forked from Minki/linux
spi: New driver for Altera SPI
This patch adds a new SPI driver to support the Altera SOPC Builder SPI component. It uses the bitbanging library. Signed-off-by: Thomas Chou <thomas@wytron.com.tw> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Thomas Chou
Grant Likely
parent
ce792580ea
commit
0b782531c0
4
Documentation/devicetree/bindings/spi/spi_altera.txt
Normal file
4
Documentation/devicetree/bindings/spi/spi_altera.txt
Normal file
@ -0,0 +1,4 @@
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Altera SPI
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Required properties:
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- compatible : should be "ALTR,spi-1.0".
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@ -53,6 +53,12 @@ if SPI_MASTER
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comment "SPI Master Controller Drivers"
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config SPI_ALTERA
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tristate "Altera SPI Controller"
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select SPI_BITBANG
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help
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This is the driver for the Altera SPI Controller.
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config SPI_ATH79
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tristate "Atheros AR71XX/AR724X/AR913X SPI controller driver"
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depends on ATH79 && GENERIC_GPIO
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@ -9,6 +9,7 @@ ccflags-$(CONFIG_SPI_DEBUG) := -DDEBUG
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obj-$(CONFIG_SPI_MASTER) += spi.o
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# SPI master controller drivers (bus)
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obj-$(CONFIG_SPI_ALTERA) += spi_altera.o
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obj-$(CONFIG_SPI_ATMEL) += atmel_spi.o
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obj-$(CONFIG_SPI_ATH79) += ath79_spi.o
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obj-$(CONFIG_SPI_BFIN) += spi_bfin5xx.o
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339
drivers/spi/spi_altera.c
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339
drivers/spi/spi_altera.c
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@ -0,0 +1,339 @@
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/*
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* Altera SPI driver
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*
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* Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
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*
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* Based on spi_s3c24xx.c, which is:
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* Copyright (c) 2006 Ben Dooks
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* Copyright (c) 2006 Simtec Electronics
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* Ben Dooks <ben@simtec.co.uk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/errno.h>
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#include <linux/platform_device.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/spi_bitbang.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#define DRV_NAME "spi_altera"
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#define ALTERA_SPI_RXDATA 0
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#define ALTERA_SPI_TXDATA 4
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#define ALTERA_SPI_STATUS 8
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#define ALTERA_SPI_CONTROL 12
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#define ALTERA_SPI_SLAVE_SEL 20
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#define ALTERA_SPI_STATUS_ROE_MSK 0x8
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#define ALTERA_SPI_STATUS_TOE_MSK 0x10
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#define ALTERA_SPI_STATUS_TMT_MSK 0x20
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#define ALTERA_SPI_STATUS_TRDY_MSK 0x40
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#define ALTERA_SPI_STATUS_RRDY_MSK 0x80
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#define ALTERA_SPI_STATUS_E_MSK 0x100
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#define ALTERA_SPI_CONTROL_IROE_MSK 0x8
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#define ALTERA_SPI_CONTROL_ITOE_MSK 0x10
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#define ALTERA_SPI_CONTROL_ITRDY_MSK 0x40
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#define ALTERA_SPI_CONTROL_IRRDY_MSK 0x80
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#define ALTERA_SPI_CONTROL_IE_MSK 0x100
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#define ALTERA_SPI_CONTROL_SSO_MSK 0x400
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struct altera_spi {
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/* bitbang has to be first */
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struct spi_bitbang bitbang;
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struct completion done;
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void __iomem *base;
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int irq;
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int len;
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int count;
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int bytes_per_word;
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unsigned long imr;
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/* data buffers */
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const unsigned char *tx;
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unsigned char *rx;
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};
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static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
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{
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return spi_master_get_devdata(sdev->master);
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}
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static void altera_spi_chipsel(struct spi_device *spi, int value)
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{
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struct altera_spi *hw = altera_spi_to_hw(spi);
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if (spi->mode & SPI_CS_HIGH) {
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switch (value) {
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case BITBANG_CS_INACTIVE:
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writel(1 << spi->chip_select,
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hw->base + ALTERA_SPI_SLAVE_SEL);
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hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
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writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
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break;
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case BITBANG_CS_ACTIVE:
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hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
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writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
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writel(0, hw->base + ALTERA_SPI_SLAVE_SEL);
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break;
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}
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} else {
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switch (value) {
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case BITBANG_CS_INACTIVE:
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hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
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writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
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break;
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case BITBANG_CS_ACTIVE:
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writel(1 << spi->chip_select,
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hw->base + ALTERA_SPI_SLAVE_SEL);
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hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
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writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
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break;
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}
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}
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}
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static int altera_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
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{
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return 0;
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}
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static int altera_spi_setup(struct spi_device *spi)
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{
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return 0;
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}
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static inline unsigned int hw_txbyte(struct altera_spi *hw, int count)
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{
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if (hw->tx) {
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switch (hw->bytes_per_word) {
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case 1:
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return hw->tx[count];
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case 2:
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return (hw->tx[count * 2]
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| (hw->tx[count * 2 + 1] << 8));
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}
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}
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return 0;
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}
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static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
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{
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struct altera_spi *hw = altera_spi_to_hw(spi);
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hw->tx = t->tx_buf;
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hw->rx = t->rx_buf;
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hw->count = 0;
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hw->bytes_per_word = (t->bits_per_word ? : spi->bits_per_word) / 8;
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hw->len = t->len / hw->bytes_per_word;
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if (hw->irq >= 0) {
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/* enable receive interrupt */
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hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
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writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
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/* send the first byte */
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writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
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wait_for_completion(&hw->done);
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/* disable receive interrupt */
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hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
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writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
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} else {
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/* send the first byte */
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writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
