i2c: mux: Add register-based mux i2c-mux-reg
Based on i2c-mux-gpio driver, similarly the register-based mux switch from one bus to another by setting a single register. The register can be on PCIe bus, local bus, or any memory-mapped address. The endianness of such register can be specified in device tree if used, or in platform data. Signed-off-by: York Sun <yorksun@freescale.com> Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
York Sun
Wolfram Sang
Родитель
7a59b00a09
Коммит
b3fdd32799
|
|
@ -0,0 +1,74 @@
|
|||
Register-based I2C Bus Mux
|
||||
|
||||
This binding describes an I2C bus multiplexer that uses a single register
|
||||
to route the I2C signals.
|
||||
|
||||
Required properties:
|
||||
- compatible: i2c-mux-reg
|
||||
- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
|
||||
port is connected to.
|
||||
* Standard I2C mux properties. See mux.txt in this directory.
|
||||
* I2C child bus nodes. See mux.txt in this directory.
|
||||
|
||||
Optional properties:
|
||||
- reg: this pair of <offset size> specifies the register to control the mux.
|
||||
The <offset size> depends on its parent node. It can be any memory-mapped
|
||||
address. The size must be either 1, 2, or 4 bytes. If reg is omitted, the
|
||||
resource of this device will be used.
|
||||
- little-endian: The existence indicates the register is in little endian.
|
||||
- big-endian: The existence indicates the register is in big endian.
|
||||
If both little-endian and big-endian are omitted, the endianness of the
|
||||
CPU will be used.
|
||||
- write-only: The existence indicates the register is write-only.
|
||||
- idle-state: value to set the muxer to when idle. When no value is
|
||||
given, it defaults to the last value used.
|
||||
|
||||
Whenever an access is made to a device on a child bus, the value set
|
||||
in the revelant node's reg property will be output to the register.
|
||||
|
||||
If an idle state is defined, using the idle-state (optional) property,
|
||||
whenever an access is not being made to a device on a child bus, the
|
||||
register will be set according to the idle value.
|
||||
|
||||
If an idle state is not defined, the most recently used value will be
|
||||
left programmed into the register.
|
||||
|
||||
Example of a mux on PCIe card, the host is a powerpc SoC (big endian):
|
||||
|
||||
i2c-mux {
|
||||
/* the <offset size> depends on the address translation
|
||||
* of the parent device. If omitted, device resource
|
||||
* will be used instead. The size is to determine
|
||||
* whether iowrite32, iowrite16, or iowrite8 will be used.
|
||||
*/
|
||||
reg = <0x6028 0x4>;
|
||||
little-endian; /* little endian register on PCIe */
|
||||
compatible = "i2c-mux-reg";
|
||||
#address-cells = <1>;
|
||||
#size-cells = <0>;
|
||||
i2c-parent = <&i2c1>;
|
||||
i2c@0 {
|
||||
reg = <0>;
|
||||
#address-cells = <1>;
|
||||
#size-cells = <0>;
|
||||
|
||||
si5338: clock-generator@70 {
|
||||
compatible = "silabs,si5338";
|
||||
reg = <0x70>;
|
||||
/* other stuff */
|
||||
};
|
||||
};
|
||||
|
||||
i2c@1 {
|
||||
/* data is written using iowrite32 */
|
||||
reg = <1>;
|
||||
#address-cells = <1>;
|
||||
#size-cells = <0>;
|
||||
|
||||
si5338: clock-generator@70 {
|
||||
compatible = "silabs,si5338";
|
||||
reg = <0x70>;
|
||||
/* other stuff */
|
||||
};
|
||||
};
|
||||
};
|
||||
|
|
@ -61,4 +61,15 @@ config I2C_MUX_PINCTRL
|
|||
This driver can also be built as a module. If so, the module will be
|
||||
called pinctrl-i2cmux.
|
||||
|
||||
config I2C_MUX_REG
|
||||
tristate "Register-based I2C multiplexer"
|
||||
help
|
||||
If you say yes to this option, support will be included for a
|
||||
register based I2C multiplexer. This driver provides access to
|
||||
I2C busses connected through a MUX, which is controlled
|
||||
by a single register.
|
||||
|
||||
This driver can also be built as a module. If so, the module
|
||||
will be called i2c-mux-reg.
