diff options
author | Mark Brown <broonie@kernel.org> | 2023-04-18 19:19:48 +0300 |
---|---|---|
committer | Mark Brown <broonie@kernel.org> | 2023-04-18 19:19:48 +0300 |
commit | 01875342ae659629b72c730ead5461eb330a9a02 (patch) | |
tree | 6cc679387b2a1ca5d1742169a75200b278416c1c /drivers/spi | |
parent | 2087e85bb66ee3652dafe732bb9b9b896229eafc (diff) | |
parent | b1b90514eaa3454223d6f576a108cc0a58924a65 (diff) | |
download | linux-01875342ae659629b72c730ead5461eb330a9a02.tar.xz |
spi: spi-cadence: Add Slave mode support
Merge series from Srinivas Goud <srinivas.goud@amd.com>:
Currently SPI Cadence controller works in Master mode only.
Update driver to support Slave mode and also Full duplex transfer
support in Slave mode
Diffstat (limited to 'drivers/spi')
-rw-r--r-- | drivers/spi/spi-cadence.c | 324 |
1 files changed, 203 insertions, 121 deletions
diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c index 49936237e583..ac85d5562212 100644 --- a/drivers/spi/spi-cadence.c +++ b/drivers/spi/spi-cadence.c @@ -1,6 +1,6 @@ // SPDX-License-Identifier: GPL-2.0-or-later /* - * Cadence SPI controller driver (master mode only) + * Cadence SPI controller driver (master and slave mode) * * Copyright (C) 2008 - 2014 Xilinx, Inc. * @@ -139,17 +139,21 @@ static inline void cdns_spi_write(struct cdns_spi *xspi, u32 offset, u32 val) /** * cdns_spi_init_hw - Initialize the hardware and configure the SPI controller * @xspi: Pointer to the cdns_spi structure + * @is_slave: Flag to indicate slave or master mode + * * On reset the SPI controller is configured to slave or master mode. + * In master mode baud rate divisor is set to 4, threshold value for TX FIFO + * not full interrupt is set to 1 and size of the word to be transferred as 8 bit. * - * On reset the SPI controller is configured to be in master mode, baud rate - * divisor is set to 4, threshold value for TX FIFO not full interrupt is set - * to 1 and size of the word to be transferred as 8 bit. * This function initializes the SPI controller to disable and clear all the * interrupts, enable manual slave select and manual start, deselect all the * chip select lines, and enable the SPI controller. */ -static void cdns_spi_init_hw(struct cdns_spi *xspi) +static void cdns_spi_init_hw(struct cdns_spi *xspi, bool is_slave) { - u32 ctrl_reg = CDNS_SPI_CR_DEFAULT; + u32 ctrl_reg = 0; + + if (!is_slave) + ctrl_reg |= CDNS_SPI_CR_DEFAULT; if (xspi->is_decoded_cs) ctrl_reg |= CDNS_SPI_CR_PERI_SEL; @@ -173,7 +177,7 @@ static void cdns_spi_init_hw(struct cdns_spi *xspi) */ static void cdns_spi_chipselect(struct spi_device *spi, bool is_high) { - struct cdns_spi *xspi = spi_master_get_devdata(spi->master); + struct cdns_spi *xspi = spi_controller_get_devdata(spi->controller); u32 ctrl_reg; ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR); @@ -204,7 +208,7 @@ static void cdns_spi_chipselect(struct spi_device *spi, bool is_high) */ static void cdns_spi_config_clock_mode(struct spi_device *spi) { - struct cdns_spi *xspi = spi_master_get_devdata(spi->master); + struct cdns_spi *xspi = spi_controller_get_devdata(spi->controller); u32 ctrl_reg, new_ctrl_reg; new_ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR); @@ -247,7 +251,7 @@ static void cdns_spi_config_clock_mode(struct spi_device *spi) static void cdns_spi_config_clock_freq(struct spi_device *spi, struct spi_transfer *transfer) { - struct cdns_spi *xspi = spi_master_get_devdata(spi->master); + struct cdns_spi *xspi = spi_controller_get_devdata(spi->controller); u32 ctrl_reg, baud_rate_val; unsigned long frequency; @@ -285,7 +289,7 @@ static void cdns_spi_config_clock_freq(struct spi_device *spi, static int cdns_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *transfer) { - struct cdns_spi *xspi = spi_master_get_devdata(spi->master); + struct cdns_spi *xspi = spi_controller_get_devdata(spi->controller); cdns_spi_config_clock_freq(spi, transfer); @@ -325,6 +329,25 @@ static void cdns_spi_fill_tx_fifo(struct cdns_spi *xspi) } /** + * cdns_spi_read_rx_fifo - Reads the RX FIFO with as many bytes as possible + * @xspi: Pointer to the cdns_spi structure + * @count: Read byte count + */ +static void cdns_spi_read_rx_fifo(struct cdns_spi *xspi, unsigned long count) +{ + u8 data; + + /* Read out the data from the RX FIFO */ + while (count > 0) { + data = cdns_spi_read(xspi, CDNS_SPI_RXD); + if (xspi->rxbuf) + *xspi->rxbuf++ = data; + xspi->rx_bytes--; + count--; + } +} + +/** * cdns_spi_irq - Interrupt service routine of the SPI controller * @irq: IRQ number * @dev_id: Pointer to the xspi structure @@ -340,8 +363,8 @@ static void cdns_spi_fill_tx_fifo(struct cdns_spi *xspi) */ static irqreturn_t cdns_spi_irq(int irq, void *dev_id) { - struct spi_master *master = dev_id; - struct cdns_spi *xspi = spi_master_get_devdata(master); + struct spi_controller *ctlr = dev_id; + struct cdns_spi *xspi = spi_controller_get_devdata(ctlr); irqreturn_t status; u32 intr_status; @@ -355,33 +378,39 @@ static irqreturn_t cdns_spi_irq(int irq, void *dev_id) * transferred is non-zero */ cdns_spi_write(xspi, CDNS_SPI_IDR, CDNS_SPI_IXR_DEFAULT); - spi_finalize_current_transfer(master); + spi_finalize_current_transfer(ctlr); status = IRQ_HANDLED; } else if (intr_status & CDNS_SPI_IXR_TXOW) { - unsigned long trans_cnt; - - trans_cnt = xspi->rx_bytes - xspi->tx_bytes; + int trans_cnt = cdns_spi_read(xspi, CDNS_SPI_THLD); + /* Set threshold to one if number of pending are + * less than half fifo + */ + if (xspi->tx_bytes < xspi->tx_fifo_depth >> 1) + cdns_spi_write(xspi, CDNS_SPI_THLD, 1); - /* Read out the data from the RX FIFO */ while (trans_cnt) { - u8 data; - - data = cdns_spi_read(xspi, CDNS_SPI_RXD); - if (xspi->rxbuf) - *xspi->rxbuf++ = data; - - xspi->rx_bytes--; + cdns_spi_read_rx_fifo(xspi, 1); + + if (xspi->tx_bytes) { + if (xspi->txbuf) + cdns_spi_write(xspi, CDNS_SPI_TXD, + *xspi->txbuf++); + else + cdns_spi_write(xspi, CDNS_SPI_TXD, 0); + xspi->tx_bytes--; + } trans_cnt--; } - - if (xspi->tx_bytes) { - /* There is more data to send */ - cdns_spi_fill_tx_fifo(xspi); - } else { - /* Transfer is completed */ + if (!xspi->tx_bytes) { + /* Fixed delay due to controller limitation with + * RX_NEMPTY incorrect status + * Xilinx AR:65885 contains more details + */ + udelay(10); + cdns_spi_read_rx_fifo(xspi, xspi->rx_bytes); cdns_spi_write(xspi, CDNS_SPI_IDR, CDNS_SPI_IXR_DEFAULT); - spi_finalize_current_transfer(master); + spi_finalize_current_transfer(ctlr); } status = IRQ_HANDLED; } @@ -389,37 +418,47 @@ static irqreturn_t cdns_spi_irq(int irq, void *dev_id) return status; } -static int cdns_prepare_message(struct spi_master *master, +static int cdns_prepare_message(struct spi_controller *ctlr, struct spi_message *msg) { - cdns_spi_config_clock_mode(msg->spi); + if (!spi_controller_is_slave(ctlr)) + cdns_spi_config_clock_mode(msg->spi); return 0; } /** * cdns_transfer_one - Initiates the SPI transfer - * @master: Pointer to spi_master structure + * @ctlr: Pointer to spi_controller structure * @spi: Pointer to the spi_device structure * @transfer: Pointer to the spi_transfer structure which provides * information about next transfer parameters * - * This function fills the TX FIFO, starts the SPI transfer and + * This function in master mode fills the TX FIFO, starts the SPI transfer and * returns a positive transfer count so that core will wait for completion. + * This function in slave mode fills the TX FIFO and wait for transfer trigger. * * Return: Number of bytes transferred in the last transfer */ -static int cdns_transfer_one(struct spi_master *master, +static int cdns_transfer_one(struct spi_controller *ctlr, struct spi_device *spi, struct spi_transfer *transfer) { - struct cdns_spi *xspi = spi_master_get_devdata(master); + struct cdns_spi *xspi = spi_controller_get_devdata(ctlr); xspi->txbuf = transfer->tx_buf; xspi->rxbuf = transfer->rx_buf; xspi->tx_bytes = transfer->len; xspi->rx_bytes = transfer->len; - cdns_spi_setup_transfer(spi, transfer); + if (!spi_controller_is_slave(ctlr)) + cdns_spi_setup_transfer(spi, transfer); + + /* Set TX empty threshold to half of FIFO depth + * only if TX bytes are more than half FIFO depth. + */ + if (xspi->tx_bytes > (xspi->tx_fifo_depth >> 1)) + cdns_spi_write(xspi, CDNS_SPI_THLD, xspi->tx_fifo_depth >> 1); + cdns_spi_fill_tx_fifo(xspi); spi_transfer_delay_exec(transfer); @@ -429,16 +468,16 @@ static int cdns_transfer_one(struct spi_master *master, /** * cdns_prepare_transfer_hardware - Prepares hardware for transfer. - * @master: Pointer to the spi_master structure which provides + * @ctlr: Pointer to the spi_controller structure which provides * information about the controller. * * This function enables SPI master controller. * * Return: 0 always */ -static int cdns_prepare_transfer_hardware(struct spi_master *master) +static int cdns_prepare_transfer_hardware(struct spi_controller *ctlr) { - struct cdns_spi *xspi = spi_master_get_devdata(master); + struct cdns_spi *xspi = spi_controller_get_devdata(ctlr); cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_ENABLE); @@ -447,24 +486,33 @@ static int cdns_prepare_transfer_hardware(struct spi_master *master) /** * cdns_unprepare_transfer_hardware - Relaxes hardware after transfer - * @master: Pointer to the spi_master structure which provides + * @ctlr: Pointer to the spi_controller structure which provides * information about the controller. * * This function disables the SPI master controller when no slave selected. + * This function flush out if any pending data in FIFO. * * Return: 0 always */ -static int cdns_unprepare_transfer_hardware(struct spi_master *master) +static int