Mule is an MCU that emulates a set of I2C devices which are reachable
through an I2C-mux.
The emulated devices share a single I2C address with the mux itself
where the requested register is what determines which logic is executed
(mux logic or device logic):
1- The devices on the mux can be selected (mux function) by writing the
appropriate device number to an I2C config register (0xff) that is not
used by any device logic.
2- Any access to a register other than the config register will be
handled by the previously selected device.
Signed-off-by: Farouk Bouabid <[email protected]>
---
drivers/i2c/muxes/Kconfig | 18 +++++
drivers/i2c/muxes/Makefile | 1 +
drivers/i2c/muxes/i2c-mux-mule.c | 157 +++++++++++++++++++++++++++++++++++++++
3 files changed, 176 insertions(+)
diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index db1b9057612a..70876259796d 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -119,4 +119,22 @@ config I2C_MUX_MLXCPLD
This driver can also be built as a module. If so, the module
will be called i2c-mux-mlxcpld.
+config I2C_MUX_MULE
+ tristate "Mule I2C device multiplexer"
+ depends on OF
+ help
+ Mule is an MCU that emulates a set of I2C devices which are reachable
+ through an I2C-mux.
+
+ The emulated devices share a single I2C address with the mux itself
+ where the requested register is what determines which logic is executed
+ (mux logic or device logic).
+
+ If you say yes to this option, support will be included for a
+ Mule I2C device multiplexer. This driver provides access to
+ I2C devices connected on the Mule I2C mux.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-mux-mule.
+
endmenu
diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
index 6d9d865e8518..4b24f49515a7 100644
--- a/drivers/i2c/muxes/Makefile
+++ b/drivers/i2c/muxes/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o
obj-$(CONFIG_I2C_MUX_GPMUX) += i2c-mux-gpmux.o
obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o
obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o
+obj-$(CONFIG_I2C_MUX_MULE) += i2c-mux-mule.o
obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
diff --git a/drivers/i2c/muxes/i2c-mux-mule.c b/drivers/i2c/muxes/i2c-mux-mule.c
new file mode 100644
index 000000000000..db27fa560995
--- /dev/null
+++ b/drivers/i2c/muxes/i2c-mux-mule.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mule I2C device multiplexer
+ *
+ * Copyright (C) 2024 Theobroma Systems Design und Consulting GmbH
+ */
+
+#include <linux/i2c-mux.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define MUX_CONFIG_REG 0xff
+#define MUX_DEFAULT_DEV 0x0
+
+struct mule_i2c_reg_mux {
+ struct regmap *regmap;
+};
+
+static const struct regmap_config mule_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
+static inline int __mux_select(struct regmap *regmap, u32 dev)
+{
+ return regmap_write(regmap, MUX_CONFIG_REG, dev);
+}
+
+static int mux_select(struct i2c_mux_core *muxc, u32 dev)
+{
+ struct mule_i2c_reg_mux *mux = muxc->priv;
+
+ return __mux_select(mux->regmap, dev);
+}
+
+static int mux_deselect(struct i2c_mux_core *muxc, u32 dev)
+{
+ return mux_select(muxc, MUX_DEFAULT_DEV);
+}
+
+static void mux_remove(void *data)
+{
+ struct i2c_mux_core *muxc = data;
+
+ i2c_mux_del_adapters(muxc);
+
+ mux_deselect(muxc, MUX_DEFAULT_DEV);
+}
+
+static int mule_i2c_mux_probe(struct i2c_client *client)
+{
+ struct i2c_adapter *adap = client->adapter;
+ struct mule_i2c_reg_mux *priv;
+ struct i2c_mux_core *muxc;
+ struct device_node *dev;
+ unsigned int readback;
+ int ndev, ret;
+ bool old_fw;
+
+ /* Count devices on the mux */
+ ndev = of_get_child_count(client->dev.of_node);
+ dev_dbg(&client->dev, "%u devices on the mux\n", ndev);
+
+ muxc = i2c_mux_alloc(adap, &client->dev,
+ ndev, sizeof(*priv),
+ I2C_MUX_LOCKED,
+ mux_select, mux_deselect);
+ if (!muxc)
+ return -ENOMEM;
+
+ muxc->share_addr_with_children = 1;
+ priv = i2c_mux_priv(muxc);
+
+ priv->regmap = devm_regmap_init_i2c(client, &mule_regmap_config);
+ if (IS_ERR(priv->regmap))
+ return dev_err_probe(&client->dev, PTR_ERR(priv->regmap),
+ "Failed to allocate i2c register map\n");
+
+ i2c_set_clientdata(client, muxc);
+
+ /*
+ * Mux 0 is guaranteed to exist on all old and new mule fw.
