From e69752f803b1d2465f8f3858db544cad85dccca0 Mon Sep 17 00:00:00 2001 From: Daogao Xu Date: Thu, 28 Feb 2019 15:01:10 +0800 Subject: [PATCH] i2c: add retry-process when slave NACK. [1/1] PD#SWPL-4761 Problem: When slave device is busy processing, it is unable to handle the incoming communication attempts. i2c master have to repeatedly attemp communication until the slave sends an ACK after receiving its slave address. Solution: add retry-process when slave NACK. Verify: mesonaxg_s420_32_release Change-Id: Ieb195176cac4b80e223ea6adb502ffd3bc9ef728 Signed-off-by: Daogao Xu --- drivers/amlogic/i2c/i2c-meson-master.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/amlogic/i2c/i2c-meson-master.c b/drivers/amlogic/i2c/i2c-meson-master.c index 578d73de18cb..568abf625477 100644 --- a/drivers/amlogic/i2c/i2c-meson-master.c +++ b/drivers/amlogic/i2c/i2c-meson-master.c @@ -110,6 +110,7 @@ struct meson_i2c { int count; int pos; int error; + int retries; spinlock_t lock; struct completion done; @@ -342,6 +343,8 @@ static void meson_i2c_prepare_xfer(struct meson_i2c *i2c) if (write) meson_i2c_put_data(i2c, i2c->msg->buf + i2c->pos, i2c->count); + + i2c->retries = 0; } static void meson_i2c_stop(struct meson_i2c *i2c) @@ -364,7 +367,6 @@ static irqreturn_t meson_i2c_irq(int irqno, void *dev_id) spin_lock(&i2c->lock); - meson_i2c_reset_tokens(i2c); ctrl = readl(i2c->regs + REG_CTRL); dev_dbg(i2c->dev, "irq: state %d, pos %d, count %d, ctrl %08x\n", @@ -378,12 +380,15 @@ static irqreturn_t meson_i2c_irq(int irqno, void *dev_id) * condition. */ dev_dbg(i2c->dev, "error bit set\n"); - i2c->error = -ENXIO; - i2c->state = STATE_IDLE; - complete(&i2c->done); + if (++i2c->retries >= i2c->adap.retries) { + i2c->error = -ENXIO; + i2c->state = STATE_IDLE; + complete(&i2c->done); + } goto out; } + meson_i2c_reset_tokens(i2c); switch (i2c->state) { case STATE_READ: if (i2c->count > 0) {