Generic bitbanged MDIO library

Previously, bitbanged MDIO was only supported in individual
hardware-specific drivers.  This code factors out the higher level
protocol implementation, reducing the hardware-specific portion to
functions setting direction, data, and clock.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/include/linux/mdio-bitbang.h b/include/linux/mdio-bitbang.h
new file mode 100644
index 000000000000..8ea9a42a4c02
--- /dev/null
+++ b/include/linux/mdio-bitbang.h
@@ -0,0 +1,42 @@
+#ifndef __LINUX_MDIO_BITBANG_H
+#define __LINUX_MDIO_BITBANG_H
+
+#include <linux/phy.h>
+#include <linux/module.h>
+
+struct mdiobb_ctrl;
+
+struct mdiobb_ops {
+        struct module *owner;
+
+        /* Set the Management Data Clock high if level is one,
+         * low if level is zero.
+         */
+        void (*set_mdc)(struct mdiobb_ctrl *ctrl, int level);
+
+        /* Configure the Management Data I/O pin as an input if
+         * "output" is zero, or an output if "output" is one.
+         */
+        void (*set_mdio_dir)(struct mdiobb_ctrl *ctrl, int output);
+
+        /* Set the Management Data I/O pin high if value is one,
+         * low if "value" is zero.  This may only be called
+         * when the MDIO pin is configured as an output.
+         */
+        void (*set_mdio_data)(struct mdiobb_ctrl *ctrl, int value);
+
+        /* Retrieve the state Management Data I/O pin. */
+        int (*get_mdio_data)(struct mdiobb_ctrl *ctrl);
+};
+
+struct mdiobb_ctrl {
+        const struct mdiobb_ops *ops;
+};
+
+/* The returned bus is not yet registered with the phy layer. */
+struct mii_bus *alloc_mdio_bitbang(struct mdiobb_ctrl *ctrl);
+
+/* The bus must already have been unregistered. */
+void free_mdio_bitbang(struct mii_bus *bus);
+
+#endif