* [PATCH v6 1/3] dt-bindings: mfd: x-powers: Add AC200
2026-08-11 8:27 [PATCH v6 0/3] mfd: add X-Powers AC200 support James Hilliard
@ 2026-08-11 8:27 ` James Hilliard
2026-08-11 8:27 ` [PATCH v6 2/3] mfd: syscon: Add managed registration for external regmaps James Hilliard
2026-08-11 8:27 ` [PATCH v6 3/3] mfd: ac200: Add X-Powers AC200 support James Hilliard
2 siblings, 0 replies; 7+ messages in thread
From: James Hilliard @ 2026-08-11 8:27 UTC (permalink / raw)
To: Lee Jones, Arnd Bergmann, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, James Hilliard
Cc: mfd, devicetree, linux-kernel
The AC200 is an I2C-controlled mixed-signal companion IC containing
audio, video, RTC and Fast Ethernet PHY functions.
Describe the parent device and its shared input clock. The Ethernet PHY
is represented by a PHY package on its MDIO bus, with a phandle back to
this device for access to the package control registers, so it does not
require an MFD child node. Function-specific supplies belong to their
consumer bindings rather than the shared parent.
The input clock must run at 24 or 27 MHz when the Ethernet PHY is used,
matching the rates encoded by its documented clock selector.
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
.../devicetree/bindings/mfd/x-powers,ac200.yaml | 49 ++++++++++++++++++++++
1 file changed, 49 insertions(+)
diff --git a/Documentation/devicetree/bindings/mfd/x-powers,ac200.yaml b/Documentation/devicetree/bindings/mfd/x-powers,ac200.yaml
new file mode 100644
index 000000000000..609831b15c80
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/x-powers,ac200.yaml
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/x-powers,ac200.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: X-Powers AC200 mixed-signal IC
+
+maintainers:
+ - James Hilliard <james.hilliard1@gmail.com>
+
+description:
+ The AC200 is a mixed-signal companion IC containing audio, video, RTC and
+ Fast Ethernet PHY functions. Its control registers are accessed over I2C.
+
+properties:
+ compatible:
+ const: x-powers,ac200
+
+ reg:
+ maxItems: 1
+
+ clocks:
+ maxItems: 1
+ description:
+ AC200 input clock. When using the Ethernet PHY, its configured rate must
+ be 24 or 27 MHz, matching the rates encoded by the documented EPHY clock
+ selector.
+
+required:
+ - compatible
+ - reg
+ - clocks
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ mixed-signal@10 {
+ compatible = "x-powers,ac200";
+ reg = <0x10>;
+ clocks = <&pwm 5>;
+ };
+ };
+...
--
2.53.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v6 2/3] mfd: syscon: Add managed registration for external regmaps
2026-08-11 8:27 [PATCH v6 0/3] mfd: add X-Powers AC200 support James Hilliard
2026-08-11 8:27 ` [PATCH v6 1/3] dt-bindings: mfd: x-powers: Add AC200 James Hilliard
@ 2026-08-11 8:27 ` James Hilliard
2026-08-11 8:46 ` Arnd Bergmann
2026-08-11 8:27 ` [PATCH v6 3/3] mfd: ac200: Add X-Powers AC200 support James Hilliard
2 siblings, 1 reply; 7+ messages in thread
From: James Hilliard @ 2026-08-11 8:27 UTC (permalink / raw)
To: Lee Jones, Arnd Bergmann, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, James Hilliard
Cc: mfd, devicetree, linux-kernel
of_syscon_register_regmap() publishes an externally owned regmap in the
global syscon list, but provides no way for a removable driver to
withdraw it. Registering a devm-managed regmap from such a driver would
therefore leave a stale pointer after unbind.
Factor external registration through an internal helper and add
devm_of_syscon_register_regmap(). The managed action removes the entry
under the syscon list lock before later devres actions release the
regmap. Hold a device-node reference for the lifetime of every
externally registered entry so its lookup key also remains valid.
Consumers of a removable provider remain responsible for ordering
teardown, for example with a managed device link.