|
||||
|
||||
endmenu
|
||||
|
|
|
|||
|
|
@ -7,5 +7,6 @@ obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o
|
|||
obj-$(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
|
||||
obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o
|
||||
|
||||
ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
|
||||
|
|
|
|||
|
|
@ -0,0 +1,294 @@
|
|||
/*
|
||||
* I2C multiplexer using a single register
|
||||
*
|
||||
* Copyright 2015 Freescale Semiconductor
|
||||
* York Sun <yorksun@freescale.com>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify it
|
||||
* under the terms of the GNU General Public License as published by the
|
||||
* Free Software Foundation; either version 2 of the License, or (at your
|
||||
* option) any later version.
|
||||
*/
|
||||
|
||||
#include <linux/i2c.h>
|
||||
#include <linux/i2c-mux.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/io.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/of_address.h>
|
||||
#include <linux/platform_data/i2c-mux-reg.h>
|
||||
#include <linux/platform_device.h>
|
||||
#include <linux/slab.h>
|
||||
|
||||
struct regmux {
|
||||
struct i2c_adapter *parent;
|
||||
struct i2c_adapter **adap; /* child busses */
|
||||
struct i2c_mux_reg_platform_data data;
|
||||
};
|
||||
|
||||
static int i2c_mux_reg_set(const struct regmux *mux, unsigned int chan_id)
|
||||
{
|
||||
if (!mux->data.reg)
|
||||
return -EINVAL;
|
||||
|
||||
switch (mux->data.reg_size) {
|
||||
case 4:
|
||||
if (mux->data.little_endian) {
|
||||
iowrite32(chan_id, mux->data.reg);
|
||||
if (!mux->data.write_only)
|
||||
ioread32(mux->data.reg);
|
||||
} else {
|
||||
iowrite32be(chan_id, mux->data.reg);
|
||||
if (!mux->data.write_only)
|
||||
ioread32(mux->data.reg);
|
||||
}
|
||||
break;
|
||||
case 2:
|
||||
if (mux->data.little_endian) {
|
||||
iowrite16(chan_id, mux->data.reg);
|
||||
if (!mux->data.write_only)
|
||||
ioread16(mux->data.reg);
|
||||
} else {
|
||||
iowrite16be(chan_id, mux->data.reg);
|
||||
if (!mux->data.write_only)
|
||||
ioread16be(mux->data.reg);
|
||||
}
|
||||
break;
|
||||
case 1:
|
||||
iowrite8(chan_id, mux->data.reg);
|
||||
if (!mux->data.write_only)
|
||||
ioread8(mux->data.reg);
|
||||
break;
|
||||
default:
|
||||
pr_err("Invalid register size\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int i2c_mux_reg_select(struct i2c_adapter *adap, void *data,
|
||||
unsigned int chan)
|
||||
{
|
||||
struct regmux *mux = data;
|
||||
|
||||
return i2c_mux_reg_set(mux, chan);
|
||||
}
|
||||
|
||||
static int i2c_mux_reg_deselect(struct i2c_adapter *adap, void *data,
|
||||
unsigned int chan)
|
||||
{
|
||||
struct regmux *mux = data;
|
||||
|
||||
if (mux->data.idle_in_use)
|
||||
return i2c_mux_reg_set(mux, mux->data.idle);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_OF
|
||||
static int i2c_mux_reg_probe_dt(struct regmux *mux,
|
||||
struct platform_device *pdev)
|
||||
{
|
||||
struct device_node *np = pdev->dev.of_node;
|
||||
struct device_node *adapter_np, *child;
|
||||
struct i2c_adapter *adapter;
|
||||
struct resource res;
|
||||
unsigned *values;
|
||||
int i = 0;
|
||||
|
||||
if (!np)
|
||||
return -ENODEV;
|
||||
|
||||
adapter_np = of_parse_phandle(np, "i2c-parent", 0);
|
||||
if (!adapter_np) {
|
||||
dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
|
||||
return -ENODEV;
|
||||
}
|
||||
adapter = of_find_i2c_adapter_by_node(adapter_np);
|
||||
if (!adapter)
|
||||
return -EPROBE_DEFER;
|
||||
|
||||
mux->parent = adapter;
|
||||
mux->data.parent = i2c_adapter_id(adapter);
|
||||
put_device(&adapter->dev);
|
||||
|
||||
mux->data.n_values = of_get_child_count(np);
|
||||
if (of_find_property(np, "little-endian", NULL)) {
|
||||
mux->data.little_endian = true;
|
||||
} else if (of_find_property(np, "big-endian", NULL)) {
|
||||
mux->data.little_endian = false;
|
||||
} else {
|
||||
#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : \
|
||||
defined(__LITTLE_ENDIAN)
|
||||
mux->data.little_endian = true;
|
||||
#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : \
|
||||
defined(__BIG_ENDIAN)
|
||||
mux->data.little_endian = false;
|
||||
#else
|
||||
#error Endianness not defined?
