The initial version of `spi_set_cs_timing()` was implemented with
consideration only for clock-cycles as delay.
For cases like `CS setup` time, it's sometimes needed that micro-seconds
(or nano-seconds) are required, or sometimes even longer delays, for cases
where the device needs a little longer to start transferring that after CS
is asserted.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
drivers/spi/spi-tegra114.c | 22 ++++++++++++++++++++--
drivers/spi/spi.c | 16 ++++++++++------
include/linux/spi/spi.h | 9 ++++++---
3 files changed, 36 insertions(+), 11 deletions(-)
diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index 5ac2ceb234fc..d8db4af08fff 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -723,15 +723,31 @@ 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)
+static int tegra_spi_set_hw_cs_timing(struct spi_device *spi,
+ struct spi_delay *setup,
+ struct spi_delay *hold,
+ struct spi_delay *inactive)
{
struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
+ u8 setup_dly, hold_dly, inactive_dly;
u32 setup_hold;
u32 spi_cs_timing;
u32 inactive_cycles;
u8 cs_state;
+ if ((setup && setup->unit != SPI_DELAY_UNIT_SCK) ||
+ (hold && hold->unit != SPI_DELAY_UNIT_SCK) ||
+ (inactive && inactive != SPI_DELAY_UNIT_SCK)) {
+ dev_err(&spi->dev,
+ "Invalid delay unit %d, should be SPI_DELAY_UNIT_SCK\n",
+ SPI_DELAY_UNIT_SCK);
+ return -EINVAL;
+ }
+
+ setup_dly = setup ? setup->value : 0;
+ hold_dly = hold ? hold->value : 0;
+ inactive_dly = inactive ? inactive->value : 0;
+
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) {
@@ -758,6 +774,8 @@ static void tegra_spi_set_hw_cs_timing(struct spi_device *spi, u8 setup_dly,
tspi->spi_cs_timing2 = spi_cs_timing;
tegra_spi_writel(tspi, spi_cs_timing, SPI_CS_TIMING2);
}
+
+ return 0;
}
static u32 tegra_spi_setup_transfer_one(struct spi_device *spi,
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index c55d55acbbb0..54d00c0a26d2 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3147,15 +3147,19 @@ EXPORT_SYMBOL_GPL(spi_setup);
/**
* spi_set_cs_timing - configure CS setup, hold, and inactive delays
* @spi: the device that requires specific CS timing configuration
- * @setup: CS setup time in terms of clock count
- * @hold: CS hold time in terms of clock count
- * @inactive_dly: CS inactive delay between transfers in terms of clock count
+ * @setup: CS setup time specified via @spi_delay
+ * @hold: CS hold time specified via @spi_delay
+ * @inactive: CS inactive delay between transfers specified via @spi_delay
+ *
+ * Return: zero on success, else a negative error code.
*/
-void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold,
- u8 inactive_dly)
+int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
+ struct spi_delay *hold, struct spi_delay *inactive)
{
if (spi->controller->set_cs_timing)
- spi->controller->set_cs_timing(spi, setup, hold, inactive_dly);
+ return spi->controller->set_cs_timing(spi, setup, hold,
+ inactive);
+ return -ENOTSUPP;
}
EXPORT_SYMBOL_GPL(spi_set_cs_timing);
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index c7f90a0129be..292e752ce34a 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -517,8 +517,8 @@ struct spi_controller {
* to configure specific CS timing through spi_set_cs_timing() after
* spi_setup().
*/
- void (*set_cs_timing)(struct spi_device *spi, u8 setup_clk_cycles,
- u8 hold_clk_cycles, u8 inactive_clk_cycles);
+ int (*set_cs_timing)(struct spi_device *spi, struct spi_delay *setup,
+ struct spi_delay *hold, struct spi_delay *inactive);
/* bidirectional bulk transfers
*
@@ -1007,7 +1007,10 @@ static inline void spi_message_free(struct spi_message *m)
kfree(m);
}
-extern void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold, u8 inactive_dly);
+extern int spi_set_cs_timing(struct spi_device *spi,
+ struct spi_delay *setup,
+ struct spi_delay *hold,
+ struct spi_delay *inactive);
extern int spi_setup(struct spi_device *spi);
extern int spi_async(struct spi_device *spi, struct spi_message *message);
--
2.20.1