cdns_unprepare_transfer_hardware(struct spi_controller *ctlr) { - struct cdns_spi *xspi = spi_master_get_devdata(master); + struct cdns_spi *xspi = spi_controller_get_devdata(ctlr); u32 ctrl_reg; + unsigned int cnt = xspi->tx_fifo_depth; + + if (spi_controller_is_slave(ctlr)) { + while (cnt--) + cdns_spi_read(xspi, CDNS_SPI_RXD); + } /* Disable the SPI if slave is deselected */ ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR); ctrl_reg = (ctrl_reg & CDNS_SPI_CR_SSCTRL) >> CDNS_SPI_SS_SHIFT; - if (ctrl_reg == CDNS_SPI_NOSS) + if (ctrl_reg == CDNS_SPI_NOSS || spi_controller_is_slave(ctlr)) cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE); + /* Reset to default */ + cdns_spi_write(xspi, CDNS_SPI_THLD, 0x1); return 0; } @@ -487,6 +535,27 @@ static void cdns_spi_detect_fifo_depth(struct cdns_spi *xspi) } /** + * cdns_slave_abort - Abort slave transfer + * @ctlr: Pointer to the spi_controller structure + * + * This function abort slave transfer if there any transfer timeout. + * + * Return: 0 always + */ +static int cdns_slave_abort(struct spi_controller *ctlr) +{ + struct cdns_spi *xspi = spi_controller_get_devdata(ctlr); + u32 intr_status; + + intr_status = cdns_spi_read(xspi, CDNS_SPI_ISR); + cdns_spi_write(xspi, CDNS_SPI_ISR, intr_status); + cdns_spi_write(xspi, CDNS_SPI_IDR, (CDNS_SPI_IXR_MODF | CDNS_SPI_IXR_RXNEMTY)); + spi_finalize_current_transfer(ctlr); + + return 0; +} + +/** * cdns_spi_probe - Probe method for the SPI driver * @pdev: Pointer to the platform_device structure * @@ -497,71 +566,79 @@ static void cdns_spi_detect_fifo_depth(struct cdns_spi *xspi) static int cdns_spi_probe(struct platform_device *pdev) { int ret = 0, irq; - struct spi_master *master; + struct spi_controller *ctlr; struct cdns_spi *xspi; u32 num_cs; + bool slave; - master = spi_alloc_master(&pdev->dev, sizeof(*xspi)); - if (!master) + slave = of_property_read_bool(pdev->dev.of_node, "spi-slave"); + if (slave) + ctlr = spi_alloc_slave(&pdev->dev, sizeof(*xspi)); + else + ctlr = spi_alloc_master(&pdev->dev, sizeof(*xspi)); + + if (!ctlr) return -ENOMEM; - xspi = spi_master_get_devdata(master); - master->dev.of_node = pdev->dev.of_node; - platform_set_drvdata(pdev, master); + xspi = spi_controller_get_devdata(ctlr); + ctlr->dev.of_node = pdev->dev.of_node; + platform_set_drvdata(pdev, ctlr); xspi->regs = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(xspi->regs)) { ret = PTR_ERR(xspi->regs); - goto remove_master; + goto remove_ctlr; } xspi->pclk = devm_clk_get(&pdev->dev, "pclk"); if (IS_ERR(xspi->pclk)) { dev_err(&pdev->dev, "pclk clock not found.\n"); ret = PTR_ERR(xspi->pclk); - goto remove_master; - } - - xspi->ref_clk = devm_clk_get(&pdev->dev, "ref_clk"); - if (IS_ERR(xspi->ref_clk)) { - dev_err(&pdev->dev, "ref_clk clock not found.\n"); - ret = PTR_ERR(xspi->ref_clk); - goto remove_master; + goto remove_ctlr; } ret = clk_prepare_enable(xspi->pclk); if (ret) { dev_err(&pdev->dev, "Unable to enable APB clock.\n"); - goto remove_master; + goto remove_ctlr; } - ret = clk_prepare_enable(xspi->ref_clk); - if (ret) { - dev_err(&pdev->dev, "Unable to enable device clock.