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Subject[PATCH V3 8/9] spi: tegra114: add support for HW CS timing
Date
This patch implements set_cs_timing SPI controller method to allow
SPI client driver to configure device specific SPI CS timings.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
---
drivers/spi/spi-tegra114.c | 48 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 46 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index 732347d83366..8476a38cf4fb 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -95,8 +95,10 @@
(reg = (((val) & 0x1) << ((cs) * 8 + 5)) | \
((reg) & ~(1 << ((cs) * 8 + 5))))
#define SPI_SET_CYCLES_BETWEEN_PACKETS(reg, cs, val) \
- (reg = (((val) & 0xF) << ((cs) * 8)) | \
- ((reg) & ~(0xF << ((cs) * 8))))
+ (reg = (((val) & 0x1F) << ((cs) * 8)) | \
+ ((reg) & ~(0x1F << ((cs) * 8))))
+#define MAX_SETUP_HOLD_CYCLES 16
+#define MAX_INACTIVE_CYCLES 32

#define SPI_TRANS_STATUS 0x010
#define SPI_BLK_CNT(val) (((val) >> 0) & 0xFFFF)
@@ -206,6 +208,8 @@ struct tegra_spi_data {
u32 command1_reg;
u32 dma_control_reg;
u32 def_command1_reg;
+ u32 spi_cs_timing1;
+ u32 spi_cs_timing2;

struct completion xfer_completion;
struct spi_transfer *curr_xfer;
@@ -723,6 +727,43 @@ static void tegra_spi_deinit_dma_param(struct tegra_spi_data *tspi,
dma_release_channel(dma_chan);
}

+static void tegra_spi_set_hw_cs_timing(struct spi_device *spi, u8 setup_dly,
+ u8 hold_dly, u8 inactive_dly)
+{
+ struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
+ u32 setup_hold;
+ u32 spi_cs_timing;
+ u32 inactive_cycles;
+ u8 cs_state;
+
+ setup_dly = min_t(u8, setup_dly, MAX_SETUP_HOLD_CYCLES);
+ hold_dly = min_t(u8, hold_dly, MAX_SETUP_HOLD_CYCLES);
+ if (setup_dly && hold_dly) {
+ setup_hold = SPI_SETUP_HOLD(setup_dly - 1, hold_dly - 1);
+ spi_cs_timing = SPI_CS_SETUP_HOLD(tspi->spi_cs_timing1,
+ spi->chip_select,
+ setup_hold);
+ if (tspi->spi_cs_timing1 != spi_cs_timing) {
+ tspi->spi_cs_timing1 = spi_cs_timing;
+ tegra_spi_writel(tspi, spi_cs_timing, SPI_CS_TIMING1);
+ }
+ }
+
+ inactive_cycles = min_t(u8, inactive_dly, MAX_INACTIVE_CYCLES);
+ if (inactive_cycles)
+ inactive_cycles--;
+ cs_state = inactive_cycles ? 0 : 1;
+ spi_cs_timing = tspi->spi_cs_timing2;
+ SPI_SET_CS_ACTIVE_BETWEEN_PACKETS(spi_cs_timing, spi->chip_select,
+ cs_state);
+ SPI_SET_CYCLES_BETWEEN_PACKETS(spi_cs_timing, spi->chip_select,
+ inactive_cycles);
+ if (tspi->spi_cs_timing2 != spi_cs_timing) {
+ tspi->spi_cs_timing2 = spi_cs_timing;
+ tegra_spi_writel(tspi, spi_cs_timing, SPI_CS_TIMING2);
+ }
+}
+
static u32 tegra_spi_setup_transfer_one(struct spi_device *spi,
struct spi_transfer *t, bool is_first_of_msg,
bool is_single_xfer)
@@ -1232,6 +1273,7 @@ static int tegra_spi_probe(struct platform_device *pdev)
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
master->setup = tegra_spi_setup;
master->transfer_one_message = tegra_spi_transfer_one_message;
+ master->set_cs_timing = tegra_spi_set_hw_cs_timing;
master->num_chipselect = MAX_CHIP_SELECT;
master->auto_runtime_pm = true;
bus_num = of_alias_get_id(pdev->dev.of_node, "spi");
@@ -1307,6 +1349,8 @@ static int tegra_spi_probe(struct platform_device *pdev)
reset_control_deassert(tspi->rst);
tspi->def_command1_reg = SPI_M_S;
tegra_spi_writel(tspi, tspi->def_command1_reg, SPI_COMMAND1);
+ tspi->spi_cs_timing1 = tegra_spi_readl(tspi, SPI_CS_TIMING1);
+ tspi->spi_cs_timing2 = tegra_spi_readl(tspi, SPI_CS_TIMING2);
pm_runtime_put(&pdev->dev);
ret = request_threaded_irq(tspi->irq, tegra_spi_isr,
tegra_spi_isr_thread, IRQF_ONESHOT,
--
2.7.4
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