From 61367d0b8f5edf5146059ba8b79ce4e4485340b2 Mon Sep 17 00:00:00 2001 From: dillon min Date: Mon, 25 May 2020 11:45:47 +0800 Subject: [PATCH] spi: stm32: Add 'SPI_SIMPLEX_RX', 'SPI_3WIRE_RX' support for stm32f4 in l3gd20 driver startup, there is a setup failed error return from stm32 spi driver " [ 2.687630] st-gyro-spi spi0.0: supply vdd not found, using dummy regulator [ 2.696869] st-gyro-spi spi0.0: supply vddio not found, using dummy regulator [ 2.706707] spi_stm32 40015000.spi: SPI transfer setup failed [ 2.713741] st-gyro-spi spi0.0: SPI transfer failed: -22 [ 2.721096] spi_master spi0: failed to transfer one message from queue [ 2.729268] iio iio:device0: failed to read Who-Am-I register. [ 2.737504] st-gyro-spi: probe of spi0.0 failed with error -22 " after debug into spi-stm32 driver, st-gyro-spi split two steps to read l3gd20 id first: send command to l3gd20 with read id command in tx_buf, rx_buf is null. second: read id with tx_buf is null, rx_buf not null. so, for second step, stm32 driver recongise this process as 'SPI_SIMPLE_RX' from stm32_spi_communication_type(), but there is no related process for this type in stm32f4_spi_set_mode(), then we get error from stm32_spi_transfer_one_setup(). we can use two method to fix this bug. 1, use stm32 spi's "In unidirectional receive-only mode (BIDIMODE=0 and RXONLY=1)". but as our code running in sdram, the read latency is too large to get so many receive overrun error in interrupts handler. 2, use stm32 spi's "In full-duplex (BIDIMODE=0 and RXONLY=0)", as tx_buf is null, so add flag 'SPI_MASTER_MUST_TX' to spi master. Change since V4: 1 remove dummy data sent out by stm32 spi driver 2 add flag 'SPI_MASTER_MUST_TX' to spi master Signed-off-by: dillon min Link: https://lore.kernel.org/r/1590378348-8115-8-git-send-email-dillon.minfei@gmail.com Signed-off-by: Mark Brown --- drivers/spi/spi-stm32.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index 44ac6eb3..4c643df 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -811,7 +811,9 @@ static irqreturn_t stm32f4_spi_irq_event(int irq, void *dev_id) mask |= STM32F4_SPI_SR_TXE; } - if (!spi->cur_usedma && spi->cur_comm == SPI_FULL_DUPLEX) { + if (!spi->cur_usedma && (spi->cur_comm == SPI_FULL_DUPLEX || + spi->cur_comm == SPI_SIMPLEX_RX || + spi->cur_comm == SPI_3WIRE_RX)) { /* TXE flag is set and is handled when RXNE flag occurs */ sr &= ~STM32F4_SPI_SR_TXE; mask |= STM32F4_SPI_SR_RXNE | STM32F4_SPI_SR_OVR; @@ -850,7 +852,7 @@ static irqreturn_t stm32f4_spi_irq_event(int irq, void *dev_id) stm32f4_spi_read_rx(spi); if (spi->rx_len == 0) end = true; - else /* Load data for discontinuous mode */ + else if (spi->tx_buf)/* Load data for discontinuous mode */ stm32f4_spi_write_tx(spi); } @@ -1151,7 +1153,9 @@ static int stm32f4_spi_transfer_one_irq(struct stm32_spi *spi) /* Enable the interrupts relative to the current communication mode */ if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX) { cr2 |= STM32F4_SPI_CR2_TXEIE; - } else if (spi->cur_comm == SPI_FULL_DUPLEX) { + } else if (spi->cur_comm == SPI_FULL_DUPLEX || + spi->cur_comm == SPI_SIMPLEX_RX || + spi->cur_comm == SPI_3WIRE_RX) { /* In transmit-only mode, the OVR flag is set in the SR register * since the received data are never read. Therefore set OVR * interrupt only when rx buffer is available. @@ -1462,10 +1466,16 @@ static int stm32f4_spi_set_mode(struct stm32_spi *spi, unsigned int comm_type) stm32_spi_set_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_BIDIMODE | STM32F4_SPI_CR1_BIDIOE); - } else if (comm_type == SPI_FULL_DUPLEX) { + } else if (comm_type == SPI_FULL_DUPLEX || + comm_type == SPI_SIMPLEX_RX) { stm32_spi_clr_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_BIDIMODE | STM32F4_SPI_CR1_BIDIOE); + } else if (comm_type == SPI_3WIRE_RX) { + stm32_spi_set_bits(spi, STM32F4_SPI_CR1, + STM32F4_SPI_CR1_BIDIMODE); + stm32_spi_clr_bits(spi, STM32F4_SPI_CR1, + STM32F4_SPI_CR1_BIDIOE); } else { return -EINVAL; } @@ -1906,6 +1916,7 @@ static int stm32_spi_probe(struct platform_device *pdev) master->prepare_message = stm32_spi_prepare_msg; master->transfer_one = stm32_spi_transfer_one; master->unprepare_message = stm32_spi_unprepare_msg; + master->flags = SPI_MASTER_MUST_TX; spi->dma_tx = dma_request_chan(spi->dev, "tx"); if (IS_ERR(spi->dma_tx)) { -- 2.7.4