The existing SYSCON implementation only supports MMIO (memory mapped) accesses, facilitated by Regmap. This extends support for registers held behind I2C busses.
Signed-off-by: Lee Jones <[email protected]> --- Changelog: v2 => v3 - Change 'is CONFIG' present check to include loadable modules - s/#ifdef CONFIG_MFD_SYSCON_I2C/#if IS_ENABLED(CONFIG_MFD_SYSCON_I2C)/ v1 => v2 - Remove legacy references to OF - Allow building as a module (fixes h8300 0-day issue) drivers/mfd/Kconfig | 7 +++ drivers/mfd/Makefile | 1 + drivers/mfd/syscon-i2c.c | 90 ++++++++++++++++++++++++++++++++++ include/linux/mfd/syscon-i2c.h | 26 ++++++++++ 4 files changed, 124 insertions(+) create mode 100644 drivers/mfd/syscon-i2c.c create mode 100644 include/linux/mfd/syscon-i2c.h diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index 0a59249198d34..f25f80f68edca 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -1300,6 +1300,13 @@ config MFD_SYSCON Select this option to enable accessing system control registers via regmap. +config MFD_SYSCON_I2C + tristate "System Controller Register R/W Based on I2C Regmap" + select REGMAP_I2C + help + Select this option to enable accessing system control registers + via I2C using regmap. + config MFD_DAVINCI_VOICECODEC tristate select MFD_CORE diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile index f935d10cbf0fc..0aec1f42ac979 100644 --- a/drivers/mfd/Makefile +++ b/drivers/mfd/Makefile @@ -219,6 +219,7 @@ obj-$(CONFIG_MFD_RK808) += rk808.o obj-$(CONFIG_MFD_RN5T618) += rn5t618.o obj-$(CONFIG_MFD_SEC_CORE) += sec-core.o sec-irq.o obj-$(CONFIG_MFD_SYSCON) += syscon.o +obj-$(CONFIG_MFD_SYSCON_I2C) += syscon-i2c.o obj-$(CONFIG_MFD_LM3533) += lm3533-core.o lm3533-ctrlbank.o obj-$(CONFIG_MFD_VEXPRESS_SYSREG) += vexpress-sysreg.o obj-$(CONFIG_MFD_RETU) += retu-mfd.o diff --git a/drivers/mfd/syscon-i2c.c b/drivers/mfd/syscon-i2c.c new file mode 100644 index 0000000000000..be20ff45ece07 --- /dev/null +++ b/drivers/mfd/syscon-i2c.c @@ -0,0 +1,90 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * System Control Driver accessed over I2C + * + * Copyright (C) 2020 Linaro Ltd. + * + * Author: Lee Jones <[email protected]> + */ + +#include <linux/device.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/list.h> +#include <linux/mfd/syscon-i2c.h> +#include <linux/regmap.h> + +static DEFINE_SPINLOCK(syscon_i2c_list_slock); +static LIST_HEAD(syscon_i2c_list); + +struct syscon { + struct device *dev; + struct regmap *regmap; + struct list_head list; +}; + +static const struct regmap_config syscon_i2c_regmap_config = { + .reg_bits = 8, + .val_bits = 8, +}; + +static struct syscon *syscon_i2c_register(struct i2c_client *client) +{ + struct regmap_config syscon_config = syscon_i2c_regmap_config; + struct device *dev = &client->dev; + struct syscon *syscon; + struct regmap *regmap; + int ret; + + syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); + if (!syscon) + return ERR_PTR(-ENOMEM); + + syscon_config.name = dev_name(dev); + + regmap = devm_regmap_init_i2c(client, &syscon_config); + if (IS_ERR(regmap)) { + dev_err(dev, "Failed to initialise Regmap I2C\n"); + ret = PTR_ERR(regmap); + return ERR_PTR(ret); + } + + syscon->regmap = regmap; + syscon->dev = dev; + + spin_lock(&syscon_i2c_list_slock); + list_add_tail(&syscon->list, &syscon_i2c_list); + spin_unlock(&syscon_i2c_list_slock); + + return syscon; +} + +static struct regmap *syscon_i2c_get_regmap(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct syscon *entry, *syscon = NULL; + + spin_lock(&syscon_i2c_list_slock); + + list_for_each_entry(entry, &syscon_i2c_list, list) + if (entry->dev == dev) { + syscon = entry; + break; + } + + spin_unlock(&syscon_i2c_list_slock); + + if (!syscon) + syscon = syscon_i2c_register(client); + + if (IS_ERR(syscon)) + return ERR_CAST(syscon); + + return syscon->regmap; +} + +struct regmap *syscon_i2c_to_regmap(struct i2c_client *client) +{ + return syscon_i2c_get_regmap(client); +} +EXPORT_SYMBOL_GPL(syscon_i2c_to_regmap); diff --git a/include/linux/mfd/syscon-i2c.h b/include/linux/mfd/syscon-i2c.h new file mode 100644 index 0000000000000..490bc37b603cb --- /dev/null +++ b/include/linux/mfd/syscon-i2c.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * System Control Driver accessed via I2C + * + * Copyright (C) 2020 Linaro Ltd. + * + * Author: Lee Jones <[email protected]> + */ + +#ifndef __LINUX_MFD_SYSCON_I2C_H__ +#define __LINUX_MFD_SYSCON_I2C_H__ + +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/i2c.h> + +#if IS_ENABLED(CONFIG_MFD_SYSCON_I2C) +extern struct regmap *syscon_i2c_to_regmap(struct i2c_client *client); +#else +static inline struct regmap *syscon_i2c_to_regmap(struct i2c_client *client) +{ + return ERR_PTR(-ENOTSUPP); +} +#endif + +#endif /* __LINUX_MFD_SYSCON_I2C_H__ */ -- 2.25.1
