/* * 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/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 { 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_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; writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); writel(0, hw->base + ALTERA_SPI_SLAVE_SEL); } else { writel(BIT(spi->chip_select), hw->base + ALTERA_SPI_SLAVE_SEL); hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK; writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); } } 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; } } writel(txd, hw->base + ALTERA_SPI_TXDATA); } static void altera_spi_rx_word(struct altera_spi *hw) { 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++; } 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); 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 */ altera_spi_tx_word(hw); } else { while (hw->count < hw->len) { altera_spi_tx_word(hw); while (!(readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)) cpu_relax(); altera_spi_rx_word(hw); } spi_finalize_current_transfer(master); } return t->len; } 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; writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); spi_finalize_current_transfer(master); } 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; master->transfer_one = altera_spi_txrx; master->set_cs = altera_spi_set_cs; hw = spi_master_get_devdata(master); /* 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) { 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; dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, 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 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), }, }; 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);