[PATCH v2 2/5] spi: add controller driver for Atheros AR7XXX/AR9XXX SoCs
Antony Pavlov
antonynpavlov at gmail.com
Mon Apr 7 00:59:57 PDT 2014
Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
---
drivers/spi/Kconfig | 4 +
drivers/spi/Makefile | 1 +
drivers/spi/ath79_spi.c | 299 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 304 insertions(+)
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 422693c..60eaaaa 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -10,6 +10,10 @@ config DRIVER_SPI_ALTERA
bool "Altera SPI Master driver"
depends on NIOS2
+config DRIVER_SPI_ATH79
+ bool "Atheros AR71XX/AR724X/AR913X/AR933X SPI controller driver"
+ depends on MACH_MIPS_ATH79
+
config DRIVER_SPI_ATMEL
bool "Atmel (AT91) SPI Master driver"
depends on ARCH_AT91
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 1036f8f..7469479 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -1,4 +1,5 @@
obj-$(CONFIG_SPI) += spi.o
+obj-$(CONFIG_DRIVER_SPI_ATH79) += ath79_spi.o
obj-$(CONFIG_DRIVER_SPI_IMX) += imx_spi.o
obj-$(CONFIG_DRIVER_SPI_MVEBU) += mvebu_spi.o
obj-$(CONFIG_DRIVER_SPI_MXS) += mxs_spi.o
diff --git a/drivers/spi/ath79_spi.c b/drivers/spi/ath79_spi.c
new file mode 100644
index 0000000..d9ab269
--- /dev/null
+++ b/drivers/spi/ath79_spi.c
@@ -0,0 +1,299 @@
+/*
+ * Copyright (C) 2013, 2014 Antony Pavlov <antonynpavlov at gmail.com>
+ *
+ * This file is part of barebox.
+ * See file CREDITS for list of people who contributed to this project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <common.h>
+#include <init.h>
+#include <driver.h>
+#include <spi/spi.h>
+#include <io.h>
+#include <clock.h>
+
+struct ath79_spi {
+ struct spi_master master;
+ void __iomem *regs;
+ u32 val;
+ u32 reg_ctrl;
+};
+
+#define AR71XX_SPI_REG_FS 0x00 /* Function Select */
+#define AR71XX_SPI_REG_CTRL 0x04 /* SPI Control */
+#define AR71XX_SPI_REG_IOC 0x08 /* SPI I/O Control */
+#define AR71XX_SPI_REG_RDS 0x0c /* Read Data Shift */
+
+#define AR71XX_SPI_FS_GPIO BIT(0) /* Enable GPIO mode */
+
+#define AR71XX_SPI_IOC_DO BIT(0) /* Data Out pin */
+#define AR71XX_SPI_IOC_CLK BIT(8) /* CLK pin */
+#define AR71XX_SPI_IOC_CS(n) BIT(16 + (n))
+#define AR71XX_SPI_IOC_CS0 AR71XX_SPI_IOC_CS(0)
+#define AR71XX_SPI_IOC_CS1 AR71XX_SPI_IOC_CS(1)
+#define AR71XX_SPI_IOC_CS2 AR71XX_SPI_IOC_CS(2)
+#define AR71XX_SPI_IOC_CS_ALL (AR71XX_SPI_IOC_CS0 | AR71XX_SPI_IOC_CS1 | \
+ AR71XX_SPI_IOC_CS2)
+
+static inline u32 ath79_spi_rr(struct ath79_spi *sp, int reg)
+{
+ return cpu_readl(sp->regs + reg);
+}
+
+static inline void ath79_spi_wr(struct ath79_spi *sp, u32 val, int reg)
+{
+ cpu_writel(val, sp->regs + reg);
+}
+
+static inline void setbits(struct ath79_spi *sp, int bits, int on)
+{
+ /*
+ * We are the only user of SCSPTR so no locking is required.
+ * Reading bit 2 and 0 in SCSPTR gives pin state as input.
+ * Writing the same bits sets the output value.
+ * This makes regular read-modify-write difficult so we
+ * use sp->val to keep track of the latest register value.
