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linux_dsm_epyc7002/drivers/power/supply/isp1704_charger.c
Colin Ian King 72e538f6ee power: supply: isp1704: remove redundant assignment to variable ret 
The variable ret is being assigned with a value that is never
read and it is being updated later with a new value. The
assignment is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2019-09-02 21:12:45 +02:00

515 lines
13 KiB
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ISP1704 USB Charger Detection driver
*
* Copyright (C) 2010 Nokia Corporation
* Copyright (C) 2012 - 2013 Pali Rohár <pali.rohar@gmail.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/device.h>
#include <linux/sysfs.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/gpio/consumer.h>
#include <linux/usb/otg.h>
#include <linux/usb/ulpi.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
/* Vendor specific Power Control register */
#define ISP1704_PWR_CTRL 0x3d
#define ISP1704_PWR_CTRL_SWCTRL (1 << 0)
#define ISP1704_PWR_CTRL_DET_COMP (1 << 1)
#define ISP1704_PWR_CTRL_BVALID_RISE (1 << 2)
#define ISP1704_PWR_CTRL_BVALID_FALL (1 << 3)
#define ISP1704_PWR_CTRL_DP_WKPU_EN (1 << 4)
#define ISP1704_PWR_CTRL_VDAT_DET (1 << 5)
#define ISP1704_PWR_CTRL_DPVSRC_EN (1 << 6)
#define ISP1704_PWR_CTRL_HWDETECT (1 << 7)
#define NXP_VENDOR_ID 0x04cc
static u16 isp170x_id[] = {
0x1704,
0x1707,
};
struct isp1704_charger {
struct device *dev;
struct power_supply *psy;
struct power_supply_desc psy_desc;
struct gpio_desc *enable_gpio;
struct usb_phy *phy;
struct notifier_block nb;
struct work_struct work;
/* properties */
char model[8];
unsigned present:1;
unsigned online:1;
unsigned current_max;
};
static inline int isp1704_read(struct isp1704_charger *isp, u32 reg)
{
return usb_phy_io_read(isp->phy, reg);
}
static inline int isp1704_write(struct isp1704_charger *isp, u32 reg, u32 val)
{
return usb_phy_io_write(isp->phy, val, reg);
}
static void isp1704_charger_set_power(struct isp1704_charger *isp, bool on)
{
gpiod_set_value(isp->enable_gpio, on);
}
/*
* Determine is the charging port DCP (dedicated charger) or CDP (Host/HUB
* chargers).
*
* REVISIT: The method is defined in Battery Charging Specification and is
* applicable to any ULPI transceiver. Nothing isp170x specific here.
*/
static inline int isp1704_charger_type(struct isp1704_charger *isp)
{
u8 reg;
u8 func_ctrl;
u8 otg_ctrl;
int type = POWER_SUPPLY_TYPE_USB_DCP;
func_ctrl = isp1704_read(isp, ULPI_FUNC_CTRL);
otg_ctrl = isp1704_read(isp, ULPI_OTG_CTRL);
/* disable pulldowns */
reg = ULPI_OTG_CTRL_DM_PULLDOWN | ULPI_OTG_CTRL_DP_PULLDOWN;
isp1704_write(isp, ULPI_CLR(ULPI_OTG_CTRL), reg);
/* full speed */
isp1704_write(isp, ULPI_CLR(ULPI_FUNC_CTRL),
ULPI_FUNC_CTRL_XCVRSEL_MASK);
isp1704_write(isp, ULPI_SET(ULPI_FUNC_CTRL),
ULPI_FUNC_CTRL_FULL_SPEED);
/* Enable strong pull-up on DP (1.5K) and reset */
reg = ULPI_FUNC_CTRL_TERMSELECT | ULPI_FUNC_CTRL_RESET;
isp1704_write(isp, ULPI_SET(ULPI_FUNC_CTRL), reg);
usleep_range(1000, 2000);
reg = isp1704_read(isp, ULPI_DEBUG);
if ((reg & 3) != 3)
type = POWER_SUPPLY_TYPE_USB_CDP;
/* recover original state */
isp1704_write(isp, ULPI_FUNC_CTRL, func_ctrl);
isp1704_write(isp, ULPI_OTG_CTRL, otg_ctrl);
return type;
}
/*
* ISP1704 detects PS/2 adapters as charger. To make sure the detected charger
* is actually a dedicated charger, the following steps need to be taken.
