提交 a74c313a 编写于 作者: C Chris Packham 提交者: Wolfram Sang

i2c: mpc: Use atomic read and fix break condition

Maxime points out that the polling code in mpc_i2c_isr should use the
_atomic API because it is called in an irq context and that the
behaviour of the MCF bit is that it is 1 when the byte transfer is
complete. All of this means the original code was effectively a
udelay(100).

Fix this by using readb_poll_timeout_atomic() and removing the negation
of the break condition.

Fixes: 4a8ac5e4 ("i2c: mpc: Poll for MCF")
Reported-by: NMaxime Bizon <mbizon@freebox.fr>
Signed-off-by: NChris Packham <chris.packham@alliedtelesis.co.nz>
Tested-by: NMaxime Bizon <mbizon@freebox.fr>
Signed-off-by: NWolfram Sang <wsa@kernel.org>
上级 b503de23
......@@ -636,7 +636,7 @@ static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
status = readb(i2c->base + MPC_I2C_SR);
if (status & CSR_MIF) {
/* Wait up to 100us for transfer to properly complete */
readb_poll_timeout(i2c->base + MPC_I2C_SR, status, !(status & CSR_MCF), 0, 100);
readb_poll_timeout_atomic(i2c->base + MPC_I2C_SR, status, status & CSR_MCF, 0, 100);
writeb(0, i2c->base + MPC_I2C_SR);
mpc_i2c_do_intr(i2c, status);
return IRQ_HANDLED;
......
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