dm: spi: Add a uclass for SPI

Add a uclass which provides access to SPI buses and includes operations
required by SPI.

For a time driver model will need to co-exist with the legacy SPI interface
so some parts of the header file are changed depending on which is in use.
The exports are adjusted also since some functions are not available with
driver model.

Boards must define CONFIG_DM_SPI to use driver model for SPI.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
(Discussed some follow-up comments which will address in future add-ons)

2 files changed, 394 insertions, 0 deletions

diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index f02c35a52c..d1f1dd0666 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -6,7 +6,11 @@
 #
 
 # There are many options which enable SPI, so make this library available
+ifdef CONFIG_DM_SPI
+obj-y += spi-uclass.o
+else
 obj-y += spi.o
+endif
 
 obj-$(CONFIG_EP93XX_SPI) += ep93xx_spi.o
 obj-$(CONFIG_ALTERA_SPI) += altera_spi.o
diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
new file mode 100644
index 0000000000..13c6b77d73
--- /dev/null
+++ b/drivers/spi/spi-uclass.c
@@ -0,0 +1,390 @@
+/*
+ * Copyright (c) 2014 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <malloc.h>
+#include <spi.h>
+#include <dm/device-internal.h>
+#include <dm/uclass-internal.h>
+#include <dm/root.h>
+#include <dm/lists.h>
+#include <dm/util.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int spi_set_speed_mode(struct udevice *bus, int speed, int mode)
+{
+	struct dm_spi_ops *ops;
+	int ret;
+
+	ops = spi_get_ops(bus);
+	if (ops->set_speed)
+		ret = ops->set_speed(bus, speed);
+	else
+		ret = -EINVAL;
+	if (ret) {
+		printf("Cannot set speed (err=%d)\n", ret);
+		return ret;
+	}
+
+	if (ops->set_mode)
+		ret = ops->set_mode(bus, mode);
+	else
+		ret = -EINVAL;
+	if (ret) {
+		printf("Cannot set mode (err=%d)\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	struct udevice *dev = slave->dev;
+	struct udevice *bus = dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+	struct dm_spi_bus *spi = bus->uclass_priv;
+	int speed;
+	int ret;
+
+	speed = slave->max_hz;
+	if (spi->max_hz) {
+		if (speed)
+			speed = min(speed, spi->max_hz);
+		else
+			speed = spi->max_hz;
+	}
+	if (!speed)
+		speed = 100000;
+	ret = spi_set_speed_mode(bus, speed, slave->mode);
+	if (ret)
+		return ret;
+
+	return ops->claim_bus ? ops->claim_bus(bus) : 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+	struct udevice *dev = slave->dev;
+	struct udevice *bus = dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+
+	if (ops->release_bus)
+		ops->release_bus(bus);
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+	     const void *dout, void *din, unsigned long flags)
+{
+	struct udevice *dev = slave->dev;
+	struct udevice *bus = dev->parent;
+
+	if (bus->uclass->uc_drv->id != UCLASS_SPI)
+		return -EOPNOTSUPP;
+
+	return spi_get_ops(bus)->xfer(dev, bitlen, dout, din, flags);
+}
+
+int spi_post_bind(struct udevice *dev)
+{
+	/* Scan the bus for devices */
+	return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset, false);
+}
+
+int spi_post_probe(struct udevice *dev)
+{
+	struct dm_spi_bus *spi = dev->uclass_priv;
+
+	spi->max_hz = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
+				     "spi-max-frequency", 0);
+
+	return 0;
+}
