This is a note to let you know that I've just added the patch titled i2c: imx: Fix reset of I2SR_IAL flag to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: i2c-imx-fix-reset-of-i2sr_ial-flag.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From fa4d30556883f2eaab425b88ba9904865a4d00f3 Mon Sep 17 00:00:00 2001 From: Christian Eggers <ceggers@xxxxxxx> Date: Wed, 7 Oct 2020 10:45:22 +0200 Subject: i2c: imx: Fix reset of I2SR_IAL flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Christian Eggers <ceggers@xxxxxxx> commit fa4d30556883f2eaab425b88ba9904865a4d00f3 upstream. 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@xxxxxxx> Fixes: 4b775022f6fd ("i2c: imx: add struct to hold more configurable quirks") Reviewed-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/i2c/busses/i2c-imx.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -404,6 +404,19 @@ static void i2c_imx_dma_free(struct 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 W1C and Vybrid uses W0C. + */ + 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) { unsigned long orig_jiffies = jiffies; @@ -416,8 +429,7 @@ static int i2c_imx_bus_busy(struct imx_i /* 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; } @@ -587,9 +599,7 @@ static irqreturn_t i2c_imx_isr(int irq, 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; } Patches currently in stable-queue which might be from ceggers@xxxxxxx are queue-4.19/i2c-imx-fix-reset-of-i2sr_ial-flag.patch