diff options
Diffstat (limited to 'drivers/spi/spi-microchip-core.c')
-rw-r--r-- | drivers/spi/spi-microchip-core.c | 604 |
1 files changed, 604 insertions, 0 deletions
diff --git a/drivers/spi/spi-microchip-core.c b/drivers/spi/spi-microchip-core.c new file mode 100644 index 0000000000..b451cd4860 --- /dev/null +++ b/drivers/spi/spi-microchip-core.c @@ -0,0 +1,604 @@ +// SPDX-License-Identifier: (GPL-2.0) +/* + * Microchip CoreSPI SPI controller driver + * + * Copyright (c) 2018-2022 Microchip Technology Inc. and its subsidiaries + * + * Author: Daire McNamara <daire.mcnamara@microchip.com> + * Author: Conor Dooley <conor.dooley@microchip.com> + * + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> + +#define MAX_LEN (0xffff) +#define MAX_CS (8) +#define DEFAULT_FRAMESIZE (8) +#define FIFO_DEPTH (32) +#define CLK_GEN_MODE1_MAX (255) +#define CLK_GEN_MODE0_MAX (15) +#define CLK_GEN_MIN (0) +#define MODE_X_MASK_SHIFT (24) + +#define CONTROL_ENABLE BIT(0) +#define CONTROL_MASTER BIT(1) +#define CONTROL_RX_DATA_INT BIT(4) +#define CONTROL_TX_DATA_INT BIT(5) +#define CONTROL_RX_OVER_INT BIT(6) +#define CONTROL_TX_UNDER_INT BIT(7) +#define CONTROL_SPO BIT(24) +#define CONTROL_SPH BIT(25) +#define CONTROL_SPS BIT(26) +#define CONTROL_FRAMEURUN BIT(27) +#define CONTROL_CLKMODE BIT(28) +#define CONTROL_BIGFIFO BIT(29) +#define CONTROL_OENOFF BIT(30) +#define CONTROL_RESET BIT(31) + +#define CONTROL_MODE_MASK GENMASK(3, 2) +#define MOTOROLA_MODE (0) +#define CONTROL_FRAMECNT_MASK GENMASK(23, 8) +#define CONTROL_FRAMECNT_SHIFT (8) + +#define STATUS_ACTIVE BIT(14) +#define STATUS_SSEL BIT(13) +#define STATUS_FRAMESTART BIT(12) +#define STATUS_TXFIFO_EMPTY_NEXT_READ BIT(11) +#define STATUS_TXFIFO_EMPTY BIT(10) +#define STATUS_TXFIFO_FULL_NEXT_WRITE BIT(9) +#define STATUS_TXFIFO_FULL BIT(8) +#define STATUS_RXFIFO_EMPTY_NEXT_READ BIT(7) +#define STATUS_RXFIFO_EMPTY BIT(6) +#define STATUS_RXFIFO_FULL_NEXT_WRITE BIT(5) +#define STATUS_RXFIFO_FULL BIT(4) +#define STATUS_TX_UNDERRUN BIT(3) +#define STATUS_RX_OVERFLOW BIT(2) +#define STATUS_RXDAT_RXED BIT(1) +#define STATUS_TXDAT_SENT BIT(0) + +#define INT_TXDONE BIT(0) +#define INT_RXRDY BIT(1) +#define INT_RX_CHANNEL_OVERFLOW BIT(2) +#define INT_TX_CHANNEL_UNDERRUN BIT(3) + +#define INT_ENABLE_MASK (CONTROL_RX_DATA_INT | CONTROL_TX_DATA_INT | \ + CONTROL_RX_OVER_INT | CONTROL_TX_UNDER_INT) + +#define REG_CONTROL (0x00) +#define REG_FRAME_SIZE (0x04) +#define REG_STATUS (0x08) +#define REG_INT_CLEAR (0x0c) +#define REG_RX_DATA (0x10) +#define REG_TX_DATA (0x14) +#define REG_CLK_GEN (0x18) +#define REG_SLAVE_SELECT (0x1c) +#define SSEL_MASK GENMASK(7, 0) +#define SSEL_DIRECT BIT(8) +#define SSELOUT_SHIFT 9 +#define SSELOUT BIT(SSELOUT_SHIFT) +#define REG_MIS (0x20) +#define REG_RIS (0x24) +#define REG_CONTROL2 (0x28) +#define REG_COMMAND (0x2c) +#define REG_PKTSIZE (0x30) +#define REG_CMD_SIZE (0x34) +#define REG_HWSTATUS (0x38) +#define REG_STAT8 (0x3c) +#define REG_CTRL2 (0x48) +#define REG_FRAMESUP (0x50) + +struct mchp_corespi { + void __iomem *regs; + struct clk *clk; + const u8 *tx_buf; + u8 *rx_buf; + u32 clk_gen; /* divider for spi output clock generated by the controller */ + u32 clk_mode; + int irq; + int tx_len; + int rx_len; + int pending; +}; + +static inline u32 