On 2017-04-24 18:12, Philipp Zabel wrote: > This adds a driver for mmio-based syscon multiplexers controlled by a > single bitfield in a syscon register range.
Single bitfield? > > Signed-off-by: Philipp Zabel <[email protected]> > --- > Changes since v1: > - Renamed MUX_SYSCON to MUX_MMIO. Instead of obtaining the regmap via syscon, > this could just as well map its own MMIO register range if a reg property > was added. > - Replaced reg, bit-mask, and bit-shift properties with mux-reg-masks array > to allow defining multiple mux bit-fields per mmio-mux instance. > - Changed mux-control-cells value to <1>, the cell value is an index into > the mux-reg-masks array. > - Replaced idle-state with idle-states array. > - Stopped clobbering mux->cached_state, that is internal to the mux core. > --- > drivers/mux/Kconfig | 13 ++++ > drivers/mux/Makefile | 1 + > drivers/mux/mux-mmio.c | 162 > +++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 176 insertions(+) > create mode 100644 drivers/mux/mux-mmio.c > > diff --git a/drivers/mux/Kconfig b/drivers/mux/Kconfig > index 34b8284d6d29e..e2bee25a1586e 100644 > --- a/drivers/mux/Kconfig > +++ b/drivers/mux/Kconfig > @@ -43,4 +43,17 @@ config MUX_GPIO > To compile the driver as a module, choose M here: the module will > be called mux-gpio. > > +config MUX_MMIO > + tristate "MMIO register bitfield-controlled Multiplexer" > + depends on OF && MFD_SYSCON > + help > + MMIO register bitfield-controlled Multiplexer controller. > + > + The driver builds a single multiplexer controller using a bitfield > + in a syscon register. For N bit wide bitfields, there will be 2^N > + possible multiplexer states. Multiple multiplexer controllers.... > + > + To compile the driver as a module, choose M here: the module will > + be called mux-mmio. > + > endif > diff --git a/drivers/mux/Makefile b/drivers/mux/Makefile > index b00a7d37d2fbe..6bac5b0fea137 100644 > --- a/drivers/mux/Makefile > +++ b/drivers/mux/Makefile > @@ -5,3 +5,4 @@ > obj-$(CONFIG_MULTIPLEXER) += mux-core.o > obj-$(CONFIG_MUX_ADG792A) += mux-adg792a.o > obj-$(CONFIG_MUX_GPIO) += mux-gpio.o > +obj-$(CONFIG_MUX_MMIO) += mux-mmio.o > diff --git a/drivers/mux/mux-mmio.c b/drivers/mux/mux-mmio.c > new file mode 100644 > index 0000000000000..0b011fb59f99b > --- /dev/null > +++ b/drivers/mux/mux-mmio.c > @@ -0,0 +1,162 @@ > +/* > + * MMIO register bitfield-controlled multiplexer driver > + * > + * Copyright (C) 2017 Pengutronix, Philipp Zabel <[email protected]> > + * > + * 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/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); > + int index = mux - mux->chip->mux; mux_control_get_index(mux) does exactly this. > + > + return regmap_field_write(fields[index], 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; > + s32 *idle_states; > + u32 *reg_masks; > + 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 syscon 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) { > + num_fields = ret / 2; > + > + reg_masks = devm_kmalloc(dev, ret * sizeof(u32), GFP_KERNEL); > + if (!reg_masks) > + return -ENOMEM; > + > + ret = of_property_read_u32_array(np, "mux-reg-masks", > + reg_masks, ret); > + } > + if (ret < 0) { > + dev_err(dev, "mux-reg-masks property missing or invalid: %d\n", > + ret); > + return ret; > + } > + > + 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; > + u32 *reg_mask = reg_masks + 2 * i; > + int bits; u32 mask; > + > + field.reg = reg_mask[0]; > + field.msb = fls(reg_mask[1]) - 1; > + field.lsb = ffs(reg_mask[1]) - 1; Perhaps add a sanity check? (untested, but you get the idea...) mask = (BIT(field.msb + 1) - 1) ^ (BIT(field.lsb) - 1); if (WARN_ON(reg_mask[1] != mask)) { /* Catches empty reg_mask[1] as well. */ dev_err(...) return -EINVAL; } > + bits = 1 + field.msb - field.lsb; > + > + fields[i] = devm_regmap_field_alloc(&pdev->dev, regmap, field); > + if (IS_ERR(fields[i])) { > + ret = PTR_ERR(fields[i]); > + dev_err(&pdev->dev, "failed to get bit-field %d: %d\n", > + i, ret); > + return ret; > + } > + > + mux->states = 1 << bits; > + } > + > + devm_kfree(dev, reg_masks); > + > + if (of_find_property(np, "idle-states", NULL)) { > + ret = of_property_count_u32_elems(np, "idle-states"); > + if (ret == num_fields) { > + idle_states = devm_kmalloc(dev, ret * sizeof(s32), > + GFP_KERNEL); > + if (!idle_states) > + return -ENOMEM; > + > + ret = of_property_read_u32_array(np, "idle-states", > + idle_states, ret); > + } else { > + idle_states = NULL; > + if (ret >= 0) > + ret = -EINVAL; > + } > + if (ret < 0) { > + dev_err(dev, "idle-states property invalid: %d\n", ret); > + return ret; > + } > + > + for (i = 0; i < num_fields; i++) { Hmm, this is the second loop over num_fields with accesses to a complete copy of a DT array. Is it not possible to use one loop and set up all aspects of each mux-control using of_property_read_u32_index calls in that loop? I have the feeling that will look neater... > + struct mux_control *mux = &mux_chip->mux[i]; > + > + if (idle_states[i] != MUX_IDLE_AS_IS) { > + if (idle_states[i] < 0 || > + idle_states[i] >= mux->states) { > + dev_err(dev, "invalid idle-state %u\n", > + idle_states[i]); > + return -EINVAL; > + } > + > + mux->idle_state = idle_states[i]; > + } > + } > + > + devm_kfree(dev, idle_states); > + } > + > + 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 <[email protected]>"); > +MODULE_LICENSE("GPL v2"); >
