--- /dev/null
+/*
+ * SPI controller driver for the Atheros AR71XX/AR724X/AR913X SoCs
+ *
+ * Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
+ *
+ * This driver has been based on the spi-gpio.c:
+ * Copyright (C) 2006,2008 David Brownell
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/bitops.h>
+#include <linux/gpio.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include <asm/mach-ath79/ath79_spi_platform.h>
+
+#define DRV_NAME "ath79-spi"
+
+#define ATH79_SPI_RRW_DELAY_FACTOR 12000
+#define MHZ (1000 * 1000)
+
+struct ath79_spi {
+ struct spi_bitbang bitbang;
+ u32 ioc_base;
+ u32 reg_ctrl;
+ void __iomem *base;
+ struct clk *clk;
+ unsigned rrw_delay;
+};
+
+static inline u32 ath79_spi_rr(struct ath79_spi *sp, unsigned reg)
+{
+ return ioread32(sp->base + reg);
+}
+
+static inline void ath79_spi_wr(struct ath79_spi *sp, unsigned reg, u32 val)
+{
+ iowrite32(val, sp->base + reg);
+}
+
+static inline struct ath79_spi *ath79_spidev_to_sp(struct spi_device *spi)
+{
+ return spi_master_get_devdata(spi->master);
+}
+
+static inline void ath79_spi_delay(struct ath79_spi *sp, unsigned nsecs)
+{
+ if (nsecs > sp->rrw_delay)
+ ndelay(nsecs - sp->rrw_delay);
+}
+
+static void ath79_spi_chipselect(struct spi_device *spi, int is_active)
+{
+ struct ath79_spi *sp = ath79_spidev_to_sp(spi);
+ int cs_high = (spi->mode & SPI_CS_HIGH) ? is_active : !is_active;
+
+ if (is_active) {
+ /* set initial clock polarity */
+ if (spi->mode & SPI_CPOL)
+ sp->ioc_base |= AR71XX_SPI_IOC_CLK;
+ else
+ sp->ioc_base &= ~AR71XX_SPI_IOC_CLK;
+
+ ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);
+ }
+
+ if (spi->chip_select) {
+ struct ath79_spi_controller_data *cdata = spi->controller_data;
+
+ /* SPI is normally active-low */
+ gpio_set_value(cdata->gpio, cs_high);
+ } else {
+ if (cs_high)
+ sp->ioc_base |= AR71XX_SPI_IOC_CS0;
+ else
+ sp->ioc_base &= ~AR71XX_SPI_IOC_CS0;
+
+ ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);
+ }
+
+}
+
+static void ath79_spi_enable(struct ath79_spi *sp)
+{
+ /* enable GPIO mode */
+ ath79_spi_wr(sp, AR71XX_SPI_REG_FS, AR71XX_SPI_FS_GPIO);
+
+ /* save CTRL register */
+ sp->reg_ctrl = ath79_spi_rr(sp, AR71XX_SPI_REG_CTRL);
+ sp->ioc_base = ath79_spi_rr(sp, AR71XX_SPI_REG_IOC);
+
+ /* TODO: setup speed? */
+ ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, 0x43);
+}
+
+static void ath79_spi_disable(struct ath79_spi *sp)
+{
+ /* restore CTRL register */
+ ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, sp->reg_ctrl);
+ /* disable GPIO mode */
+ ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0);
+}
+
+static int ath79_spi_setup_cs(struct spi_device *spi)
+{
+ struct ath79_spi_controller_data *cdata;
+ int status;
+
+ cdata = spi->controller_data;
+ if (spi->chip_select && !cdata)
+ return -EINVAL;
+
+ status = 0;
+ if (spi->chip_select) {
+ unsigned long flags;
+
+ flags = GPIOF_DIR_OUT;
+ if (spi->mode & SPI_CS_HIGH)
+ flags |= GPIOF_INIT_LOW;
+ else
+ flags |= GPIOF_INIT_HIGH;
+
+ status = gpio_request_one(cdata->gpio, flags,
+ dev_name(&spi->dev));
+ }
+
+ return status;
+}
+
+static void ath79_spi_cleanup_cs(struct spi_device *spi)
+{
+ if (spi->chip_select) {
+ struct ath79_spi_controller_data *cdata = spi->controller_data;
+ gpio_free(cdata->gpio);
+ }
+}
+
+static int ath79_spi_setup(struct spi_device *spi)
+{
+ int status = 0;
+
+ if (!spi->controller_state) {
+ status = ath79_spi_setup_cs(spi);
+ if (status)
+ return status;
+ }
+
+ status = spi_bitbang_setup(spi);
+ if (status && !spi->controller_state)
+ ath79_spi_cleanup_cs(spi);
+
+ return status;
