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Subject[PATCH v2 09/14] spi: stm32: split transfer one setup function
Date
From: Cezary Gapinski <cezary.gapinski@gmail.com>

Split stm32_spi_transfer_one_setup function into smaller chunks
to be more generic for other stm32 SPI family drivers.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
---
drivers/spi/spi-stm32.c | 270 ++++++++++++++++++++++++++++++++++--------------
1 file changed, 192 insertions(+), 78 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 9cb7d33..bc8513f 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -101,11 +101,18 @@
#define STM32H7_SPI_MBR_DIV_MIN (2 << STM32H7_SPI_CFG1_MBR_MIN)
#define STM32H7_SPI_MBR_DIV_MAX (2 << STM32H7_SPI_CFG1_MBR_MAX)

-/* SPI Communication mode */
+/* STM32H7 SPI Communication mode */
+#define STM32H7_SPI_FULL_DUPLEX 0
+#define STM32H7_SPI_SIMPLEX_TX 1
+#define STM32H7_SPI_SIMPLEX_RX 2
+#define STM32H7_SPI_HALF_DUPLEX 3
+
+/* SPI Communication type */
#define SPI_FULL_DUPLEX 0
#define SPI_SIMPLEX_TX 1
#define SPI_SIMPLEX_RX 2
-#define SPI_HALF_DUPLEX 3
+#define SPI_3WIRE_TX 3
+#define SPI_3WIRE_RX 4

#define SPI_1HZ_NS 1000000000

@@ -232,13 +239,16 @@ static int stm32_spi_get_bpw_mask(struct stm32_spi *spi)
}

/**
- * stm32_spi_prepare_mbr - Determine SPI_CFG1.MBR value
+ * stm32_spi_prepare_mbr - Determine baud rate divisor value
* @spi: pointer to the spi controller data structure
* @speed_hz: requested speed
+ * @min_div: minimum baud rate divisor
+ * @max_div: maximum baud rate divisor
*
- * Return SPI_CFG1.MBR value in case of success or -EINVAL
+ * Return baud rate divisor value in case of success or -EINVAL
*/
-static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz)
+static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz,
+ u32 min_div, u32 max_div)
{
u32 div, mbrdiv;

@@ -251,8 +261,7 @@ static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz)
* no need to check it there.
* However, we need to ensure the following calculations.
*/
- if (div < STM32H7_SPI_MBR_DIV_MIN ||
- div > STM32H7_SPI_MBR_DIV_MAX)
+ if ((div < min_div) || (div > max_div))
return -EINVAL;

/* Determine the first power of 2 greater than or equal to div */
@@ -802,7 +811,8 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi,
}

if (tx_dma_desc) {
- if (spi->cur_comm == SPI_SIMPLEX_TX) {
+ if (spi->cur_comm == SPI_SIMPLEX_TX ||
+ spi->cur_comm == SPI_3WIRE_TX) {
tx_dma_desc->callback = stm32_spi_dma_cb;
tx_dma_desc->callback_param = spi;
}
@@ -848,92 +858,130 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi,
}

/**
- * stm32_spi_transfer_one_setup - common setup to transfer a single
- * spi_transfer either using DMA or
- * interrupts.
+ * stm32_spi_set_bpw - configure bits per word
+ * @spi: pointer to the spi controller data structure
*/
-static int stm32_spi_transfer_one_setup(struct stm32_spi *spi,
- struct spi_device *spi_dev,
- struct spi_transfer *transfer)
+static void stm32_spi_set_bpw(struct stm32_spi *spi)
{
- unsigned long flags;
- u32 cfg1_clrb = 0, cfg1_setb = 0, cfg2_clrb = 0, cfg2_setb = 0;
- u32 mode, nb_words;
- int ret = 0;
+ u32 bpw, fthlv;
+ u32 cfg1_clrb = 0, cfg1_setb = 0;

- spin_lock_irqsave(&spi->lock, flags);
+ bpw = spi->cur_bpw - 1;

