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ME176C: phy: tusb1210: Implement basic charger detection (v3)
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v2: Major rewrite and cleanup:
 - Provide results using an Extcon device instead of hard-coding
   bq24192 charger driver
 - Avoid forcing device mode and restore previous mode instead
 - Use device properties instead of hard-coding Extcon device name

v3: Wake up parent USB controller before starting charger detection
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@stephan-gh
stephan-gh committed Feb 2, 2020
1 parent 1c70c94 commit a8d66d2
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Showing 2 changed files with 222 additions and 8 deletions.
6 changes: 5 additions & 1 deletion drivers/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -100,6 +100,11 @@ obj-$(CONFIG_ZORRO) += zorro/
obj-$(CONFIG_ATA_OVER_ETH) += block/aoe/
obj-$(CONFIG_PARIDE) += block/paride/
obj-$(CONFIG_TC) += tc/

# extcon/ comes before usb/ since the USB core depends on extcon devices
# for dual role support (OTG) and/or charger detection
obj-$(CONFIG_EXTCON) += extcon/

obj-$(CONFIG_USB_PHY) += usb/
obj-$(CONFIG_USB) += usb/
obj-$(CONFIG_USB_SUPPORT) += usb/
Expand Down Expand Up @@ -161,7 +166,6 @@ obj-$(CONFIG_VIRT_DRIVERS) += virt/
obj-$(CONFIG_HYPERV) += hv/

obj-$(CONFIG_PM_DEVFREQ) += devfreq/
obj-$(CONFIG_EXTCON) += extcon/
obj-$(CONFIG_MEMORY) += memory/
obj-$(CONFIG_IIO) += iio/
obj-$(CONFIG_VME_BUS) += vme/
Expand Down
224 changes: 217 additions & 7 deletions drivers/phy/ti/phy-tusb1210.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11,32 +11,63 @@
#include <linux/ulpi/regs.h>
#include <linux/gpio/consumer.h>
#include <linux/phy/ulpi_phy.h>
#include <linux/delay.h>
#include <linux/workqueue.h>
#include <linux/extcon-provider.h>

#define TUSB1210_VENDOR_SPECIFIC2 0x80
#define TUSB1210_VENDOR_SPECIFIC2_IHSTX_SHIFT 0
#define TUSB1210_VENDOR_SPECIFIC2_ZHSDRV_SHIFT 4
#define TUSB1210_VENDOR_SPECIFIC2_DP_SHIFT 6

/* Taken from https://www.ti.com/lit/ds/symlink/tusb1211.pdf */
#define TUSB1211_POWER_CONTROL 0x3d
#define TUSB1211_VENDOR_SPECIFIC3 0x85
#define TUSB1211_VENDOR_SPECIFIC3_SET 0x86
#define POWER_CONTROL_DET_COMP (1 << 1)
#define VENDOR_SPECIFIC3_SW_USB_DET (1 << 4)

struct tusb1210 {
struct ulpi *ulpi;
struct phy *phy;
struct gpio_desc *gpio_reset;
struct gpio_desc *gpio_cs;
u8 vendor_specific2;

enum phy_mode current_mode;

struct extcon_dev *edev;
struct notifier_block vbus_nb;
struct work_struct charger_work;
bool vbus_state;
int current_cable;
};

static int tusb1210_power_on(struct phy *phy)
{
struct tusb1210 *tusb = phy_get_drvdata(phy);
static const unsigned int tusb1211_extcon_cables[] = {
EXTCON_CHG_USB_SDP,
EXTCON_CHG_USB_DCP,
EXTCON_NONE,
};

gpiod_set_value_cansleep(tusb->gpio_reset, 1);
gpiod_set_value_cansleep(tusb->gpio_cs, 1);
static void tusb1210_setup(struct tusb1210 *tusb)
{
/* Wait a bit until initialization is complete */
msleep(30);