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
drivers/mfd/syscon.c | 87 ++++++++++++++++++++++++++++++++++------------
include/linux/mfd/syscon.h | 12 +++++++
2 files changed, 77 insertions(+), 22 deletions(-)
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index 21a7fcdd2737..448422fe4f21 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -10,6 +10,7 @@
#include <linux/cleanup.h>
#include <linux/clk.h>
+#include <linux/device.h>
#include <linux/err.h>
#include <linux/hwspinlock.h>
#include <linux/list.h>
@@ -193,53 +194,95 @@ static struct regmap *device_node_get_regmap(struct device_node *np,
return syscon->regmap;
}
-/**
- * of_syscon_register_regmap() - Register regmap for specified device node
- * @np: Device tree node
- * @regmap: Pointer to regmap object
- *
- * Register an externally created regmap object with syscon for the specified
- * device tree node. This regmap will then be returned to client drivers using
- * the syscon_regmap_lookup_by_phandle() API.
- *
- * Return: 0 on success, negative error code on failure.
- */
-int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
+static struct syscon *
+of_syscon_register_regmap_internal(struct device_node *np,
+ struct regmap *regmap)
{
struct syscon *entry, *syscon = NULL;
- int ret;
if (!np || !regmap)
- return -EINVAL;
+ return ERR_PTR(-EINVAL);
syscon = kzalloc_obj(*syscon);
if (!syscon)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
/* check if syscon entry already exists */
mutex_lock(&syscon_list_lock);
list_for_each_entry(entry, &syscon_list, list)
if (entry->np == np) {
- ret = -EEXIST;
- goto err_unlock;
+ mutex_unlock(&syscon_list_lock);
+ kfree(syscon);
+ return ERR_PTR(-EEXIST);
}
syscon->regmap = regmap;
- syscon->np = np;
+ syscon->np = of_node_get(np);
/* register the regmap in syscon list */
list_add_tail(&syscon->list, &syscon_list);
mutex_unlock(&syscon_list_lock);
- return 0;
+ return syscon;
+}
+
+/**
+ * of_syscon_register_regmap() - Register regmap for specified device node
+ * @np: Device tree node
+ * @regmap: Pointer to regmap object
+ *
+ * Register an externally created regmap object with syscon for the specified
+ * device tree node. This regmap will then be returned to client drivers using
+ * the syscon_regmap_lookup_by_phandle() API.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
+{
+ return PTR_ERR_OR_ZERO(of_syscon_register_regmap_internal(np, regmap));
+}
+EXPORT_SYMBOL_GPL(of_syscon_register_regmap);
+
+static void devm_of_syscon_register_regmap_release(void *data)
+{
+ struct syscon *syscon = data;
-err_unlock:
+ mutex_lock(&syscon_list_lock);
+ list_del(&syscon->list);
mutex_unlock(&syscon_list_lock);
+
+ of_node_put(syscon->np);
kfree(syscon);
- return ret;
}
-EXPORT_SYMBOL_GPL(of_syscon_register_regmap);
+
+/**
+ * devm_of_syscon_register_regmap() - Register a managed external syscon regmap
+ * @dev: Device that owns the regmap
+ * @np: Device tree node associated with the regmap
+ * @regmap: Pointer to the externally created regmap
+ *
+ * Register an externally created regmap object with syscon and remove it when
+ * @dev is unbound. Consumers must stop using the regmap before the provider is
+ * unbound, for example by establishing a managed device link to @dev.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int devm_of_syscon_register_regmap(struct device *dev,
+ struct device_node *np,
+ struct regmap *regmap)
+{
+ struct syscon *syscon;
+
+ syscon = of_syscon_register_regmap_internal(np, regmap);
+ if (IS_ERR(syscon))
+ return PTR_ERR(syscon);
+
+ return devm_add_action_or_reset(dev,
+ devm_of_syscon_register_regmap_release,
+ syscon);
+}
+EXPORT_SYMBOL_GPL(devm_of_syscon_register_regmap);
/**
* device_node_to_regmap() - Get or create a regmap for specified device node
diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
index aad9c6b50463..3e804fc1b03e 100644
--- a/include/linux/mfd/syscon.h
+++ b/include/linux/mfd/syscon.h
@@ -15,6 +15,7 @@
#include <linux/errno.h>
struct device_node;
+struct device;
#ifdef CONFIG_MFD_SYSCON
struct regmap *device_node_to_regmap(struct device_node *np);
@@ -30,6 +31,9 @@ struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
const char *property);
int of_syscon_register_regmap(struct device_node *np,
struct regmap *regmap);
+int devm_of_syscon_register_regmap(struct device *dev,
+ struct device_node *np,
+ struct regmap *regmap);
#else
static inline struct regmap *device_node_to_regmap(struct device_node *np)
{
@@ -75,6 +79,14 @@ static inline int of_syscon_register_regmap(struct device_node *np,
return -EOPNOTSUPP;
}
+static inline int
+devm_of_syscon_register_regmap(struct device *dev,
+ struct device_node *np,
+ struct regmap *regmap)
+{
+ return -EOPNOTSUPP;
+}
+
#endif
#endif /* __LINUX_MFD_SYSCON_H__ */
--
2.53.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v6 3/3] mfd: ac200: Add X-Powers AC200 support
2026-08-11 8:27 [PATCH v6 0/3] mfd: add X-Powers AC200 support James Hilliard
2026-08-11 8:27 ` [PATCH v6 1/3] dt-bindings: mfd: x-powers: Add AC200 James Hilliard
2026-08-11 8:27 ` [PATCH v6 2/3] mfd: syscon: Add managed registration for external regmaps James Hilliard
@ 2026-08-11 8:27 ` James Hilliard
2 siblings, 0 replies; 7+ messages in thread
From: James Hilliard @ 2026-08-11 8:27 UTC (permalink / raw)
To: Lee Jones, Arnd Bergmann, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, James Hilliard
Cc: mfd, devicetree, linux-kernel
The X-Powers AC200 is a mixed-signal companion IC with a paged register
map accessed over I2C.