mchp_corespi_read(struct mchp_corespi *spi, unsigned int reg) +{ + return readl(spi->regs + reg); +} + +static inline void mchp_corespi_write(struct mchp_corespi *spi, unsigned int reg, u32 val) +{ + writel(val, spi->regs + reg); +} + +static inline void mchp_corespi_disable(struct mchp_corespi *spi) +{ + u32 control = mchp_corespi_read(spi, REG_CONTROL); + + control &= ~CONTROL_ENABLE; + + mchp_corespi_write(spi, REG_CONTROL, control); +} + +static inline void mchp_corespi_read_fifo(struct mchp_corespi *spi) +{ + u8 data; + int fifo_max, i = 0; + + fifo_max = min(spi->rx_len, FIFO_DEPTH); + + while ((i < fifo_max) && !(mchp_corespi_read(spi, REG_STATUS) & STATUS_RXFIFO_EMPTY)) { + data = mchp_corespi_read(spi, REG_RX_DATA); + + if (spi->rx_buf) + *spi->rx_buf++ = data; + i++; + } + spi->rx_len -= i; + spi->pending -= i; +} + +static void mchp_corespi_enable_ints(struct mchp_corespi *spi) +{ + u32 control, mask = INT_ENABLE_MASK; + + mchp_corespi_disable(spi); + + control = mchp_corespi_read(spi, REG_CONTROL); + + control |= mask; + mchp_corespi_write(spi, REG_CONTROL, control); + + control |= CONTROL_ENABLE; + mchp_corespi_write(spi, REG_CONTROL, control); +} + +static void mchp_corespi_disable_ints(struct mchp_corespi *spi) +{ + u32 control, mask = INT_ENABLE_MASK; + + mchp_corespi_disable(spi); + + control = mchp_corespi_read(spi, REG_CONTROL); + control &= ~mask; + mchp_corespi_write(spi, REG_CONTROL, control); + + control |= CONTROL_ENABLE; + mchp_corespi_write(spi, REG_CONTROL, control); +} + +static inline void mchp_corespi_set_xfer_size(struct mchp_corespi *spi, int len) +{ + u32 control; + u16 lenpart; + + /* + * Disable the SPI controller. Writes to transfer length have + * no effect when the controller is enabled. + */ + mchp_corespi_disable(spi); + + /* + * The lower 16 bits of the frame count are stored in the control reg + * for legacy reasons, but the upper 16 written to a different register: + * FRAMESUP. While both the upper and lower bits can be *READ* from the + * FRAMESUP register, writing to the lower 16 bits is a NOP + */ + lenpart = len & 0xffff; + + control = mchp_corespi_read(spi, REG_CONTROL); + control &= ~CONTROL_FRAMECNT_MASK; + control |= lenpart << CONTROL_FRAMECNT_SHIFT; + mchp_corespi_write(spi, REG_CONTROL, control); + + lenpart = len & 0xffff0000; + mchp_corespi_write(spi, REG_FRAMESUP, lenpart); + + control |= CONTROL_ENABLE; + mchp_corespi_write(spi, REG_CONTROL, control); +} + +static inline void mchp_corespi_write_fifo(struct mchp_corespi *spi) +{ + u8 byte; + int fifo_max, i = 0; + + fifo_max = min(spi->tx_len, FIFO_DEPTH); + mchp_corespi_set_xfer_size(spi, fifo_max); + + while ((i < fifo_max) && !(mchp_corespi_read(spi, REG_STATUS) & STATUS_TXFIFO_FULL)) { + byte = spi->tx_buf ? *spi->tx_buf++ : 0xaa; + mchp_corespi_write(spi, REG_TX_DATA, byte); + i++; + } + + spi->tx_len -= i; + spi->pending += i; +} + +static inline void mchp_corespi_set_framesize(struct mchp_corespi *spi, int bt) +{ + u32 control; + + /* + * Disable the SPI controller. Writes to the frame size have + * no effect when the controller is enabled. + */ + mchp_corespi_disable(spi); + + mchp_corespi_write(spi, REG_FRAME_SIZE, bt); + + control = mchp_corespi_read(spi, REG_CONTROL); + control |= CONTROL_ENABLE; + mchp_corespi_write(spi, REG_CONTROL, control); +} + +static void mchp_corespi_set_cs(struct spi_device *spi, bool disable) +{ + u32 reg; + struct mchp_corespi *corespi = spi_master_get_devdata(spi->master); + + reg = mchp_corespi_read(corespi, REG_SLAVE_SELECT); + reg &= ~BIT(spi_get_chipselect(spi, 0)); + reg |= !disable << spi_get_chipselect(spi, 0); + + mchp_corespi_write(corespi, REG_SLAVE_SELECT, reg); +} + +static int mchp_corespi_setup(struct spi_device *spi) +{ + struct mchp_corespi *corespi = spi_master_get_devdata(spi->master); + u32 reg; + + /* + * Active high slaves need to be specifically set to their inactive + * states during probe by adding them to the "control group" & thus + * driving their select line low. + */ + if (spi->mode & SPI_CS_HIGH) { + reg = mchp_corespi_read(corespi, REG_SLAVE_SELECT); + reg |= BIT(spi_get_chipselect(spi, 0)); + mchp_corespi_write(corespi, REG_SLAVE_SELECT, reg); + } + return 0; +} + +static void mchp_corespi_init(struct spi_master *master, struct mchp_corespi *spi) +{ + unsigned long clk_hz; + u32 control = mchp_corespi_read(spi, REG_CONTROL); + + control |= CONTROL_MASTER; + + control &= ~CONTROL_MODE_MASK; + control |= MOTOROLA_MODE; + + mchp_corespi_set_framesize(spi, DEFAULT_FRAMESIZE); + + /* max. possible spi clock rate is the apb clock rate */ + clk_hz = clk_get_rate(spi->clk); + master->max_speed_hz = clk_hz; + + /* + * The controller must be configured so that it doesn't remove Chip + * Select until the entire message has been transferred, even if at + * some points TX FIFO becomes empty. + * + * BIGFIFO mode is also enabled, which sets the fifo depth to 32 frames + * for the 8 bit transfers that this driver uses. + */ + control = mchp_corespi_read(spi, REG_CONTROL); + control |= CONTROL_SPS | CONTROL_BIGFIFO; + + mchp_corespi_write(spi, REG_CONTROL, control); + + mchp_corespi_enable_ints(spi); + + /* + * It is required to enable direct mode, otherwise control over the chip + * select is relinquished to the hardware. SSELOUT is enabled too so we + * can deal with active high slaves. + */ + mchp_corespi_write(spi, REG_SLAVE_SELECT, SSELOUT | SSEL_DIRECT); + + control = mchp_corespi_read(spi, REG_CONTROL); + + control &= ~CONTROL_RESET; + control |= CONTROL_ENABLE; + + mchp_corespi_write(spi, REG_CONTROL, control); +} + +static inline void mchp_corespi_set_clk_gen(struct mchp_corespi *spi) +{ + u32 control; + + mchp_corespi_disable(spi); + + control = mchp_corespi_read(spi, REG_CONTROL); + if (spi->clk_mode) + control |= CONTROL_CLKMODE; + else + control &= ~CONTROL_CLKMODE; + + mchp_corespi_write(spi, REG_CLK_GEN, spi->clk_gen); + mchp_corespi_write(spi, REG_CONTROL, control); + mchp_corespi_write(spi, REG_CONTROL, control | CONTROL_ENABLE); +} + +static inline void mchp_corespi_set_mode(struct mchp_corespi *spi, unsigned int mode) +{ + u32 control, mode_val; + + switch (mode & SPI_MODE_X_MASK) { + case SPI_MODE_0: + mode_val = 0; + break; + case SPI_MODE_1: + mode_val = CONTROL_SPH; + break; + case SPI_MODE_2: + mode_val = CONTROL_SPO; + break; + case SPI_MODE_3: + mode_val = CONTROL_SPH | CONTROL_SPO; + break; + } + + /* + * Disable the SPI controller. Writes to the frame size have + * no effect when the controller is enabled. + */ + mchp_corespi_disable(spi); + + control = mchp_corespi_read(spi, REG_CONTROL); + control &= ~(SPI_MODE_X_MASK << MODE_X_MASK_SHIFT); + control |= mode_val; + + mchp_corespi_write(spi, REG_CONTROL, control); + + control |= CONTROL_ENABLE; + mchp_corespi_write(spi, REG_CONTROL, control); +} + +static irqreturn_t mchp_corespi_interrupt(int irq, void *dev_id) +{ + struct spi_master *master = dev_id; + struct mchp_corespi *spi = spi_master_get_devdata(master); + u32 intfield = mchp_corespi_read(spi, REG_MIS) & 0xf; + bool finalise = false; + + /* Interrupt line may be shared and not for us at all */ + if (intfield == 0) + return IRQ_NONE; + + if (intfield & INT_TXDONE) { + mchp_corespi_write(spi, REG_INT_CLEAR, INT_TXDONE); + + if (spi->rx_len) + mchp_corespi_read_fifo(spi); + + if (spi->tx_len) + mchp_corespi_write_fifo(spi); + + if (!spi->rx_len) + finalise = true; + } + + if (intfield & INT_RXRDY) + mchp_corespi_write(spi, REG_INT_CLEAR, INT_RXRDY); + + if (intfield & INT_RX_CHANNEL_OVERFLOW) { + mchp_corespi_write(spi, REG_INT_CLEAR, INT_RX_CHANNEL_OVERFLOW); + finalise = true; + dev_err(&master->dev, + "%s: RX OVERFLOW: rxlen: %d, txlen: %d\n", __func__, + spi->rx_len, spi->tx_len); + } + + if (intfield & INT_TX_CHANNEL_UNDERRUN) { + mchp_corespi_write(spi, REG_INT_CLEAR, INT_TX_CHANNEL_UNDERRUN); + finalise = true; + dev_err(&master->dev, + "%s: TX UNDERFLOW: rxlen: %d, txlen: %d\n", __func__, + spi->rx_len, spi->tx_len); + } + + if (finalise) + spi_finalize_current_transfer(master); + + return IRQ_HANDLED; +} + +static int mchp_corespi_calculate_clkgen(struct mchp_corespi *spi, + unsigned long target_hz) +{ + unsigned long clk_hz, spi_hz, clk_gen; + + clk_hz = clk_get_rate(spi->clk); + if (!clk_hz) + return -EINVAL; + spi_hz = min(target_hz, clk_hz); + + /* + * There are two possible clock modes for the controller generated + * clock's division ratio: + * CLK_MODE = 0: 1 / (2^(CLK_GEN + 1)) where CLK_GEN = 0 to 15. + * CLK_MODE = 1: 1 / (2 * CLK_GEN + 1) where CLK_GEN = 0 to 255. + * First try mode 1, fall back to 0 and if we have tried both modes and + * we /still/ can't get a good setting, we then throw the toys out of + * the pram and give up + * clk_gen is the register name for the clock divider on MPFS. + */ + clk_gen = DIV_ROUND_UP(clk_hz, 2 * spi_hz) - 1; + if (clk_gen > CLK_GEN_MODE1_MAX || clk_gen <= CLK_GEN_MIN) { + clk_gen = DIV_ROUND_UP(clk_hz, spi_hz); + clk_gen = fls(clk_gen) - 1; + + if (clk_gen > CLK_GEN_MODE0_MAX) + return -EINVAL; + + spi->clk_mode = 0; + } else { + spi->clk_mode = 1; + } + + spi->clk_gen = clk_gen; + return 0; +} + +static int mchp_corespi_transfer_one(struct spi_master *master, + struct spi_device *spi_dev, + struct spi_transfer *xfer) +{ + struct mchp_corespi *spi = spi_master_get_devdata(master); + int ret; + + ret = mchp_corespi_calculate_clkgen(spi, (unsigned long)xfer->speed_hz); + if (ret) { + dev_err(&master->dev, "failed to set clk_gen for target %u Hz\n", xfer->speed_hz); + return ret; + } + + mchp_corespi_set_clk_gen(spi); + + spi->tx_buf = xfer->tx_buf; + spi->rx_buf = xfer->rx_buf; + spi->tx_len = xfer->len; + spi->rx_len = xfer->len; + spi->pending = 0; + + mchp_corespi_set_xfer_size(spi, (spi->tx_len > FIFO_DEPTH) + ? FIFO_DEPTH : spi->tx_len); + + if (spi->tx_len) + mchp_corespi_write_fifo(spi); + return 