+ * mule fw without mux support will accept write ops to the
+ * config register, but readback returns 0xff (register not updated).
+ */
+ ret = mux_select(muxc, 0);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(priv->regmap, MUX_CONFIG_REG, &readback);
+ if (ret)
+ return ret;
+
+ old_fw = (readback != 0);
+
+ ret = devm_add_action_or_reset(&client->dev, mux_remove, muxc);
+ if (ret)
+ return ret;
+
+ /* Create device adapters */
+ for_each_child_of_node(client->dev.of_node, dev) {
+ u32 reg;
+
+ ret = of_property_read_u32(dev, "reg", ®);
+ if (ret) {
+ dev_err(&client->dev, "No reg property found for %s: %d\n",
+ of_node_full_name(dev), ret);
+ return ret;
+ }
+
+ if (old_fw && reg != 0) {
+ dev_warn(&client->dev,
+ "Mux %d not supported, please update Mule FW\n", reg);
+ continue;
+ }
+
+ ret = mux_select(muxc, reg);
+ if (ret) {
+ dev_warn(&client->dev,
+ "Mux %d not supported, please update Mule FW\n", reg);
+ continue;
+ }
+
+ ret = i2c_mux_add_adapter(muxc, 0, reg, 0);
+ if (ret) {
+ dev_err(&client->dev, "Failed to add i2c mux adapter %d: %d\n", reg, ret);
+ return ret;
+ }
+ }
+
+ mux_deselect(muxc, MUX_DEFAULT_DEV);
+
+ return 0;
+}
+
+static const struct of_device_id mule_i2c_mux_of_match[] = {
+ {.compatible = "tsd,mule-i2c-mux",},
+ {},
+};
+MODULE_DEVICE_TABLE(of, mule_i2c_mux_of_match);
+
+static struct i2c_driver mule_i2c_mux_driver = {
+ .driver = {
+ .name = "mule-i2c-mux",
+ .of_match_table = mule_i2c_mux_of_match,
+ },
+ .probe = mule_i2c_mux_probe,
+};
+
+module_i2c_driver(mule_i2c_mux_driver);
+
+MODULE_AUTHOR("Farouk Bouabid <[email protected]>");
+MODULE_DESCRIPTION("I2C mux driver for Mule");
+MODULE_LICENSE("GPL");
--
2.34.1
Hi all,
On 11.06.24 13:43, Farouk Bouabid wrote:
> Mule is an MCU that emulates a set of I2C devices which are reachable
> through an I2C-mux.
>
> The emulated devices share a single I2C address with the mux itself
> where the requested register is what determines which logic is executed
> (mux logic or device logic):
>
> 1- The devices on the mux can be selected (mux function) by writing the
> appropriate device number to an I2C config register (0xff) that is not
> used by any device logic.
>
> 2- Any access to a register other than the config register will be
> handled by the previously selected device.
>
> Signed-off-by: Farouk Bouabid <[email protected]>
> ---
> drivers/i2c/muxes/Kconfig | 18 +++++
> drivers/i2c/muxes/Makefile | 1 +
> drivers/i2c/muxes/i2c-mux-mule.c | 157 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 176 insertions(+)
>
> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
> index db1b9057612a..70876259796d 100644
> --- a/drivers/i2c/muxes/Kconfig
> +++ b/drivers/i2c/muxes/Kconfig
> @@ -119,4 +119,22 @@ config I2C_MUX_MLXCPLD
> This driver can also be built as a module. If so, the module
> will be called i2c-mux-mlxcpld.
>
> +config I2C_MUX_MULE
> + tristate "Mule I2C device multiplexer"
> + depends on OF
> + help
> + Mule is an MCU that emulates a set of I2C devices which are reachable
> + through an I2C-mux.
> +
> + The emulated devices share a single I2C address with the mux itself
> + where the requested register is what determines which logic is executed
> + (mux logic or device logic).
> +
> + If you say yes to this option, support will be included for a
> + Mule I2C device multiplexer. This driver provides access to
> + I2C devices connected on the Mule I2C mux.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-mux-mule.
