d0f8e97866
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 <wsa+renesas@sang-engineering.com> Signed-off-by: Farouk Bouabid <farouk.bouabid@cherry.de> Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
149 lines
3.7 KiB
C
149 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Theobroma Systems 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/platform_device.h>
|
|
#include <linux/property.h>
|
|
#include <linux/regmap.h>
|
|
|
|
#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 <farouk.bouabid@cherry.de>");
|
|
MODULE_DESCRIPTION("I2C mux driver for Theobroma Systems Mule");
|
|
MODULE_LICENSE("GPL");
|