1; +} + +static int mchp_corespi_prepare_message(struct spi_master *master, + struct spi_message *msg) +{ + struct spi_device *spi_dev = msg->spi; + struct mchp_corespi *spi = spi_master_get_devdata(master); + + mchp_corespi_set_framesize(spi, DEFAULT_FRAMESIZE); + mchp_corespi_set_mode(spi, spi_dev->mode); + + return 0; +} + +static int mchp_corespi_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct mchp_corespi *spi; + struct resource *res; + u32 num_cs; + int ret = 0; + + master = devm_spi_alloc_master(&pdev->dev, sizeof(*spi)); + if (!master) + return dev_err_probe(&pdev->dev, -ENOMEM, + "unable to allocate master for SPI controller\n"); + + platform_set_drvdata(pdev, master); + + if (of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs)) + num_cs = MAX_CS; + + master->num_chipselect = num_cs; + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; + master->setup = mchp_corespi_setup; + master->bits_per_word_mask = SPI_BPW_MASK(8); + master->transfer_one = mchp_corespi_transfer_one; + master->prepare_message = mchp_corespi_prepare_message; + master->set_cs = mchp_corespi_set_cs; + master->dev.of_node = pdev->dev.of_node; + + spi = spi_master_get_devdata(master); + + spi->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(spi->regs)) + return PTR_ERR(spi->regs); + + spi->irq = platform_get_irq(pdev, 0); + if (spi->irq < 0) + return spi->irq; + + ret = devm_request_irq(&pdev->dev, spi->irq, mchp_corespi_interrupt, + IRQF_SHARED, dev_name(&pdev->dev), master); + if (ret) + return dev_err_probe(&pdev->dev, ret, + "could not request irq\n"); + + spi->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(spi->clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(spi->clk), + "could not get clk\n"); + + ret = clk_prepare_enable(spi->clk); + if (ret) + return dev_err_probe(&pdev->dev, ret, + "failed to enable clock\n"); + + mchp_corespi_init(master, spi); + + ret = devm_spi_register_master(&pdev->dev, master); + if (ret) { + mchp_corespi_disable(spi); + clk_disable_unprepare(spi->clk); + return dev_err_probe(&pdev->dev, ret, + "unable to register master for SPI controller\n"); + } + + dev_info(&pdev->dev, "Registered SPI controller %d\n", master->bus_num); + + return 0; +} + +static void mchp_corespi_remove(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct mchp_corespi *spi = spi_master_get_devdata(master); + + mchp_corespi_disable_ints(spi); + clk_disable_unprepare(spi->clk); + mchp_corespi_disable(spi); +} + +#define MICROCHIP_SPI_PM_OPS (NULL) + +/* + * Platform driver data structure + */ + +#if defined(CONFIG_OF) +static const struct of_device_id mchp_corespi_dt_ids[] = { + { .compatible = "microchip,mpfs-spi" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, mchp_corespi_dt_ids); +#endif + +static struct platform_driver mchp_corespi_driver = { + .probe = mchp_corespi_probe, + .driver = { + .name = "microchip-corespi", + .pm = MICROCHIP_SPI_PM_OPS, + .of_match_table = of_match_ptr(mchp_corespi_dt_ids), + }, + .remove_new = mchp_corespi_remove, +}; +module_platform_driver(mchp_corespi_driver); +MODULE_DESCRIPTION("Microchip coreSPI SPI controller driver"); +MODULE_AUTHOR("Daire McNamara <daire.mcnamara@microchip.com>"); +MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>"); +MODULE_LICENSE("GPL"); |