diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/spi/spi-npcm-pspi.c | 464 |
1 files changed, 464 insertions, 0 deletions
diff --git a/drivers/spi/spi-npcm-pspi.c b/drivers/spi/spi-npcm-pspi.c new file mode 100644 index 000000000..7f2e4d1b0 --- /dev/null +++ b/drivers/spi/spi-npcm-pspi.c @@ -0,0 +1,464 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Nuvoton Technology corporation. + +#include <linux/kernel.h> +#include <linux/bitfield.h> +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> +#include <linux/reset.h> + +#include <asm/unaligned.h> + +#include <linux/regmap.h> +#include <linux/mfd/syscon.h> + +struct npcm_pspi { + struct completion xfer_done; + struct reset_control *reset; + struct spi_master *master; + unsigned int tx_bytes; + unsigned int rx_bytes; + void __iomem *base; + bool is_save_param; + u8 bits_per_word; + const u8 *tx_buf; + struct clk *clk; + u32 speed_hz; + u8 *rx_buf; + u16 mode; + u32 id; +}; + +#define DRIVER_NAME "npcm-pspi" + +#define NPCM_PSPI_DATA 0x00 +#define NPCM_PSPI_CTL1 0x02 +#define NPCM_PSPI_STAT 0x04 + +/* definitions for control and status register */ +#define NPCM_PSPI_CTL1_SPIEN BIT(0) +#define NPCM_PSPI_CTL1_MOD BIT(2) +#define NPCM_PSPI_CTL1_EIR BIT(5) +#define NPCM_PSPI_CTL1_EIW BIT(6) +#define NPCM_PSPI_CTL1_SCM BIT(7) +#define NPCM_PSPI_CTL1_SCIDL BIT(8) +#define NPCM_PSPI_CTL1_SCDV6_0 GENMASK(15, 9) + +#define NPCM_PSPI_STAT_BSY BIT(0) +#define NPCM_PSPI_STAT_RBF BIT(1) + +/* general definitions */ +#define NPCM_PSPI_TIMEOUT_MS 2000 +#define NPCM_PSPI_MAX_CLK_DIVIDER 256 +#define NPCM_PSPI_MIN_CLK_DIVIDER 4 +#define NPCM_PSPI_DEFAULT_CLK 25000000 + +static inline unsigned int bytes_per_word(unsigned int bits) +{ + return bits <= 8 ? 1 : 2; +} + +static inline void npcm_pspi_irq_enable(struct npcm_pspi *priv, u16 mask) +{ + u16 val; + + val = ioread16(priv->base + NPCM_PSPI_CTL1); + val |= mask; + iowrite16(val, priv->base + NPCM_PSPI_CTL1); +} + +static inline void npcm_pspi_irq_disable(struct npcm_pspi *priv, u16 mask) +{ + u16 val; + + val = ioread16(priv->base + NPCM_PSPI_CTL1); + val &= ~mask; + iowrite16(val, priv->base + NPCM_PSPI_CTL1); +} + +static inline void npcm_pspi_enable(struct npcm_pspi *priv) +{ + u16 val; + + val = ioread16(priv->base + NPCM_PSPI_CTL1); + val |= NPCM_PSPI_CTL1_SPIEN; + iowrite16(val, priv->base + NPCM_PSPI_CTL1); +} + +static inline void npcm_pspi_disable(struct npcm_pspi *priv) +{ + u16 val; + + val = ioread16(priv->base + NPCM_PSPI_CTL1); + val &= ~NPCM_PSPI_CTL1_SPIEN; + iowrite16(val, priv->base + NPCM_PSPI_CTL1); +} + +static void npcm_pspi_set_mode(struct spi_device *spi) +{ + struct npcm_pspi *priv = spi_master_get_devdata(spi->master); + u16 regtemp; + u16 mode_val; + + switch (spi->mode & SPI_MODE_X_MASK) { + case SPI_MODE_0: + mode_val = 0; + break; + case SPI_MODE_1: + mode_val = NPCM_PSPI_CTL1_SCIDL; + break; + case SPI_MODE_2: + mode_val = NPCM_PSPI_CTL1_SCM; + break; + case SPI_MODE_3: + mode_val = NPCM_PSPI_CTL1_SCIDL | NPCM_PSPI_CTL1_SCM; + break; + } + + regtemp = ioread16(priv->base + NPCM_PSPI_CTL1); + regtemp &= ~(NPCM_PSPI_CTL1_SCM | NPCM_PSPI_CTL1_SCIDL); + iowrite16(regtemp | mode_val, priv->base + NPCM_PSPI_CTL1); +} + +static void npcm_pspi_set_transfer_size(struct npcm_pspi *priv, int size) +{ + u16 regtemp; + + regtemp = ioread16(NPCM_PSPI_CTL1 + priv->base); + + switch (size) { + case 8: + regtemp &= ~NPCM_PSPI_CTL1_MOD; + break; + case 16: + regtemp |= NPCM_PSPI_CTL1_MOD; + break; + } + + iowrite16(regtemp, NPCM_PSPI_CTL1 + priv->base); +} + +static void npcm_pspi_set_baudrate(struct npcm_pspi *priv, unsigned int speed) +{ + u32 ckdiv; + u16 regtemp; + + /* the supported