Add a new subsystem that handles multiplexer controllers. The API is the same as in Linux.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com
---
Changes in v2: - Fixed warning in mux_of_xlate_default() - Improved documentation - Fixed SPL build
drivers/Kconfig | 2 + drivers/Makefile | 1 + drivers/mux/Kconfig | 7 + drivers/mux/Makefile | 6 + drivers/mux/mux-uclass.c | 270 ++++++++++++++++++++++++++++++++++ include/dm/uclass-id.h | 1 + include/dt-bindings/mux/mux.h | 17 +++ include/mux-internal.h | 103 +++++++++++++ include/mux.h | 113 ++++++++++++++ 9 files changed, 520 insertions(+) create mode 100644 drivers/mux/Kconfig create mode 100644 drivers/mux/Makefile create mode 100644 drivers/mux/mux-uclass.c create mode 100644 include/dt-bindings/mux/mux.h create mode 100644 include/mux-internal.h create mode 100644 include/mux.h
diff --git a/drivers/Kconfig b/drivers/Kconfig index 9d99ce0226..450aa76e82 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -60,6 +60,8 @@ source "drivers/mmc/Kconfig"
source "drivers/mtd/Kconfig"
+source "drivers/mux/Kconfig" + source "drivers/net/Kconfig"
source "drivers/nvme/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index 0befeddfcb..9d64742580 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -12,6 +12,7 @@ obj-$(CONFIG_$(SPL_TPL_)INPUT) += input/ obj-$(CONFIG_$(SPL_TPL_)LED) += led/ obj-$(CONFIG_$(SPL_TPL_)MMC_SUPPORT) += mmc/ obj-$(CONFIG_$(SPL_TPL_)NAND_SUPPORT) += mtd/nand/raw/ +obj-$(CONFIG_$(SPL_)MULTIPLEXER) += mux/ obj-$(CONFIG_$(SPL_TPL_)PCH_SUPPORT) += pch/ obj-$(CONFIG_$(SPL_TPL_)PCI) += pci/ obj-$(CONFIG_$(SPL_TPL_)PHY) += phy/ diff --git a/drivers/mux/Kconfig b/drivers/mux/Kconfig new file mode 100644 index 0000000000..ad0199c058 --- /dev/null +++ b/drivers/mux/Kconfig @@ -0,0 +1,7 @@ +menu "Multiplexer drivers" + +config MULTIPLEXER + bool "Multiplexer Support" + depends on DM + +endmenu diff --git a/drivers/mux/Makefile b/drivers/mux/Makefile new file mode 100644 index 0000000000..351e4363d3 --- /dev/null +++ b/drivers/mux/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0+ +# +# (C) Copyright 2019 +# Jean-Jacques Hiblot jjhiblot@ti.com + +obj-$(CONFIG_$(SPL_)MULTIPLEXER) += mux-uclass.o diff --git a/drivers/mux/mux-uclass.c b/drivers/mux/mux-uclass.c new file mode 100644 index 0000000000..6aaf4dc964 --- /dev/null +++ b/drivers/mux/mux-uclass.c @@ -0,0 +1,270 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Multiplexer subsystem + * + * Based on the linux multiplexer framework + * + * Copyright (C) 2017 Axentia Technologies AB + * Author: Peter Rosin peda@axentia.se + * + * Copyright (C) 2017-2018 Texas Instruments Incorporated - http://www.ti.com/ + * Jean-Jacques Hiblot jjhiblot@ti.com + */ + +#include <common.h> +#include <dm.h> +#include <mux-internal.h> +#include <dm/device-internal.h> +#include <dt-bindings/mux/mux.h> + +/* + * The idle-as-is "state" is not an actual state that may be selected, it + * only implies that the state should not be changed. So, use that state + * as indication that the cached state of the multiplexer is unknown. + */ +#define MUX_CACHE_UNKNOWN MUX_IDLE_AS_IS + +static inline const struct mux_control_ops *mux_dev_ops(struct udevice *dev) +{ + return (const struct mux_control_ops *)dev->driver->ops; +} + +static int mux_control_set(struct mux_control *mux, int state) +{ + int ret = mux_dev_ops(mux->dev)->set(mux, state); + + mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state; + + return ret; +} + +unsigned int mux_control_states(struct mux_control *mux) +{ + return mux->states; +} + +static int __mux_control_select(struct mux_control *mux, int state) +{ + int ret; + + if (WARN_ON(state < 0 || state >= mux->states)) + return -EINVAL; + + if (mux->cached_state == state) + return 0; + + ret = mux_control_set(mux, state); + if (ret >= 0) + return 0; + + /* The mux update failed, try to revert if appropriate... */ + if (mux->idle_state != MUX_IDLE_AS_IS) + mux_control_set(mux, mux->idle_state); + + return ret; +} + +int mux_control_select(struct mux_control *mux, unsigned int state) +{ + int ret; + + if (mux->in_use) + return -EBUSY; + + ret = __mux_control_select(mux, state); + + if (ret < 0) + return ret; + + mux->in_use = true; + + return 0; +} + +int mux_control_deselect(struct mux_control *mux) +{ + int ret = 0; + + if (mux->idle_state != MUX_IDLE_AS_IS && + mux->idle_state != mux->cached_state) + ret = mux_control_set(mux, mux->idle_state); + + mux->in_use = false; + + return ret; +} + +static int mux_of_xlate_default(struct mux_chip *mux_chip, + struct ofnode_phandle_args *args, + struct mux_control **muxp) +{ + struct mux_control *mux; + int id; + + debug("%s(muxp=%p)\n", __func__, muxp); + + if (args->args_count > 1) { + debug("Invaild args_count: %d\n", args->args_count); + return -EINVAL; + } + + if (args->args_count) + id = args->args[0]; + else + id = 0; + + if (id >= mux_chip->controllers) { + dev_err(dev, "bad mux controller %u specified in %s\n", + id, ofnode_get_name(args->node)); + return -ERANGE; + } + + mux = &mux_chip->mux[id]; + mux->id = id; + *muxp = mux; + return 0; +} + +static int mux_get_by_indexed_prop(struct udevice *dev, const char *prop_name, + int index, struct mux_control **mux) +{ + int ret; + struct ofnode_phandle_args args; + struct udevice *dev_mux; + const struct mux_control_ops *ops; + struct mux_chip *mux_chip; + + debug("%s(dev=%p, index=%d, mux=%p)\n", __func__, dev, index, mux); + + ret = dev_read_phandle_with_args(dev, prop_name, "#mux-control-cells", + 0, index, &args); + if (ret) { + debug("%s: fdtdec_parse_phandle_with_args failed: err=%d\n", + __func__, ret); + return ret; + } + + ret = uclass_get_device_by_ofnode(UCLASS_MUX, args.node, &dev_mux); + if (ret) { + debug("%s: uclass_get_device_by_ofnode failed: err=%d\n", + __func__, ret); + return ret; + } + + mux_chip = dev_get_uclass_priv(dev_mux); + + ops = mux_dev_ops(dev_mux); + if (ops->of_xlate) + ret = ops->of_xlate(mux_chip, &args, mux); + else + ret = mux_of_xlate_default(mux_chip, &args, mux); + if (ret) { + debug("of_xlate() failed: %d\n", ret); + return ret; + } + (*mux)->dev = dev_mux; + + return 0; +} + +int mux_get_by_index(struct udevice *dev, int index, struct mux_control **mux) +{ + return mux_get_by_indexed_prop(dev, "mux-controls", index, mux); +} + +int mux_control_get(struct udevice *dev, const char *name, + struct mux_control **mux) +{ + int index; + + debug("%s(dev=%p, name=%s, mux=%p)\n", __func__, dev, name, mux); + + index = dev_read_stringlist_search(dev, "mux-control-names", name); + if (index < 0) { + debug("fdt_stringlist_search() failed: %d\n", index); + return index; + } + + return mux_get_by_index(dev, index, mux); +} + +void mux_control_put(struct mux_control *mux) +{ + mux_control_deselect(mux); +} + +static void devm_mux_control_release(struct udevice *dev, void *res) +{ + mux_control_put(*(struct mux_control **)res); +} + +struct mux_control *devm_mux_control_get(struct udevice *dev, const char *id) +{ + int rc; + struct mux_control **mux; + + mux = devres_alloc(devm_mux_control_release, + sizeof(struct mux_control *), __GFP_ZERO); + if (unlikely(!mux)) + return ERR_PTR(-ENOMEM); + + rc = mux_control_get(dev, id, mux); + if (rc) + return ERR_PTR(rc); + + devres_add(dev, mux); + return *mux; +} + +int mux_alloc_controllers(struct udevice *dev, unsigned int controllers) +{ + int i; + struct mux_chip *mux_chip = dev_get_uclass_priv(dev); + + mux_chip->mux = devm_kmalloc(dev, + sizeof(struct mux_control) * controllers, + __GFP_ZERO); + if (!mux_chip->mux) + return -ENOMEM; + + mux_chip->controllers = controllers; + + for (i = 0; i < mux_chip->controllers; ++i) { + struct mux_control *mux = &mux_chip->mux[i]; + + mux->dev = dev; + mux->cached_state = MUX_CACHE_UNKNOWN; + mux->idle_state = MUX_IDLE_AS_IS; + mux->in_use = false; + mux->id = i; + } + + return 0; +} + +int mux_uclass_post_probe(struct udevice *dev) +{ + int i, ret; + struct mux_chip *mux_chip = dev_get_uclass_priv(dev); + + for (i = 0; i < mux_chip->controllers; ++i) { + struct mux_control *mux = &mux_chip->mux[i]; + + if (mux->idle_state == mux->cached_state) + continue; + + ret = mux_control_set(mux, mux->idle_state); + if (ret < 