Commit 900aed24 authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Wolfram Sang
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i2c: tegra: Make tegra_i2c_flush_fifos() usable in atomic transfer 



The tegra_i2c_flush_fifos() shouldn't sleep in atomic transfer and jiffies
are not updating if interrupts are disabled. Let's switch to use iopoll
API helpers for register-polling. The iopoll API provides helpers for both
atomic and non-atomic cases.

Note that this patch doesn't fix any known problem because normally FIFO
is flushed at the time of starting a new transfer.

Reviewed-by: default avatarMichał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: default avatarThierry Reding <treding@nvidia.com>
Signed-off-by: default avatarDmitry Osipenko <digetx@gmail.com>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent 35baff67

drivers/i2c/busses/i2c-tegra.c

+16 −9
Original line number Diff line number Diff line
@@ -470,9 +470,9 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev) 


static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)

{

	unsigned long timeout = jiffies + HZ;

	unsigned int offset;

	u32 mask, val;

	u32 mask, val, offset, reg_offset;

	void __iomem *addr;

	int err;



	if (i2c_dev->hw->has_mst_fifo) {

		mask = I2C_MST_FIFO_CONTROL_TX_FLUSH |
@@ -488,12 +488,19 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev) 
	val |= mask;

	i2c_writel(i2c_dev, val, offset);



	while (i2c_readl(i2c_dev, offset) & mask) {

		if (time_after(jiffies, timeout)) {

			dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n");

			return -ETIMEDOUT;

		}

		usleep_range(1000, 2000);

	reg_offset = tegra_i2c_reg_addr(i2c_dev, offset);

	addr = i2c_dev->base + reg_offset;



	if (i2c_dev->is_curr_atomic_xfer)

		err = readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask),

							1000, 1000000);

	else

		err = readl_relaxed_poll_timeout(addr, val, !(val & mask),

						 1000, 1000000);



	if (err) {

		dev_err(i2c_dev->dev, "failed to flush FIFO\n");

		return err;

	}

	return 0;

}