drivers: net: phy: mdio-mux: Add support for Generic Mux controls

Add support for Generic Mux controls, when Mdio mux node is a consumer
of mux produced by some other device.

Signed-off-by: Pankaj Bansal <pankaj.bansal@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 3d187cd50eb0f829d540df5b901190e1da5d1e97..7f66af446ec7339b4c9687f39818cde51fc4ca38 100644 (file)
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -87,6 +87,18 @@ config MDIO_BUS_MUX_MMIOREG
 
          Currently, only 8/16/32 bits registers are supported.
 
+config MDIO_BUS_MUX_MULTIPLEXER
+       tristate "MDIO bus multiplexer using kernel multiplexer subsystem"
+       depends on OF
+       select MULTIPLEXER
+       select MDIO_BUS_MUX
+       help
+         This module provides a driver for MDIO bus multiplexer
+         that is controlled via the kernel multiplexer subsystem. The
+         bus multiplexer connects one of several child MDIO busses to
+         a parent bus.  Child bus selection is under the control of
+         the kernel multiplexer subsystem.
+
 config MDIO_CAVIUM
        tristate
 

diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 73e9670ef7e04ae9166d4ab517214569f1b1260a..ece5dae67174f87362e7950fcd4171b3c0c63d65 100644 (file)
--- 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-$(CONFIG_MDIO_BUS_MUX_MULTIPLEXER) += mdio-mux-multiplexer.o
 obj-$(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-multiplexer.c b/drivers/net/phy/mdio-mux-multiplexer.c
new file mode 100644 (file)
index 0000000..d656438
--- /dev/null
+++ b/drivers/net/phy/mdio-mux-multiplexer.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* MDIO bus multiplexer using kernel multiplexer subsystem
+ *
+ * Copyright 2019 NXP
+ */
+
+#include <linux/platform_device.h>
+#include <linux/mdio-mux.h>
+#include <linux/module.h>
+#include <linux/mux/consumer.h>
+
+struct mdio_mux_multiplexer_state {
+       struct mux_control *muxc;
+       bool do_deselect;
+       void *mux_handle;
+};
+
+/**
+ * mdio_mux_multiplexer_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.
+ * @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_multiplexer_switch_fn(int current_child, int desired_child,
+                                         void *data)
+{
+       struct platform_device *pdev;
+       struct mdio_mux_multiplexer_state *s;
+       int ret = 0;
+
+       pdev = (struct platform_device *)data;
+       s = platform_get_drvdata(pdev);
+
+       if (!(current_child ^ desired_child))
+               return 0;
+
+       if (s->do_deselect)
+               ret = mux_control_deselect(s->muxc);
+       if (ret) {
+               dev_err(&pdev->dev, "mux_control_deselect failed in %s: %d\n",
+                       __func__, ret);
+               return ret;
+       }
+
+       ret =  mux_control_select(s->muxc, desired_child);
+       if (!ret) {
+               dev_dbg(&pdev->dev, "%s %d -> %d\n", __func__, current_child,
+                       desired_child);
+               s->do_deselect = true;
+       } else {
+               s->do_deselect = false;
+       }
+
+       return ret;
+}
+
+static int mdio_mux_multiplexer_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct mdio_mux_multiplexer_state *s;
+       int ret = 0;
+
+       s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
+       if (!s)
+               return -ENOMEM;
+
+       s->muxc = devm_mux_control_get(dev, NULL);
+       if (IS_ERR(s->muxc)) {
+               ret = PTR_ERR(s->muxc);
+               if (ret != -EPROBE_DEFER)
+                       dev_err(&pdev->dev, "Failed to get mux: %d\n", ret);
+               return ret;
+       }
+
+       platform_set_drvdata(pdev, s);
+
+       ret = mdio_mux_init(&pdev->dev, pdev->dev.of_node,
+                           mdio_mux_multiplexer_switch_fn, &s->mux_handle,
+                           pdev, NULL);
+
+       return ret;
+}
+
+static int mdio_mux_multiplexer_remove(struct platform_device *pdev)
+{
+       struct mdio_mux_multiplexer_state *s = platform_get_drvdata(pdev);
+
+       mdio_mux_uninit(s->mux_handle);
+
+       if (s->do_deselect)
+               mux_control_deselect(s->muxc);
+
+       return 0;
+}
+
+static const struct of_device_id mdio_mux_multiplexer_match[] = {
+       { .compatible = "mdio-mux-multiplexer", },
+       {},
+};
+MODULE_DEVICE_TABLE(of, mdio_mux_multiplexer_match);
+
+static struct platform_driver mdio_mux_multiplexer_driver = {
+       .driver = {
+               .name           = "mdio-mux-multiplexer",
+               .of_match_table = mdio_mux_multiplexer_match,
+       },
+       .probe          = mdio_mux_multiplexer_probe,
+       .remove         = mdio_mux_multiplexer_remove,
+};
+
+module_platform_driver(mdio_mux_multiplexer_driver);
+
+MODULE_DESCRIPTION("MDIO bus multiplexer using kernel multiplexer subsystem");
+MODULE_AUTHOR("Pankaj Bansal <pankaj.bansal@nxp.com>");
+MODULE_LICENSE("GPL");