Add support for an MDIO bus multiplexer controlled by a regmap
device, like an FPGA.
Tested on a NXP LX2160AQDS board which uses the "QIXIS" FPGA
attached to the i2c bus.
Signed-off-by: Pankaj Bansal <pankaj.ban...@nxp.com>
---
Notes:
V3:
- make the return type of uninit function to void
- reorder the Make file change to be alphabetically sorted
- fix the compilation error when mdio-mux-regmap is built as module
by adding CONFIG_MDIO_BUS_MUX_REGMAP_MODULE macro in mdio-mux.h
V2:
- Added Kconfig entry for regmap based mdio mux
- restrict the comment lines to 80 chars
- use kerneldoc formatting for this function documentation.
drivers/net/phy/Kconfig | 14 +++
drivers/net/phy/Makefile | 1 +
drivers/net/phy/mdio-mux-regmap.c | 169 ++++++++++++++++++++++++++++
include/linux/mdio-mux.h | 34 ++++++
4 files changed, 218 insertions(+)
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 3d187cd50eb0..93ef2505caba 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -87,6 +87,20 @@ config MDIO_BUS_MUX_MMIOREG
Currently, only 8/16/32 bits registers are supported.
+config MDIO_BUS_MUX_REGMAP
+ tristate "regmap device controlled MDIO bus multiplexers"
+ depends on OF_MDIO && REGMAP
+ select MDIO_BUS_MUX
+ help
+ This module provides a driver for MDIO bus multiplexers that
+ are controlled via a regmap device, like an FPGA connected to i2c bus
+ or spi bus or memory mapped FPGA.
+ The multiplexer connects one of several child MDIO busses to a
+ parent bus. Child bus selection is under the control of one of
+ the FPGA's registers.
+
+ Currently, only 32 bits registers are supported.
+
config MDIO_CAVIUM
tristate
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 5805c0b7d60e..99737128de8a 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_MDIO_BUS_MUX) += mdio-mux.o
obj-$(CONFIG_MDIO_BUS_MUX_BCM_IPROC) += mdio-mux-bcm-iproc.o
obj-$(CONFIG_MDIO_BUS_MUX_GPIO) += mdio-mux-gpio.o
obj-$(CONFIG_MDIO_BUS_MUX_MMIOREG) += mdio-mux-mmioreg.o
+obj-$(CONFIG_MDIO_BUS_MUX_REGMAP) += mdio-mux-regmap.o
obj-$(CONFIG_MDIO_CAVIUM) += mdio-cavium.o
obj-$(CONFIG_MDIO_GPIO) += mdio-gpio.o
obj-$(CONFIG_MDIO_HISI_FEMAC) += mdio-hisi-femac.o
diff --git a/drivers/net/phy/mdio-mux-regmap.c
b/drivers/net/phy/mdio-mux-regmap.c
new file mode 100644
index 000000000000..bbec43b30f3c
--- /dev/null
+++ b/drivers/net/phy/mdio-mux-regmap.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/* Simple regmap based MDIO MUX driver
+ *
+ * Copyright 2018-2019 NXP
+ *
+ * Based on mdio-mux-mmioreg.c by Timur Tabi
+ *
+ * Author:
+ * Pankaj Bansal <pankaj.ban...@nxp.com>
+ */
+
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/of_mdio.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+#include <linux/mdio-mux.h>
+#include <linux/regmap.h>
+
+struct mdio_mux_regmap_state {
+ void *mux_handle;
+ struct device *dev;
+ struct regmap *regmap;
+ u32 mux_reg;
+ u32 mask;
+};
+
+/**
+ * mdio_mux_regmap_switch_fn - This function is called by the mdio-mux layer
+ * when it thinks the mdio bus multiplexer needs
+ * to switch.
+ * @current_child: current value of the mux register (masked via s->mask).
+ * @desired_child: value of the 'reg' property of the target child MDIO node.
+ * @data: Private data used by this switch_fn passed to mdio_mux_init function
+ * via mdio_mux_init(.., .., .., .., data, ..).
+ *
+ * The first time this function is called, current_child == -1.
+ * If current_child == desired_child, then the mux is already set to the
+ * correct bus.
+ */
+static int mdio_mux_regmap_switch_fn(int current_child, int desired_child,
+ void *data)
+{
+ struct mdio_mux_regmap_state *s = data;
+ bool change;
+ int ret;
+
+ ret = regmap_update_bits_check(s->regmap,
+ s->mux_reg,
+ s->mask,
+ desired_child,
+ &change);
+
+ if (ret)
+ return ret;
+ if (change)
+ dev_dbg(s->dev, "%s %d -> %d\n", __func__, current_child,
+ desired_child);
+ return ret;
+}
+
+/**
+ * mdio_mux_regmap_init - control MDIO bus muxing using regmap constructs.
+ * @dev: device with which regmap construct is associated.
+ * @mux_node: mdio bus mux node that contains parent mdio bus phandle.
+ * This node also contains sub nodes, where each subnode denotes
+ * a child mdio bus. All the child mdio buses are muxed, i.e. at a
+ * time only one of the child mdio buses can be used.