+}
+
+static void ath79_spi_cleanup(struct spi_device *spi)
+{
+ ath79_spi_cleanup_cs(spi);
+ spi_bitbang_cleanup(spi);
+}
+
+static u32 ath79_spi_txrx_mode0(struct spi_device *spi, unsigned nsecs,
+ u32 word, u8 bits)
+{
+ struct ath79_spi *sp = ath79_spidev_to_sp(spi);
+ u32 ioc = sp->ioc_base;
+
+ /* clock starts at inactive polarity */
+ for (word <<= (32 - bits); likely(bits); bits--) {
+ u32 out;
+
+ if (word & (1 << 31))
+ out = ioc | AR71XX_SPI_IOC_DO;
+ else
+ out = ioc & ~AR71XX_SPI_IOC_DO;
+
+ /* setup MSB (to slave) on trailing edge */
+ ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out);
+ ath79_spi_delay(sp, nsecs);
+ ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out | AR71XX_SPI_IOC_CLK);
+ ath79_spi_delay(sp, nsecs);
+ if (bits == 1)
+ ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out);
+
+ word <<= 1;
+ }
+
+ return ath79_spi_rr(sp, AR71XX_SPI_REG_RDS);
+}
+
+static int ath79_spi_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct ath79_spi *sp;
+ struct ath79_spi_platform_data *pdata;
+ struct resource *r;
+ unsigned long rate;
+ int ret;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(*sp));
+ if (master == NULL) {
+ dev_err(&pdev->dev, "failed to allocate spi master\n");
+ return -ENOMEM;
+ }
+
+ sp = spi_master_get_devdata(master);
+ platform_set_drvdata(pdev, sp);
+
+ pdata = dev_get_platdata(&pdev->dev);
+
+ master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
+ master->setup = ath79_spi_setup;
+ master->cleanup = ath79_spi_cleanup;
+ if (pdata) {
+ master->bus_num = pdata->bus_num;
+ master->num_chipselect = pdata->num_chipselect;
+ }
+
+ sp->bitbang.master = master;
+ sp->bitbang.chipselect = ath79_spi_chipselect;
+ sp->bitbang.txrx_word[SPI_MODE_0] = ath79_spi_txrx_mode0;
+ sp->bitbang.setup_transfer = spi_bitbang_setup_transfer;
+ sp->bitbang.flags = SPI_CS_HIGH;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (r == NULL) {
+ ret = -ENOENT;
+ goto err_put_master;
+ }
+
+ sp->base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
+ if (!sp->base) {
+ ret = -ENXIO;
+ goto err_put_master;
+ }
+
+ sp->clk = devm_clk_get(&pdev->dev, "ahb");
+ if (IS_ERR(sp->clk)) {
+ ret = PTR_ERR(sp->clk);
+ goto err_put_master;
+ }
+
+ ret = clk_enable(sp->clk);
+ if (ret)
+ goto err_put_master;
+
+ rate = DIV_ROUND_UP(clk_get_rate(sp->clk), MHZ);
+ if (!rate) {
+ ret = -EINVAL;
+ goto err_clk_disable;
+ }
+
+ sp->rrw_delay = ATH79_SPI_RRW_DELAY_FACTOR / rate;
+ dev_dbg(&pdev->dev, "register read/write delay is %u nsecs\n",
+ sp->rrw_delay);
+
+ ath79_spi_enable(sp);
+ ret = spi_bitbang_start(&sp->bitbang);
+ if (ret)
+ goto err_disable;
+
+ return 0;
+
+err_disable:
+ ath79_spi_disable(sp);
+err_clk_disable:
+ clk_disable(sp->clk);
+err_put_master:
+ spi_master_put(sp->bitbang.master);
+
+ return ret;
+}
+
+static int ath79_spi_remove(struct platform_device *pdev)
+{
+ struct ath79_spi *sp = platform_get_drvdata(pdev);
+
+ spi_bitbang_stop(&sp->bitbang);
+ ath79_spi_disable(sp);
+ clk_disable(sp->clk);
+ spi_master_put(sp->bitbang.master);
+
+ return 0;
+}
+
+static void ath79_spi_shutdown(struct platform_device *pdev)
+{
+ ath79_spi_remove(pdev);
+}
+
+static struct platform_driver ath79_spi_driver = {
+ .probe = ath79_spi_probe,
+ .remove = ath79_spi_remove,
+ .shutdown = ath79_spi_shutdown,
+ .driver = {
+ .name = DRV_NAME,
+ },
+};
+module_platform_driver(ath79_spi_driver);
+
+MODULE_DESCRIPTION("SPI controller driver for Atheros AR71XX/AR724X/AR913X");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRV_NAME);
Code Review / kvmfornfv.git / blobdiff