rates are numbers from 4 to 256. */ + ckdiv = DIV_ROUND_CLOSEST(clk_get_rate(priv->clk), (2 * speed)) - 1; + + regtemp = ioread16(NPCM_PSPI_CTL1 + priv->base); + regtemp &= ~NPCM_PSPI_CTL1_SCDV6_0; + iowrite16(regtemp | (ckdiv << 9), NPCM_PSPI_CTL1 + priv->base); +} + +static void npcm_pspi_setup_transfer(struct spi_device *spi, + struct spi_transfer *t) +{ + struct npcm_pspi *priv = spi_master_get_devdata(spi->master); + + priv->tx_buf = t->tx_buf; + priv->rx_buf = t->rx_buf; + priv->tx_bytes = t->len; + priv->rx_bytes = t->len; + + if (!priv->is_save_param || priv->mode != spi->mode) { + npcm_pspi_set_mode(spi); + priv->mode = spi->mode; + } + + /* + * If transfer is even length, and 8 bits per word transfer, + * then implement 16 bits-per-word transfer. + */ + if (priv->bits_per_word == 8 && !(t->len & 0x1)) + t->bits_per_word = 16; + + if (!priv->is_save_param || priv->bits_per_word != t->bits_per_word) { + npcm_pspi_set_transfer_size(priv, t->bits_per_word); + priv->bits_per_word = t->bits_per_word; + } + + if (!priv->is_save_param || priv->speed_hz != t->speed_hz) { + npcm_pspi_set_baudrate(priv, t->speed_hz); + priv->speed_hz = t->speed_hz; + } + + if (!priv->is_save_param) + priv->is_save_param = true; +} + +static void npcm_pspi_send(struct npcm_pspi *priv) +{ + int wsize; + u16 val; + + wsize = min(bytes_per_word(priv->bits_per_word), priv->tx_bytes); + priv->tx_bytes -= wsize; + + if (!priv->tx_buf) + return; + + switch (wsize) { + case 1: + val = *priv->tx_buf++; + iowrite8(val, NPCM_PSPI_DATA + priv->base); + break; + case 2: + val = *priv->tx_buf++; + val = *priv->tx_buf++ | (val << 8); + iowrite16(val, NPCM_PSPI_DATA + priv->base); + break; + default: + WARN_ON_ONCE(1); + return; + } +} + +static void npcm_pspi_recv(struct npcm_pspi *priv) +{ + int rsize; + u16 val; + + rsize = min(bytes_per_word(priv->bits_per_word), priv->rx_bytes); + priv->rx_bytes -= rsize; + + if (!priv->rx_buf) + return; + + switch (rsize) { + case 1: + *priv->rx_buf++ = ioread8(priv->base + NPCM_PSPI_DATA); + break; + case 2: + val = ioread16(priv->base + NPCM_PSPI_DATA); + *priv->rx_buf++ = (val >> 8); + *priv->rx_buf++ = val & 0xff; + break; + default: + WARN_ON_ONCE(1); + return; + } +} + +static int npcm_pspi_transfer_one(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *t) +{ + struct npcm_pspi *priv = spi_master_get_devdata(master); + int status; + + npcm_pspi_setup_transfer(spi, t); + reinit_completion(&priv->xfer_done); + npcm_pspi_enable(priv); + status = wait_for_completion_timeout(&priv->xfer_done, + msecs_to_jiffies + (NPCM_PSPI_TIMEOUT_MS)); + if (status == 0) { + npcm_pspi_disable(priv); + return -ETIMEDOUT; + } + + return 0; +} + +static int npcm_pspi_prepare_transfer_hardware(struct spi_master *master) +{ + struct npcm_pspi *priv = spi_master_get_devdata(master); + + npcm_pspi_irq_enable(priv, NPCM_PSPI_CTL1_EIR | NPCM_PSPI_CTL1_EIW); + + return 0; +} + +static int npcm_pspi_unprepare_transfer_hardware(struct spi_master *master) +{ + struct npcm_pspi *priv = spi_master_get_devdata(master); + + npcm_pspi_irq_disable(priv, NPCM_PSPI_CTL1_EIR | NPCM_PSPI_CTL1_EIW); + + return 0; +} + +static void npcm_pspi_reset_hw(struct npcm_pspi *priv) +{ + reset_control_assert(priv->reset); + udelay(5); + reset_control_deassert(priv->reset); +} + +static irqreturn_t npcm_pspi_handler(int irq, void *dev_id) +{ + struct npcm_pspi *priv = dev_id; + u8 stat; + + stat = ioread8(priv->base + NPCM_PSPI_STAT); + + if (!priv->tx_buf && !priv->rx_buf) + return IRQ_NONE; + + if (priv->tx_buf) { + if (stat & NPCM_PSPI_STAT_RBF) { + ioread8(NPCM_PSPI_DATA + priv->base); + if (priv->tx_bytes == 