*/
static inline int isp1704_charger_verify(struct isp1704_charger *isp)
{
int ret = 0;
u8 r;
/* Reset the transceiver */
r = isp1704_read(isp, ULPI_FUNC_CTRL);
r |= ULPI_FUNC_CTRL_RESET;
isp1704_write(isp, ULPI_FUNC_CTRL, r);
usleep_range(1000, 2000);
/* Set normal mode */
r &= ~(ULPI_FUNC_CTRL_RESET | ULPI_FUNC_CTRL_OPMODE_MASK);
isp1704_write(isp, ULPI_FUNC_CTRL, r);
/* Clear the DP and DM pull-down bits */
r = ULPI_OTG_CTRL_DP_PULLDOWN | ULPI_OTG_CTRL_DM_PULLDOWN;
isp1704_write(isp, ULPI_CLR(ULPI_OTG_CTRL), r);
/* Enable strong pull-up on DP (1.5K) and reset */
r = ULPI_FUNC_CTRL_TERMSELECT | ULPI_FUNC_CTRL_RESET;
isp1704_write(isp, ULPI_SET(ULPI_FUNC_CTRL), r);
usleep_range(1000, 2000);
/* Read the line state */
if (!isp1704_read(isp, ULPI_DEBUG)) {
/* Disable strong pull-up on DP (1.5K) */
isp1704_write(isp, ULPI_CLR(ULPI_FUNC_CTRL),
ULPI_FUNC_CTRL_TERMSELECT);
return 1;
}
/* Is it a charger or PS/2 connection */
/* Enable weak pull-up resistor on DP */
isp1704_write(isp, ULPI_SET(ISP1704_PWR_CTRL),
ISP1704_PWR_CTRL_DP_WKPU_EN);
/* Disable strong pull-up on DP (1.5K) */
isp1704_write(isp, ULPI_CLR(ULPI_FUNC_CTRL),
ULPI_FUNC_CTRL_TERMSELECT);
/* Enable weak pull-down resistor on DM */
isp1704_write(isp, ULPI_SET(ULPI_OTG_CTRL),
ULPI_OTG_CTRL_DM_PULLDOWN);
/* It's a charger if the line states are clear */
if (!(isp1704_read(isp, ULPI_DEBUG)))
ret = 1;
/* Disable weak pull-up resistor on DP */
isp1704_write(isp, ULPI_CLR(ISP1704_PWR_CTRL),
ISP1704_PWR_CTRL_DP_WKPU_EN);
return ret;
}
static inline int isp1704_charger_detect(struct isp1704_charger *isp)
{
unsigned long timeout;
u8 pwr_ctrl;
int ret = 0;
pwr_ctrl = isp1704_read(isp, ISP1704_PWR_CTRL);
/* set SW control bit in PWR_CTRL register */
isp1704_write(isp, ISP1704_PWR_CTRL,
ISP1704_PWR_CTRL_SWCTRL);
/* enable manual charger detection */
isp1704_write(isp, ULPI_SET(ISP1704_PWR_CTRL),
ISP1704_PWR_CTRL_SWCTRL
| ISP1704_PWR_CTRL_DPVSRC_EN);
usleep_range(1000, 2000);
timeout = jiffies + msecs_to_jiffies(300);
do {
/* Check if there is a charger */
if (isp1704_read(isp, ISP1704_PWR_CTRL)
& ISP1704_PWR_CTRL_VDAT_DET) {
ret = isp1704_charger_verify(isp);
break;
}
} while (!time_after(jiffies, timeout) && isp->online);
/* recover original state */
isp1704_write(isp, ISP1704_PWR_CTRL, pwr_ctrl);
return ret;
}
static inline int isp1704_charger_detect_dcp(struct isp1704_charger *isp)
{
if (isp1704_charger_detect(isp) &&
isp1704_charger_type(isp) == POWER_SUPPLY_TYPE_USB_DCP)
return true;
else
return false;
}
static void isp1704_charger_work(struct work_struct *data)
{
struct isp1704_charger *isp =
container_of(data, struct isp1704_charger, work);
static DEFINE_MUTEX(lock);
mutex_lock(&lock);
switch (isp->phy->last_event) {
case USB_EVENT_VBUS:
/* do not call wall charger detection more times */
if (!isp->present) {
isp->online = true;
isp->present = 1;
isp1704_charger_set_power(isp, 1);
/* detect wall charger */
if (isp1704_charger_detect_dcp(isp)) {
isp->psy_desc.type = POWER_SUPPLY_TYPE_USB_DCP;
isp->current_max = 1800;
} else {
isp->psy_desc.type = POWER_SUPPLY_TYPE_USB;
isp->current_max = 500;
}
/* enable data pullups */
if (isp->phy->otg->gadget)
usb_gadget_connect(isp->phy->otg->gadget);
}
if (isp->psy_desc.type != POWER_SUPPLY_TYPE_USB_DCP) {
/*
* Only 500mA here or high speed chirp
* handshaking may break
*/
if (isp->current_max > 500)
isp->current_max = 500;
if (isp->current_max > 100)
isp->psy_desc.type = POWER_SUPPLY_TYPE_USB_CDP;
}
break;
case USB_EVENT_NONE:
isp->online = false;
isp->present = 0;
isp->current_max = 0;
isp->psy_desc.type = POWER_SUPPLY_TYPE_USB;
/*
* Disable data pullups. We need to prevent the controller from
* enumerating.