+ */
+
+ if (on)
+ sp->val |= bits;
+ else
+ sp->val &= ~bits;
+
+ ath79_spi_wr(sp, sp->val, AR71XX_SPI_REG_IOC);
+}
+
+static inline struct ath79_spi *ath79_spidev_to_sp(struct spi_device *spi)
+{
+ return container_of(spi->master, struct ath79_spi, master);
+}
+
+static inline void setsck(struct spi_device *spi, int on)
+{
+ struct ath79_spi *sc = ath79_spidev_to_sp(spi);
+
+ setbits(sc, AR71XX_SPI_IOC_CLK, on);
+}
+
+static inline void setmosi(struct spi_device *spi, int on)
+{
+ struct ath79_spi *sc = ath79_spidev_to_sp(spi);
+
+ setbits(sc, AR71XX_SPI_IOC_DO, on);
+}
+
+static inline u32 getmiso(struct spi_device *spi)
+{
+ struct ath79_spi *sc = ath79_spidev_to_sp(spi);
+
+ return !!((ath79_spi_rr(sc, AR71XX_SPI_REG_RDS) & 1));
+}
+
+#include "spi-bitbang-txrx.h"
+
+static inline void ath79_spi_chipselect(struct ath79_spi *sp, int chipselect)
+{
+ int off_bits;
+
+ off_bits = 0xffffffff;
+
+ switch (chipselect) {
+ case 0:
+ off_bits &= ~AR71XX_SPI_IOC_CS0;
+ break;
+
+ case 1:
+ off_bits &= ~AR71XX_SPI_IOC_CS1;
+ break;
+
+ case 2:
+ off_bits &= ~AR71XX_SPI_IOC_CS2;
+ break;
+
+ case 3:
+ break;
+ }
+
+ /* by default inactivate chip selects */
+ sp->val |= AR71XX_SPI_IOC_CS_ALL;
+ sp->val &= off_bits;
+
+ ath79_spi_wr(sp, sp->val, AR71XX_SPI_REG_IOC);
+}
+
+static int ath79_spi_setup(struct spi_device *spi)
+{
+ struct spi_master *master = spi->master;
+ struct device_d spi_dev = spi->dev;
+
+ if (spi->bits_per_word != 8) {
+ dev_err(master->dev, "master doesn't support %d bits per word requested by %s\n",
+ spi->bits_per_word, spi_dev.name);
+ return -EINVAL;
+ }
+
+ if ((spi->mode & (SPI_CPHA | SPI_CPOL)) != SPI_MODE_0) {
+ dev_err(master->dev, "master doesn't support SPI_MODE%d requested by %s\n",
+ spi->mode & (SPI_CPHA | SPI_CPOL), spi_dev.name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int ath79_spi_read(struct spi_device *spi, void *buf, size_t nbyte)
+{
+ ssize_t cnt = 0;
+ u8 *rxf_buf = buf;
+
+ while (cnt < nbyte) {
+ *rxf_buf = bitbang_txrx_be_cpha1(spi, 1000, 1, 0, 8);
+ rxf_buf++;
+ cnt++;
+ }
+
+ return cnt;
+}
+
+static int ath79_spi_write(struct spi_device *spi,
+ const void *buf, size_t nbyte)
+{
+ ssize_t cnt = 0;
+ const u8 *txf_buf = buf;
+
+ while (cnt < nbyte) {
+ bitbang_txrx_be_cpha1(spi, 1000, 1, (u32)*txf_buf, 8);
+ txf_buf++;
+ cnt++;
+ }
+
+ return 0;
+}
+
+static int ath79_spi_transfer(struct spi_device *spi, struct spi_message *mesg)
+{
+ struct ath79_spi *sc = ath79_spidev_to_sp(spi);
+ struct spi_transfer *t;
+
+ mesg->actual_length = 0;
+
+ /* activate chip select signal */
+ ath79_spi_chipselect(sc, spi->chip_select);
+
+ list_for_each_entry(t, &mesg->transfers, transfer_list) {
+
+ if (t->tx_buf)
+ ath79_spi_write(spi, t->tx_buf, t->len);
+
+ if (t->rx_buf)
+ ath79_spi_read(spi, t->rx_buf, t->len);
+
+ mesg->actual_length += t->len;
+ }
+
+ /* inactivate chip select signal */
+ ath79_spi_chipselect(sc, -1);
+
+ return 0;
+}
+
+static void ath79_spi_enable(struct ath79_spi *sp)
+{
+ /* enable GPIO mode */
+ ath79_spi_wr(sp, AR71XX_SPI_FS_GPIO, AR71XX_SPI_REG_FS);
+
+ /* save CTRL register */
+ sp->reg_ctrl = ath79_spi_rr(sp, AR71XX_SPI_REG_CTRL);
+ sp->val = ath79_spi_rr(sp, AR71XX_SPI_REG_IOC);
+
+ /* TODO: setup speed? */
+ ath79_spi_wr(sp, 0x43, AR71XX_SPI_REG_CTRL);
+}
+
+static void ath79_spi_disable(struct ath79_spi *sp)
+{
+ /* restore CTRL register */
+ ath79_spi_wr(sp, sp->reg_ctrl, AR71XX_SPI_REG_CTRL);
+ /* disable GPIO mode */
+ ath79_spi_wr(sp, 0, AR71XX_SPI_REG_FS);
+}
+
+static int ath79_spi_probe(struct device_d *dev)
+{
+ struct spi_master *master;
+ struct ath79_spi *ath79_spi;
+
+ ath79_spi = xzalloc(sizeof(*ath79_spi));
+ dev->priv = ath79_spi;
+
+ master = &ath79_spi->master;
+ master->dev = dev;
+
+ master->bus_num = dev->id;
+ master->setup = ath79_spi_setup;
+ master->transfer = ath79_spi_transfer;
+ master->num_chipselect = 3;
+
+ if (IS_ENABLED(CONFIG_OFDEVICE)) {
+ struct device_node *node = dev->device_node;
+ u32 num_cs;
+ int ret;
+
+ ret = of_property_read_u32(node, "num-chipselects", &num_cs);
+ if (ret)
+ num_cs = 3;
+
+ if (num_cs > 3) {
+ dev_err(dev, "master doesn't support num-chipselects > 3\n");
+ }
+
+ master->num_chipselect = num_cs;
+ }
+
+ ath79_spi->regs = dev_request_mem_region(dev, 0);
+
+ /* enable gpio mode */
+ ath79_spi_enable(ath79_spi);
+
+ /* inactivate chip select signal */
+ ath79_spi_chipselect(ath79_spi, -1);
+
+ spi_register_master(master);
+
+ return 0;
+}
+
+static void ath79_spi_remove(struct device_d *dev)
+{
+ struct ath79_spi *sp = dev->priv;
+
+ ath79_spi_disable(sp);
+}
+
+static __maybe_unused struct of_device_id ath79_spi_dt_ids[] = {
+ {
+ .compatible = "qca,ath79-spi",
+ },
+ {
+ /* sentinel */
+ }
+};
+
+static struct driver_d ath79_spi_driver = {
+ .name = "ath79-spi",
+ .probe = ath79_spi_probe,
+ .remove = ath79_spi_remove,
+ .of_compatible = DRV_OF_COMPAT(ath79_spi_dt_ids),
+};
+device_platform_driver(ath79_spi_driver);
--
1.9.0
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