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:
V2:
- replaced be32_to_cpup with of_property_read_u32
- incorporated Andrew's comments
drivers/net/phy/Kconfig | 13 +++
drivers/net/phy/Makefile | 1 +
drivers/net/phy/mdio-mux-regmap.c | 171 ++++++++++++++++++++++++++++
3 files changed, 185 insertions(+)
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 82070792edbb..d1ac9e70cbb2 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -87,6 +87,19 @@ config MDIO_BUS_MUX_MMIOREG
Currently, only 8/16/32 bits registers are supported.
+config MDIO_BUS_MUX_REGMAP
+ tristate "REGMAP 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.
+ 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 upto 32 bits registers are supported.
+
config MDIO_CAVIUM
tristate
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 5805c0b7d60e..33053f9f320d 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..6068d05a728a
--- /dev/null
+++ b/drivers/net/phy/mdio-mux-regmap.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/* Simple regmap based MDIO MUX driver
+ *
+ * Copyright 2018 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 regmap *regmap;
+ u32 mux_reg;
+ u32 mask;
+};
+
+/* MDIO multiplexing switch function
+ *
+ * This function is called by the mdio-mux layer when it thinks the mdio bus
+ * multiplexer needs to switch.
+ *
+ * 'current_child' is the current value of the mux register (masked via
+ * s->mask).
+ *
+ * 'desired_child' is the value of the 'reg' property of the target child MDIO
+ * node.
+ *
+ * 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)
+ pr_debug("%s %d -> %d\n", __func__, current_child,
+ desired_child);
+ return ret;
+}
+
+static int mdio_mux_regmap_probe(struct platform_device *pdev)
+{
+ struct device_node *np2, *np = pdev->dev.of_node;
+ struct mdio_mux_regmap_state *s;
+ int ret;
+ u32 val;
+
+ dev_dbg(&pdev->dev, "probing node %pOF\n", np);
+
+ s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
+ if (!s)
+ return -ENOMEM;
+
+ s->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ if (IS_ERR(s->regmap)) {
+ dev_err(&pdev->dev, "Failed to get parent regmap\n");
+ return PTR_ERR(s->regmap);
+ }
+
+ ret = of_property_read_u32(np, "reg", &s->mux_reg);
+ if (ret) {
+ dev_err(&pdev->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(&pdev->dev, "error while reading reg\n");
+ return ret;
+ }
+
+ ret = regmap_write(s->regmap, s->mux_reg, val);
+ if (ret) {
+ dev_err(&pdev->dev, "error while writing reg\n");
+ return ret;
+ }
+
+ ret = of_property_read_u32(np, "mux-mask", &s->mask);
+ if (ret) {
+ dev_err(&pdev->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(np, np2) {
+ ret = of_property_read_u32(np2, "reg", &val);
+ if (ret) {
+ dev_err(&pdev->dev, "mdio-mux child node %pOF is
missing a 'reg' property\n", np2);
+ of_node_put(np2);
+ return -ENODEV;
+ }
+ if (val & ~s->mask) {
+ dev_err(&pdev->dev, "mdio-mux child node %pOF has a
'reg' value with unmasked bits\n", np2);
+ of_node_put(np2);
+ return -ENODEV;
+ }
+ }
+
+ ret = mdio_mux_init(&pdev->dev, pdev->dev.of_node,
+ mdio_mux_regmap_switch_fn,
+ &s->mux_handle, s, NULL);
+ if (ret) {
+ if (ret != -EPROBE_DEFER)
+ dev_err(&pdev->dev,
+ "failed to register mdio-mux bus %pOF\n", np);
+ return ret;
+ }
+
+ pdev->dev.platform_data = s;
+
+ return 0;
+}
+
+static int mdio_mux_regmap_remove(struct platform_device *pdev)
+{
+ struct mdio_mux_regmap_state *s = dev_get_platdata(&pdev->dev);
+
+ mdio_mux_uninit(s->mux_handle);
+
+ return 0;
+}
+
+static const struct of_device_id mdio_mux_regmap_match[] = {
+ {
+ .compatible = "mdio-mux-regmap",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, mdio_mux_regmap_match);
+
+static struct platform_driver mdio_mux_regmap_driver = {
+ .driver = {
+ .name = "mdio-mux-regmap",
+ .of_match_table = mdio_mux_regmap_match,
+ },
+ .probe = mdio_mux_regmap_probe,
+ .remove = mdio_mux_regmap_remove,
+};
+
+module_platform_driver(mdio_mux_regmap_driver);
+
+MODULE_AUTHOR("Pankaj Bansal <pankaj.ban...@nxp.com>");
+MODULE_DESCRIPTION("regmap device MDIO MUX driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1