*
* FIXME: This is here to allow charger detection with Host/HUB
* chargers. The pullups may be enabled elsewhere, so this can
* not be the final solution.
*/
if (isp->phy->otg->gadget)
usb_gadget_disconnect(isp->phy->otg->gadget);
isp1704_charger_set_power(isp, 0);
break;
default:
goto out;
}
power_supply_changed(isp->psy);
out:
mutex_unlock(&lock);
}
static int isp1704_notifier_call(struct notifier_block *nb,
unsigned long val, void *v)
{
struct isp1704_charger *isp =
container_of(nb, struct isp1704_charger, nb);
schedule_work(&isp->work);
return NOTIFY_OK;
}
static int isp1704_charger_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct isp1704_charger *isp = power_supply_get_drvdata(psy);
switch (psp) {
case POWER_SUPPLY_PROP_PRESENT:
val->intval = isp->present;
break;
case POWER_SUPPLY_PROP_ONLINE:
val->intval = isp->online;
break;
case POWER_SUPPLY_PROP_CURRENT_MAX:
val->intval = isp->current_max;
break;
case POWER_SUPPLY_PROP_MODEL_NAME:
val->strval = isp->model;
break;
case POWER_SUPPLY_PROP_MANUFACTURER:
val->strval = "NXP";
break;
default:
return -EINVAL;
}
return 0;
}
static enum power_supply_property power_props[] = {
POWER_SUPPLY_PROP_PRESENT,
POWER_SUPPLY_PROP_ONLINE,
POWER_SUPPLY_PROP_CURRENT_MAX,
POWER_SUPPLY_PROP_MODEL_NAME,
POWER_SUPPLY_PROP_MANUFACTURER,
};
static inline int isp1704_test_ulpi(struct isp1704_charger *isp)
{
int vendor;
int product;
int i;
int ret;
/* Test ULPI interface */
ret = isp1704_write(isp, ULPI_SCRATCH, 0xaa);
if (ret < 0)
return ret;
ret = isp1704_read(isp, ULPI_SCRATCH);
if (ret < 0)
return ret;
if (ret != 0xaa)
return -ENODEV;
/* Verify the product and vendor id matches */
vendor = isp1704_read(isp, ULPI_VENDOR_ID_LOW);
vendor |= isp1704_read(isp, ULPI_VENDOR_ID_HIGH) << 8;
if (vendor != NXP_VENDOR_ID)
return -ENODEV;
product = isp1704_read(isp, ULPI_PRODUCT_ID_LOW);
product |= isp1704_read(isp, ULPI_PRODUCT_ID_HIGH) << 8;
for (i = 0; i < ARRAY_SIZE(isp170x_id); i++) {
if (product == isp170x_id[i]) {
sprintf(isp->model, "isp%x", product);
return product;
}
}
dev_err(isp->dev, "product id %x not matching known ids", product);
return -ENODEV;
}
static int isp1704_charger_probe(struct platform_device *pdev)
{
struct isp1704_charger *isp;
int ret = -ENODEV;
struct power_supply_config psy_cfg = {};
isp = devm_kzalloc(&pdev->dev, sizeof(*isp), GFP_KERNEL);
if (!isp)
return -ENOMEM;
isp->enable_gpio = devm_gpiod_get(&pdev->dev, "nxp,enable",
GPIOD_OUT_HIGH);
if (IS_ERR(isp->enable_gpio)) {
ret = PTR_ERR(isp->enable_gpio);
dev_err(&pdev->dev, "Could not get reset gpio: %d\n", ret);
return ret;
}
if (pdev->dev.of_node)
isp->phy = devm_usb_get_phy_by_phandle(&pdev->dev, "usb-phy", 0);
else
isp->phy = devm_usb_get_phy(&pdev->dev, USB_PHY_TYPE_USB2);
if (IS_ERR(isp->phy)) {