> +
> endmenu
> diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
> index 6d9d865e8518..4b24f49515a7 100644
> --- a/drivers/i2c/muxes/Makefile
> +++ b/drivers/i2c/muxes/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o
> obj-$(CONFIG_I2C_MUX_GPMUX) += i2c-mux-gpmux.o
> obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o
> obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o
> +obj-$(CONFIG_I2C_MUX_MULE) += i2c-mux-mule.o
> obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
> obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
> obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
> diff --git a/drivers/i2c/muxes/i2c-mux-mule.c b/drivers/i2c/muxes/i2c-mux-mule.c
> new file mode 100644
> index 000000000000..db27fa560995
> --- /dev/null
> +++ b/drivers/i2c/muxes/i2c-mux-mule.c
> @@ -0,0 +1,157 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Mule I2C device multiplexer
> + *
> + * Copyright (C) 2024 Theobroma Systems Design und Consulting GmbH
> + */
> +
> +#include <linux/i2c-mux.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +
> +#define MUX_CONFIG_REG 0xff
> +#define MUX_DEFAULT_DEV 0x0
> +
> +struct mule_i2c_reg_mux {
> + struct regmap *regmap;
> +};
> +
> +static const struct regmap_config mule_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> +};
> +
> +static inline int __mux_select(struct regmap *regmap, u32 dev)
> +{
> + return regmap_write(regmap, MUX_CONFIG_REG, dev);
> +}
> +
> +static int mux_select(struct i2c_mux_core *muxc, u32 dev)
> +{
> + struct mule_i2c_reg_mux *mux = muxc->priv;
> +
> + return __mux_select(mux->regmap, dev);
> +}
> +
> +static int mux_deselect(struct i2c_mux_core *muxc, u32 dev)
> +{
> + return mux_select(muxc, MUX_DEFAULT_DEV);
> +}
> +
> +static void mux_remove(void *data)
> +{
> + struct i2c_mux_core *muxc = data;
> +
> + i2c_mux_del_adapters(muxc);
> +
> + mux_deselect(muxc, MUX_DEFAULT_DEV);
> +}
> +
> +static int mule_i2c_mux_probe(struct i2c_client *client)
> +{
> + struct i2c_adapter *adap = client->adapter;
> + struct mule_i2c_reg_mux *priv;
> + struct i2c_mux_core *muxc;
> + struct device_node *dev;
> + unsigned int readback;
> + int ndev, ret;
> + bool old_fw;
> +
> + /* Count devices on the mux */
> + ndev = of_get_child_count(client->dev.of_node);
> + dev_dbg(&client->dev, "%u devices on the mux\n", ndev);
> +
> + muxc = i2c_mux_alloc(adap, &client->dev,
> + ndev, sizeof(*priv),
> + I2C_MUX_LOCKED,
> + mux_select, mux_deselect);
> + if (!muxc)
> + return -ENOMEM;
> +
> + muxc->share_addr_with_children = 1;
> + priv = i2c_mux_priv(muxc);
> +
> + priv->regmap = devm_regmap_init_i2c(client, &mule_regmap_config);
> + if (IS_ERR(priv->regmap))
> + return dev_err_probe(&client->dev, PTR_ERR(priv->regmap),
> + "Failed to allocate i2c register map\n");
> +
> + i2c_set_clientdata(client, muxc);
> +
> + /*
> + * Mux 0 is guaranteed to exist on all old and new mule fw.
> + * mule fw without mux support will accept write ops to the
> + * config register, but readback returns 0xff (register not updated).
> + */
> + ret = mux_select(muxc, 0);
> + if (ret)
> + return ret;
> +
> + ret = regmap_read(priv->regmap, MUX_CONFIG_REG, &readback);
> + if (ret)
> + return ret;
> +
> + old_fw = (readback != 0);
> +
> + ret = devm_add_action_or_reset(&client->dev, mux_remove, muxc);
> + if (ret)
> + return ret;
> +
> + /* Create device adapters */
> + for_each_child_of_node(client->dev.of_node, dev) {
> + u32 reg;
> +
> + ret = of_property_read_u32(dev, "reg", ®);
> + if (ret) {
> + dev_err(&client->dev, "No reg property found for %s: %d\n",
> + of_node_full_name(dev), ret);
> + return ret;
> + }
> +
> + if (old_fw && reg != 0) {
> + dev_warn(&client->dev,
> + "Mux %d not supported, please update Mule FW\n", reg);
> + continue;
> + }
> +
> + ret = mux_select(muxc, reg);
> + if (ret) {
> + dev_warn(&client->dev,
> + "Mux %d not supported, please update Mule FW\n", reg);
> + continue;
> + }
> +
> + ret = i2c_mux_add_adapter(muxc, 0, reg, 0);
The class parameter was recently removed from this function but I forgot
to remove it. Sorry for the noise, I will send a v4 for this fix.
