From 6c613f68aabf33385c01e949204ac5ed30887161 Mon Sep 17 00:00:00 2001 From: Alexandru Ardelean Date: Thu, 26 Sep 2019 13:51:35 +0300 Subject: [PATCH] spi: core,atmel: convert `word_delay_usecs` -> `word_delay` for spi_device This change does a conversion from the `word_delay_usecs` -> `word_delay` for the `spi_device` struct. This allows users to specify inter-word delays in other unit types (nano-seconds or clock cycles), depending on how users want. The Atmel SPI driver is the only current user of the `word_delay_usecs` field (from the `spi_device` struct). So, it needed a slight conversion to use the `word_delay` as an `spi_delay` struct. In SPI core, the only required mechanism is to update the `word_delay` information per `spi_transfer`. This requires a bit more logic than before, because it needs that both delays be converted to a common unit (nano-seconds) for comparison. Signed-off-by: Alexandru Ardelean Link: https://lore.kernel.org/r/20190926105147.7839-8-alexandru.ardelean@analog.com Signed-off-by: Mark Brown --- drivers/spi/spi-atmel.c | 26 ++++++++++++++++++++++++-- drivers/spi/spi.c | 24 ++++++++++++++++++++++-- include/linux/spi/spi.h | 7 ++----- 3 files changed, 48 insertions(+), 9 deletions(-) diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index 3ed5e663da6f..1471b049f99a 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -1149,12 +1149,31 @@ atmel_spi_pdc_interrupt(int irq, void *dev_id) return ret; } +static int atmel_word_delay_csr(struct spi_device *spi, struct atmel_spi *as) +{ + struct spi_delay *delay = &spi->word_delay; + u32 value = delay->value; + + switch (delay->unit) { + case SPI_DELAY_UNIT_NSECS: + value /= 1000; + break; + case SPI_DELAY_UNIT_USECS: + break; + default: + return -EINVAL; + } + + return (as->spi_clk / 1000000 * value) >> 5; +} + static int atmel_spi_setup(struct spi_device *spi) { struct atmel_spi *as; struct atmel_spi_device *asd; u32 csr; unsigned int bits = spi->bits_per_word; + int word_delay_csr; as = spi_master_get_devdata(spi->master); @@ -1178,11 +1197,14 @@ static int atmel_spi_setup(struct spi_device *spi) */ csr |= SPI_BF(DLYBS, 0); + word_delay_csr = atmel_word_delay_csr(spi, as); + if (word_delay_csr < 0) + return word_delay_csr; + /* DLYBCT adds delays between words. This is useful for slow devices * that need a bit of time to setup the next transfer. */ - csr |= SPI_BF(DLYBCT, - (as->spi_clk / 1000000 * spi->word_delay_usecs) >> 5); + csr |= SPI_BF(DLYBCT, word_delay_csr); asd = spi->controller_state; if (!asd) { diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index b69c14082c52..307e440dd92d 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -3281,6 +3281,26 @@ void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold, } EXPORT_SYMBOL_GPL(spi_set_cs_timing); +static int _spi_xfer_word_delay_update(struct spi_transfer *xfer, + struct spi_device *spi) +{ + int delay1, delay2; + + delay1 = _spi_delay_to_ns(&xfer->word_delay, xfer); + if (delay1 < 0) + return delay1; + + delay2 = _spi_delay_to_ns(&spi->word_delay, xfer); + if (delay2 < 0) + return delay2; + + if (delay1 < delay2) + memcpy(&xfer->word_delay, &spi->word_delay, + sizeof(xfer->word_delay)); + + return 0; +} + static int __spi_validate(struct spi_device *spi, struct spi_message *message) { struct spi_controller *ctlr = spi->controller; @@ -3416,8 +3436,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) return -EINVAL; } - if (xfer->word_delay_usecs < spi->word_delay_usecs) - xfer->word_delay_usecs = spi->word_delay_usecs; + if (_spi_xfer_word_delay_update(xfer, spi)) + return -EINVAL; } message->status = -EINPROGRESS; diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 6cb67ad53ffa..ebeb272aeb0f 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -139,7 +139,7 @@ extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer); * the spi_master. * @cs_gpiod: gpio descriptor of the chipselect line (optional, NULL when * not using a GPIO line) - * @word_delay_usecs: microsecond delay to be inserted between consecutive + * @word_delay: delay to be inserted between consecutive * words of a transfer * * @statistics: statistics for the spi_device @@ -189,7 +189,7 @@ struct spi_device { const char *driver_override; int cs_gpio; /* LEGACY: chip select gpio */ struct gpio_desc *cs_gpiod; /* chip select gpio desc */ - uint8_t word_delay_usecs; /* inter-word delay */ + struct spi_delay word_delay; /* inter-word delay */ /* the statistics */ struct spi_statistics statistics; @@ -781,8 +781,6 @@ extern void spi_res_release(struct spi_controller *ctlr, * @delay_usecs: microseconds to delay after this transfer before * (optionally) changing the chipselect status, then starting * 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: 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 @@ -897,7 +895,6 @@ struct spi_transfer { #define SPI_NBITS_DUAL 0x02 /* 2bits transfer */ #define SPI_NBITS_QUAD 0x04 /* 4bits transfer */ u8 bits_per_word; - u8 word_delay_usecs; u16 delay_usecs; struct spi_delay cs_change_delay; struct spi_delay word_delay;