- if (spi->cur_bpw != transfer->bits_per_word) {
- u32 bpw, fthlv;
-
- spi->cur_bpw = transfer->bits_per_word;
- bpw = spi->cur_bpw - 1;
+ cfg1_clrb |= STM32H7_SPI_CFG1_DSIZE;
+ cfg1_setb |= (bpw << STM32H7_SPI_CFG1_DSIZE_SHIFT) &
+ STM32H7_SPI_CFG1_DSIZE;

- cfg1_clrb |= STM32H7_SPI_CFG1_DSIZE;
- cfg1_setb |= (bpw << STM32H7_SPI_CFG1_DSIZE_SHIFT) &
- STM32H7_SPI_CFG1_DSIZE;
+ spi->cur_fthlv = stm32_spi_prepare_fthlv(spi);
+ fthlv = spi->cur_fthlv - 1;

- spi->cur_fthlv = stm32_spi_prepare_fthlv(spi);
- fthlv = spi->cur_fthlv - 1;
+ cfg1_clrb |= STM32H7_SPI_CFG1_FTHLV;
+ cfg1_setb |= (fthlv << STM32H7_SPI_CFG1_FTHLV_SHIFT) &
+ STM32H7_SPI_CFG1_FTHLV;

- cfg1_clrb |= STM32H7_SPI_CFG1_FTHLV;
- cfg1_setb |= (fthlv << STM32H7_SPI_CFG1_FTHLV_SHIFT) &
- STM32H7_SPI_CFG1_FTHLV;
- }
-
- if (spi->cur_speed != transfer->speed_hz) {
- int mbr;
+ writel_relaxed(
+ (readl_relaxed(spi->base + STM32H7_SPI_CFG1) &
+ ~cfg1_clrb) | cfg1_setb,
+ spi->base + STM32H7_SPI_CFG1);
+}

- /* Update spi->cur_speed with real clock speed */
- mbr = stm32_spi_prepare_mbr(spi, transfer->speed_hz);
- if (mbr < 0) {
- ret = mbr;
- goto out;
- }
+/**
+ * stm32_spi_set_mbr - Configure baud rate divisor in master mode
+ * @spi: pointer to the spi controller data structure
+ * @mbrdiv: baud rate divisor value
+ */
+static void stm32_spi_set_mbr(struct stm32_spi *spi, u32 mbrdiv)
+{
+ u32 cfg1_clrb = 0, cfg1_setb = 0;

- transfer->speed_hz = spi->cur_speed;
+ cfg1_clrb |= STM32H7_SPI_CFG1_MBR;
+ cfg1_setb |= ((u32)mbrdiv << STM32H7_SPI_CFG1_MBR_SHIFT) &
+ STM32H7_SPI_CFG1_MBR;

- cfg1_clrb |= STM32H7_SPI_CFG1_MBR;
- cfg1_setb |= ((u32)mbr << STM32H7_SPI_CFG1_MBR_SHIFT) &
- STM32H7_SPI_CFG1_MBR;
- }
+ writel_relaxed((readl_relaxed(spi->base + STM32H7_SPI_CFG1) &
+ ~cfg1_clrb) | cfg1_setb,
+ spi->base + STM32H7_SPI_CFG1);
+}

- if (cfg1_clrb || cfg1_setb)
- writel_relaxed((readl_relaxed(spi->base + STM32H7_SPI_CFG1) &
- ~cfg1_clrb) | cfg1_setb,
- spi->base + STM32H7_SPI_CFG1);
+/**
+ * stm32_spi_communication_type - return transfer communication type
+ * @spi_dev: pointer to the spi device
+ * transfer: pointer to spi transfer
+ */
+static unsigned int stm32_spi_communication_type(struct spi_device *spi_dev,
+ struct spi_transfer *transfer)
+{
+ unsigned int type = SPI_FULL_DUPLEX;

