1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * (C) Copyright 2019
4 * Alex Marginean, NXP
5 */
6
7#include <dm.h>
8#include <errno.h>
9#include <log.h>
10#include <miiphy.h>
11#include <i2c.h>
12
13/*
14 * This driver is used for MDIO muxes driven by writing to a register of an I2C
15 * chip.  The board it was developed for uses a mux controlled by on-board FPGA
16 * which in turn is accessed as a chip over I2C.
17 */
18
19struct mdio_mux_i2creg_priv {
20	struct udevice *chip;
21	int reg;
22	int mask;
23};
24
25static int mdio_mux_i2creg_select(struct udevice *mux, int cur, int sel)
26{
27	struct mdio_mux_i2creg_priv *priv = dev_get_priv(mux);
28	u8 val, val_old;
29
30	/* if last selection didn't change we're good to go */
31	if (cur == sel)
32		return 0;
33
34	val_old = dm_i2c_reg_read(priv->chip, priv->reg);
35	val = (val_old & ~priv->mask) | (sel & priv->mask);
36	debug("%s: chip %s, reg %x, val %x => %x\n", __func__, priv->chip->name,
37	      priv->reg, val_old, val);
38	dm_i2c_reg_write(priv->chip, priv->reg, val);
39
40	return 0;
41}
42
43static const struct mdio_mux_ops mdio_mux_i2creg_ops = {
44	.select = mdio_mux_i2creg_select,
45};
46
47static int mdio_mux_i2creg_probe(struct udevice *dev)
48{
49	struct mdio_mux_i2creg_priv *priv = dev_get_priv(dev);
50	ofnode chip_node, bus_node;
51	struct udevice *i2c_bus;
52	u32 reg_mask[2];
53	u32 chip_addr;
54	int err;
55
56	/* read the register addr/mask pair */
57	err = dev_read_u32_array(dev, "mux-reg-masks", reg_mask, 2);
58	if (err) {
59		debug("%s: error reading mux-reg-masks property\n", __func__);
60		return err;
61	}
62
63	/* parent should be an I2C chip, grandparent should be an I2C bus */
64	chip_node = ofnode_get_parent(dev_ofnode(dev));
65	bus_node = ofnode_get_parent(chip_node);
66
67	err = uclass_get_device_by_ofnode(UCLASS_I2C, bus_node, &i2c_bus);
68	if (err) {
69		debug("%s: can't find I2C bus for node %s\n", __func__,
70		      ofnode_get_name(bus_node));
71		return err;
72	}
73
74	err = ofnode_read_u32(chip_node, "reg", &chip_addr);
75	if (err) {
76		debug("%s: can't read chip address in %s\n", __func__,
77		      ofnode_get_name(chip_node));
78		return err;
79	}
80
81	err = i2c_get_chip(i2c_bus, (uint)chip_addr, 1, &priv->chip);
82	if (err) {
83		debug("%s: can't find i2c chip device for addr %x\n", __func__,
84		      chip_addr);
85		return err;
86	}
87
88	priv->reg = (int)reg_mask[0];
89	priv->mask = (int)reg_mask[1];
90
91	debug("%s: chip %s, reg %x, mask %x\n", __func__, priv->chip->name,
92	      priv->reg, priv->mask);
93
94	return 0;
95}
96
97static const struct udevice_id mdio_mux_i2creg_ids[] = {
98	{ .compatible = "mdio-mux-i2creg" },
99	{ }
100};
101
102U_BOOT_DRIVER(mdio_mux_i2creg) = {
103	.name		= "mdio_mux_i2creg",
104	.id		= UCLASS_MDIO_MUX,
105	.of_match	= mdio_mux_i2creg_ids,
106	.probe		= mdio_mux_i2creg_probe,
107	.ops		= &mdio_mux_i2creg_ops,
108	.priv_auto	= sizeof(struct mdio_mux_i2creg_priv),
109};
110