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Subject[PATCH v4 3/3] netdev/of/phy: Add MDIO bus multiplexer driven by GPIO lines.
Date
From: David Daney <david.daney@cavium.com>

The GPIO pins select which sub bus is connected to the master.

Initially tested with an sn74cbtlv3253 switch device wired into the
MDIO bus.

Signed-off-by: David Daney <david.daney@cavium.com>
---
.../devicetree/bindings/net/mdio-mux-gpio.txt | 127 +++++++++++++++++
drivers/net/phy/Kconfig | 10 ++
drivers/net/phy/Makefile | 1 +
drivers/net/phy/mdio-mux-gpio.c | 142 ++++++++++++++++++++
4 files changed, 280 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/net/mdio-mux-gpio.txt
create mode 100644 drivers/net/phy/mdio-mux-gpio.c
diff --git a/Documentation/devicetree/bindings/net/mdio-mux-gpio.txt b/Documentation/devicetree/bindings/net/mdio-mux-gpio.txt
new file mode 100644
index 0000000..7938411
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/mdio-mux-gpio.txt
@@ -0,0 +1,127 @@
+Properties for an MDIO bus multiplexer/switch controlled by GPIO pins.
+
+This is a special case of a MDIO bus multiplexer. One or more GPIO
+lines are used to control which child bus is connected.
+
+Required properties in addition to the generic multiplexer properties:
+
+- compatible : mdio-mux-gpio.
+- gpios : GPIO specifiers for each GPIO line. One or more must be specified.
+
+
+Example :
+
+ /* The parent MDIO bus. */
+ smi1: mdio@1180000001900 {
+ compatible = "cavium,octeon-3860-mdio";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ reg = <0x11800 0x00001900 0x0 0x40>;
+ };
+
+ /*
+ An NXP sn74cbtlv3253 dual 1-of-4 switch controlled by a
+ pair of GPIO lines. Child busses 2 and 3 populated with 4
+ PHYs each.
+ */
+ mdio-mux {
+ compatible = "mdio-mux-gpio";
+ gpios = <&gpio1 3 0>, <&gpio1 4 0>;
+ mdio-parent-bus = <&smi1>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ mdio@2 {
+ reg = <2>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ phy11: ethernet-phy@1 {
+ reg = <1>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <10 8>; /* Pin 10, active low */
+ };
+ phy12: ethernet-phy@2 {
+ reg = <2>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <10 8>; /* Pin 10, active low */
+ };
+ phy13: ethernet-phy@3 {
+ reg = <3>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <10 8>; /* Pin 10, active low */
+ };
+ phy14: ethernet-phy@4 {
+ reg = <4>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <10 8>; /* Pin 10, active low */
+ };
+ };
+
+ mdio@3 {
+ reg = <3>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ phy21: ethernet-phy@1 {
+ reg = <1>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <12 8>; /* Pin 12, active low */
+ };
+ phy22: ethernet-phy@2 {
+ reg = <2>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <12 8>; /* Pin 12, active low */
+ };
+ phy23: ethernet-phy@3 {
+ reg = <3>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <12 8>; /* Pin 12, active low */
+ };
+ phy24: ethernet-phy@4 {
+ reg = <4>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <12 8>; /* Pin 12, active low */
+ };
+ };
+ };
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 222b06b..39d8c66 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -143,6 +143,16 @@ config MDIO_BUS_MUX
to a parent bus. Switching between child busses is done by
device specific drivers.

+config MDIO_BUS_MUX_GPIO
+ tristate "Support for GPIO controlled MDIO bus multiplexers"
+ depends on GENERIC_GPIO
+ select MDIO_BUS_MUX
+ help
+ This module provides a driver for MDIO bus multiplexers that
+ are controlled via GPIO lines. The multiplexer connects one of
+ several child MDIO busses to a parent bus. Child bus
+ selection is under the control of GPIO lines.
+
endif # PHYLIB

