Merge branch '2020-06-15-misc-bugfixes'

[oweals/u-boot.git] / drivers / i2c / i2c-emul-uclass.c

diff --git a/drivers/i2c/i2c-emul-uclass.c b/drivers/i2c/i2c-emul-uclass.c
index a2bdd5aa844a73493d5cb10c8c4916427ea1f934..1b70e140545dd938fff9540543a652bbab94ce3d 100644 (file)
--- a/drivers/i2c/i2c-emul-uclass.c
+++ b/drivers/i2c/i2c-emul-uclass.c
@@ -6,8 +6,86 @@
 #include <common.h>
 #include <dm.h>
 #include <i2c.h>
+#include <log.h>
+#include <dm/device-internal.h>
+#include <dm/uclass-internal.h>
+
+/*
+ * i2c emulation works using an 'emul' node at the bus level. Each device in
+ * that node is in the UCLASS_I2C_EMUL uclass, and emulates one i2c device. A
+ * pointer to the device it emulates is in the 'dev' property of the emul device
+ * uclass platdata (struct i2c_emul_platdata), put there by i2c_emul_find().
+ * When sandbox wants an emulator for a device, it calls i2c_emul_find() which
+ * searches for the emulator with the correct address. To find the device for an
+ * emulator, call i2c_emul_get_device().
+ *
+ * The 'emul' node is in the UCLASS_I2C_EMUL_PARENT uclass. We use a separate
+ * uclass so avoid having strange devices on the I2C bus.
+ */
+
+/**
+ * struct i2c_emul_uc_platdata - information about the emulator for this device
+ *
+ * This is used by devices in UCLASS_I2C_EMUL to record information about the
+ * device being emulated. It is accessible with dev_get_uclass_platdata()
+ *
+ * @dev: Device being emulated
+ */
+struct i2c_emul_uc_platdata {
+       struct udevice *dev;
+};
+
+struct udevice *i2c_emul_get_device(struct udevice *emul)
+{
+       struct i2c_emul_uc_platdata *uc_plat = dev_get_uclass_platdata(emul);
+
+       return uc_plat->dev;
+}
+
+int i2c_emul_find(struct udevice *dev, struct udevice **emulp)
+{
+       struct i2c_emul_uc_platdata *uc_plat;
+       struct udevice *emul;
+       int ret;
+
+       ret = uclass_find_device_by_phandle(UCLASS_I2C_EMUL, dev,
+                                           "sandbox,emul", &emul);
+       if (ret) {
+               log_err("No emulators for device '%s'\n", dev->name);
+               return ret;
+       }
+       uc_plat = dev_get_uclass_platdata(emul);
+       uc_plat->dev = dev;
+       *emulp = emul;
+
+       return device_probe(emul);
+}
 
 UCLASS_DRIVER(i2c_emul) = {
        .id             = UCLASS_I2C_EMUL,
        .name           = "i2c_emul",
+       .per_device_platdata_auto_alloc_size =
+                sizeof(struct i2c_emul_uc_platdata),
+};
+
+/*
+ * This uclass is a child of the i2c bus. Its platdata is not defined here so
+ * is defined by its parent, UCLASS_I2C, which uses struct dm_i2c_chip. See
+ * per_child_platdata_auto_alloc_size in UCLASS_DRIVER(i2c).
+ */
+UCLASS_DRIVER(i2c_emul_parent) = {
+       .id             = UCLASS_I2C_EMUL_PARENT,
+       .name           = "i2c_emul_parent",
+       .post_bind      = dm_scan_fdt_dev,
+};
+
+static const struct udevice_id i2c_emul_parent_ids[] = {
+       { .compatible = "sandbox,i2c-emul-parent" },
+       { }
+};
+
+U_BOOT_DRIVER(i2c_emul_parent_drv) = {
+       .name           = "i2c_emul_parent_drv",
+       .id             = UCLASS_I2C_EMUL_PARENT,
+       .of_match       = i2c_emul_parent_ids,
 };