dm: i2c: Add support for multiplexed I2C buses

[karo-tx-uboot.git] / drivers / i2c / muxes / i2c-mux-uclass.c

diff --git a/drivers/i2c/muxes/i2c-mux-uclass.c b/drivers/i2c/muxes/i2c-mux-uclass.c
new file mode 100644 (file)
index 0000000..3f52bff
--- /dev/null
+++ b/drivers/i2c/muxes/i2c-mux-uclass.c
@@ -0,0 +1,198 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <i2c.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * struct i2c_mux: Information the uclass stores about an I2C mux
+ *
+ * @selected:  Currently selected mux, or -1 for none
+ * @i2c_bus: I2C bus to use for communcation
+ */
+struct i2c_mux {
+       int selected;
+       struct udevice *i2c_bus;
+};
+
+/**
+ * struct i2c_mux_bus: Information about each bus the mux controls
+ *
+ * @channel: Channel number used to select this bus
+ */
+struct i2c_mux_bus {
+       uint channel;
+};
+
+/* Find out the mux channel number */
+static int i2c_mux_child_post_bind(struct udevice *dev)
+{
+       struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
+       int channel;
+
+       channel = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "reg", -1);
+       if (channel < 0)
+               return -EINVAL;
+       plat->channel = channel;
+
+       return 0;
+}
+
+/* Find the I2C buses selected by this mux */
+static int i2c_mux_post_bind(struct udevice *mux)
+{
+       const void *blob = gd->fdt_blob;
+       int ret;
+       int offset;
+
+       debug("%s: %s\n", __func__, mux->name);
+       /*
+        * There is no compatible string in the sub-nodes, so we must manually
+        * bind these
+        */
+       for (offset = fdt_first_subnode(blob, mux->of_offset);
+            offset > 0;
+            offset = fdt_next_subnode(blob, offset)) {
+               struct udevice *dev;
+               const char *name;
+
+               name = fdt_get_name(blob, offset, NULL);
+               ret = device_bind_driver_to_node(mux, "i2c_mux_bus_drv", name,
+                                                offset, &dev);
+               debug("   - bind ret=%d, %s\n", ret, dev ? dev->name : NULL);
+               if (ret)
+                       return ret;
+       }
+
+       return 0;
+}
+
+/* Set up the mux ready for use */
+static int i2c_mux_post_probe(struct udevice *mux)
+{
+       struct i2c_mux *priv = dev_get_uclass_priv(mux);
+       int ret;
+
+       debug("%s: %s\n", __func__, mux->name);
+       priv->selected = -1;
+
+       ret = uclass_get_device_by_phandle(UCLASS_I2C, mux, "i2c-parent",
+                                          &priv->i2c_bus);
+       if (ret)
+               return ret;
+       debug("%s: bus=%p/%s\n", __func__, priv->i2c_bus, priv->i2c_bus->name);
+
+       return 0;
+}
+
+int i2c_mux_select(struct udevice *dev)
+{
+       struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
+       struct udevice *mux = dev->parent;
+       struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
+
+       if (!ops->select)
+               return -ENOSYS;
+
+       return ops->select(mux, dev, plat->channel);
+}
+
+int i2c_mux_deselect(struct udevice *dev)
+{
+       struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
+       struct udevice *mux = dev->parent;
+       struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
+
+       if (!ops->deselect)
+               return -ENOSYS;
+
+       return ops->deselect(mux, dev, plat->channel);
+}
+
+static int i2c_mux_bus_set_bus_speed(struct udevice *dev, unsigned int speed)
+{
+       struct udevice *mux = dev->parent;
+       struct i2c_mux *priv = dev_get_uclass_priv(mux);
+       int ret, ret2;
+
+       ret = i2c_mux_select(dev);
+       if (ret)
+               return ret;
+       ret = dm_i2c_set_bus_speed(priv->i2c_bus, speed);
+       ret2 = i2c_mux_deselect(dev);
+
+       return ret ? ret : ret2;
+}
+
+static int i2c_mux_bus_probe(struct udevice *dev, uint chip_addr,
+                            uint chip_flags)
+{
+       struct udevice *mux = dev->parent;
+       struct i2c_mux *priv = dev_get_uclass_priv(mux);
+       struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
+       int ret, ret2;
+
+       debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
+       if (!ops->probe_chip)
+               return -ENOSYS;
+       ret = i2c_mux_select(dev);
+       if (ret)
+               return ret;
+       ret = ops->probe_chip(priv->i2c_bus, chip_addr, chip_flags);
+       ret2 = i2c_mux_deselect(dev);
+
+       return ret ? ret : ret2;
+}
+
+static int i2c_mux_bus_xfer(struct udevice *dev, struct i2c_msg *msg,
+                           int nmsgs)
+{
+       struct udevice *mux = dev->parent;
+       struct i2c_mux *priv = dev_get_uclass_priv(mux);
+       struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
+       int ret, ret2;
+
+       debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
+       if (!ops->xfer)
+               return -ENOSYS;
+       ret = i2c_mux_select(dev);
+       if (ret)
+               return ret;
+       ret = ops->xfer(priv->i2c_bus, msg, nmsgs);
+       ret2 = i2c_mux_deselect(dev);
+
+       return ret ? ret : ret2;
+}
+
+static const struct dm_i2c_ops i2c_mux_bus_ops = {
+       .xfer           = i2c_mux_bus_xfer,
+       .probe_chip     = i2c_mux_bus_probe,
+       .set_bus_speed  = i2c_mux_bus_set_bus_speed,
+};
+
+U_BOOT_DRIVER(i2c_mux_bus) = {
+       .name           = "i2c_mux_bus_drv",
+       .id             = UCLASS_I2C,
+       .per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
+       .ops    = &i2c_mux_bus_ops,
+};
+
+UCLASS_DRIVER(i2c_mux) = {
+       .id             = UCLASS_I2C_MUX,
+       .name           = "i2c_mux",
+       .post_bind      = i2c_mux_post_bind,
+       .post_probe     = i2c_mux_post_probe,
+       .per_device_auto_alloc_size = sizeof(struct i2c_mux),
+       .per_child_platdata_auto_alloc_size = sizeof(struct i2c_mux_bus),
+       .child_post_bind = i2c_mux_child_post_bind,
+};