diff options
Diffstat (limited to 'drivers/mux/mmio.c')
| -rw-r--r-- | drivers/mux/mmio.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/drivers/mux/mmio.c b/drivers/mux/mmio.c new file mode 100644 index 000000000000..37c1de359a70 --- /dev/null +++ b/drivers/mux/mmio.c @@ -0,0 +1,141 @@ +/* + * 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"); |