+ * @data: to store the address of data allocated by this function
+ */
+int mdio_mux_regmap_init(struct device *dev,
+ struct device_node *mux_node,
+ void **data)
+{
+ struct device_node *child;
+ struct mdio_mux_regmap_state *s;
+ int ret;
+ u32 val;
+
+ dev_dbg(dev, "probing node %pOF\n", mux_node);
+
+ s = devm_kzalloc(dev, sizeof(*s), GFP_KERNEL);
+ if (!s)
+ return -ENOMEM;
+
+ s->regmap = dev_get_regmap(dev, NULL);
+ if (IS_ERR(s->regmap)) {
+ dev_err(dev, "Failed to get parent regmap\n");
+ return PTR_ERR(s->regmap);
+ }
+
+ ret = of_property_read_u32(mux_node, "reg", &s->mux_reg);
+ if (ret) {
+ dev_err(dev, "missing or invalid reg property\n");
+ return -ENODEV;
+ }
+
+ /* Test Register read write */
+ ret = regmap_read(s->regmap, s->mux_reg, &val);
+ if (ret) {
+ dev_err(dev, "error while reading reg\n");
+ return ret;
+ }
+
+ ret = regmap_write(s->regmap, s->mux_reg, val);
+ if (ret) {
+ dev_err(dev, "error while writing reg\n");
+ return ret;
+ }
+
+ ret = of_property_read_u32(mux_node, "mux-mask", &s->mask);
+ if (ret) {
+ dev_err(dev, "missing or invalid mux-mask property\n");
+ return -ENODEV;
+ }
+
+ /* Verify that the 'reg' property of each child MDIO bus does not
+ * set any bits outside of the 'mask'.
+ */
+ for_each_available_child_of_node(mux_node, child) {
+ ret = of_property_read_u32(child, "reg", &val);
+ if (ret) {
+ dev_err(dev, "%pOF is missing a 'reg' property\n",
+ child);
+ of_node_put(child);
+ return -ENODEV;
+ }
+ if (val & ~s->mask) {
+ dev_err(dev,
+ "%pOF has a 'reg' value with unmasked bits\n",
+ child);
+ of_node_put(child);
+ return -ENODEV;
+ }
+ }
+
+ ret = mdio_mux_init(dev, mux_node, mdio_mux_regmap_switch_fn,
+ &s->mux_handle, s, NULL);
+ if (ret) {
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "failed to register mdio-mux bus %pOF\n",
+ mux_node);
+ return ret;
+ }
+
+ *data = s;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mdio_mux_regmap_init);
+
+/**
+ * mdio_mux_regmap_uninit - relinquish the control of MDIO bus muxing using
+ * regmap constructs.
+ * @data: address of data allocated by mdio_mux_regmap_init
+ */
+void mdio_mux_regmap_uninit(void *data)
+{
+ struct mdio_mux_regmap_state *s = data;
+
+ mdio_mux_uninit(s->mux_handle);
+}
+EXPORT_SYMBOL_GPL(mdio_mux_regmap_uninit);
+
+MODULE_AUTHOR("Pankaj Bansal <pankaj.ban...@nxp.com>");
+MODULE_DESCRIPTION("regmap based MDIO MUX driver");
+MODULE_LICENSE("GPL");
+
diff --git a/include/linux/mdio-mux.h b/include/linux/mdio-mux.h
index a5d58f221939..bb5d0e2774bf 100644
--- a/include/linux/mdio-mux.h
+++ b/include/linux/mdio-mux.h
@@ -29,4 +29,38 @@ int mdio_mux_init(struct device *dev,
void mdio_mux_uninit(void *mux_handle);
+#if defined(CONFIG_MDIO_BUS_MUX_REGMAP) || \
+ defined(CONFIG_MDIO_BUS_MUX_REGMAP_MODULE)
+/**
+ * mdio_mux_regmap_init - control MDIO bus muxing using regmap constructs.
+ * @dev: device with which regmap construct is associated.
+ * @mux_node: mdio bus mux node that contains parent mdio bus phandle.
+ * This node also contains sub nodes, where each subnode denotes
+ * a child mdio bus. All the child mdio buses are muxed, i.e. at a
+ * time only one of the child mdio buses can be used.
+ * @data: to store the address of data allocated by this function
+ */
+int mdio_mux_regmap_init(struct device *dev,
+ struct device_node *mux_node,
+ void **data);
+
+/**
+ * mdio_mux_regmap_uninit - relinquish the control of MDIO bus muxing using
+ * regmap constructs.
+ * @data: address of data allocated by mdio_mux_regmap_init
+ */
+void mdio_mux_regmap_uninit(void *data);
+#else /* CONFIG_MDIO_BUS_MUX_REGMAP(_MODULE) */
+static inline int mdio_mux_regmap_init(struct device *dev,
+ struct device_node *mux_node,
+ void **data)
+{
+ return -ENODEV;
+}
+
+static inline void mdio_mux_regmap_uninit(void *data)
+{
+}
+#endif /* CONFIG_MDIO_BUS_MUX_REGMAP(_MODULE) */
+
#endif /* __LINUX_MDIO_MUX_H */
--
2.17.1
