| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Altera SPI driver |
| * |
| * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw> |
| * |
| * Based on spi_s3c24xx.c, which is: |
| * Copyright (c) 2006 Ben Dooks |
| * Copyright (c) 2006 Simtec Electronics |
| * Ben Dooks <ben@simtec.co.uk> |
| */ |
| |
| #include <linux/interrupt.h> |
| #include <linux/errno.h> |
| #include <linux/module.h> |
| #include <linux/platform_device.h> |
| #include <linux/spi/altera.h> |
| #include <linux/spi/spi.h> |
| #include <linux/io.h> |
| #include <linux/of.h> |
| |
| #define DRV_NAME "spi_altera" |
| |
| #define ALTERA_SPI_RXDATA 0 |
| #define ALTERA_SPI_TXDATA 4 |
| #define ALTERA_SPI_STATUS 8 |
| #define ALTERA_SPI_CONTROL 12 |
| #define ALTERA_SPI_SLAVE_SEL 20 |
| |
| #define ALTERA_SPI_STATUS_ROE_MSK 0x8 |
| #define ALTERA_SPI_STATUS_TOE_MSK 0x10 |
| #define ALTERA_SPI_STATUS_TMT_MSK 0x20 |
| #define ALTERA_SPI_STATUS_TRDY_MSK 0x40 |
| #define ALTERA_SPI_STATUS_RRDY_MSK 0x80 |
| #define ALTERA_SPI_STATUS_E_MSK 0x100 |
| |
| #define ALTERA_SPI_CONTROL_IROE_MSK 0x8 |
| #define ALTERA_SPI_CONTROL_ITOE_MSK 0x10 |
| #define ALTERA_SPI_CONTROL_ITRDY_MSK 0x40 |
| #define ALTERA_SPI_CONTROL_IRRDY_MSK 0x80 |
| #define ALTERA_SPI_CONTROL_IE_MSK 0x100 |
| #define ALTERA_SPI_CONTROL_SSO_MSK 0x400 |
| |
| #define ALTERA_SPI_MAX_CS 32 |
| |
| enum altera_spi_type { |
| ALTERA_SPI_TYPE_UNKNOWN, |
| ALTERA_SPI_TYPE_SUBDEV, |
| }; |
| |
| struct altera_spi { |
| int irq; |
| int len; |
| int count; |
| int bytes_per_word; |
| u32 imr; |
| |
| /* data buffers */ |
| const unsigned char *tx; |
| unsigned char *rx; |
| |
| struct regmap *regmap; |
| u32 regoff; |
| struct device *dev; |
| }; |
| |
| static const struct regmap_config spi_altera_config = { |
| .reg_bits = 32, |
| .reg_stride = 4, |
| .val_bits = 32, |
| .fast_io = true, |
| }; |
| |
| static int altr_spi_writel(struct altera_spi *hw, unsigned int reg, |
| unsigned int val) |
| { |
| int ret; |
| |
| ret = regmap_write(hw->regmap, hw->regoff + reg, val); |
| if (ret) |
| dev_err(hw->dev, "fail to write reg 0x%x val 0x%x: %d\n", |
| reg, val, ret); |
| |
| return ret; |
| } |
| |
| static int altr_spi_readl(struct altera_spi *hw, unsigned int reg, |
| unsigned int *val) |
| { |
| int ret; |
| |
| ret = regmap_read(hw->regmap, hw->regoff + reg, val); |
| if (ret) |
| dev_err(hw->dev, "fail to read reg 0x%x: %d\n", reg, ret); |
| |
| return ret; |
| } |
| |
| static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev) |
| { |
| return spi_master_get_devdata(sdev->master); |
| } |
| |
| static void altera_spi_set_cs(struct spi_device *spi, bool is_high) |
| { |
| struct altera_spi *hw = altera_spi_to_hw(spi); |
| |
| if (is_high) { |
| hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK; |
| altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); |
| altr_spi_writel(hw, ALTERA_SPI_SLAVE_SEL, 0); |
| } else { |
| altr_spi_writel(hw, ALTERA_SPI_SLAVE_SEL, |
| BIT(spi->chip_select)); |
| hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK; |
| altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); |
| } |
| } |
| |
| static void altera_spi_tx_word(struct altera_spi *hw) |
| { |
| unsigned int txd = 0; |
| |
| if (hw->tx) { |
| switch (hw->bytes_per_word) { |