ret = PTR_ERR(isp->phy);
dev_err(&pdev->dev, "usb_get_phy failed\n");
goto fail0;
}
isp->dev = &pdev->dev;
platform_set_drvdata(pdev, isp);
isp1704_charger_set_power(isp, 1);
ret = isp1704_test_ulpi(isp);
if (ret < 0) {
dev_err(&pdev->dev, "isp1704_test_ulpi failed\n");
goto fail1;
}
isp->psy_desc.name = "isp1704";
isp->psy_desc.type = POWER_SUPPLY_TYPE_USB;
isp->psy_desc.properties = power_props;
isp->psy_desc.num_properties = ARRAY_SIZE(power_props);
isp->psy_desc.get_property = isp1704_charger_get_property;
psy_cfg.drv_data = isp;
isp->psy = power_supply_register(isp->dev, &isp->psy_desc, &psy_cfg);
if (IS_ERR(isp->psy)) {
ret = PTR_ERR(isp->psy);
dev_err(&pdev->dev, "power_supply_register failed\n");
goto fail1;
}
/*
* REVISIT: using work in order to allow the usb notifications to be
* made atomically in the future.
*/
INIT_WORK(&isp->work, isp1704_charger_work);
isp->nb.notifier_call = isp1704_notifier_call;
ret = usb_register_notifier(isp->phy, &isp->nb);
if (ret) {
dev_err(&pdev->dev, "usb_register_notifier failed\n");
goto fail2;
}
dev_info(isp->dev, "registered with product id %s\n", isp->model);
/*
* Taking over the D+ pullup.
*
* FIXME: The device will be disconnected if it was already
* enumerated. The charger driver should be always loaded before any
* gadget is loaded.
*/
if (isp->phy->otg->gadget)
usb_gadget_disconnect(isp->phy->otg->gadget);
if (isp->phy->last_event == USB_EVENT_NONE)
isp1704_charger_set_power(isp, 0);
/* Detect charger if VBUS is valid (the cable was already plugged). */
if (isp->phy->last_event == USB_EVENT_VBUS &&
!isp->phy->otg->default_a)
schedule_work(&isp->work);
return 0;
fail2:
power_supply_unregister(isp->psy);
fail1:
isp1704_charger_set_power(isp, 0);
fail0:
dev_err(&pdev->dev, "failed to register isp1704 with error %d\n", ret);
return ret;
}
static int isp1704_charger_remove(struct platform_device *pdev)
{
struct isp1704_charger *isp = platform_get_drvdata(pdev);
usb_unregister_notifier(isp->phy, &isp->nb);
power_supply_unregister(isp->psy);
isp1704_charger_set_power(isp, 0);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id omap_isp1704_of_match[] = {
{ .compatible = "nxp,isp1704", },
{ .compatible = "nxp,isp1707", },
{},
};
MODULE_DEVICE_TABLE(of, omap_isp1704_of_match);
#endif
static struct platform_driver isp1704_charger_driver = {
.driver = {
.name = "isp1704_charger",
.of_match_table = of_match_ptr(omap_isp1704_of_match),
},
.probe = isp1704_charger_probe,
.remove = isp1704_charger_remove,
};
module_platform_driver(isp1704_charger_driver);
MODULE_ALIAS("platform:isp1704_charger");
MODULE_AUTHOR("Nokia Corporation");
MODULE_DESCRIPTION("ISP170x USB Charger driver");
MODULE_LICENSE("GPL");
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