Enable the shared input clock and prevent its rate from changing. Match
the vendor driver's 40 ms wait before the first register access,
initialize the paged regmap, report the chip and package revision, and
apply common reset.
The Ethernet PHY link endpoint is independently enumerated on its MDIO
bus, so publish the regmap through managed syscon registration for lookup
through its AC200 firmware reference rather than creating an artificial
MFD platform child. The managed entry is withdrawn before the regmap is
released, while the function driver separately manages the PHY analog
supply.
Cache only the common page selector. Individual functions can reset
independently and invalidate their other registers without regmap's
knowledge, so leave all functional registers volatile.
Reset the chip during managed teardown and system shutdown. Consumers
can use device links to ensure that they unbind before the shared AC200
resources are released.
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
drivers/mfd/Kconfig | 12 ++++
drivers/mfd/Makefile | 1 +
drivers/mfd/ac200.c | 170 +++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 183 insertions(+)
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index e4fd4572472f..f8354a0f6b5c 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -205,6 +205,18 @@ config MFD_AC100
This driver include only the core APIs. You have to select individual
components like codecs or RTC under the corresponding menus.
+config MFD_AC200
+ tristate "X-Powers AC200"
+ depends on I2C
+ depends on OF
+ select MFD_SYSCON
+ select REGMAP_I2C
+ help
+ Support for the X-Powers AC200 mixed-signal companion IC. The AC200
+ contains audio, video, RTC and Fast Ethernet PHY functions and is
+ co-packaged with some Allwinner H6 and H616 SoCs. This driver provides
+ the shared register access used by the individual function drivers.
+
config MFD_AXP20X
tristate
select MFD_CORE
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 72d3944b0ad8..f8101d2a9ce9 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -150,6 +150,7 @@ obj-$(CONFIG_MFD_DA9052_SPI) += da9052-spi.o
obj-$(CONFIG_MFD_DA9052_I2C) += da9052-i2c.o
obj-$(CONFIG_MFD_AC100) += ac100.o
+obj-$(CONFIG_MFD_AC200) += ac200.o
obj-$(CONFIG_MFD_AXP20X) += axp20x.o
obj-$(CONFIG_MFD_AXP20X_I2C) += axp20x-i2c.o
obj-$(CONFIG_MFD_AXP20X_RSB) += axp20x-rsb.o
diff --git a/drivers/mfd/ac200.c b/drivers/mfd/ac200.c
new file mode 100644
index 000000000000..25066bb36ac7
--- /dev/null
+++ b/drivers/mfd/ac200.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MFD core driver for the X-Powers AC200
+ *
+ * Copyright (C) 2019 Jernej Skrabec <jernej.skrabec@gmail.com>
+ * Copyright (C) 2026 James Hilliard <james.hilliard1@gmail.com>
+ *
+ * Based on the AC100 driver:
+ * Copyright (C) 2016 Chen-Yu Tsai
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#define AC200_SYS_VERSION_REG 0x0000
+#define AC200_SYS_VERSION_PACKAGE_MASK GENMASK(15, 14)
+#define AC200_SYS_VERSION_CHIP_MASK GENMASK(11, 0)
+
+#define AC200_SYS_CONTROL_REG 0x0002
+#define AC200_SYS_CONTROL_CHIP_RESET_DEASSERT BIT(0)
+
+/* Interface register accessible from every register page. */
+#define AC200_TWI_REG_ADDR_H 0x00fe
+#define AC200_MAX_REG 0xa1f2
+
+struct ac200 {
+ struct regmap *regmap;
+};
+
+static const struct regmap_range_cfg ac200_range_cfg[] = {
+ {
+ .range_max = AC200_MAX_REG,
+ .selector_reg = AC200_TWI_REG_ADDR_H,
+ .selector_mask = 0xff,
+ .window_len = 256,
+ },
+};
+
+/*
+ * Each AC200 sub-block can reset independently, invalidating its register
+ * contents without regmap's knowledge. Cache only the common page selector;
+ * this avoids a selector read-modify-write for every access on the same page
+ * without ever returning stale functional-register values.
