The patch spi: tegra114: add support for hw based cs has been applied to the spi tree at https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.3 All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark >From 1bf9f3c9232d08651aa6990001e7b042c95303dc Mon Sep 17 00:00:00 2001 From: Sowjanya Komatineni <skomatineni@xxxxxxxxxx> Date: Mon, 13 May 2019 22:03:53 -0700 Subject: [PATCH] spi: tegra114: add support for hw based cs Tegra SPI controller supports both HW and SW based CS control for SPI transfers. This patch adds support for HW based CS control where CS is driven to active state during the transfer and is driven inactive at the end of the transfer directly by the HW. This patch enables the use of HW based CS only for single transfers without cs_change request. Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> --- drivers/spi/spi-tegra114.c | 39 ++++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 12 deletions(-) diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c index f47417dd9edb..0cb0932d32fd 100644 --- a/drivers/spi/spi-tegra114.c +++ b/drivers/spi/spi-tegra114.c @@ -193,6 +193,7 @@ struct tegra_spi_data { unsigned dma_buf_size; unsigned max_buf_size; bool is_curr_dma_xfer; + bool use_hw_based_cs; struct completion rx_dma_complete; struct completion tx_dma_complete; @@ -723,7 +724,9 @@ static void tegra_spi_deinit_dma_param(struct tegra_spi_data *tspi, } static u32 tegra_spi_setup_transfer_one(struct spi_device *spi, - struct spi_transfer *t, bool is_first_of_msg) + struct spi_transfer *t, + bool is_first_of_msg, + bool is_single_xfer) { struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master); u32 speed = t->speed_hz; @@ -780,11 +783,17 @@ static u32 tegra_spi_setup_transfer_one(struct spi_device *spi, if (spi->cs_gpiod) gpiod_set_value(spi->cs_gpiod, 1); - command1 |= SPI_CS_SW_HW; - if (spi->mode & SPI_CS_HIGH) - command1 |= SPI_CS_SW_VAL; - else - command1 &= ~SPI_CS_SW_VAL; + if (is_single_xfer && !(t->cs_change)) { + tspi->use_hw_based_cs = true; + command1 &= ~(SPI_CS_SW_HW | SPI_CS_SW_VAL); + } else { + tspi->use_hw_based_cs = false; + command1 |= SPI_CS_SW_HW; + if (spi->mode & SPI_CS_HIGH) + command1 |= SPI_CS_SW_VAL; + else + command1 &= ~SPI_CS_SW_VAL; + } tegra_spi_writel(tspi, 0, SPI_COMMAND2); } else { @@ -905,11 +914,14 @@ static void tegra_spi_transfer_end(struct spi_device *spi) if (spi->cs_gpiod) gpiod_set_value(spi->cs_gpiod, 0); - if (cs_val) - tspi->command1_reg |= SPI_CS_SW_VAL; - else - tspi->command1_reg &= ~SPI_CS_SW_VAL; - tegra_spi_writel(tspi, tspi->command1_reg, SPI_COMMAND1); + if (!tspi->use_hw_based_cs) { + if (cs_val) + tspi->command1_reg |= SPI_CS_SW_VAL; + else + tspi->command1_reg &= ~SPI_CS_SW_VAL; + tegra_spi_writel(tspi, tspi->command1_reg, SPI_COMMAND1); + } + tegra_spi_writel(tspi, tspi->def_command1_reg, SPI_COMMAND1); } @@ -936,16 +948,19 @@ static int tegra_spi_transfer_one_message(struct spi_master *master, struct spi_device *spi = msg->spi; int ret; bool skip = false; + int single_xfer; msg->status = 0; msg->actual_length = 0; + single_xfer = list_is_singular(&msg->transfers); list_for_each_entry(xfer, &msg->transfers, transfer_list) { u32 cmd1; reinit_completion(&tspi->xfer_completion); - cmd1 = tegra_spi_setup_transfer_one(spi, xfer, is_first_msg); + cmd1 = tegra_spi_setup_transfer_one(spi, xfer, is_first_msg, + single_xfer); if (!xfer->len) { ret = 0; -- 2.20.1
