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Subject[PATCH v4 04/19] spi: sprd: convert transfer word delay to spi_delay struct
Date
The Spreadtrum SPI driver is the only user of the `word_delay` field in
the `spi_transfer` struct.

This change converts the field to use the `spi_delay` struct. This also
enforces the users to specify the delay unit to be `SPI_DELAY_UNIT_SCK`.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/spi/spi-sprd.c | 15 ++++++++++++---
include/linux/spi/spi.h | 4 ++--
2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/spi-sprd.c b/drivers/spi/spi-sprd.c
index 1b7eebb72c07..7e72e8facff7 100644
--- a/drivers/spi/spi-sprd.c
+++ b/drivers/spi/spi-sprd.c
@@ -669,11 +669,15 @@ static void sprd_spi_set_speed(struct sprd_spi *ss, u32 speed_hz)
writel_relaxed(clk_div, ss->base + SPRD_SPI_CLKD);
}

-static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
+static int sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
{
+ struct spi_delay *d = &t->word_delay;
u16 word_delay, interval;
u32 val;

+ if (d->unit != SPI_DELAY_UNIT_SCK)
+ return -EINVAL;
+
val = readl_relaxed(ss->base + SPRD_SPI_CTL7);
val &= ~(SPRD_SPI_SCK_REV | SPRD_SPI_NG_TX | SPRD_SPI_NG_RX);
/* Set default chip selection, clock phase and clock polarity */
@@ -686,7 +690,7 @@ static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
* formula as below per datasheet:
* interval time (source clock cycles) = interval * 4 + 10.
*/
- word_delay = clamp_t(u16, t->word_delay, SPRD_SPI_MIN_DELAY_CYCLE,
+ word_delay = clamp_t(u16, d->value, SPRD_SPI_MIN_DELAY_CYCLE,
SPRD_SPI_MAX_DELAY_CYCLE);
interval = DIV_ROUND_UP(word_delay - 10, 4);
ss->word_delay = interval * 4 + 10;
@@ -711,6 +715,8 @@ static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
val &= ~SPRD_SPI_DATA_LINE2_EN;

writel_relaxed(val, ss->base + SPRD_SPI_CTL7);
+
+ return 0;
}

static int sprd_spi_setup_transfer(struct spi_device *sdev,
@@ -719,13 +725,16 @@ static int sprd_spi_setup_transfer(struct spi_device *sdev,
struct sprd_spi *ss = spi_controller_get_devdata(sdev->controller);
u8 bits_per_word = t->bits_per_word;
u32 val, mode = 0;
+ int ret;

ss->len = t->len;
ss->tx_buf = t->tx_buf;
ss->rx_buf = t->rx_buf;

ss->hw_mode = sdev->mode;
- sprd_spi_init_hw(ss, t);
+ ret = sprd_spi_init_hw(ss, t);
+ if (ret)
+ return ret;

/* Set tansfer speed and valid bits */
sprd_spi_set_speed(ss, t->speed_hz);
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 9ded3f44d58e..16397b210e0c 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -759,7 +759,7 @@ extern void spi_res_release(struct spi_controller *ctlr,
* the next transfer or completing this @spi_message.
* @word_delay_usecs: microseconds to inter word delay after each word size
* (set by bits_per_word) transmission.
- * @word_delay: clock cycles to inter word delay after each word size
+ * @word_delay: inter word delay to be introduced after each word size
* (set by bits_per_word) transmission.
* @effective_speed_hz: the effective SCK-speed that was used to
* transfer this transfer. Set to 0 if the spi bus driver does
@@ -847,8 +847,8 @@ struct spi_transfer {
u8 word_delay_usecs;
u16 delay_usecs;
struct spi_delay cs_change_delay;
+ struct spi_delay word_delay;
u32 speed_hz;
- u16 word_delay;

u32 effective_speed_hz;

--
2.20.1
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