/* Restore the optional eye diagram optimization value */
if (tusb->vendor_specific2)
ulpi_write(tusb->ulpi, TUSB1210_VENDOR_SPECIFIC2,
tusb->vendor_specific2);
}

static int tusb1210_power_on(struct phy *phy)
{
struct tusb1210 *tusb = phy_get_drvdata(phy);

gpiod_set_value_cansleep(tusb->gpio_reset, 1);
gpiod_set_value_cansleep(tusb->gpio_cs, 1);

tusb1210_setup(tusb);
return 0;
}

Expand All @@ -50,6 +81,15 @@ static int tusb1210_power_off(struct phy *phy)
return 0;
}

static void tusb1210_reset(struct tusb1210 *tusb)
{
gpiod_set_value_cansleep(tusb->gpio_reset, 0);
usleep_range(200, 500);
gpiod_set_value_cansleep(tusb->gpio_reset, 1);

tusb1210_setup(tusb);
}

static int tusb1210_set_mode(struct phy *phy, enum phy_mode mode, int submode)
{
struct tusb1210 *tusb = phy_get_drvdata(phy);
Expand All @@ -59,6 +99,8 @@ static int tusb1210_set_mode(struct phy *phy, enum phy_mode mode, int submode)
if (ret < 0)
return ret;

tusb->current_mode = mode;

switch (mode) {
case PHY_MODE_USB_HOST:
ret |= (ULPI_OTG_CTRL_DRVVBUS_EXT
Expand All @@ -83,6 +125,124 @@ static int tusb1210_set_mode(struct phy *phy, enum phy_mode mode, int submode)
return ulpi_write(tusb->ulpi, ULPI_OTG_CTRL, ret);
}

static void tusb1211_update_charger_type(struct tusb1210 *tusb, int new_cable)
{
if (tusb->current_cable == new_cable)
return;

if (new_cable != EXTCON_NONE)
extcon_set_state_sync(tusb->edev, new_cable, true);
if (tusb->current_cable != EXTCON_NONE)
extcon_set_state_sync(tusb->edev, tusb->current_cable, false);

tusb->current_cable = new_cable;
}

static void tusb1211_detect_charger_type(struct tusb1210 *tusb)
{
int ret, new_cable;

/* Power on USB controller */
ret = pm_runtime_get_sync(tusb->ulpi->dev.parent);
if (ret < 0) {
dev_err(&tusb->phy->dev,
"Failed to power on USB controller for charger detection: %d\n",
ret);
return;
}

mutex_lock(&tusb->phy->mutex);

/* Enable charger detection */
ret = ulpi_write(tusb->ulpi, TUSB1211_VENDOR_SPECIFIC3_SET,
VENDOR_SPECIFIC3_SW_USB_DET);
if (ret) {
dev_err(&tusb->phy->dev,
"Failed to enable charger detection: %d\n", ret);
ret = 0; /* Detect as SDP */
goto err;
}

/*
* Allow the PHY to finish the charger detection
* TODO: Is there a way to check if charger detection is complete?
*/
msleep(500);

/* Read POWER_CONTROL register */
ret = ulpi_read(tusb->ulpi, TUSB1211_POWER_CONTROL);
if (ret < 0) {
dev_err(&tusb->phy->dev,
"Failed to read POWER_CONTROL register for charger detection: %d\n",
ret);
ret = 0; /* Detect as SDP */
}

err:
/*
* This is quite naive (e.g. doesn't handle CDP and ACA properly),
* but should do the job for now.
*/
if (ret & POWER_CONTROL_DET_COMP) {
/* Charging port detected => DCP */
dev_info(&tusb->phy->dev, "Detected charger type: DCP\n");
new_cable = EXTCON_CHG_USB_DCP;
} else {
/* No charging port detected => SDP */
dev_info(&tusb->phy->dev, "Detected charger type: SDP\n");
new_cable = EXTCON_CHG_USB_SDP;
}

/*
* Reset chip to disable charger detection
* For some reason we cannot clear the bit without causing the PHY
* to freeze...
*/
tusb1210_reset(tusb);

/* Restore mode */
tusb1210_set_mode(tusb->phy, tusb->current_mode, 0);

