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- // 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);
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