0) { + dev_err(&mux_chip->dev, "unable to set idle state\n"); + return ret; + } + } + return 0; +} + +UCLASS_DRIVER(mux) = { + .id = UCLASS_MUX, + .name = "mux", + .post_probe = mux_uclass_post_probe, + .per_device_auto_alloc_size = sizeof(struct mux_chip), +}; diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h index 0c563d898b..28822689a9 100644 --- a/include/dm/uclass-id.h +++ b/include/dm/uclass-id.h @@ -66,6 +66,7 @@ enum uclass_id { UCLASS_MMC, /* SD / MMC card or chip */ UCLASS_MOD_EXP, /* RSA Mod Exp device */ UCLASS_MTD, /* Memory Technology Device (MTD) device */ + UCLASS_MUX, /* Multiplexer device */ UCLASS_NOP, /* No-op devices */ UCLASS_NORTHBRIDGE, /* Intel Northbridge / SDRAM controller */ UCLASS_NVME, /* NVM Express device */ diff --git a/include/dt-bindings/mux/mux.h b/include/dt-bindings/mux/mux.h new file mode 100644 index 0000000000..042719218d --- /dev/null +++ b/include/dt-bindings/mux/mux.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * This header provides constants for most Multiplexer bindings. + * + * Most Multiplexer bindings specify an idle state. In most cases, the + * the multiplexer can be left as is when idle, and in some cases it can + * disconnect the input/output and leave the multiplexer in a high + * impedance state. + */ + +#ifndef _DT_BINDINGS_MUX_MUX_H +#define _DT_BINDINGS_MUX_MUX_H + +#define MUX_IDLE_AS_IS (-1) +#define MUX_IDLE_DISCONNECT (-2) + +#endif diff --git a/include/mux-internal.h b/include/mux-internal.h new file mode 100644 index 0000000000..c590bd0c74 --- /dev/null +++ b/include/mux-internal.h @@ -0,0 +1,103 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Based on the linux multiplexer framework + * + * Copyright (C) 2017 Axentia Technologies AB + * Author: Peter Rosin peda@axentia.se + * + * Copyright (C) 2017-2018 Texas Instruments Incorporated - http://www.ti.com/ + * Jean-Jacques Hiblot jjhiblot@ti.com + */ + +#ifndef _MUX_UCLASS_H +#define _MUX_UCLASS_H + +/* See mux.h for background documentation. */ + +#include <mux.h> + +struct ofnode_phandle_args; + +/** + * struct mux_chip - Represents a chip holding mux controllers. + * @controllers: Number of mux controllers handled by the chip. + * @mux: Array of mux controllers that are handled. + * @dev: Device structure. + * @ops: Mux controller operations. + * + * This a per-device uclass-private data. + */ +struct mux_chip { + unsigned int controllers; + struct mux_control *mux; +}; + +/** + * struct mux_control_ops - Mux controller operations for a mux chip. + * @set: Set the state of the given mux controller. + */ +struct mux_control_ops { + /** + * set - Apply a state to a multiplexer control + * + * @mux: A multiplexer control + * @return 0 if OK, or a negative error code. + */ + int (*set)(struct mux_control *mux, int state); + + /** + * of_xlate - Translate a client's device-tree (OF) multiplexer + * specifier. + * + * If this function pointer is set to NULL, the multiplexer core will + * use a default implementation, which assumes #mux-control-cells = <1> + * and that the DT cell contains a simple integer channel ID. + * + * @dev_mux: The multiplexer device. A single device may handle + * several multiplexer controls. + * @args: The multiplexer specifier values from device tree. + * @mux: (out) A multiplexer control + * @return 0 if OK, or a negative error code. + */ + int (*of_xlate)(struct mux_chip *dev_mux, + struct ofnode_phandle_args *args, + struct mux_control **mux); +}; + +/** + * struct mux_control - Represents a mux controller. + * @chip: The mux chip that is handling this mux controller. + * @cached_state: The current mux controller state, or -1 if none. + * @states: The number of mux controller states. + * @idle_state: The mux controller state to use when inactive, or one + * of MUX_IDLE_AS_IS and MUX_IDLE_DISCONNECT. + * + * Mux drivers may only change @states and @idle_state, and may only do so + * between allocation and registration of the mux controller. Specifically, + * @cached_state is internal to the mux core and should never be written by + * mux drivers. + */ +struct