- mode = SPI_FULL_DUPLEX;
if (spi_dev->mode & SPI_3WIRE) { /* MISO/MOSI signals shared */
/*
* SPI_3WIRE and xfer->tx_buf != NULL and xfer->rx_buf != NULL
- * is forbidden und unvalidated by SPI subsystem so depending
+ * is forbidden and unvalidated by SPI subsystem so depending
* on the valid buffer, we can determine the direction of the
* transfer.
*/
- mode = SPI_HALF_DUPLEX;
if (!transfer->tx_buf)
- stm32_spi_clr_bits(spi, STM32H7_SPI_CR1,
- STM32H7_SPI_CR1_HDDIR);
- else if (!transfer->rx_buf)
- stm32_spi_set_bits(spi, STM32H7_SPI_CR1,
- STM32H7_SPI_CR1_HDDIR);
+ type = SPI_3WIRE_RX;
+ else
+ type = SPI_3WIRE_TX;
} else {
if (!transfer->tx_buf)
- mode = SPI_SIMPLEX_RX;
+ type = SPI_SIMPLEX_RX;
else if (!transfer->rx_buf)
- mode = SPI_SIMPLEX_TX;
+ type = SPI_SIMPLEX_TX;
}
- if (spi->cur_comm != mode) {
- spi->cur_comm = mode;

- cfg2_clrb |= STM32H7_SPI_CFG2_COMM;
- cfg2_setb |= (mode << STM32H7_SPI_CFG2_COMM_SHIFT) &
- STM32H7_SPI_CFG2_COMM;
+ return type;
+}
+
+/**
+ * stm32_spi_set_mode - configure communication mode
+ * @spi: pointer to the spi controller data structure
+ * @comm_type: type of communication to configure
+ */
+static int stm32_spi_set_mode(struct stm32_spi *spi, unsigned int comm_type)
+{
+ u32 mode;
+ u32 cfg2_clrb = 0, cfg2_setb = 0;
+
+ if (comm_type == SPI_3WIRE_RX) {
+ mode = STM32H7_SPI_HALF_DUPLEX;
+ stm32_spi_clr_bits(spi, STM32H7_SPI_CR1, STM32H7_SPI_CR1_HDDIR);
+ } else if (comm_type == SPI_3WIRE_TX) {
+ mode = STM32H7_SPI_HALF_DUPLEX;
+ stm32_spi_set_bits(spi, STM32H7_SPI_CR1, STM32H7_SPI_CR1_HDDIR);
+ } else if (comm_type == SPI_SIMPLEX_RX) {
+ mode = STM32H7_SPI_SIMPLEX_RX;
+ } else if (comm_type == SPI_SIMPLEX_TX) {
+ mode = STM32H7_SPI_SIMPLEX_TX;
+ } else {
+ mode = STM32H7_SPI_FULL_DUPLEX;
}

+ cfg2_clrb |= STM32H7_SPI_CFG2_COMM;
+ cfg2_setb |= (mode << STM32H7_SPI_CFG2_COMM_SHIFT) &
+ STM32H7_SPI_CFG2_COMM;
+
+ writel_relaxed(
+ (readl_relaxed(spi->base + STM32H7_SPI_CFG2) &
+ ~cfg2_clrb) | cfg2_setb,
+ spi->base + STM32H7_SPI_CFG2);
+
+ return 0;
+}
+
+/**
+ * stm32_spi_data_idleness - configure minimum time delay inserted between two
+ * consecutive data frames in master mode
+ * @spi: pointer to the spi controller data structure
+ * @len: transfer len
+ */
+static void stm32_spi_data_idleness(struct stm32_spi *spi, u32 len)
+{
+ u32 cfg2_clrb = 0, cfg2_setb = 0;
+
cfg2_clrb |= STM32H7_SPI_CFG2_MIDI;
- if ((transfer->len > 1) && (spi->cur_midi > 0)) {
+ if ((len > 1) && (spi->cur_midi > 0)) {
u32 sck_period_ns = DIV_ROUND_UP(SPI_1HZ_NS, spi->cur_speed);
u32 midi = min((u32)DIV_ROUND_UP(spi->cur_midi, sck_period_ns),
(u32)STM32H7_SPI_CFG2_MIDI >>
@@ -941,15 +989,85 @@ static int stm32_spi_transfer_one_setup(struct stm32_spi *spi,

dev_dbg(spi->dev, "period=%dns, midi=%d(=%dns)\n",
sck_period_ns, midi, midi * sck_period_ns);
-
cfg2_setb |= (midi << STM32H7_SPI_CFG2_MIDI_SHIFT) &
STM32H7_SPI_CFG2_MIDI;
}

