mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-10-05 16:37:50 +00:00
Code Issues Releases Wiki Activity

spi/tegra-slink: Factor runtime PM out into transfer prepare/unprepare

Browse source 
Currently the tegra slink driver acquires a runtime PM reference for the
duration of each transfer. This may result in the IP being powered down
between transfers which would be at best wasteful. Instead it is better
to do this in the callbacks that are generated before and after starting
a series of transfers, keeping the IP powered throughout.

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
This commit is contained in:
Mark Brown 2013-07-27 12:34:24 +01:00
parent 9f178c22fb
commit bafe886936
1 changed files with 25 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

32
drivers/spi/spi-tegra20-slink.c
View file

@ -824,6 +824,20 @@ static int tegra_slink_setup(struct spi_device *spi)
return 0;
}
static int tegra_slink_prepare_transfer(struct spi_master *spi)
{
struct tegra_slink_data *tspi = spi_master_get_devdata(spi);
int ret;
ret = pm_runtime_get_sync(tspi->dev);
if (ret < 0) {
dev_err(tspi->dev, "runtime PM get failed: %d\n", ret);
return ret;
}
return ret;
}
static int tegra_slink_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
@ -836,11 +850,6 @@ static int tegra_slink_transfer_one_message(struct spi_master *master,
msg->status = 0;
msg->actual_length = 0;
ret = pm_runtime_get_sync(tspi->dev);
if (ret < 0) {
dev_err(tspi->dev, "runtime get failed: %d\n", ret);
goto done;
}
single_xfer = list_is_singular(&msg->transfers);
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
@ -878,13 +887,20 @@ static int tegra_slink_transfer_one_message(struct spi_master *master,
exit:
tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
pm_runtime_put(tspi->dev);
done:
msg->status = ret;
spi_finalize_current_message(master);
return ret;
}
static int tegra_slink_unprepare_transfer(struct spi_master *spi)
{
struct tegra_slink_data *tspi = spi_master_get_devdata(spi);
pm_runtime_put(tspi->dev);
return 0;
}
static irqreturn_t handle_cpu_based_xfer(struct tegra_slink_data *tspi)
{
struct spi_transfer *t = tspi->curr_xfer;
@ -1085,7 +1101,9 @@ static int tegra_slink_probe(struct platform_device *pdev)
/* the spi->mode bits understood by this driver: */
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
master->setup = tegra_slink_setup;
master->prepare_transfer_hardware = tegra_slink_prepare_transfer;
master->transfer_one_message = tegra_slink_transfer_one_message;
master->unprepare_transfer_hardware = tegra_slink_unprepare_transfer;
master->num_chipselect = MAX_CHIP_SELECT;
master->bus_num = -1;