|
||||
#endif
|
||||
}
|
||||
if (of_find_property(np, "write-only", NULL))
|
||||
mux->data.write_only = true;
|
||||
else
|
||||
mux->data.write_only = false;
|
||||
|
||||
values = devm_kzalloc(&pdev->dev,
|
||||
sizeof(*mux->data.values) * mux->data.n_values,
|
||||
GFP_KERNEL);
|
||||
if (!values) {
|
||||
dev_err(&pdev->dev, "Cannot allocate values array");
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
for_each_child_of_node(np, child) {
|
||||
of_property_read_u32(child, "reg", values + i);
|
||||
i++;
|
||||
}
|
||||
mux->data.values = values;
|
||||
|
||||
if (!of_property_read_u32(np, "idle-state", &mux->data.idle))
|
||||
mux->data.idle_in_use = true;
|
||||
|
||||
/* map address from "reg" if exists */
|
||||
if (of_address_to_resource(np, 0, &res)) {
|
||||
mux->data.reg_size = resource_size(&res);
|
||||
if (mux->data.reg_size > 4) {
|
||||
dev_err(&pdev->dev, "Invalid address size\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
mux->data.reg = devm_ioremap_resource(&pdev->dev, &res);
|
||||
if (IS_ERR(mux->data.reg))
|
||||
return PTR_ERR(mux->data.reg);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
#else
|
||||
static int i2c_mux_reg_probe_dt(struct gpiomux *mux,
|
||||
struct platform_device *pdev)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
#endif
|
||||
|
||||
static int i2c_mux_reg_probe(struct platform_device *pdev)
|
||||
{
|
||||
struct regmux *mux;
|
||||
struct i2c_adapter *parent;
|
||||
struct resource *res;
|
||||
int (*deselect)(struct i2c_adapter *, void *, u32);
|
||||
unsigned int class;
|
||||
int i, ret, nr;
|
||||
|
||||
mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
|
||||
if (!mux)
|
||||
return -ENOMEM;
|
||||
|
||||
platform_set_drvdata(pdev, mux);
|
||||
|
||||
if (dev_get_platdata(&pdev->dev)) {
|
||||
memcpy(&mux->data, dev_get_platdata(&pdev->dev),
|
||||
sizeof(mux->data));
|
||||
|
||||
parent = i2c_get_adapter(mux->data.parent);
|
||||
if (!parent)
|
||||
return -EPROBE_DEFER;
|
||||
|
||||
mux->parent = parent;
|
||||
} else {
|
||||
ret = i2c_mux_reg_probe_dt(mux, pdev);
|
||||
if (ret < 0) {
|
||||
dev_err(&pdev->dev, "Error parsing device tree");
|
||||
return ret;
|
||||
}
|
||||
}
|
||||
|
||||
if (!mux->data.reg) {
|
||||
dev_info(&pdev->dev,
|
||||
"Register not set, using platform resource\n");
|
||||
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
mux->data.reg_size = resource_size(res);
|
||||
if (mux->data.reg_size > 4) {
|
||||
dev_err(&pdev->dev, "Invalid resource size\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
mux->data.reg = devm_ioremap_resource(&pdev->dev, res);
|
||||
if (IS_ERR(mux->data.reg))
|
||||
return PTR_ERR(mux->data.reg);
|
||||
}
|
||||
|
||||
mux->adap = devm_kzalloc(&pdev->dev,
|
||||
sizeof(*mux->adap) * mux->data.n_values,
|
||||
GFP_KERNEL);
|
||||
if (!mux->adap) {
|
||||
dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
if (mux->data.idle_in_use)
|
||||
deselect = i2c_mux_reg_deselect;
|
||||
else
|
||||
deselect = NULL;
|
||||
|
||||
for (i = 0; i < mux->data.n_values; i++) {
|
||||
nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
|
||||
class = mux->data.classes ? mux->data.classes[i] : 0;
|
||||
|
||||
mux->adap[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev, mux,