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while (1) {
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unsigned int rxd;
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while (!(readl(hw->base + ALTERA_SPI_STATUS) &
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ALTERA_SPI_STATUS_RRDY_MSK))
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cpu_relax();
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rxd = readl(hw->base + ALTERA_SPI_RXDATA);
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if (hw->rx) {
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switch (hw->bytes_per_word) {
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case 1:
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hw->rx[hw->count] = rxd;
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break;
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case 2:
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hw->rx[hw->count * 2] = rxd;
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hw->rx[hw->count * 2 + 1] = rxd >> 8;
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break;
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}
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}
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hw->count++;
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if (hw->count < hw->len)
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writel(hw_txbyte(hw, hw->count),
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hw->base + ALTERA_SPI_TXDATA);
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else
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break;
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}
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}
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return hw->count * hw->bytes_per_word;
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}
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static irqreturn_t altera_spi_irq(int irq, void *dev)
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{
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struct altera_spi *hw = dev;
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unsigned int rxd;
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rxd = readl(hw->base + ALTERA_SPI_RXDATA);
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if (hw->rx) {
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switch (hw->bytes_per_word) {
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case 1:
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hw->rx[hw->count] = rxd;
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break;
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case 2:
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hw->rx[hw->count * 2] = rxd;
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hw->rx[hw->count * 2 + 1] = rxd >> 8;
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break;
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}
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}
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hw->count++;
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if (hw->count < hw->len)
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writel(hw_txbyte(hw, hw->count), hw->base + ALTERA_SPI_TXDATA);
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else
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complete(&hw->done);
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return IRQ_HANDLED;
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}
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static int __devinit altera_spi_probe(struct platform_device *pdev)
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{
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struct altera_spi_platform_data *platp = pdev->dev.platform_data;
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struct altera_spi *hw;
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struct spi_master *master;
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struct resource *res;
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int err = -ENODEV;
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master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
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if (!master)
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return err;
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/* setup the master state. */
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master->bus_num = pdev->id;
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master->num_chipselect = 16;
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master->mode_bits = SPI_CS_HIGH;
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master->setup = altera_spi_setup;
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hw = spi_master_get_devdata(master);
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platform_set_drvdata(pdev, hw);
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/* setup the state for the bitbang driver */
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hw->bitbang.master = spi_master_get(master);
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if (!hw->bitbang.master)
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return err;
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hw->bitbang.setup_transfer = altera_spi_setupxfer;
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hw->bitbang.chipselect = altera_spi_chipsel;
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hw->bitbang.txrx_bufs = altera_spi_txrx;
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/* find and map our resources */
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res)
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goto exit_busy;
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if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
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pdev->name))
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goto exit_busy;
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hw->base = devm_ioremap_nocache(&pdev->dev, res->start,
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resource_size(res));
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if (!hw->base)
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goto exit_busy;
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/* program defaults into the registers */
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hw->imr = 0; /* disable spi interrupts */
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writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
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writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */
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if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
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readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */
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/* irq is optional */
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hw->irq = platform_get_irq(pdev, 0);
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if (hw->irq >= 0) {
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init_completion(&hw->done);
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err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
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pdev->name, hw);
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if (err)
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goto exit;
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}
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/* find platform data */
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if (!platp)
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hw->bitbang.master->dev.of_node = pdev->dev.of_node;
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/* register our spi controller */
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err = spi_bitbang_start(&hw->bitbang);
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if (err)
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goto exit;
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dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
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return 0;
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exit_busy:
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err = -EBUSY;
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exit:
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platform_set_drvdata(pdev, NULL);
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spi_master_put(master);
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return err;
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}
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static int __devexit altera_spi_remove(struct platform_device *dev)
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{
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struct altera_spi *hw = platform_get_drvdata(dev);
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struct spi_master *master = hw->bitbang.master;
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spi_bitbang_stop(&hw->bitbang);
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platform_set_drvdata(dev, NULL);
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spi_master_put(master);
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return 0;
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}
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#ifdef CONFIG_OF
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static const struct of_device_id altera_spi_match[] = {
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{ .compatible = "ALTR,spi-1.0", },
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{},
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};
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MODULE_DEVICE_TABLE(of, altera_spi_match);
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#else /* CONFIG_OF */
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#define altera_spi_match NULL
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#endif /* CONFIG_OF */
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static struct platform_driver altera_spi_driver = {
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.probe = altera_spi_probe,
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.remove = __devexit_p(altera_spi_remove),
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.driver = {
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.name = DRV_NAME,
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.owner = THIS_MODULE,
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.pm = NULL,
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.of_match_table = altera_spi_match,
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},
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};
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static int __init altera_spi_init(void)
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{
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return platform_driver_register(&altera_spi_driver);
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}
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module_init(altera_spi_init);
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static void __exit altera_spi_exit(void)
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{
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platform_driver_unregister(&altera_spi_driver);
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}
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module_exit(altera_spi_exit);
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MODULE_DESCRIPTION("Altera SPI driver");
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MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:" DRV_NAME);
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