+ */
+static bool ac200_volatile_reg(struct device *dev, unsigned int reg)
+{
+ return reg != AC200_TWI_REG_ADDR_H;
+}
+
+static const struct regmap_config ac200_regmap_config = {
+ .name = "ac200",
+ .reg_bits = 8,
+ .reg_stride = 2,
+ .val_bits = 16,
+ .ranges = ac200_range_cfg,
+ .num_ranges = ARRAY_SIZE(ac200_range_cfg),
+ .max_register = AC200_MAX_REG,
+ .volatile_reg = ac200_volatile_reg,
+ .cache_type = REGCACHE_MAPLE,
+};
+
+static void ac200_disable(void *data)
+{
+ struct ac200 *ddata = data;
+
+ regmap_write(ddata->regmap, AC200_SYS_CONTROL_REG, 0);
+}
+
+static int ac200_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ unsigned int version;
+ struct ac200 *ddata;
+ struct clk *clk;
+ int ret;
+
+ ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
+ if (!ddata)
+ return -ENOMEM;
+
+ clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(clk))
+ return dev_err_probe(dev, PTR_ERR(clk),
+ "failed to enable input clock\n");
+
+ ret = devm_clk_rate_exclusive_get(dev, clk);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to lock clock rate\n");
+
+ ddata->regmap = devm_regmap_init_i2c(client, &ac200_regmap_config);
+ if (IS_ERR(ddata->regmap))
+ return dev_err_probe(dev, PTR_ERR(ddata->regmap),
+ "failed to initialize regmap\n");
+
+ i2c_set_clientdata(client, ddata);
+
+ /*
+ * No minimum delay is documented. Match the vendor driver's 40 ms delay
+ * before its first AC200 register access after enabling the input clock.
+ */
+ msleep(40);
+
+ ret = regmap_read(ddata->regmap, AC200_SYS_VERSION_REG, &version);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "failed to read chip version\n");
+
+ dev_info(dev, "AC200 revision %#lx in package %lu\n",
+ FIELD_GET(AC200_SYS_VERSION_CHIP_MASK, version),
+ FIELD_GET(AC200_SYS_VERSION_PACKAGE_MASK, version));
+
+ /* Reset the chip after dependent function drivers have unbound. */
+ ret = devm_add_action_or_reset(dev, ac200_disable, ddata);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(ddata->regmap, AC200_SYS_CONTROL_REG, 0);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(ddata->regmap, AC200_SYS_CONTROL_REG,
+ AC200_SYS_CONTROL_CHIP_RESET_DEASSERT);
+ if (ret)
+ return ret;
+
+ ret = devm_of_syscon_register_regmap(dev, dev->of_node,
+ ddata->regmap);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "failed to register regmap\n");
+
+ return 0;
+}
+
+static void ac200_shutdown(struct i2c_client *client)
+{
+ ac200_disable(i2c_get_clientdata(client));
+}
+
+static const struct of_device_id ac200_of_match[] = {
+ { .compatible = "x-powers,ac200" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ac200_of_match);
+
+static const struct i2c_device_id ac200_i2c_ids[] = {
+ { .name = "ac200" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ac200_i2c_ids);
+
+static struct i2c_driver ac200_driver = {
+ .driver = {
+ .name = "ac200",
+ .of_match_table = ac200_of_match,
+ },
+ .probe = ac200_probe,
+ .shutdown = ac200_shutdown,
+ .id_table = ac200_i2c_ids,
+};
+module_i2c_driver(ac200_driver);
+
+MODULE_AUTHOR("James Hilliard <james.hilliard1@gmail.com>");
+MODULE_DESCRIPTION("X-Powers AC200 MFD core driver");
+MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related [flat|nested] 7+ messages in thread