\n"); - goto clk_dis_apb; - } + if (!spi_controller_is_slave(ctlr)) { + xspi->ref_clk = devm_clk_get(&pdev->dev, "ref_clk"); + if (IS_ERR(xspi->ref_clk)) { + dev_err(&pdev->dev, "ref_clk clock not found.\n"); + ret = PTR_ERR(xspi->ref_clk); + goto clk_dis_apb; + } - pm_runtime_use_autosuspend(&pdev->dev); - pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT); - pm_runtime_get_noresume(&pdev->dev); - pm_runtime_set_active(&pdev->dev); - pm_runtime_enable(&pdev->dev); + ret = clk_prepare_enable(xspi->ref_clk); + if (ret) { + dev_err(&pdev->dev, "Unable to enable device clock.\n"); + goto clk_dis_apb; + } - ret = of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs); - if (ret < 0) - master->num_chipselect = CDNS_SPI_DEFAULT_NUM_CS; - else - master->num_chipselect = num_cs; + pm_runtime_use_autosuspend(&pdev->dev); + pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT); + pm_runtime_get_noresume(&pdev->dev); + pm_runtime_set_active(&pdev->dev); + pm_runtime_enable(&pdev->dev); - ret = of_property_read_u32(pdev->dev.of_node, "is-decoded-cs", - &xspi->is_decoded_cs); - if (ret < 0) - xspi->is_decoded_cs = 0; + ret = of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs); + if (ret < 0) + ctlr->num_chipselect = CDNS_SPI_DEFAULT_NUM_CS; + else + ctlr->num_chipselect = num_cs; + + ret = of_property_read_u32(pdev->dev.of_node, "is-decoded-cs", + &xspi->is_decoded_cs); + if (ret < 0) + xspi->is_decoded_cs = 0; + } cdns_spi_detect_fifo_depth(xspi); /* SPI controller initializations */ - cdns_spi_init_hw(xspi); + cdns_spi_init_hw(xspi, spi_controller_is_slave(ctlr)); irq = platform_get_irq(pdev, 0); if (irq <= 0) { @@ -570,48 +647,53 @@ static int cdns_spi_probe(struct platform_device *pdev) } ret = devm_request_irq(&pdev->dev, irq, cdns_spi_irq, - 0, pdev->name, master); + 0, pdev->name, ctlr); if (ret != 0) { ret = -ENXIO; dev_err(&pdev->dev, "request_irq failed\n"); goto clk_dis_all; } - master->use_gpio_descriptors = true; - master->prepare_transfer_hardware = cdns_prepare_transfer_hardware; - master->prepare_message = cdns_prepare_message; - master->transfer_one = cdns_transfer_one; - master->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware; - master->set_cs = cdns_spi_chipselect; - master->auto_runtime_pm = true; - master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; - - xspi->clk_rate = clk_get_rate(xspi->ref_clk); - /* Set to default valid value */ - master->max_speed_hz = xspi->clk_rate / 4; - xspi->speed_hz = master->max_speed_hz; - - master->bits_per_word_mask = SPI_BPW_MASK(8); - - pm_runtime_mark_last_busy(&pdev->dev); - pm_runtime_put_autosuspend(&pdev->dev); - - ret = spi_register_master(master); + ctlr->use_gpio_descriptors = true; + ctlr->prepare_transfer_hardware = cdns_prepare_transfer_hardware; + ctlr->prepare_message = cdns_prepare_message; + ctlr->transfer_one = cdns_transfer_one; + ctlr->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware; + ctlr->mode_bits = SPI_CPOL | SPI_CPHA; + ctlr->bits_per_word_mask = SPI_BPW_MASK(8); + + if (!spi_controller_is_slave(ctlr)) { + ctlr->mode_bits |= SPI_CS_HIGH; + ctlr->set_cs = cdns_spi_chipselect; + ctlr->auto_runtime_pm = true; + xspi->clk_rate = clk_get_rate(xspi->ref_clk); + /* Set to default valid value */ + ctlr->max_speed_hz = xspi->clk_rate / 