+
+int spi_chip_select(struct udevice *dev)
+{
+	struct spi_slave *slave = dev_get_parentdata(dev);
+
+	return slave ? slave->cs : -ENOENT;
+}
+
+/**
+ * spi_find_chip_select() - Find the slave attached to chip select
+ *
+ * @bus:	SPI bus to search
+ * @cs:		Chip select to look for
+ * @devp:	Returns the slave device if found
+ * @return 0 if found, -ENODEV on error
+ */
+static int spi_find_chip_select(struct udevice *bus, int cs,
+				struct udevice **devp)
+{
+	struct udevice *dev;
+
+	for (device_find_first_child(bus, &dev); dev;
+	     device_find_next_child(&dev)) {
+		struct spi_slave store;
+		struct spi_slave *slave = dev_get_parentdata(dev);
+
+		if (!slave)  {
+			slave = &store;
+			spi_ofdata_to_platdata(gd->fdt_blob, dev->of_offset,
+					       slave);
+		}
+		debug("%s: slave=%p, cs=%d\n", __func__, slave,
+		      slave ? slave->cs : -1);
+		if (slave && slave->cs == cs) {
+			*devp = dev;
+			return 0;
+		}
+	}
+
+	return -ENODEV;
+}
+
+int spi_cs_is_valid(unsigned int busnum, unsigned int cs)
+{
+	struct spi_cs_info info;
+	struct udevice *bus;
+	int ret;
+
+	ret = uclass_find_device_by_seq(UCLASS_SPI, busnum, false, &bus);
+	if (ret) {
+		debug("%s: No bus %d\n", __func__, busnum);
+		return ret;
+	}
+
+	return spi_cs_info(bus, cs, &info);
+}
+
+int spi_cs_info(struct udevice *bus, uint cs, struct spi_cs_info *info)
+{
+	struct spi_cs_info local_info;
+	struct dm_spi_ops *ops;
+	int ret;
+
+	if (!info)
+		info = &local_info;
+
+	/* If there is a device attached, return it */
+	info->dev = NULL;
+	ret = spi_find_chip_select(bus, cs, &info->dev);
+	if (!ret)
+		return 0;
+
+	/*
+	 * Otherwise ask the driver. For the moment we don't have CS info.
+	 * When we do we could provide the driver with a helper function
+	 * to figure out what chip selects are valid, or just handle the
+	 * request.
+	 */
+	ops = spi_get_ops(bus);
+	if (ops->cs_info)
+		return ops->cs_info(bus, cs, info);
+
+	/*
+	 * We could assume there is at least one valid chip select, but best
+	 * to be sure and return an error in this case. The driver didn't
+	 * care enough to tell us.
+	 */
+	return -ENODEV;
+}
+
+int spi_bind_device(struct udevice *bus, int cs, const char *drv_name,
+		    const char *dev_name, struct udevice **devp)
+{
+	struct driver *drv;
+	int ret;
+
+	drv = lists_driver_lookup_name(drv_name);
+	if (!drv) {
+		printf("Cannot find driver '%s'\n", drv_name);
+		return -ENOENT;
+	}
+	ret = device_bind(bus, drv, dev_name, NULL, -1, devp);
+	if (ret) {
+		printf("Cannot create device named '%s' (err=%d)\n",
+		       dev_name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+int spi_find_bus_and_cs(int busnum, int cs, struct udevice **busp,
+			struct udevice **devp)
+{
+	struct udevice *bus, *dev;
+	int ret;
+
+	ret = uclass_find_device_by_seq(UCLASS_SPI, busnum, false, &bus);
+	if (ret) {
+		debug("%s: No bus %d\n", __func__, busnum);
+		return ret;
+	}
+	ret = spi_find_chip_select(bus, cs, &dev);
+	if (ret) {
+		debug("%s: No cs %d\n", __func__, cs);
+		return ret;
+	}
+	*busp = bus;
+	*devp = dev;
+
+	return ret;
+}
+
+int spi_get_bus_and_cs(int busnum, int cs, int speed, int mode,
+		       const char *drv_name, const char *dev_name,
+		       struct udevice **busp, struct spi_slave **devp)
+{
+	struct udevice *bus, *dev;
+	struct spi_slave *slave;