0) { + npcm_pspi_disable(priv); + complete(&priv->xfer_done); + return IRQ_HANDLED; + } + } + + if ((stat & NPCM_PSPI_STAT_BSY) == 0) + if (priv->tx_bytes) + npcm_pspi_send(priv); + } + + if (priv->rx_buf) { + if (stat & NPCM_PSPI_STAT_RBF) { + if (!priv->rx_bytes) + return IRQ_NONE; + + npcm_pspi_recv(priv); + + if (!priv->rx_bytes) { + npcm_pspi_disable(priv); + complete(&priv->xfer_done); + return IRQ_HANDLED; + } + } + + if (((stat & NPCM_PSPI_STAT_BSY) == 0) && !priv->tx_buf) + iowrite8(0x0, NPCM_PSPI_DATA + priv->base); + } + + return IRQ_HANDLED; +} + +static int npcm_pspi_probe(struct platform_device *pdev) +{ + struct npcm_pspi *priv; + struct spi_master *master; + unsigned long clk_hz; + int irq; + int ret; + + master = spi_alloc_master(&pdev->dev, sizeof(*priv)); + if (!master) + return -ENOMEM; + + platform_set_drvdata(pdev, master); + + priv = spi_master_get_devdata(master); + priv->master = master; + priv->is_save_param = false; + + priv->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->base)) { + ret = PTR_ERR(priv->base); + goto out_master_put; + } + + priv->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(priv->clk)) { + dev_err(&pdev->dev, "failed to get clock\n"); + ret = PTR_ERR(priv->clk); + goto out_master_put; + } + + ret = clk_prepare_enable(priv->clk); + if (ret) + goto out_master_put; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + ret = irq; + goto out_disable_clk; + } + + priv->reset = devm_reset_control_get(&pdev->dev, NULL); + if (IS_ERR(priv->reset)) { + ret = PTR_ERR(priv->reset); + goto out_disable_clk; + } + + /* reset SPI-HW block */ + npcm_pspi_reset_hw(priv); + + ret = devm_request_irq(&pdev->dev, irq, npcm_pspi_handler, 0, + "npcm-pspi", priv); + if (ret) { + dev_err(&pdev->dev, "failed to request IRQ\n"); + goto out_disable_clk; + } + + init_completion(&priv->xfer_done); + + clk_hz = clk_get_rate(priv->clk); + + master->max_speed_hz = DIV_ROUND_UP(clk_hz, NPCM_PSPI_MIN_CLK_DIVIDER); + master->min_speed_hz = DIV_ROUND_UP(clk_hz, NPCM_PSPI_MAX_CLK_DIVIDER); + master->mode_bits = SPI_CPHA | SPI_CPOL; + master->dev.of_node = pdev->dev.of_node; + master->bus_num = -1; + master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16); + master->transfer_one = npcm_pspi_transfer_one; + master->prepare_transfer_hardware = + npcm_pspi_prepare_transfer_hardware; + master->unprepare_transfer_hardware = + npcm_pspi_unprepare_transfer_hardware; + master->use_gpio_descriptors = true; + + /* set to default clock rate */ + npcm_pspi_set_baudrate(priv, NPCM_PSPI_DEFAULT_CLK); + + ret = devm_spi_register_master(&pdev->dev, master); + if (ret) + goto out_disable_clk; + + pr_info("NPCM Peripheral SPI %d probed\n", master->bus_num); + + return 0; + +out_disable_clk: + clk_disable_unprepare(priv->clk); + +out_master_put: + spi_master_put(master); + return ret; +} + +static int npcm_pspi_remove(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct npcm_pspi *priv = spi_master_get_devdata(master); + + npcm_pspi_reset_hw(priv); + clk_disable_unprepare(priv->clk); + + return 0; +} + +static const struct of_device_id npcm_pspi_match[] = { + { .compatible = "nuvoton,npcm750-pspi", .data = NULL }, + { .compatible = "nuvoton,npcm845-pspi", .data = NULL }, + {} +}; +MODULE_DEVICE_TABLE(of, npcm_pspi_match); + +static struct platform_driver npcm_pspi_driver = { + .driver = { + .name = DRIVER_NAME, + .of_match_table = npcm_pspi_match, + }, + .probe = npcm_pspi_probe, + .remove = npcm_pspi_remove, +}; +module_platform_driver(npcm_pspi_driver); + +MODULE_DESCRIPTION("NPCM peripheral SPI Controller driver"); +MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>"); +MODULE_LICENSE("GPL v2"); + |