- if (cfg2_clrb || cfg2_setb)
- writel_relaxed((readl_relaxed(spi->base + STM32H7_SPI_CFG2) &
- ~cfg2_clrb) | cfg2_setb,
- spi->base + STM32H7_SPI_CFG2);
+ writel_relaxed((readl_relaxed(spi->base + STM32H7_SPI_CFG2) &
+ ~cfg2_clrb) | cfg2_setb,
+ spi->base + STM32H7_SPI_CFG2);
+}
+
+/**
+ * stm32_spi_number_of_data - configure number of data at current transfer
+ * @spi: pointer to the spi controller data structure
+ * @len: transfer length
+ */
+static int stm32_spi_number_of_data(struct stm32_spi *spi, u32 nb_words)
+{
+ u32 cr2_clrb = 0, cr2_setb = 0;
+
+ if (nb_words <= (STM32H7_SPI_CR2_TSIZE >>
+ STM32H7_SPI_CR2_TSIZE_SHIFT)) {
+ cr2_clrb |= STM32H7_SPI_CR2_TSIZE;
+ cr2_setb = nb_words << STM32H7_SPI_CR2_TSIZE_SHIFT;
+ writel_relaxed((readl_relaxed(spi->base + STM32H7_SPI_CR2) &
+ ~cr2_clrb) | cr2_setb,
+ spi->base + STM32H7_SPI_CR2);
+ } else {
+ return -EMSGSIZE;
+ }
+
+ return 0;
+}
+
+/**
+ * stm32_spi_transfer_one_setup - common setup to transfer a single
+ * spi_transfer either using DMA or
+ * interrupts.
+ */
+static int stm32_spi_transfer_one_setup(struct stm32_spi *spi,
+ struct spi_device *spi_dev,
+ struct spi_transfer *transfer)
+{
+ unsigned long flags;
+ unsigned int comm_type;
+ int nb_words, ret = 0;
+
+ spin_lock_irqsave(&spi->lock, flags);
+
+ if (spi->cur_bpw != transfer->bits_per_word) {
+ spi->cur_bpw = transfer->bits_per_word;
+ stm32_spi_set_bpw(spi);
+ }
+
+ if (spi->cur_speed != transfer->speed_hz) {
+ int mbr;
+
+ /* Update spi->cur_speed with real clock speed */
+ mbr = stm32_spi_prepare_mbr(spi, transfer->speed_hz,
+ STM32H7_SPI_MBR_DIV_MIN,
+ STM32H7_SPI_MBR_DIV_MAX);
+ if (mbr < 0) {
+ ret = mbr;
+ goto out;
+ }
+
+ transfer->speed_hz = spi->cur_speed;
+ stm32_spi_set_mbr(spi, mbr);
+ }
+
+ comm_type = stm32_spi_communication_type(spi_dev, transfer);
+ if (spi->cur_comm != comm_type) {
+ stm32_spi_set_mode(spi, comm_type);
+
+ if (ret < 0)
+ goto out;
+
+ spi->cur_comm = comm_type;
+ }
+
+ stm32_spi_data_idleness(spi, transfer->len);

if (spi->cur_bpw <= 8)
nb_words = transfer->len;
@@ -957,14 +1075,10 @@ static int stm32_spi_transfer_one_setup(struct stm32_spi *spi,
nb_words = DIV_ROUND_UP(transfer->len * 8, 16);
else
nb_words = DIV_ROUND_UP(transfer->len * 8, 32);
- nb_words <<= STM32H7_SPI_CR2_TSIZE_SHIFT;

- if (nb_words <= STM32H7_SPI_CR2_TSIZE) {
- writel_relaxed(nb_words, spi->base + STM32H7_SPI_CR2);
- } else {
- ret = -EMSGSIZE;
+ ret = stm32_spi_number_of_data(spi, nb_words);
+ if (ret < 0)
goto out;
- }

spi->cur_xferlen = transfer->len;

--
2.7.4
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