+	bool created = false;
+	int ret;
+
+	ret = uclass_get_device_by_seq(UCLASS_SPI, busnum, &bus);
+	if (ret) {
+		printf("Invalid bus %d (err=%d)\n", busnum, ret);
+		return ret;
+	}
+	ret = spi_find_chip_select(bus, cs, &dev);
+
+	/*
+	 * If there is no such device, create one automatically. This means
+	 * that we don't need a device tree node or platform data for the
+	 * SPI flash chip - we will bind to the correct driver.
+	 */
+	if (ret == -ENODEV && drv_name) {
+		debug("%s: Binding new device '%s', busnum=%d, cs=%d, driver=%s\n",
+		      __func__, dev_name, busnum, cs, drv_name);
+		ret = spi_bind_device(bus, cs, drv_name, dev_name, &dev);
+		if (ret)
+			return ret;
+		created = true;
+	} else if (ret) {
+		printf("Invalid chip select %d:%d (err=%d)\n", busnum, cs,
+		       ret);
+		return ret;
+	}
+
+	if (!device_active(dev)) {
+		slave = (struct spi_slave *)calloc(1,
+						   sizeof(struct spi_slave));
+		if (!slave) {
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		ret = spi_ofdata_to_platdata(gd->fdt_blob, dev->of_offset,
+					     slave);
+		if (ret)
+			goto err;
+		slave->cs = cs;
+		slave->dev = dev;
+		ret = device_probe_child(dev, slave);
+		free(slave);
+		if (ret)
+			goto err;
+	}
+
+	ret = spi_set_speed_mode(bus, speed, mode);
+	if (ret)
+		goto err;
+
+	*busp = bus;
+	*devp = dev_get_parentdata(dev);
+	debug("%s: bus=%p, slave=%p\n", __func__, bus, *devp);
+
+	return 0;
+
+err:
+	if (created) {
+		device_remove(dev);
+		device_unbind(dev);
+	}
+
+	return ret;
+}
+
+/* Compatibility function - to be removed */
+struct spi_slave *spi_setup_slave_fdt(const void *blob, int node,
+				      int bus_node)
+{
+	struct udevice *bus, *dev;
+	int ret;
+
+	ret = uclass_get_device_by_of_offset(UCLASS_SPI, bus_node, &bus);
+	if (ret)
+		return NULL;
+	ret = device_get_child_by_of_offset(bus, node, &dev);
+	if (ret)
+		return NULL;
+	return dev_get_parentdata(dev);
+}
+
+/* Compatibility function - to be removed */
+struct spi_slave *spi_setup_slave(unsigned int busnum, unsigned int cs,
+				  unsigned int speed, unsigned int mode)
+{
+	struct spi_slave *slave;
+	struct udevice *dev;
+	int ret;
+
+	ret = spi_get_bus_and_cs(busnum, cs, speed, mode, NULL, 0, &dev,
+				  &slave);
+	if (ret)
+		return NULL;
+
+	return slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	device_remove(slave->dev);
+	slave->dev = NULL;
+}
+
+int spi_ofdata_to_platdata(const void *blob, int node,
+			   struct spi_slave *spi)
+{
+	int mode = 0;
+
+	spi->cs = fdtdec_get_int(blob, node, "reg", -1);
+	spi->max_hz = fdtdec_get_int(blob, node, "spi-max-frequency", 0);
+	if (fdtdec_get_bool(blob, node, "spi-cpol"))
+		mode |= SPI_CPOL;
+	if (fdtdec_get_bool(blob, node, "spi-cpha"))
+		mode |= SPI_CPHA;
+	if (fdtdec_get_bool(blob, node, "spi-cs-high"))
+		mode |= SPI_CS_HIGH;
+	if (fdtdec_get_bool(blob, node, "spi-half-duplex"))
+		mode |= SPI_PREAMBLE;
+	spi->mode = mode;
+
+	return 0;
+}
+
+UCLASS_DRIVER(spi) = {
+	.id		= UCLASS_SPI,
+	.name		= "spi",
+	.post_bind	= spi_post_bind,
+	.post_probe	= spi_post_probe,
+	.per_device_auto_alloc_size = sizeof(struct dm_spi_bus),
+};
+
+UCLASS_DRIVER(spi_generic) = {
+	.id		= UCLASS_SPI_GENERIC,
+	.name		= "spi_generic",
+};
+
+U_BOOT_DRIVER(spi_generic_drv) = {
+	.name		= "spi_generic_drv",
+	.id		= UCLASS_SPI_GENERIC,
+};