mux_control { + bool in_use; + struct udevice *dev; + int cached_state; + unsigned int states; + int idle_state; + int id; +}; + +/** + * mux_control_get_index() - Get the index of the given mux controller + * @mux: The mux-control to get the index for. + * + * Return: The index of the mux controller within the mux chip the mux + * controller is a part of. + */ +static inline unsigned int mux_control_get_index(struct mux_control *mux) +{ + return mux->id; +} + +int mux_alloc_controllers(struct udevice *dev, unsigned int controllers); + +#endif diff --git a/include/mux.h b/include/mux.h new file mode 100644 index 0000000000..060f71a47c --- /dev/null +++ b/include/mux.h @@ -0,0 +1,113 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Based on the linux multiplexer framework + * + * At its core, a multiplexer (or mux), also known as a data selector, is a + * device that selects between several analog or digital input signals and + * forwards it to a single output line. This notion can be extended to work + * with buses, like a I2C bus multiplexer for example. + * + * Copyright (C) 2017 Axentia Technologies AB + * Author: Peter Rosin peda@axentia.se + * + * Copyright (C) 2017-2018 Texas Instruments Incorporated - http://www.ti.com/ + * Jean-Jacques Hiblot jjhiblot@ti.com + */ + +#ifndef _MUX_H_ +#define _MUX_H_ + +#include <linux/errno.h> +#include <linux/types.h> + +struct udevice; +struct mux_control; + +#if CONFIG_IS_ENABLED(MULTIPLEXER) +/** + * mux_control_states() - Query the number of multiplexer states. + * @mux: The mux-control to query. + * + * Return: The number of multiplexer states. + */ +unsigned int mux_control_states(struct mux_control *mux); + +/** + * mux_control_select() - Select the given multiplexer state. + * @mux: The mux-control to request a change of state from. + * @state: The new requested state. + * + * On successfully selecting the mux-control state, it will be locked until + * there is a call to mux_control_deselect(). If the mux-control is already + * selected when mux_control_select() is called, the function will indicate + * -EBUSY + * + * Therefore, make sure to call mux_control_deselect() when the operation is + * complete and the mux-control is free for others to use, but do not call + * mux_control_deselect() if mux_control_select() fails. + * + * Return: 0 when the mux-control state has the requested state or a negative + * errno on error. + */ +int __must_check mux_control_select(struct mux_control *mux, + unsigned int state); +#define mux_control_try_select(mux) mux_control_select(mux) + +/** + * mux_control_deselect() - Deselect the previously selected multiplexer state. + * @mux: The mux-control to deselect. + * + * It is required that a single call is made to mux_control_deselect() for + * each and every successful call made to either of mux_control_select() or + * mux_control_try_select(). + * + * Return: 0 on success and a negative errno on error. An error can only + * occur if the mux has an idle state. Note that even if an error occurs, the + * mux-control is unlocked and is thus free for the next access. + */ +int mux_control_deselect(struct mux_control *mux); + +int mux_get_by_index(struct udevice *dev, int index, struct mux_control **mux); +int mux_control_get(struct udevice *dev, const char *name, + struct mux_control **mux); + +void mux_control_put(struct mux_control *mux); + +struct mux_control *devm_mux_control_get(struct udevice *dev, + const char *mux_name); +#else +unsigned int mux_control_states(struct mux_control *mux) +{ + return -ENOSYS; +} + +int __must_check mux_control_select(struct mux_control *mux, + unsigned int state) +{ + return -ENOSYS; +} + +#define mux_control_try_select(mux) mux_control_select(mux) + +int mux_control_deselect(struct mux_control *mux) +{ + return -ENOSYS; +} + +struct mux_control *mux_control_get(struct udevice *dev, const char *mux_name) +{ + return NULL; +} + +void mux_control_put(struct mux_control *mux) +{ +} + +struct mux_control *devm_mux_control_get(struct udevice *dev, + const char *mux_name) +{ + return NULL; +} +#endif + +#endif