From d0f8e97866bf258b420ebf2b46755399ca01e585 Mon Sep 17 00:00:00 2001 From: Farouk Bouabid Date: Fri, 6 Sep 2024 17:54:13 +0200 Subject: [PATCH] i2c: muxes: add support for tsd,mule-i2c multiplexer Theobroma Systems Mule is an MCU that emulates a set of I2C devices, among which an amc6821 and devices that are reachable through an I2C-mux. The devices on the mux can be selected by writing the appropriate device number to an I2C config register (amc6821 reg 0xff). This driver is expected to be probed as a platform device with amc6821 as its parent i2c device. Add support for the mule-i2c-mux platform driver. The amc6821 driver support for the mux will be added in a later commit. Reviewed-by: Wolfram Sang Signed-off-by: Farouk Bouabid Signed-off-by: Andi Shyti --- drivers/i2c/muxes/Kconfig | 16 ++++ drivers/i2c/muxes/Makefile | 1 + drivers/i2c/muxes/i2c-mux-mule.c | 148 +++++++++++++++++++++++++++++++ 3 files changed, 165 insertions(+) create mode 100644 drivers/i2c/muxes/i2c-mux-mule.c diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig index db1b9057612a..6d2f66810cdc 100644 --- a/drivers/i2c/muxes/Kconfig +++ b/drivers/i2c/muxes/Kconfig @@ -119,4 +119,20 @@ 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 "Theobroma Systems Mule I2C device multiplexer" + depends on OF && SENSORS_AMC6821 + help + Mule is an MCU that emulates a set of I2C devices, among which + devices that are reachable through an I2C-mux. The devices on the mux + can be selected by writing the appropriate device number to an I2C + configuration register. + + If you say yes to this option, support will be included for a + Theobroma Systems Mule I2C multiplexer. This driver provides access to + I2C devices connected on this 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..8e942470b35f --- /dev/null +++ b/drivers/i2c/muxes/i2c-mux-mule.c @@ -0,0 +1,148 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Theobroma Systems Mule I2C device multiplexer + * + * Copyright (C) 2024 Theobroma Systems Design und Consulting GmbH + */ + +#include +#include +#include +#include +#include +#include +#include + +#define MULE_I2C_MUX_CONFIG_REG 0xff +#define MULE_I2C_MUX_DEFAULT_DEV 0x0 + +struct mule_i2c_reg_mux { + struct regmap *regmap; +}; + +static int mule_i2c_mux_select(struct i2c_mux_core *muxc, u32 dev) +{ + struct mule_i2c_reg_mux *mux = muxc->priv; + + return regmap_write(mux->regmap, MULE_I2C_MUX_CONFIG_REG, dev); +} + +static int mule_i2c_mux_deselect(struct i2c_mux_core *muxc, u32 dev) +{ + return mule_i2c_mux_select(muxc, MULE_I2C_MUX_DEFAULT_DEV); +} + +static void mule_i2c_mux_remove(void *data) +{ + struct i2c_mux_core *muxc = data; + + i2c_mux_del_adapters(muxc); + + mule_i2c_mux_deselect(muxc, MULE_I2C_MUX_DEFAULT_DEV); +} + +static int mule_i2c_mux_probe(struct platform_device *pdev) +{ + struct device *mux_dev = &pdev->dev; + struct mule_i2c_reg_mux *priv; + struct i2c_client *client; + 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(mux_dev->of_node); + dev_dbg(mux_dev, "%d devices on the mux\n", ndev); + + client = to_i2c_client(mux_dev->parent); + + muxc = i2c_mux_alloc(client->adapter, mux_dev, ndev, sizeof(*priv), + I2C_MUX_LOCKED, mule_i2c_mux_select, mule_i2c_mux_deselect); + if (!muxc) + return -ENOMEM; + + priv = i2c_mux_priv(muxc); + + priv->regmap = dev_get_regmap(mux_dev->parent, NULL); + if (IS_ERR(priv->regmap)) + return dev_err_probe(mux_dev, PTR_ERR(priv->regmap), + "No parent i2c register map\n"); + + platform_set_drvdata(pdev, muxc); + + /* + * MULE_I2C_MUX_DEFAULT_DEV 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 = mule_i2c_mux_select(muxc, MULE_I2C_MUX_DEFAULT_DEV); + if (ret) + return dev_err_probe(mux_dev, ret, + "Failed to write config register\n"); + + ret = regmap_read(priv->regmap, MULE_I2C_MUX_CONFIG_REG, &readback); + if (ret) + return dev_err_probe(mux_dev, ret, + "Failed to read config register\n"); + + old_fw = (readback != MULE_I2C_MUX_DEFAULT_DEV); + + ret = devm_add_action_or_reset(mux_dev, mule_i2c_mux_remove, muxc); + if (ret) + return dev_err_probe(mux_dev, ret, + "Failed to register mux remove\n"); + + /* Create device adapters */ + for_each_child_of_node(mux_dev->of_node, dev) { + u32 reg; + + ret = of_property_read_u32(dev, "reg", ®); + if (ret) + return dev_err_probe(mux_dev, ret, + "No reg property found for %s\n", + of_node_full_name(dev)); + + if (old_fw && reg != 0) { + dev_warn(mux_dev, + "Mux is not supported, please update Mule FW\n"); + continue; + } + + ret = mule_i2c_mux_select(muxc, reg); + if (ret) { + dev_warn(mux_dev, + "Device %d not supported, please update Mule FW\n", reg); + continue; + } + + ret = i2c_mux_add_adapter(muxc, 0, reg); + if (ret) + return ret; + } + + mule_i2c_mux_deselect(muxc, MULE_I2C_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 platform_driver mule_i2c_mux_driver = { + .driver = { + .name = "mule-i2c-mux", + .of_match_table = mule_i2c_mux_of_match, + }, + .probe = mule_i2c_mux_probe, +}; + +module_platform_driver(mule_i2c_mux_driver); + +MODULE_AUTHOR("Farouk Bouabid "); +MODULE_DESCRIPTION("I2C mux driver for Theobroma Systems Mule"); +MODULE_LICENSE("GPL");