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// SPDX-License-Identifier: GPL-2.0-only
/*
* I2C multiplexer for the 2 I2C Masters of the RTL9300
* with up to 8 channels each, but which are not entirely
* independent of each other
*/
#include <linux/i2c-mux.h>
#include <linux/module.h>
#include <linux/mux/consumer.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include "../busses/i2c-rtl9300.h"
#define NUM_MASTERS 2
#define NUM_BUSSES 8
#define REG(mst, x) (mux->base + x + (mst ? mux->i2c->mst2_offset : 0))
#define REG_MASK(mst, clear, set, reg) \
writel((readl(REG((mst),(reg))) & ~(clear)) | (set), REG((mst),(reg)))
struct channel {
u8 sda_num;
u8 scl_num;
};
static struct channel channels[NUM_MASTERS * NUM_BUSSES];
struct rtl9300_mux {
void __iomem *base;
struct device *dev;
struct i2c_adapter *parent;
struct rtl9300_i2c * i2c;
};
struct i2c_mux_data {
int scl0_pin;
int scl1_pin;
int sda0_pin;
int sda_pins;
int (*i2c_mux_select)(struct i2c_mux_core *muxc, u32 chan);
int (*i2c_mux_deselect)(struct i2c_mux_core *muxc, u32 chan);
void (*sda_sel)(struct i2c_mux_core *muxc, int pin);
};
static int rtl9300_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
{
struct rtl9300_mux *mux = i2c_mux_priv(muxc);
/* Set SCL pin */
REG_MASK(channels[chan].scl_num, 0,
BIT(RTL9300_I2C_CTRL1_GPIO8_SCL_SEL), RTL9300_I2C_CTRL1);
/* Set SDA pin */
REG_MASK(channels[chan].scl_num, 0x7 << RTL9300_I2C_CTRL1_SDA_OUT_SEL,
channels[chan].sda_num << RTL9300_I2C_CTRL1_SDA_OUT_SEL, RTL9300_I2C_CTRL1);
mux->i2c->sda_num = channels[chan].sda_num;
mux->i2c->scl_num = channels[chan].scl_num;
return 0;
}
static int rtl9310_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
{
struct rtl9300_mux *mux = i2c_mux_priv(muxc);
/* Set SCL pin */
REG_MASK(0, 0, BIT(RTL9310_I2C_MST_IF_SEL_GPIO_SCL_SEL + channels[chan].scl_num),
RTL9310_I2C_MST_IF_SEL);
/* Set SDA pin */
REG_MASK(channels[chan].scl_num, 0xf << RTL9310_I2C_CTRL_SDA_OUT_SEL,
channels[chan].sda_num << RTL9310_I2C_CTRL_SDA_OUT_SEL, RTL9310_I2C_CTRL);
mux->i2c->sda_num = channels[chan].sda_num;
mux->i2c->scl_num = channels[chan].scl_num;
return 0;
}
static int rtl9300_i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
{
return 0;
}
static void rtl9300_sda_sel(struct i2c_mux_core *muxc, int pin)
{
struct rtl9300_mux *mux = i2c_mux_priv(muxc);
u32 v;
/* Set SDA pin to I2C functionality */
v = readl(REG(0, RTL9300_I2C_MST_GLB_CTRL));
v |= BIT(pin);
writel(v, REG(0, RTL9300_I2C_MST_GLB_CTRL));
}
static void rtl9310_sda_sel(struct i2c_mux_core *muxc, int pin)
{
struct rtl9300_mux *mux = i2c_mux_priv(muxc);
u32 v;
/* Set SDA pin to I2C functionality */
v = readl(REG(0, RTL9310_I2C_MST_IF_SEL));
v |= BIT(pin);
writel(v, REG(0, RTL9310_I2C_MST_IF_SEL));
}
static struct device_node *mux_parent_adapter(struct device *dev, struct rtl9300_mux *mux)
{
struct device_node *node = dev->of_node;
struct device_node *parent_np;
struct i2c_adapter *parent;
parent_np = of_parse_phandle(node, "i2c-parent", 0);
if (!parent_np) {
dev_err(dev, "Cannot parse i2c-parent\n");
return ERR_PTR(-ENODEV);
}
parent = of_find_i2c_adapter_by_node(parent_np);
of_node_put(parent_np);
if (!parent)
return ERR_PTR(-EPROBE_DEFER);
if (!(of_device_is_compatible(parent_np, "realtek,rtl9300-i2c") ||
of_device_is_compatible(parent_np, "realtek,rtl9310-i2c"))){
dev_err(dev, "I2C parent not an RTL9300 I2C controller\n");
return ERR_PTR(-ENODEV);
}
mux->parent = parent;
mux->i2c = (struct rtl9300_i2c *)i2c_get_adapdata(parent);
mux->base = mux->i2c->base;
return parent_np;
}
struct i2c_mux_data rtl9300_i2c_mux_data = {
.scl0_pin = 8,
.scl1_pin = 17,
.sda0_pin = 9,
.sda_pins = 8,
.i2c_mux_select = rtl9300_i2c_mux_select,