|
||||
nr, mux->data.values[i],
|
||||
class, i2c_mux_reg_select,
|
||||
deselect);
|
||||
if (!mux->adap[i]) {
|
||||
ret = -ENODEV;
|
||||
dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
|
||||
goto add_adapter_failed;
|
||||
}
|
||||
}
|
||||
|
||||
dev_dbg(&pdev->dev, "%d port mux on %s adapter\n",
|
||||
mux->data.n_values, mux->parent->name);
|
||||
|
||||
return 0;
|
||||
|
||||
add_adapter_failed:
|
||||
for (; i > 0; i--)
|
||||
i2c_del_mux_adapter(mux->adap[i - 1]);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int i2c_mux_reg_remove(struct platform_device *pdev)
|
||||
{
|
||||
struct regmux *mux = platform_get_drvdata(pdev);
|
||||
int i;
|
||||
|
||||
for (i = 0; i < mux->data.n_values; i++)
|
||||
i2c_del_mux_adapter(mux->adap[i]);
|
||||
|
||||
i2c_put_adapter(mux->parent);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct of_device_id i2c_mux_reg_of_match[] = {
|
||||
{ .compatible = "i2c-mux-reg", },
|
||||
{},
|
||||
};
|
||||
MODULE_DEVICE_TABLE(of, i2c_mux_reg_of_match);
|
||||
|
||||
static struct platform_driver i2c_mux_reg_driver = {
|
||||
.probe = i2c_mux_reg_probe,
|
||||
.remove = i2c_mux_reg_remove,
|
||||
.driver = {
|
||||
.name = "i2c-mux-reg",
|
||||
},
|
||||
};
|
||||
|
||||
module_platform_driver(i2c_mux_reg_driver);
|
||||
|
||||
MODULE_DESCRIPTION("Register-based I2C multiplexer driver");
|
||||
MODULE_AUTHOR("York Sun <yorksun@freescale.com>");
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_ALIAS("platform:i2c-mux-reg");
|
||||
|
|
@ -0,0 +1,44 @@
|
|||
/*
|
||||
* I2C multiplexer using a single register
|
||||
*
|
||||
* Copyright 2015 Freescale Semiconductor
|
||||
* York Sun <yorksun@freescale.com>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify it
|
||||
* under the terms of the GNU General Public License as published by the
|
||||
* Free Software Foundation; either version 2 of the License, or (at your
|
||||
* option) any later version.
|
||||
*/
|
||||
|
||||
#ifndef __LINUX_PLATFORM_DATA_I2C_MUX_REG_H
|
||||
#define __LINUX_PLATFORM_DATA_I2C_MUX_REG_H
|
||||
|
||||
/**
|
||||
* struct i2c_mux_reg_platform_data - Platform-dependent data for i2c-mux-reg
|
||||
* @parent: Parent I2C bus adapter number
|
||||
* @base_nr: Base I2C bus number to number adapters from or zero for dynamic
|
||||
* @values: Array of value for each channel
|
||||
* @n_values: Number of multiplexer channels
|
||||
* @little_endian: Indicating if the register is in little endian
|
||||
* @write_only: Reading the register is not allowed by hardware
|
||||
* @classes: Optional I2C auto-detection classes
|
||||
* @idle: Value to write to mux when idle
|
||||
* @idle_in_use: indicate if idle value is in use
|
||||
* @reg: Virtual address of the register to switch channel
|
||||
* @reg_size: register size in bytes
|
||||
*/
|
||||
struct i2c_mux_reg_platform_data {
|
||||
int parent;
|
||||
int base_nr;
|
||||
const unsigned int *values;
|
||||
int n_values;
|
||||
bool little_endian;
|
||||
bool write_only;
|
||||
const unsigned int *classes;
|
||||
u32 idle;
|
||||
bool idle_in_use;
|
||||
void __iomem *reg;
|
||||
resource_size_t reg_size;
|
||||
};
|
||||
|
||||
#endif /* __LINUX_PLATFORM_DATA_I2C_MUX_REG_H */
|
||||
Загрузка…
Ссылка в новой задаче