Cheers,
Farouk
Le 11/06/2024 à 13:43, Farouk Bouabid a écrit :
> Mule is an MCU that emulates a set of I2C devices which are reachable
> through an I2C-mux.
>
> The emulated devices share a single I2C address with the mux itself
> where the requested register is what determines which logic is executed
> (mux logic or device logic):
>
> 1- The devices on the mux can be selected (mux function) by writing the
> appropriate device number to an I2C config register (0xff) that is not
> used by any device logic.
>
> 2- Any access to a register other than the config register will be
> handled by the previously selected device.
>
> Signed-off-by: Farouk Bouabid <[email protected]>
> ---
Hi,
...
> +static int mule_i2c_mux_probe(struct i2c_client *client)
> +{
> + struct i2c_adapter *adap = client->adapter;
> + struct mule_i2c_reg_mux *priv;
> + struct i2c_mux_core *muxc;
> + struct device_node *dev;
> + unsigned int readback;
> + int ndev, ret;
> + bool old_fw;
> +
> + /* Count devices on the mux */
> + ndev = of_get_child_count(client->dev.of_node);
> + dev_dbg(&client->dev, "%u devices on the mux\n", ndev);
Should this be %d?
> +
> + muxc = i2c_mux_alloc(adap, &client->dev,
> + ndev, sizeof(*priv),
> + I2C_MUX_LOCKED,
> + mux_select, mux_deselect);
Nitpick: this could be written with less lines.
> + if (!muxc)
> + return -ENOMEM;
> +
> + muxc->share_addr_with_children = 1;
> + priv = i2c_mux_priv(muxc);
> +
> + priv->regmap = devm_regmap_init_i2c(client, &mule_regmap_config);
> + if (IS_ERR(priv->regmap))
> + return dev_err_probe(&client->dev, PTR_ERR(priv->regmap),
> + "Failed to allocate i2c register map\n");
> +
> + i2c_set_clientdata(client, muxc);
> +
> + /*
> + * Mux 0 is guaranteed to exist on all old and new mule fw.
> + * mule fw without mux support will accept write ops to the
> + * config register, but readback returns 0xff (register not updated).
> + */
> + ret = mux_select(muxc, 0);
Should this 0 be MUX_DEFAULT_DEV (for consistency)?
> + if (ret)
> + return ret;
> +
> + ret = regmap_read(priv->regmap, MUX_CONFIG_REG, &readback);
> + if (ret)
> + return ret;
> +
> + old_fw = (readback != 0);
> +
> + ret = devm_add_action_or_reset(&client->dev, mux_remove, muxc);
> + if (ret)
> + return ret;
> +
> + /* Create device adapters */
> + for_each_child_of_node(client->dev.of_node, dev) {
> + u32 reg;
> +
> + ret = of_property_read_u32(dev, "reg", ®);
> + if (ret) {
> + dev_err(&client->dev, "No reg property found for %s: %d\n",
> + of_node_full_name(dev), ret);
return dev_err_probe() as above?
> + return ret;
> + }
> +
> + if (old_fw && reg != 0) {
> + dev_warn(&client->dev,
> + "Mux %d not supported, please update Mule FW\n", reg);
> + continue;
> + }
> +
> + ret = mux_select(muxc, reg);
> + if (ret) {
> + dev_warn(&client->dev,
> + "Mux %d not supported, please update Mule FW\n", reg);
> + continue;
> + }
> +
> + ret = i2c_mux_add_adapter(muxc, 0, reg, 0);
> + if (ret) {
> + dev_err(&client->dev, "Failed to add i2c mux adapter %d: %d\n", reg, ret);
return dev_err_probe() as above?
> + return ret;
> + }
> + }
> +
> + mux_deselect(muxc, MUX_DEFAULT_DEV);
> +
> + return 0;
> +}
...
> The class parameter was recently removed from this function but I forgot to
> remove it. Sorry for the noise, I will send a v4 for this fix.
Please wait for my comments to the series. Hopefully later this evening.