/*
* mtu3_dr.c - dual role switch and host glue layer
*
* Copyright (C) 2016 MediaTek Inc.
*
* Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/debugfs.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include "mtu3.h"
#include "mtu3_dr.h"
#define USB2_PORT 2
#define USB3_PORT 3
enum mtu3_vbus_id_state {
MTU3_ID_FLOAT = 1,
MTU3_ID_GROUND,
MTU3_VBUS_OFF,
MTU3_VBUS_VALID,
};
static void toggle_opstate(struct ssusb_mtk *ssusb)
{
if (!ssusb->otg_switch.is_u3_drd) {
mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION);
mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN);
}
}
/* only port0 supports dual-role mode */
static int ssusb_port0_switch(struct ssusb_mtk *ssusb,
int version, bool tohost)
{
void __iomem *ibase = ssusb->ippc_base;
u32 value;
dev_dbg(ssusb->dev, "%s (switch u%d port0 to %s)\n", __func__,
version, tohost ? "host" : "device");
if (version == USB2_PORT) {
/* 1. power off and disable u2 port0 */
value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
value |= SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS;
mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
/* 2. power on, enable u2 port0 and select its mode */
value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
value &= ~(SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS);
value = tohost ? (value | SSUSB_U2_PORT_HOST_SEL) :
(value & (~SSUSB_U2_PORT_HOST_SEL));
mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
} else {
/* 1. power off and disable u3 port0 */
value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
value |= SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS;
mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
/* 2. power on, enable u3 port0 and select its mode */
value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
value &= ~(SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS);
value = tohost ? (value | SSUSB_U3_PORT_HOST_SEL) :
(value & (~SSUSB_U3_PORT_HOST_SEL));
mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
}
return 0;
}
static void switch_port_to_host(struct ssusb_mtk *ssusb)
{
u32 check_clk = 0;
dev_dbg(ssusb->dev, "%s\n", __func__);
ssusb_port0_switch(ssusb, USB2_PORT, true);
if (ssusb->otg_switch.is_u3_drd) {
ssusb_port0_switch(ssusb, USB3_PORT, true);
check_clk = SSUSB_U3_MAC_RST_B_STS;
}
ssusb_check_clocks(ssusb, check_clk);
/* after all clocks are stable */
toggle_opstate(ssusb);
}
static void switch_port_to_device(struct ssusb_mtk *ssusb)
{
u32 check_clk = 0;
dev_dbg(ssusb->dev, "%s\n", __func__);
ssusb_port0_switch(ssusb, USB2_PORT, false);
if (ssusb->otg_switch.is_u3_drd) {
ssusb_port0_switch(ssusb, USB3_PORT, false);
check_clk = SSUSB_U3_MAC_RST_B_STS;
}
ssusb_check_clocks(ssusb, check_clk);
}
int ssusb_set_vbus(struct otg_switch_mtk *otg_sx, int is_on)
{
struct ssusb_mtk *ssusb =
container_of(otg_sx, struct ssusb_mtk, otg_switch);
struct regulator *vbus = otg_sx->vbus;
int ret;
/* vbus is optional */
if (!vbus)
return 0;
dev_dbg(ssusb->dev, "%s: turn %s\n", __func__, is_on ? "on" : "off");
if (is_on) {
ret = regulator_enable(vbus);
if (ret) {
dev_err(ssusb->dev, "vbus regulator enable failed\n");
return ret;
}
} else {
regulator_disable(vbus);
}
return 0;
}
/*
* switch to host: -> MTU3_VBUS_OFF --> MTU3_ID_GROUND
* switch to device: -> MTU3_ID_FLOAT --> MTU3_VBUS_VALID
*/
static void ssusb_set_mailbox(struct otg_switch_mtk *otg_sx,
enum mtu3_vbus_id_state status)
{
struct ssusb_mtk *ssusb =
container_of(otg_sx, struct ssusb_mtk, otg_switch);
struct mtu3 *mtu = ssusb->u3d;
dev_dbg(ssusb->dev, "mailbox state(%d)\n", status);
switch (status) {
case MTU3_ID_GROUND:
switch_port_to_host(ssusb);
ssusb_set_vbus(otg_sx, 1);
ssusb->is_host = true;
break;
case MTU3_ID_FLOAT:
ssusb->is_host = false;
ssusb_set_vbus(otg_sx, 0);
switch_port_to_device(ssusb);
break;
case MTU3_VBUS_OFF:
mtu3_stop(mtu);
pm_relax(ssusb->dev);
break;
case MTU3_VBUS_VALID:
/* avoid suspend when works as device */
pm_stay_awake(ssusb->dev);
mtu3_start(mtu);
break;
default:
dev_err(ssusb->dev, "invalid state\n");
}
}
static int ssusb_id_notifier(struct notifier_block *nb,
unsigned long event, void *ptr)
{
struct otg_switch_mtk *otg_sx =
container_of(nb, struct otg_switch_mtk, id_nb);
if (event)
ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND);
else
ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
return NOTIFY_DONE;
}
static int ssusb_vbus_notifier(struct notifier_block *nb,
unsigned long event, void *ptr)
{
struct otg_switch_mtk *otg_sx =
