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Commit 38ed55ca authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Wolfram Sang
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i2c: meson: improve interrupt handler and detect spurious interrupts 



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: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent e4d6bc38

drivers/i2c/busses/i2c-meson.c

+7 −4
Original line number Diff line number Diff line
@@ -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);

	}