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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: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
This commit is contained in:
Dmitry Osipenko 2020-09-30 01:18:44 +03:00 committed by Wolfram Sang
parent 35baff672f
commit 900aed24d3
1 changed files with 16 additions and 9 deletions
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25
drivers/i2c/busses/i2c-tegra.c
View File

@ -470,9 +470,9 @@ err_out:
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;
}