.i2c_mux_deselect = rtl9300_i2c_mux_deselect,
.sda_sel = rtl9300_sda_sel,
};
struct i2c_mux_data rtl9310_i2c_mux_data = {
.scl0_pin = 13,
.scl1_pin = 14,
.sda0_pin = 0,
.sda_pins = 16,
.i2c_mux_select = rtl9310_i2c_mux_select,
.i2c_mux_deselect = rtl9300_i2c_mux_deselect,
.sda_sel = rtl9310_sda_sel,
};
static const struct of_device_id rtl9300_i2c_mux_of_match[] = {
{ .compatible = "realtek,i2c-mux-rtl9300", .data = (void *) &rtl9300_i2c_mux_data},
{ .compatible = "realtek,i2c-mux-rtl9310", .data = (void *) &rtl9310_i2c_mux_data},
{},
};
MODULE_DEVICE_TABLE(of, rtl9300_i2c_mux_of_match);
static int rtl9300_i2c_mux_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *node = dev->of_node;
struct device_node *parent_np;
struct device_node *child;
struct i2c_mux_core *muxc;
struct rtl9300_mux *mux;
struct i2c_mux_data *mux_data;
int children;
int ret;
pr_info("%s probing I2C adapter\n", __func__);
if (!node) {
dev_err(dev, "No DT found\n");
return -EINVAL;
}
mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
if (!mux)
return -ENOMEM;
mux->dev = dev;
mux_data = (struct i2c_mux_data *) device_get_match_data(dev);
parent_np = mux_parent_adapter(dev, mux);
if (IS_ERR(parent_np))
return dev_err_probe(dev, PTR_ERR(parent_np), "i2c-parent adapter not found\n");
pr_info("%s base memory %08x\n", __func__, (u32)mux->base);
children = of_get_child_count(node);
muxc = i2c_mux_alloc(mux->parent, dev, children, 0, 0,
mux_data->i2c_mux_select, mux_data->i2c_mux_deselect);
if (!muxc) {
ret = -ENOMEM;
goto err_parent;
}
muxc->priv = mux;
platform_set_drvdata(pdev, muxc);
for_each_child_of_node(node, child) {
u32 chan;
u32 pin;
ret = of_property_read_u32(child, "reg", &chan);
if (ret < 0) {
dev_err(dev, "no reg property for node '%pOFn'\n",
child);
goto err_children;
}
if (chan >= NUM_MASTERS * NUM_BUSSES) {
dev_err(dev, "invalid reg %u\n", chan);
ret = -EINVAL;
goto err_children;
}
if (of_property_read_u32(child, "scl-pin", &pin)) {
dev_warn(dev, "SCL pin not found in DT, using default\n");
pin = mux_data->scl0_pin;
}
if (!(pin == mux_data->scl0_pin || pin == mux_data->scl1_pin)) {
dev_warn(dev, "SCL pin %d not supported\n", pin);
ret = -EINVAL;
goto err_children;
}
channels[chan].scl_num = pin == mux_data->scl0_pin ? 0 : 1;
pr_info("%s channel %d scl_num %d\n", __func__, chan, channels[chan].scl_num);
if (of_property_read_u32(child, "sda-pin", &pin)) {
dev_warn(dev, "SDA pin not found in DT, using default \n");
pin = mux_data->sda0_pin;
}
channels[chan].sda_num = pin - mux_data->sda0_pin;
if (channels[chan].sda_num < 0 || channels[chan].sda_num >= mux_data->sda_pins) {
dev_warn(dev, "SDA pin %d not supported\n", pin);
return -EINVAL;
}
pr_info("%s channel %d sda_num %d\n", __func__, chan, channels[chan].sda_num);
mux_data->sda_sel(muxc, channels[chan].sda_num);
ret = i2c_mux_add_adapter(muxc, 0, chan, 0);
if (ret)
goto err_children;
}
dev_info(dev, "%d-port mux on %s adapter\n", children, mux->parent->name);
return 0;
err_children:
i2c_mux_del_adapters(muxc);
err_parent:
i2c_put_adapter(mux->parent);
return ret;
}
static int rtl9300_i2c_mux_remove(struct platform_device *pdev)
{
struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
i2c_mux_del_adapters(muxc);
i2c_put_adapter(muxc->parent);
return 0;
}
static struct platform_driver i2c_mux_driver = {
.probe = rtl9300_i2c_mux_probe,
.remove = rtl9300_i2c_mux_remove,
.driver = {
.name = "i2c-mux-rtl9300",
.of_match_table = rtl9300_i2c_mux_of_match,
},
};
module_platform_driver(i2c_mux_driver);
MODULE_DESCRIPTION("RTL9300 I2C multiplexer driver");
MODULE_AUTHOR("Birger Koblitz");
MODULE_LICENSE("GPL v2");
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