spi: add common fdt SPI driver interface

Add a common interface to fdt based SPI drivers.  Each driver is
represented by a table entry in fdt_spi_drivers[].  If there are
multiple SPI drivers in the table, the first driver to return success
from spi_init() will be registered as the SPI driver.

Signed-off-by: Allen Martin <amartin@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>

1 files changed, 171 insertions, 0 deletions

diff --git a/drivers/spi/fdt_spi.c b/drivers/spi/fdt_spi.c
new file mode 100644
index 0000000..c6ae719
--- /dev/null
+++ b/drivers/spi/fdt_spi.c
@@ -0,0 +1,171 @@
+/*
+ * Common fdt based SPI driver front end
+ *
+ * Copyright (c) 2013 NVIDIA Corporation
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <asm/io.h>
+#include <asm/gpio.h>
+#include <asm/arch/clock.h>
+#include <asm/arch-tegra/clk_rst.h>
+#include <asm/arch-tegra20/tegra20_sflash.h>
+#include <asm/arch-tegra20/tegra20_slink.h>
+#include <spi.h>
+#include <fdtdec.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct fdt_spi_driver {
+	int compat;
+	int max_ctrls;
+	int (*init)(int *node_list, int count);
+	int (*claim_bus)(struct spi_slave *slave);
+	int (*release_bus)(struct spi_slave *slave);
+	int (*cs_is_valid)(unsigned int bus, unsigned int cs);
+	struct spi_slave *(*setup_slave)(unsigned int bus, unsigned int cs,
+					unsigned int max_hz, unsigned int mode);
+	void (*free_slave)(struct spi_slave *slave);
+	void (*cs_activate)(struct spi_slave *slave);
+	void (*cs_deactivate)(struct spi_slave *slave);
+	int (*xfer)(struct spi_slave *slave, unsigned int bitlen,
+		    const void *data_out, void *data_in, unsigned long flags);
+};
+
+static struct fdt_spi_driver fdt_spi_drivers[] = {
+#ifdef CONFIG_TEGRA20_SFLASH
+	{
+		.compat		= COMPAT_NVIDIA_TEGRA20_SFLASH,
+		.max_ctrls	= 1,
+		.init		= tegra20_spi_init,
+		.claim_bus	= tegra20_spi_claim_bus,
+		.cs_is_valid	= tegra20_spi_cs_is_valid,
+		.setup_slave	= tegra20_spi_setup_slave,
+		.free_slave	= tegra20_spi_free_slave,
+		.cs_activate	= tegra20_spi_cs_activate,
+		.cs_deactivate	= tegra20_spi_cs_deactivate,
+		.xfer		= tegra20_spi_xfer,
+	},
+#endif
+#ifdef CONFIG_TEGRA20_SLINK
+	{
+		.compat		= COMPAT_NVIDIA_TEGRA20_SLINK,
+		.max_ctrls	= CONFIG_TEGRA_SLINK_CTRLS,
+		.init		= tegra30_spi_init,
+		.claim_bus	= tegra30_spi_claim_bus,
+		.cs_is_valid	= tegra30_spi_cs_is_valid,
+		.setup_slave	= tegra30_spi_setup_slave,
+		.free_slave	= tegra30_spi_free_slave,
+		.cs_activate	= tegra30_spi_cs_activate,
+		.cs_deactivate	= tegra30_spi_cs_deactivate,
+		.xfer		= tegra30_spi_xfer,
+	},
+#endif
+};
+
+static struct fdt_spi_driver *driver;
+
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	if (!driver)
+		return 0;
+	else if (!driver->cs_is_valid)
+		return 1;
+	else
+		return driver->cs_is_valid(bus, cs);
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+		unsigned int max_hz, unsigned int mode)
+{
+	if (!driver || !driver->setup_slave)
+		return NULL;
+
+	return driver->setup_slave(bus, cs, max_hz, mode);
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	if (driver && driver->free_slave)
+		return driver->free_slave(slave);
+}
+
+static int spi_init_driver(struct fdt_spi_driver *driver)
+{
+	int count;
+	int node_list[driver->max_ctrls];
+
+	count = fdtdec_find_aliases_for_id(gd->fdt_blob, "spi",
+					   driver->compat,
+					   node_list,
+					   driver->max_ctrls);
+	return driver->init(node_list, count);
+}
+
+void spi_init(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(fdt_spi_drivers); i++) {
+		driver = &fdt_spi_drivers[i];
+		if (!spi_init_driver(driver))
+			break;
+	}
+	if (i == ARRAY_SIZE(fdt_spi_drivers))
+		driver = NULL;
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	if (!driver)
+		return 1;
+	if (!driver->claim_bus)
+		return 0;
+
+	return driver->claim_bus(slave);
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+	if (driver && driver->release_bus)
+		driver->release_bus(slave);
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+	if (driver && driver->cs_activate)
+		driver->cs_activate(slave);
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+	if (driver && driver->cs_deactivate)
+		driver->cs_deactivate(slave);
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+	     const void *data_out, void *data_in, unsigned long flags)
+{
+	if (!driver || !driver->xfer)
+		return -1;
+
+	return driver->xfer(slave, bitlen, data_out, data_in, flags);
+}