i2c: riic: Clear NACK in tend isr

commit a71e2ac1f32097fbb2beab098687a7a95c84543e upstream.

The NACKF flag should be cleared in INTRIICNAKI interrupt processing as
description in HW manual.

This issue shows up quickly when PREEMPT_RT is applied and a device is
probed that is not plugged in (like a touchscreen controller). The result
is endless interrupts that halt system boot.

Fixes: 310c18a41450 ("i2c: riic: add driver")
Cc: stable@vger.kernel.org
Reported-by: Chien Nguyen <chien.nguyen.eb@rvc.renesas.com>
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
index c811af4c8d817bcf353068bf2e3f95f56953155b..e420b41a34bae39ac8ef3f8a7725efe19d9ac71a 100644 (file)
--- a/drivers/i2c/busses/i2c-riic.c
+++ b/drivers/i2c/busses/i2c-riic.c
@@ -212,6 +212,7 @@ static irqreturn_t riic_tend_isr(int irq, void *data)
        if (readb(riic->base + RIIC_ICSR2) & ICSR2_NACKF) {
                /* We got a NACKIE */
                readb(riic->base + RIIC_ICDRR); /* dummy read */
+               riic_clear_set_bit(riic, ICSR2_NACKF, 0, RIIC_ICSR2);
                riic->err = -ENXIO;
        } else if (riic->bytes_left) {
                return IRQ_NONE;