/* Update state on the Extcon device */
tusb1211_update_charger_type(tusb, new_cable);

mutex_unlock(&tusb->phy->mutex);

pm_runtime_put(tusb->ulpi->dev.parent);
}

static void tusb1211_no_charger(struct tusb1210 *tusb)
{
dev_info(&tusb->phy->dev, "Detected charger type: NONE\n");
tusb1211_update_charger_type(tusb, EXTCON_NONE);
}

static void tusb1211_update_charger_state(struct work_struct *work)
{
struct tusb1210 *tusb = container_of(work, struct tusb1210, charger_work);

if (tusb->vbus_state) {
tusb1211_detect_charger_type(tusb);
} else {
tusb1211_no_charger(tusb);
}
}

static inline void tusb1211_schedule_charger_check(
struct tusb1210 *tusb, bool state)
{
tusb->vbus_state = state;
schedule_work(&tusb->charger_work);
}

static int tusb1211_vbus_notifier(struct notifier_block *nb,
unsigned long event, void *ptr)
{
struct tusb1210 *tusb = container_of(nb, struct tusb1210, vbus_nb);
tusb1211_schedule_charger_check(tusb, event);
return NOTIFY_OK;
}

static const struct phy_ops phy_ops = {
.power_on = tusb1210_power_on,
.power_off = tusb1210_power_off,
Expand All @@ -93,11 +253,15 @@ static const struct phy_ops phy_ops = {
static int tusb1210_probe(struct ulpi *ulpi)
{
struct tusb1210 *tusb;
struct extcon_dev *vbus_edev;
int ret;
u8 val, reg;
const char *extcon_name;

tusb = devm_kzalloc(&ulpi->dev, sizeof(*tusb), GFP_KERNEL);
if (!tusb)
return -ENOMEM;
tusb->ulpi = ulpi;

tusb->gpio_reset = devm_gpiod_get_optional(&ulpi->dev, "reset",
GPIOD_OUT_LOW);
Expand Down Expand Up @@ -139,10 +303,56 @@ static int tusb1210_probe(struct ulpi *ulpi)
if (IS_ERR(tusb->phy))
return PTR_ERR(tusb->phy);

tusb->ulpi = ulpi;

phy_set_drvdata(tusb->phy, tusb);
ulpi_set_drvdata(ulpi, tusb);

/* Enable charger detection only for TUSB1211 */
if (ulpi->id.product != 0x1508)
return 0;

/* Charger detection depends on an Extcon devices for VBUS notifications */
if (device_property_read_string(&ulpi->dev,
"extcon-vbus-name", &extcon_name))
return 0;

/* Lookup Extcon device */
vbus_edev = extcon_get_extcon_dev(extcon_name);
if (!vbus_edev) {
dev_err(&tusb->phy->dev, "VBUS extcon device '%s' does not exist\n",
extcon_name);
return -ENODEV;
}
if (IS_ERR(vbus_edev))
return PTR_ERR(vbus_edev);

/* Setup new extcon device for results */
tusb->edev = devm_extcon_dev_allocate(&tusb->phy->dev,
tusb1211_extcon_cables);
if (IS_ERR(tusb->edev))
return PTR_ERR(tusb->edev);

ret = devm_extcon_dev_register(&tusb->phy->dev, tusb->edev);
if (ret) {
dev_err(&tusb->phy->dev,
"Error registering extcon device: %d\n", ret);
return ret;
}

INIT_WORK(&tusb->charger_work, tusb1211_update_charger_state);

/* Setup notifier */
tusb->vbus_nb.notifier_call = tusb1211_vbus_notifier;
ret = devm_extcon_register_notifier(&tusb->phy->dev, vbus_edev,
EXTCON_USB, &tusb->vbus_nb);
if (ret) {
dev_err(&tusb->phy->dev,
"Failed to register VBUS extcon notifier: %d\n", ret);
}

/* Detect initial state */
tusb1211_schedule_charger_check(tusb,
extcon_get_state(vbus_edev, EXTCON_USB));

return 0;
}

Expand Down

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