[U-Boot] [PATCH 1/2] drivers: net: driver for MDIO muxes controlled over I2C

Alex Marginean alexandru.marginean at nxp.com
Fri Jul 12 14:20:47 UTC 2019


This driver is used for MDIO muxes driven over I2C.  This is currently
used on Freescale LS1028A QDS board, on which the physical MDIO MUX is
controlled by an on-board FPGA which in turn is configured through I2C.

Signed-off-by: Alex Marginean <alexm.osslist at gmail.com>
---

Depends on https://patchwork.ozlabs.org/project/uboot/list/?series=119124

 drivers/net/Kconfig            |   8 +++
 drivers/net/Makefile           |   1 +
 drivers/net/mdio_mux_i2c_reg.c | 108 +++++++++++++++++++++++++++++++++
 3 files changed, 117 insertions(+)
 create mode 100644 drivers/net/mdio_mux_i2c_reg.c

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 4d85fb1716..93535f7acb 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -595,4 +595,12 @@ config FSL_ENETC
 	  This driver supports the NXP ENETC Ethernet controller found on some
 	  of the NXP SoCs.
 
+config MDIO_MUX_I2C_REG
+	bool "MDIO MUX accessed as a register over I2C"
+	depends on DM_MDIO_MUX && DM_I2C
+	help
+	  This driver is used for MDIO muxes driven by writing to a register of
+	  an I2C chip.  The board it was developed for uses a mux controlled by
+	  on-board FPGA which in turn is accessed as a chip over I2C.
+
 endif # NETDEVICES
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 97119cec7c..9470f02dc6 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -80,3 +80,4 @@ obj-$(CONFIG_HIGMACV300_ETH) += higmacv300.o
 obj-$(CONFIG_MDIO_SANDBOX) += mdio_sandbox.o
 obj-$(CONFIG_FSL_ENETC) += fsl_enetc.o fsl_enetc_mdio.o
 obj-$(CONFIG_MDIO_MUX_SANDBOX) += mdio_mux_sandbox.o
+obj-$(CONFIG_MDIO_MUX_I2C_REG) += mdio_mux_i2c_reg.o
diff --git a/drivers/net/mdio_mux_i2c_reg.c b/drivers/net/mdio_mux_i2c_reg.c
new file mode 100644
index 0000000000..eb75c5e032
--- /dev/null
+++ b/drivers/net/mdio_mux_i2c_reg.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2019
+ * Alex Marginean, NXP
+ */
+
+#include <dm.h>
+#include <errno.h>
+#include <miiphy.h>
+#include <i2c.h>
+
+/*
+ * This driver is used for MDIO muxes driven by writing to a register of an I2C
+ * chip.  The board it was developed for uses a mux controlled by on-board FPGA
+ * which in turn is accessed as a chip over I2C.
+ */
+
+struct mmux_i2c_reg_priv {
+	struct udevice *chip;
+	int reg;
+	int mask;
+};
+
+static int mmux_i2c_reg_select(struct udevice *mux, int cur, int sel)
+{
+	struct mmux_i2c_reg_priv *priv = dev_get_priv(mux);
+	u8 val, val_old;
+
+	/* if last selection didn't change we're good to go */
+	if (cur == sel)
+		return 0;
+
+	val_old = dm_i2c_reg_read(priv->chip, priv->reg);
+	val = (val_old & ~priv->mask) | (sel & priv->mask);
+	debug("%s: chip %s, reg %x, val %x => %x\n", __func__, priv->chip->name,
+	      priv->reg, val_old, val);
+	dm_i2c_reg_write(priv->chip, priv->reg, val);
+
+	return 0;
+}
+
+static const struct mdio_mux_ops mmux_i2c_reg_ops = {
+	.select = mmux_i2c_reg_select,
+};
+
+static int mmux_i2c_reg_probe(struct udevice *dev)
+{
+	struct mmux_i2c_reg_priv *priv = dev_get_priv(dev);
+	ofnode chip_node, bus_node;
+	struct udevice *i2c_bus;
+	u32 reg_mask[2];
+	u32 chip_addr;
+	int err;
+
+	/* read the register addr/mask pair */
+	err = dev_read_u32_array(dev, "mux-reg-masks", reg_mask, 2);
+	if (err) {
+		debug("%s: error reading mux-reg-masks property\n", __func__);
+		return err;
+	}
+
+	/* parent should be an I2C chip, grandparent should be an I2C bus */
+	chip_node = ofnode_get_parent(dev->node);
+	bus_node = ofnode_get_parent(chip_node);
+
+	err = uclass_get_device_by_ofnode(UCLASS_I2C, bus_node, &i2c_bus);
+	if (err) {
+		debug("%s: can't find I2C bus for node %s\n", __func__,
+		      ofnode_get_name(bus_node));
+		return err;
+	}
+
+	err = ofnode_read_u32(chip_node, "reg", &chip_addr);
+	if (err) {
+		debug("%s: can't read chip address in %s\n", __func__,
+		      ofnode_get_name(chip_node));
+		return err;
+	}
+
+	err = i2c_get_chip(i2c_bus, (uint)chip_addr, 1, &priv->chip);
+	if (err) {
+		debug("%s: can't find i2c chip device for addr %x\n", __func__,
+		      chip_addr);
+		return err;
+	}
+
+	priv->reg = (int)reg_mask[0];
+	priv->mask = (int)reg_mask[1];
+
+	debug("%s: chip %s, reg %x, mask %x\n", __func__, priv->chip->name,
+	      priv->reg, priv->mask);
+
+	return 0;
+}
+
+static const struct udevice_id mmux_i2c_reg_ids[] = {
+	{ .compatible = "mdio-mux-i2c-reg" },
+	{ }
+};
+
+U_BOOT_DRIVER(mmux_i2c_reg) = {
+	.name		= "mdio_mux_i2c_reg",
+	.id		= UCLASS_MDIO_MUX,
+	.of_match	= mmux_i2c_reg_ids,
+	.probe		= mmux_i2c_reg_probe,
+	.ops		= &mmux_i2c_reg_ops,
+	.priv_auto_alloc_size = sizeof(struct mmux_i2c_reg_priv),
+};
-- 
2.17.1



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