config MICREL_KS8995MA
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index a6b50e7..f51af68 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -26,3 +26,4 @@ obj-$(CONFIG_MDIO_OCTEON) += mdio-octeon.o
obj-$(CONFIG_MICREL_KS8995MA) += spi_ks8995.o
obj-$(CONFIG_AMD_PHY) += amd.o
obj-$(CONFIG_MDIO_BUS_MUX) += mdio-mux.o
+obj-$(CONFIG_MDIO_BUS_MUX_GPIO) += mdio-mux-gpio.o
diff --git a/drivers/net/phy/mdio-mux-gpio.c b/drivers/net/phy/mdio-mux-gpio.c
new file mode 100644
index 0000000..e0cc4ef
--- /dev/null
+++ b/drivers/net/phy/mdio-mux-gpio.c
@@ -0,0 +1,142 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2011, 2012 Cavium, Inc.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/of_mdio.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/phy.h>
+#include <linux/mdio-mux.h>
+#include <linux/of_gpio.h>
+
+#define DRV_VERSION "1.0"
+#define DRV_DESCRIPTION "GPIO controlled MDIO bus multiplexer driver"
+
+#define MDIO_MUX_GPIO_MAX_BITS 8
+
+struct mdio_mux_gpio_state {
+ int gpio[MDIO_MUX_GPIO_MAX_BITS];
+ unsigned int num_gpios;
+ void *mux_handle;
+};
+
+static int mdio_mux_gpio_switch_fn(int current_child, int desired_child,
+ void *data)
+{
+ int change;
+ unsigned int n;
+ struct mdio_mux_gpio_state *s = data;
+
+ if (current_child == desired_child)
+ return 0;
+
+ change = current_child == -1 ? -1 : current_child ^ desired_child;
+
+ for (n = 0; n < s->num_gpios; n++) {
+ if (change & 1)
+ gpio_set_value_cansleep(s->gpio[n],
+ (desired_child & 1) != 0);
+ change >>= 1;
+ desired_child >>= 1;
+ }
+
+ return 0;
+}
+
+static int __devinit mdio_mux_gpio_probe(struct platform_device *pdev)
+{
+ enum of_gpio_flags f;
+ struct mdio_mux_gpio_state *s;
+ unsigned int num_gpios;
+ unsigned int n;
+ int r;
+
+ if (!pdev->dev.of_node)
+ return -ENODEV;
+
+ num_gpios = of_gpio_count(pdev->dev.of_node);
+ if (num_gpios == 0 || num_gpios > MDIO_MUX_GPIO_MAX_BITS)
+ return -ENODEV;
+
+ s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
+ if (!s)
+ return -ENOMEM;
+
+ s->num_gpios = num_gpios;
+
+ for (n = 0; n < num_gpios; ) {
+ int gpio = of_get_gpio_flags(pdev->dev.of_node, n, &f);
+ if (gpio < 0) {
+ r = (gpio == -ENODEV) ? -EPROBE_DEFER : gpio;
+ goto err;
+ }
+ s->gpio[n] = gpio;
+
+ n++;
+
+ r = gpio_request(gpio, "mdio_mux_gpio");
+ if (r)
+ goto err;
+
+ r = gpio_direction_output(gpio, 0);
+ if (r)
+ goto err;
+ }
+
+ r = mdio_mux_init(&pdev->dev,
+ mdio_mux_gpio_switch_fn, &s->mux_handle, s);
+
+ if (r == 0) {
+ pdev->dev.platform_data = s;
+ return 0;
+ }
+err:
+ while (n) {
+ n--;
+ gpio_free(s->gpio[n]);
+ }
+ devm_kfree(&pdev->dev, s);
+ return r;
+}
+
+static int __devexit mdio_mux_gpio_remove(struct platform_device *pdev)
+{
+ struct mdio_mux_gpio_state *s = pdev->dev.platform_data;
+ mdio_mux_uninit(s->mux_handle);
+ return 0;
+}
+
+static struct of_device_id mdio_mux_gpio_match[] = {
+ {
+ .compatible = "mdio-mux-gpio",
+ },
+ {
+ /* Legacy compatible property. */
+ .compatible = "cavium,mdio-mux-sn74cbtlv3253",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, mdio_mux_gpio_match);
+
+static struct platform_driver mdio_mux_gpio_driver = {
+ .driver = {
+ .name = "mdio-mux-gpio",
+ .owner = THIS_MODULE,
+ .of_match_table = mdio_mux_gpio_match,
+ },
+ .probe = mdio_mux_gpio_probe,
+ .remove = __devexit_p(mdio_mux_gpio_remove),
+};
+
+module_platform_driver(mdio_mux_gpio_driver);
+
+MODULE_DESCRIPTION(DRV_DESCRIPTION);
+MODULE_VERSION(DRV_VERSION);
+MODULE_AUTHOR("David Daney");
+MODULE_LICENSE("GPL");
--
1.7.2.3


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