The Atheros AR71XX/AR724X/AR913X SoCs have a built-in SPI controller. This
patch implements a driver for that.
Signed-off-by: Gabor Juhos <juhosg@xxxxxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
Cc: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: spi-devel-general@xxxxxxxxxxxxxxxxxxxxx
---
Changes since RFC:
- remove DRV_DESC definition and use its previous value directly in the
MODULE_DESCRIPTION() macro,
- use io{read,write}32 accesors instead of __raw_{read,write}l,
- use __dev{init,exit,exit_p} annotations where in the appropriate places,
- initialize 'master->bus_num' field to -1 if no platform data specified,
so that a bus number can be dynamically assigned,
- rename ath79_spi_drv to ath79_spi_driver to avoid section mismatch
warnings
.../include/asm/mach-ath79/ath79_spi_platform.h | 19 ++
drivers/spi/Kconfig | 8 +
drivers/spi/Makefile | 1 +
drivers/spi/ath79_spi.c | 290 ++++++++++++++++++++
4 files changed, 318 insertions(+), 0 deletions(-)
create mode 100644 arch/mips/include/asm/mach-ath79/ath79_spi_platform.h
create mode 100644 drivers/spi/ath79_spi.c
diff --git a/arch/mips/include/asm/mach-ath79/ath79_spi_platform.h b/arch/mips/include/asm/mach-ath79/ath79_spi_platform.h
new file mode 100644
index 0000000..aa71216
--- /dev/null
+++ b/arch/mips/include/asm/mach-ath79/ath79_spi_platform.h
@@ -0,0 +1,19 @@
+/*
+ * Platform data definition for Atheros AR71XX/AR724X/AR913X SPI controller
+ *
+ * Copyright (C) 2008-2010 Gabor Juhos <juhosg@xxxxxxxxxxx>
+ *
+ * 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.
+ */
+
+#ifndef _ATH79_SPI_PLATFORM_H
+#define _ATH79_SPI_PLATFORM_H
+
+struct ath79_spi_platform_data {
+ unsigned bus_num;
+ unsigned num_chipselect;
+};
+
+#endif /* _ATH79_SPI_PLATFORM_H */
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 78f9fd0..f2093e1 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -53,6 +53,14 @@ if SPI_MASTER
comment "SPI Master Controller Drivers"
+config SPI_ATH79
+ tristate "Atheros AR71XX/AR724X/AR913X SPI controller driver"
+ depends on ATH79 && GENERIC_GPIO
+ select SPI_BITBANG
+ help
+ This enables support for the SPI controller present on the
+ Atheros AR71XX/AR724X/AR913X SoCs.
+
config SPI_ATMEL
tristate "Atmel SPI Controller"
depends on (ARCH_AT91 || AVR32)
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 8bc1a5a..875bc3d 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_SPI_MASTER) += spi.o
# SPI master controller drivers (bus)
obj-$(CONFIG_SPI_ATMEL) += atmel_spi.o
+obj-$(CONFIG_SPI_ATH79) += ath79_spi.o
obj-$(CONFIG_SPI_BFIN) += spi_bfin5xx.o
obj-$(CONFIG_SPI_BITBANG) += spi_bitbang.o
obj-$(CONFIG_SPI_AU1550) += au1550_spi.o
diff --git a/drivers/spi/ath79_spi.c b/drivers/spi/ath79_spi.c
new file mode 100644
index 0000000..96f169a
--- /dev/null
+++ b/drivers/spi/ath79_spi.c
@@ -0,0 +1,290 @@
+/*
+ * SPI controller driver for the Atheros AR71XX/AR724X/AR913X SoCs
+ *
+ * Copyright (C) 2009-2010 Gabor Juhos <juhosg@xxxxxxxxxxx>
+ *
+ * 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/init.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.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 <asm/mach-ath79/ar71xx_regs.h>
+#include <asm/mach-ath79/ath79_spi_platform.h>
+
+#define DRV_NAME "ath79-spi"
+
+struct ath79_spi {
+ struct spi_bitbang bitbang;
+ u32 ioc_base;
+ u32 reg_ctrl;
+
+ void __iomem *base;
+
+ struct platform_device *pdev;
+};
+
