142 lines
3.5 KiB
C
142 lines
3.5 KiB
C
/*
|
|
* 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");
|