| case 1: |
| txd = hw->tx[hw->count]; |
| break; |
| case 2: |
| txd = (hw->tx[hw->count * 2] |
| | (hw->tx[hw->count * 2 + 1] << 8)); |
| break; |
| case 4: |
| txd = (hw->tx[hw->count * 4] |
| | (hw->tx[hw->count * 4 + 1] << 8) |
| | (hw->tx[hw->count * 4 + 2] << 16) |
| | (hw->tx[hw->count * 4 + 3] << 24)); |
| break; |
| |
| } |
| } |
| |
| altr_spi_writel(hw, ALTERA_SPI_TXDATA, txd); |
| } |
| |
| static void altera_spi_rx_word(struct altera_spi *hw) |
| { |
| unsigned int rxd; |
| |
| altr_spi_readl(hw, ALTERA_SPI_RXDATA, &rxd); |
| if (hw->rx) { |
| switch (hw->bytes_per_word) { |
| case 1: |
| hw->rx[hw->count] = rxd; |
| break; |
| case 2: |
| hw->rx[hw->count * 2] = rxd; |
| hw->rx[hw->count * 2 + 1] = rxd >> 8; |
| break; |
| case 4: |
| hw->rx[hw->count * 4] = rxd; |
| hw->rx[hw->count * 4 + 1] = rxd >> 8; |
| hw->rx[hw->count * 4 + 2] = rxd >> 16; |
| hw->rx[hw->count * 4 + 3] = rxd >> 24; |
| break; |
| |
| } |
| } |
| |
| hw->count++; |
| } |
| |
| static int altera_spi_txrx(struct spi_master *master, |
| struct spi_device *spi, struct spi_transfer *t) |
| { |
| struct altera_spi *hw = spi_master_get_devdata(master); |
| u32 val; |
| |
| hw->tx = t->tx_buf; |
| hw->rx = t->rx_buf; |
| hw->count = 0; |
| hw->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8); |
| hw->len = t->len / hw->bytes_per_word; |
| |
| if (hw->irq >= 0) { |
| /* enable receive interrupt */ |
| hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK; |
| altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); |
| |
| /* send the first byte */ |
| altera_spi_tx_word(hw); |
| |
| return 1; |
| } |
| |
| while (hw->count < hw->len) { |
| altera_spi_tx_word(hw); |
| |
| for (;;) { |
| altr_spi_readl(hw, ALTERA_SPI_STATUS, &val); |
| if (val & ALTERA_SPI_STATUS_RRDY_MSK) |
| break; |
| |
| cpu_relax(); |
| } |
| |
| altera_spi_rx_word(hw); |
| } |
| spi_finalize_current_transfer(master); |
| |
| return 0; |
| } |
| |
| static irqreturn_t altera_spi_irq(int irq, void *dev) |
| { |
| struct spi_master *master = dev; |
| struct altera_spi *hw = spi_master_get_devdata(master); |
| |
| altera_spi_rx_word(hw); |
| |
| if (hw->count < hw->len) { |
| altera_spi_tx_word(hw); |
| } else { |
| /* disable receive interrupt */ |
| hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK; |
| altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); |
| |
| spi_finalize_current_transfer(master); |
| } |
| |
| return IRQ_HANDLED; |
| } |
| |
| static int altera_spi_probe(struct platform_device *pdev) |
| { |
| const struct platform_device_id *platid = platform_get_device_id(pdev); |
| struct altera_spi_platform_data *pdata = dev_get_platdata(&pdev->dev); |
| enum altera_spi_type type = ALTERA_SPI_TYPE_UNKNOWN; |
| struct altera_spi *hw; |
| struct spi_master *master; |
| int err = -ENODEV; |
| u32 val; |
| u16 i; |
| |
| master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi)); |
| if (!master) |
| return err; |
| |
| /* setup the master state. */ |
| master->bus_num = pdev->id; |
| |
| if (pdata) { |
| if (pdata->num_chipselect > ALTERA_SPI_MAX_CS) { |
| dev_err(&pdev->dev, |
| "Invalid number of chipselect: %hu\n", |
| pdata->num_chipselect); |
| err = -EINVAL; |
| goto exit; |
| } |
| |
| master->num_chipselect = pdata->num_chipselect; |