+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 *spidev_to_sp(struct spi_device *spi)
+{
+ return spi_master_get_devdata(spi->master);
+}
+
+static void ath79_spi_chipselect(struct spi_device *spi, int is_active)
+{
+ struct ath79_spi *sp = 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) {
+ unsigned long gpio = (unsigned long) spi->controller_data;
+
+ /* SPI is normally active-low */
+ gpio_set_value(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 int ath79_spi_setup_cs(struct spi_device *spi)
+{
+ struct ath79_spi *sp = spidev_to_sp(spi);
+
+ /* 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);
+
+ if (spi->chip_select) {
+ unsigned long gpio = (unsigned long) spi->controller_data;
+ int status = 0;
+
+ status = gpio_request(gpio, dev_name(&spi->dev));
+ if (status)
+ return status;
+
+ status = gpio_direction_output(gpio, spi->mode & SPI_CS_HIGH);
+ if (status) {
+ gpio_free(gpio);
+ return status;
+ }
+ } else {
+ if (spi->mode & SPI_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);
+ }
+
+ return 0;
+}
+
+static void ath79_spi_cleanup_cs(struct spi_device *spi)
+{
+ struct ath79_spi *sp = spidev_to_sp(spi);
+
+ if (spi->chip_select) {
+ unsigned long gpio = (unsigned long) spi->controller_data;
+ gpio_free(gpio);
+ }
+
+ /* 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(struct spi_device *spi)
+{
+ int status = 0;
+
+ if (spi->bits_per_word > 32)
+ return -EINVAL;
+
+ 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 = 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_wr(sp, AR71XX_SPI_REG_IOC, out | AR71XX_SPI_IOC_CLK);
+
+ word <<= 1;
+ }
+
+ return ath79_spi_rr(sp, AR71XX_SPI_REG_RDS);
+}
+
+static __devinit 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;
+ 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 = pdev->dev.platform_data;
+
+ master->setup = ath79_spi_setup;
+ master->cleanup = ath79_spi_cleanup;
+ if (pdata) {
+ master->bus_num = pdata->bus_num;
+ master->num_chipselect = pdata->num_chipselect;
+ } else {
+ master->bus_num = -1;
+ master->num_chipselect = 1;
+ }
+
+ sp->bitbang.master = spi_master_get(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 = ioremap(r->start, r->end - r->start + 1);
+ if (!sp->base) {
+ ret = -ENXIO;
+ goto err_put_master;
+ }
+
+ ret = spi_bitbang_start(&sp->bitbang);
+ if (ret)
+ goto err_unmap;
+
+ return 0;
+
+err_unmap:
+ iounmap(sp->base);
+err_put_master:
+ platform_set_drvdata(pdev, NULL);
+ spi_master_put(sp->bitbang.master);
+
+ return ret;
+}
+
+static __devexit int ath79_spi_remove(struct platform_device *pdev)
+{
+ struct ath79_spi *sp = platform_get_drvdata(pdev);
+
+ spi_bitbang_stop(&sp->bitbang);
+ iounmap(sp->base);
+ platform_set_drvdata(pdev, NULL);
+ spi_master_put(sp->bitbang.master);
+
+ return 0;
+}
+
+static struct platform_driver ath79_spi_driver = {
+ .probe = ath79_spi_probe,
+ .remove = __devexit_p(ath79_spi_remove),
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static __init int ath79_spi_init(void)
+{
+ return platform_driver_register(&ath79_spi_driver);
+}
+module_init(ath79_spi_init);
+
+static __exit void ath79_spi_exit(void)
+{
+ platform_driver_unregister(&ath79_spi_driver);
+}
+module_exit(ath79_spi_exit);
+
+MODULE_DESCRIPTION("SPI controller driver for Atheros AR71XX/AR724X/AR91X");
+MODULE_AUTHOR("Gabor Juhos <juhosg@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRV_NAME);
--
1.7.2.1
