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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@gmail.com> Acked-by: Joe Hershberger <joe.hershberger@ni.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
108 lines
2.6 KiB
C
108 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* (C) Copyright 2019
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* Alex Marginean, NXP
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*/
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#include <dm.h>
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#include <errno.h>
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#include <miiphy.h>
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#include <i2c.h>
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/*
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* This driver is used for MDIO muxes driven by writing to a register of an I2C
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* chip. The board it was developed for uses a mux controlled by on-board FPGA
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* which in turn is accessed as a chip over I2C.
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*/
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struct mdio_mux_i2creg_priv {
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struct udevice *chip;
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int reg;
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int mask;
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};
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static int mdio_mux_i2creg_select(struct udevice *mux, int cur, int sel)
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{
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struct mdio_mux_i2creg_priv *priv = dev_get_priv(mux);
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u8 val, val_old;
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/* if last selection didn't change we're good to go */
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if (cur == sel)
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return 0;
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val_old = dm_i2c_reg_read(priv->chip, priv->reg);
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val = (val_old & ~priv->mask) | (sel & priv->mask);
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debug("%s: chip %s, reg %x, val %x => %x\n", __func__, priv->chip->name,
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priv->reg, val_old, val);
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dm_i2c_reg_write(priv->chip, priv->reg, val);
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return 0;
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}
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static const struct mdio_mux_ops mdio_mux_i2creg_ops = {
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.select = mdio_mux_i2creg_select,
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};
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static int mdio_mux_i2creg_probe(struct udevice *dev)
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{
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struct mdio_mux_i2creg_priv *priv = dev_get_priv(dev);
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ofnode chip_node, bus_node;
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struct udevice *i2c_bus;
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u32 reg_mask[2];
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u32 chip_addr;
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int err;
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/* read the register addr/mask pair */
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err = dev_read_u32_array(dev, "mux-reg-masks", reg_mask, 2);
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if (err) {
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debug("%s: error reading mux-reg-masks property\n", __func__);
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return err;
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}
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/* parent should be an I2C chip, grandparent should be an I2C bus */
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chip_node = ofnode_get_parent(dev->node);
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bus_node = ofnode_get_parent(chip_node);
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err = uclass_get_device_by_ofnode(UCLASS_I2C, bus_node, &i2c_bus);
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if (err) {
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debug("%s: can't find I2C bus for node %s\n", __func__,
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ofnode_get_name(bus_node));
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return err;
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}
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err = ofnode_read_u32(chip_node, "reg", &chip_addr);
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if (err) {
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debug("%s: can't read chip address in %s\n", __func__,
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ofnode_get_name(chip_node));
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return err;
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}
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err = i2c_get_chip(i2c_bus, (uint)chip_addr, 1, &priv->chip);
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if (err) {
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debug("%s: can't find i2c chip device for addr %x\n", __func__,
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chip_addr);
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return err;
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}
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priv->reg = (int)reg_mask[0];
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priv->mask = (int)reg_mask[1];
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debug("%s: chip %s, reg %x, mask %x\n", __func__, priv->chip->name,
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priv->reg, priv->mask);
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return 0;
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}
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static const struct udevice_id mdio_mux_i2creg_ids[] = {
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{ .compatible = "mdio-mux-i2creg" },
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{ }
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};
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U_BOOT_DRIVER(mdio_mux_i2creg) = {
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.name = "mdio_mux_i2creg",
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.id = UCLASS_MDIO_MUX,
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.of_match = mdio_mux_i2creg_ids,
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.probe = mdio_mux_i2creg_probe,
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.ops = &mdio_mux_i2creg_ops,
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.priv_auto_alloc_size = sizeof(struct mdio_mux_i2creg_priv),
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};
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