container_of(nb, struct otg_switch_mtk, vbus_nb);
if (event)
ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
else
ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
return NOTIFY_DONE;
}
static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx)
{
struct ssusb_mtk *ssusb =
container_of(otg_sx, struct ssusb_mtk, otg_switch);
struct extcon_dev *edev = otg_sx->edev;
int ret;
/* extcon is optional */
if (!edev)
return 0;
otg_sx->vbus_nb.notifier_call = ssusb_vbus_notifier;
ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB,
&otg_sx->vbus_nb);
if (ret < 0)
dev_err(ssusb->dev, "failed to register notifier for USB\n");
otg_sx->id_nb.notifier_call = ssusb_id_notifier;
ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST,
&otg_sx->id_nb);
if (ret < 0)
dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n");
dev_dbg(ssusb->dev, "EXTCON_USB: %d, EXTCON_USB_HOST: %d\n",
extcon_get_state(edev, EXTCON_USB),
extcon_get_state(edev, EXTCON_USB_HOST));
/* default as host, switch to device mode if needed */
if (extcon_get_state(edev, EXTCON_USB_HOST) == false)
ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
if (extcon_get_state(edev, EXTCON_USB) == true)
ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
return 0;
}
static void extcon_register_dwork(struct work_struct *work)
{
struct delayed_work *dwork = to_delayed_work(work);
struct otg_switch_mtk *otg_sx =
container_of(dwork, struct otg_switch_mtk, extcon_reg_dwork);
ssusb_extcon_register(otg_sx);
}
/*
* We provide an interface via debugfs to switch between host and device modes
* depending on user input.
* This is useful in special cases, such as uses TYPE-A receptacle but also
* wants to support dual-role mode.
* It generates cable state changes by pulling up/down IDPIN and
* notifies driver to switch mode by "extcon-usb-gpio".
* NOTE: when use MICRO receptacle, should not enable this interface.
*/
static void ssusb_mode_manual_switch(struct ssusb_mtk *ssusb, int to_host)
{
struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
if (to_host)
pinctrl_select_state(otg_sx->id_pinctrl, otg_sx->id_ground);
else
pinctrl_select_state(otg_sx->id_pinctrl, otg_sx->id_float);
}
static int ssusb_mode_show(struct seq_file *sf, void *unused)
{
struct ssusb_mtk *ssusb = sf->private;
seq_printf(sf, "current mode: %s(%s drd)\n(echo device/host)\n",
ssusb->is_host ? "host" : "device",
ssusb->otg_switch.manual_drd_enabled ? "manual" : "auto");
return 0;
}
static int ssusb_mode_open(struct inode *inode, struct file *file)
{
return single_open(file, ssusb_mode_show, inode->i_private);
}
static ssize_t ssusb_mode_write(struct file *file,
const char __user *ubuf, size_t count, loff_t *ppos)
{
struct seq_file *sf = file->private_data;
struct ssusb_mtk *ssusb = sf->private;
char buf[16];
if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
return -EFAULT;
if (!strncmp(buf, "host", 4) && !ssusb->is_host) {
ssusb_mode_manual_switch(ssusb, 1);
} else if (!strncmp(buf, "device", 6) && ssusb->is_host) {
ssusb_mode_manual_switch(ssusb, 0);
} else {
dev_err(ssusb->dev, "wrong or duplicated setting\n");
return -EINVAL;
}
return count;
}
static const struct file_operations ssusb_mode_fops = {
.open = ssusb_mode_open,
.write = ssusb_mode_write,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static void ssusb_debugfs_init(struct ssusb_mtk *ssusb)
{
struct dentry *root;
struct dentry *file;
root = debugfs_create_dir(dev_name(ssusb->dev), usb_debug_root);
if (IS_ERR_OR_NULL(root)) {
if (!root)
dev_err(ssusb->dev, "create debugfs root failed\n");
return;
}
ssusb->dbgfs_root = root;
file = debugfs_create_file("mode", S_IRUGO | S_IWUSR, root,
ssusb, &ssusb_mode_fops);
if (!file)
dev_dbg(ssusb->dev, "create debugfs mode failed\n");
}
static void ssusb_debugfs_exit(struct ssusb_mtk *ssusb)
{
debugfs_remove_recursive(ssusb->dbgfs_root);
}
int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
{
struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
INIT_DELAYED_WORK(&otg_sx->extcon_reg_dwork, extcon_register_dwork);
if (otg_sx->manual_drd_enabled)
ssusb_debugfs_init(ssusb);
/* It is enough to delay 1s for waiting for host initialization */
schedule_delayed_work(&otg_sx->extcon_reg_dwork, HZ);
return 0;
}
void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)
{
struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
cancel_delayed_work(&otg_sx->extcon_reg_dwork);
if (otg_sx->manual_drd_enabled)
ssusb_debugfs_exit(ssusb);
}