spi: New driver for Altera SPI (0b782531) · Commits · e / devices / android_kernel_oneplus_sm8150

Documentation/devicetree/bindings/spi/spi_altera.txt

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		Altera SPI

		Required properties:
		- compatible : should be "ALTR,spi-1.0".

drivers/spi/Kconfig

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		@@ -53,6 +53,12 @@ if SPI_MASTER

		comment "SPI Master Controller Drivers"

		config SPI_ALTERA
		tristate "Altera SPI Controller"
		select SPI_BITBANG
		help
		This is the driver for the Altera SPI Controller.

		config SPI_ATH79
		tristate "Atheros AR71XX/AR724X/AR913X SPI controller driver"
		depends on ATH79 && GENERIC_GPIO

drivers/spi/Makefile

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		@@ -9,6 +9,7 @@ ccflags-$(CONFIG_SPI_DEBUG) := -DDEBUG
		obj-$(CONFIG_SPI_MASTER) += spi.o

		# SPI master controller drivers (bus)
		obj-$(CONFIG_SPI_ALTERA) += spi_altera.o
		obj-$(CONFIG_SPI_ATMEL) += atmel_spi.o
		obj-$(CONFIG_SPI_ATH79) += ath79_spi.o
		obj-$(CONFIG_SPI_BFIN) += spi_bfin5xx.o

drivers/spi/spi_altera.c

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		/*
		* 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/init.h>
		#include <linux/interrupt.h>
		#include <linux/errno.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 int altera_spi_setupxfer(struct spi_device spi, struct spi_transfer t)
		{
		return 0;
		}

		static int altera_spi_setup(struct spi_device *spi)
		{
		return 0;
		}

		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 = (t->bits_per_word ? : spi->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 {
		/* send the first byte */
		writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);

		while (1) {
		unsigned int rxd;

		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++;

		if (hw->count < hw->len)
		writel(hw_txbyte(hw, hw->count),
		hw->base + ALTERA_SPI_TXDATA);
		else
		break;
		}

		}

		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 __devinit altera_spi_probe(struct platform_device *pdev)
		{
		struct altera_spi_platform_data *platp = pdev->dev.platform_data;
		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->setup = altera_spi_setup;

		hw = spi_master_get_devdata(master);
		platform_set_drvdata(pdev, hw);

		/* setup the state for the bitbang driver */
		hw->bitbang.master = spi_master_get(master);
		if (!hw->bitbang.master)
		return err;
		hw->bitbang.setup_transfer = altera_spi_setupxfer;
		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);
		if (!res)
		goto exit_busy;
		if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
		pdev->name))
		goto exit_busy;
		hw->base = devm_ioremap_nocache(&pdev->dev, res->start,
		resource_size(res));
		if (!hw->base)
		goto exit_busy;
		/* 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;
		}
		/* find platform data */
		if (!platp)
		hw->bitbang.master->dev.of_node = pdev->dev.of_node;

		/* 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_busy:
		err = -EBUSY;
		exit:
		platform_set_drvdata(pdev, NULL);
		spi_master_put(master);
		return err;
		}

		static int __devexit 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);
		platform_set_drvdata(dev, NULL);
		spi_master_put(master);
		return 0;
		}

		#ifdef CONFIG_OF
		static const struct of_device_id altera_spi_match[] = {
		{ .compatible = "ALTR,spi-1.0", },
		{},
		};
		MODULE_DEVICE_TABLE(of, altera_spi_match);
		#else /* CONFIG_OF */
		#define altera_spi_match NULL
		#endif /* CONFIG_OF */

		static struct platform_driver altera_spi_driver = {
		.probe = altera_spi_probe,
		.remove = __devexit_p(altera_spi_remove),
		.driver = {
		.name = DRV_NAME,
		.owner = THIS_MODULE,
		.pm = NULL,
		.of_match_table = altera_spi_match,
		},
		};

		static int __init altera_spi_init(void)
		{
		return platform_driver_register(&altera_spi_driver);
		}
		module_init(altera_spi_init);

		static void __exit altera_spi_exit(void)
		{
		platform_driver_unregister(&altera_spi_driver);
		}
		module_exit(altera_spi_exit);

		MODULE_DESCRIPTION("Altera SPI driver");
		MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
		MODULE_LICENSE("GPL");
		MODULE_ALIAS("platform:" DRV_NAME);