4; + xspi->speed_hz = ctlr->max_speed_hz; + pm_runtime_mark_last_busy(&pdev->dev); + pm_runtime_put_autosuspend(&pdev->dev); + } else { + ctlr->mode_bits |= SPI_NO_CS; + ctlr->slave_abort = cdns_slave_abort; + } + ret = spi_register_controller(ctlr); if (ret) { - dev_err(&pdev->dev, "spi_register_master failed\n"); + dev_err(&pdev->dev, "spi_register_controller failed\n"); goto clk_dis_all; } return ret; clk_dis_all: - pm_runtime_set_suspended(&pdev->dev); - pm_runtime_disable(&pdev->dev); - clk_disable_unprepare(xspi->ref_clk); + if (!spi_controller_is_slave(ctlr)) { + pm_runtime_set_suspended(&pdev->dev); + pm_runtime_disable(&pdev->dev); + clk_disable_unprepare(xspi->ref_clk); + } clk_dis_apb: clk_disable_unprepare(xspi->pclk); -remove_master: - spi_master_put(master); +remove_ctlr: + spi_controller_put(ctlr); return ret; } @@ -627,8 +709,8 @@ remove_master: */ static void cdns_spi_remove(struct platform_device *pdev) { - struct spi_master *master = platform_get_drvdata(pdev); - struct cdns_spi *xspi = spi_master_get_devdata(master); + struct spi_controller *ctlr = platform_get_drvdata(pdev); + struct cdns_spi *xspi = spi_controller_get_devdata(ctlr); cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE); @@ -637,7 +719,7 @@ static void cdns_spi_remove(struct platform_device *pdev) pm_runtime_set_suspended(&pdev->dev); pm_runtime_disable(&pdev->dev); - spi_unregister_master(master); + spi_unregister_controller(ctlr); } /** @@ -651,9 +733,9 @@ static void cdns_spi_remove(struct platform_device *pdev) */ static int __maybe_unused cdns_spi_suspend(struct device *dev) { - struct spi_master *master = dev_get_drvdata(dev); + struct spi_controller *ctlr = dev_get_drvdata(dev); - return spi_master_suspend(master); + return spi_controller_suspend(ctlr); } /** @@ -666,11 +748,11 @@ static int __maybe_unused cdns_spi_suspend(struct device *dev) */ static int __maybe_unused cdns_spi_resume(struct device *dev) { - struct spi_master *master = dev_get_drvdata(dev); - struct cdns_spi *xspi = spi_master_get_devdata(master); + struct spi_controller *ctlr = dev_get_drvdata(dev); + struct cdns_spi *xspi = spi_controller_get_devdata(ctlr); - cdns_spi_init_hw(xspi); - return spi_master_resume(master); + cdns_spi_init_hw(xspi, spi_controller_is_slave(ctlr)); + return spi_controller_resume(ctlr); } /** @@ -683,8 +765,8 @@ static int __maybe_unused cdns_spi_resume(struct device *dev) */ static int __maybe_unused cdns_spi_runtime_resume(struct device *dev) { - struct spi_master *master = dev_get_drvdata(dev); - struct cdns_spi *xspi = spi_master_get_devdata(master); + struct spi_controller *ctlr = dev_get_drvdata(dev); + struct cdns_spi *xspi = spi_controller_get_devdata(ctlr); int ret; ret = clk_prepare_enable(xspi->pclk); @@ -712,8 +794,8 @@ static int __maybe_unused cdns_spi_runtime_resume(struct device *dev) */ static int __maybe_unused cdns_spi_runtime_suspend(struct device *dev) { - struct spi_master *master = dev_get_drvdata(dev); - struct cdns_spi *xspi = spi_master_get_devdata(master); + struct spi_controller *ctlr = dev_get_drvdata(dev); + struct cdns_spi *xspi = spi_controller_get_devdata(ctlr); clk_disable_unprepare(xspi->ref_clk); clk_disable_unprepare(xspi->pclk); |