx, bool atomic) */ readb_poll_timeout_atomic(addr, regval, regval & I2SR_IIF, 5, 1000 + 100); i2c_imx->i2csr = regval; - imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR); + i2c_imx_clear_irq(i2c_imx, I2SR_IIF | I2SR_IAL); } else { wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10); } @@ -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; }