| master->mode_bits = pdata->mode_bits; |
| master->bits_per_word_mask = pdata->bits_per_word_mask; |
| } else { |
| master->num_chipselect = 16; |
| master->mode_bits = SPI_CS_HIGH; |
| master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16); |
| } |
| |
| master->dev.of_node = pdev->dev.of_node; |
| master->transfer_one = altera_spi_txrx; |
| master->set_cs = altera_spi_set_cs; |
| |
| hw = spi_master_get_devdata(master); |
| hw->dev = &pdev->dev; |
| |
| if (platid) |
| type = platid->driver_data; |
| |
| /* find and map our resources */ |
| if (type == ALTERA_SPI_TYPE_SUBDEV) { |
| struct resource *regoff; |
| |
| hw->regmap = dev_get_regmap(pdev->dev.parent, NULL); |
| if (!hw->regmap) { |
| dev_err(&pdev->dev, "get regmap failed\n"); |
| goto exit; |
| } |
| |
| regoff = platform_get_resource(pdev, IORESOURCE_REG, 0); |
| if (regoff) |
| hw->regoff = regoff->start; |
| } else { |
| void __iomem *res; |
| |
| res = devm_platform_ioremap_resource(pdev, 0); |
| if (IS_ERR(res)) { |
| err = PTR_ERR(res); |
| goto exit; |
| } |
| |
| hw->regmap = devm_regmap_init_mmio(&pdev->dev, res, |
| &spi_altera_config); |
| if (IS_ERR(hw->regmap)) { |
| dev_err(&pdev->dev, "regmap mmio init failed\n"); |
| err = PTR_ERR(hw->regmap); |
| goto exit; |
| } |
| } |
| |
| /* program defaults into the registers */ |
| hw->imr = 0; /* disable spi interrupts */ |
| altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); |
| altr_spi_writel(hw, ALTERA_SPI_STATUS, 0); /* clear status reg */ |
| altr_spi_readl(hw, ALTERA_SPI_STATUS, &val); |
| if (val & ALTERA_SPI_STATUS_RRDY_MSK) |
| altr_spi_readl(hw, ALTERA_SPI_RXDATA, &val); /* flush rxdata */ |
| /* irq is optional */ |
| hw->irq = platform_get_irq(pdev, 0); |
| if (hw->irq >= 0) { |
| err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0, |
| pdev->name, master); |
| if (err) |
| goto exit; |
| } |
| |
| err = devm_spi_register_master(&pdev->dev, master); |
| if (err) |
| goto exit; |
| |
| if (pdata) { |
| for (i = 0; i < pdata->num_devices; i++) { |
| if (!spi_new_device(master, pdata->devices + i)) |
| dev_warn(&pdev->dev, |
| "unable to create SPI device: %s\n", |
| pdata->devices[i].modalias); |
| } |
| } |
| |
| dev_info(&pdev->dev, "regoff %u, irq %d\n", hw->regoff, hw->irq); |
| |
| return 0; |
| exit: |
| spi_master_put(master); |
| return err; |
| } |
| |
| #ifdef CONFIG_OF |
| static const struct of_device_id altera_spi_match[] = { |
| { .compatible = "ALTR,spi-1.0", }, |
| { .compatible = "altr,spi-1.0", }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(of, altera_spi_match); |
| #endif /* CONFIG_OF */ |
| |
| static const struct platform_device_id altera_spi_ids[] = { |
| { DRV_NAME, ALTERA_SPI_TYPE_UNKNOWN }, |
| { "subdev_spi_altera", ALTERA_SPI_TYPE_SUBDEV }, |
| { } |
| }; |
| MODULE_DEVICE_TABLE(platform, altera_spi_ids); |
| |
| static struct platform_driver altera_spi_driver = { |
| .probe = altera_spi_probe, |
| .driver = { |
| .name = DRV_NAME, |
| .pm = NULL, |
| .of_match_table = of_match_ptr(altera_spi_match), |
| }, |
| .id_table = altera_spi_ids, |
| }; |
| module_platform_driver(altera_spi_driver); |
| |
| MODULE_DESCRIPTION("Altera SPI driver"); |
| MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS("platform:" DRV_NAME); |