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/*
* MMIO register bitfield-controlled multiplexer driver
*
* Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/mux/driver.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
static int mux_mmio_set(struct mux_control *mux, int state)
{
struct regmap_field **fields = mux_chip_priv(mux->chip);
return regmap_field_write(fields[mux_control_get_index(mux)], state);
}
static const struct mux_control_ops mux_mmio_ops = {
.set = mux_mmio_set,
};
static const struct of_device_id mux_mmio_dt_ids[] = {
{ .compatible = "mmio-mux", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mux_mmio_dt_ids);
static int mux_mmio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct regmap_field **fields;
struct mux_chip *mux_chip;
struct regmap *regmap;
int num_fields;
int ret;
int i;
regmap = syscon_node_to_regmap(np->parent);
if (IS_ERR(regmap)) {
ret = PTR_ERR(regmap);
dev_err(dev, "failed to get regmap: %d\n", ret);
return ret;
}
ret = of_property_count_u32_elems(np, "mux-reg-masks");
if (ret == 0 || ret % 2)
ret = -EINVAL;
if (ret < 0) {
dev_err(dev, "mux-reg-masks property missing or invalid: %d\n",
ret);
return ret;
}
num_fields = ret / 2;
mux_chip = devm_mux_chip_alloc(dev, num_fields, num_fields *
sizeof(*fields));
if (IS_ERR(mux_chip))
return PTR_ERR(mux_chip);
fields = mux_chip_priv(mux_chip);
for (i = 0; i < num_fields; i++) {
struct mux_control *mux = &mux_chip->mux[i];
struct reg_field field;
s32 idle_state = MUX_IDLE_AS_IS;
u32 reg, mask;
int bits;
ret = of_property_read_u32_index(np, "mux-reg-masks",
2 * i, ®);
if (!ret)
ret = of_property_read_u32_index(np, "mux-reg-masks",
2 * i + 1, &mask);
if (ret < 0) {
dev_err(dev, "bitfield %d: failed to read mux-reg-masks property: %d\n",
i, ret);
return ret;
}
field.reg = reg;
field.msb = fls(mask) - 1;
field.lsb = ffs(mask) - 1;
if (mask != GENMASK(field.msb, field.lsb)) {
dev_err(dev, "bitfield %d: invalid mask 0x%x\n",
i, mask);
return -EINVAL;
}
fields[i] = devm_regmap_field_alloc(dev, regmap, field);
if (IS_ERR(fields[i])) {
ret = PTR_ERR(fields[i]);
dev_err(dev, "bitfield %d: failed allocate: %d\n",
i, ret);
return ret;
}
bits = 1 + field.msb - field.lsb;
mux->states = 1 << bits;
of_property_read_u32_index(np, "idle-states", i,
(u32 *)&idle_state);
if (idle_state != MUX_IDLE_AS_IS) {
if (idle_state < 0 || idle_state >= mux->states) {
dev_err(dev, "bitfield: %d: out of range idle state %d\n",
i, idle_state);
return -EINVAL;
}
mux->idle_state = idle_state;
}
}
mux_chip->ops = &mux_mmio_ops;
return devm_mux_chip_register(dev, mux_chip);
}
static struct platform_driver mux_mmio_driver = {
.driver = {
.name = "mmio-mux",
.of_match_table = of_match_ptr(mux_mmio_dt_ids),
},
.probe = mux_mmio_probe,
};
module_platform_driver(mux_mmio_driver);
MODULE_DESCRIPTION("MMIO register bitfield-controlled multiplexer driver");
MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
MODULE_LICENSE("GPL v2");
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