diff options
Diffstat (limited to 'drivers/spi/spi-altera.c')
| -rw-r--r-- | drivers/spi/spi-altera.c | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/drivers/spi/spi-altera.c b/drivers/spi/spi-altera.c new file mode 100644 index 00000000000..5b5709a5c95 --- /dev/null +++ b/drivers/spi/spi-altera.c @@ -0,0 +1,295 @@ +/* + * 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> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/interrupt.h> +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> +#include <linux/spi/spi_bitbang.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 + +struct altera_spi { + /* bitbang has to be first */ + struct spi_bitbang bitbang; + struct completion done; + + void __iomem *base; + int irq; + int len; + int count; + int bytes_per_word; + unsigned long imr; + + /* data buffers */ + const unsigned char *tx; + unsigned char *rx; +}; + +static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev) +{ + return spi_master_get_devdata(sdev->master); +} + +static void altera_spi_chipsel(struct spi_device *spi, int value) +{ + struct altera_spi *hw = altera_spi_to_hw(spi); + + if (spi->mode & SPI_CS_HIGH) { + switch (value) { + case BITBANG_CS_INACTIVE: + writel(1 << spi->chip_select, + hw->base + ALTERA_SPI_SLAVE_SEL); + hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK; + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); + break; + + case BITBANG_CS_ACTIVE: + hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK; + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); + writel(0, hw->base + ALTERA_SPI_SLAVE_SEL); + break; + } + } else { + switch (value) { + case BITBANG_CS_INACTIVE: + hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK; + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); + break; + + case BITBANG_CS_ACTIVE: + writel(1 << spi->chip_select, + hw->base + ALTERA_SPI_SLAVE_SEL); + hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK; + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); + break; + } + } +} + +static inline unsigned int hw_txbyte(struct altera_spi *hw, int count) +{ + if (hw->tx) { + switch (hw->bytes_per_word) { + case 1: + return hw->tx[count]; + case 2: + return (hw->tx[count * 2] + | (hw->tx[count * 2 + 1] << 8)); + } + } + return 0; +} + +static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t) +{ + struct altera_spi *hw = altera_spi_to_hw(spi); + + 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; + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); + + /* send the first byte */ + writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA); + + wait_for_completion(&hw->done); + /* disable receive interrupt */ + hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK; + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); + } else { + while (hw->count < hw->len) { + unsigned int rxd; + + writel(hw_txbyte(hw, hw->count), + hw->base + ALTERA_SPI_TXDATA); + + while (!(readl(hw->base + ALTERA_SPI_STATUS) & + ALTERA_SPI_STATUS_RRDY_MSK)) + cpu_relax(); + + rxd = readl(hw->base + ALTERA_SPI_RXDATA); + 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; + } + } + + hw->count++; + } + } + + return hw->count * hw->bytes_per_word; +} + +static irqreturn_t altera_spi_irq(int irq, void *dev) +{ + struct altera_spi *hw = dev; + unsigned int rxd; + + rxd = readl(hw->base + ALTERA_SPI_RXDATA); + 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; + } + } + + hw->count++; + + if (hw->count < hw->len) + writel(hw_txbyte(hw, hw->count), hw->base + ALTERA_SPI_TXDATA); + else + complete(&hw->done); + + return IRQ_HANDLED; +} + +static int altera_spi_probe(struct platform_device *pdev) +{ + struct altera_spi *hw; + struct spi_master *master; + struct resource *res; + int err = -ENODEV; + + master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi)); + if (!master) + return err; + + /* setup the master state. */ + master->bus_num = pdev->id; + 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; + + hw = spi_master_get_devdata(master); + platform_set_drvdata(pdev, hw); + + /* setup the state for the bitbang driver */ + hw->bitbang.master = master; + hw->bitbang.chipselect = altera_spi_chipsel; + hw->bitbang.txrx_bufs = altera_spi_txrx; + + /* find and map our resources */ + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + hw->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(hw->base)) { + err = PTR_ERR(hw->base); + goto exit; + } + /* program defaults into the registers */ + hw->imr = 0; /* disable spi interrupts */ + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); + writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */ + if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK) + readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */ + /* irq is optional */ + hw->irq = platform_get_irq(pdev, 0); + if (hw->irq >= 0) { + init_completion(&hw->done); + err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0, + pdev->name, hw); + if (err) + goto exit; + } + + /* register our spi controller */ + err = spi_bitbang_start(&hw->bitbang); + if (err) + goto exit; + dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq); + + return 0; +exit: + spi_master_put(master); + return err; +} + +static int altera_spi_remove(struct platform_device *dev) +{ + struct altera_spi *hw = platform_get_drvdata(dev); + struct spi_master *master = hw->bitbang.master; + + spi_bitbang_stop(&hw->bitbang); + spi_master_put(master); + return 0; +} + +#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 struct platform_driver altera_spi_driver = { + .probe = altera_spi_probe, + .remove = altera_spi_remove, + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + .pm = NULL, + .of_match_table = of_match_ptr(altera_spi_match), + }, +}; +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); |