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i2c: meson: improve interrupt handler and detect spurious interrupts

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If state is STATE_IDLE no interrupt should occur. Return IRQ_NONE
if such a spurious interrupt is detected.
Not having to take care of STATE_IDLE later in the interrupt handler
allows to further simplify the interrupt handler in subsequent
patches of this series.

In addition move resetting REG_CTRL_START bit to the start of the
interrupt handler to ensure that the start bit is always reset.
Currently the start bit is not reset for STATE_STOP because
i2c->state is set to STATE_IDLE.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Heiner Kallweit 2017-03-25 14:10:08 +01:00 committed by Wolfram Sang
parent e4d6bc380c
commit 38ed55ca9e
1 changed files with 7 additions and 4 deletions
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11
drivers/i2c/busses/i2c-meson.c
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@ -231,12 +231,18 @@ static irqreturn_t meson_i2c_irq(int irqno, void *dev_id)
spin_lock(&i2c->lock);
meson_i2c_reset_tokens(i2c);
meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0);
ctrl = readl(i2c->regs + REG_CTRL);
dev_dbg(i2c->dev, "irq: state %d, pos %d, count %d, ctrl %08x\n",
i2c->state, i2c->pos, i2c->count, ctrl);
if (ctrl & REG_CTRL_ERROR && i2c->state != STATE_IDLE) {
if (i2c->state == STATE_IDLE) {
spin_unlock(&i2c->lock);
return IRQ_NONE;
}
if (ctrl & REG_CTRL_ERROR) {
/*
* The bit is set when the IGNORE_NAK bit is cleared
* and the device didn't respond. In this case, the
@ -279,15 +285,12 @@ static irqreturn_t meson_i2c_irq(int irqno, void *dev_id)
i2c->state = STATE_IDLE;
complete(&i2c->done);
break;
case STATE_IDLE:
break;
}
out:
if (i2c->state != STATE_IDLE) {
/* Restart the processing */
meson_i2c_write_tokens(i2c);
meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0);
meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START,
REG_CTRL_START);
}