Re: [PATCH v6 3/5] USB: ohci: da8xx: Allow a regulator to handle VBUS

From: David Lechner
Date: Tue Nov 22 2016 - 15:37:23 EST

On 11/21/2016 10:30 AM, Axel Haslam wrote:
Using a regulator to handle VBUS will eliminate the need for
platform data and callbacks, and make the driver more generic
allowing different types of regulators to handle VBUS.

The regulator equivalents to the platform callbacks are:
set_power -> regulator_enable/regulator_disable
get_power -> regulator_is_enabled
get_oci -> regulator_get_error_flags
ocic_notify -> regulator event notification

Signed-off-by: Axel Haslam <ahaslam@xxxxxxxxxxxx>
---
drivers/usb/host/ohci-da8xx.c | 97 +++++++++++++++++++++++++++++++++++++++++--
1 file changed, 94 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/ohci-da8xx.c b/drivers/usb/host/ohci-da8xx.c
index 90763ad..d0eb754 100644
--- a/drivers/usb/host/ohci-da8xx.c
+++ b/drivers/usb/host/ohci-da8xx.c
@@ -20,6 +20,7 @@
#include <linux/platform_device.h>
#include <linux/phy/phy.h>
#include <linux/platform_data/usb-davinci.h>
+#include <linux/regulator/consumer.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <asm/unaligned.h>
@@ -36,8 +37,12 @@ static int (*orig_ohci_hub_control)(struct usb_hcd *hcd, u16 typeReq,
static int (*orig_ohci_hub_status_data)(struct usb_hcd *hcd, char *buf);

struct da8xx_ohci_hcd {
+ struct usb_hcd *hcd;
struct clk *usb11_clk;
struct phy *usb11_phy;
+ struct regulator *vbus_reg;
+ struct notifier_block nb;
+ unsigned int reg_enabled;
};

#define to_da8xx_ohci(hcd) (struct da8xx_ohci_hcd *)(hcd_to_ohci(hcd)->priv)
@@ -83,56 +88,103 @@ static void ohci_da8xx_disable(struct usb_hcd *hcd)

static int ohci_da8xx_set_power(struct usb_hcd *hcd, int on)
{
+ struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
struct device *dev = hcd->self.controller;
struct da8xx_ohci_root_hub *hub = dev_get_platdata(dev);
+ int ret;

if (hub && hub->set_power)
return hub->set_power(1, on);

+ if (!da8xx_ohci->vbus_reg)
+ return 0;
+
+ if (on && !da8xx_ohci->reg_enabled) {
+ ret = regulator_enable(da8xx_ohci->vbus_reg);
+ if (ret) {
+ dev_err(dev, "Failed to enable regulator: %d\n", ret);
+ return ret;
+ }
+ da8xx_ohci->reg_enabled = 1;
+
+ } else if (!on && da8xx_ohci->reg_enabled) {
+ ret = regulator_disable(da8xx_ohci->vbus_reg);
+ if (ret) {
+ dev_err(dev, "Failed to disable regulator: %d\n", ret);
+ return ret;
+ }
+ da8xx_ohci->reg_enabled = 0;
+ }
+
return 0;
}

static int ohci_da8xx_get_power(struct usb_hcd *hcd)
{
+ struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
struct device *dev = hcd->self.controller;
struct da8xx_ohci_root_hub *hub = dev_get_platdata(dev);

if (hub && hub->get_power)
return hub->get_power(1);

+ if (da8xx_ohci->vbus_reg)
+ return regulator_is_enabled(da8xx_ohci->vbus_reg);
+
return 1;
}

static int ohci_da8xx_get_oci(struct usb_hcd *hcd)
{
+ struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
struct device *dev = hcd->self.controller;
struct da8xx_ohci_root_hub *hub = dev_get_platdata(dev);
+ unsigned int flags;
+ int ret;

if (hub && hub->get_oci)
return hub->get_oci(1);

+ if (!da8xx_ohci->vbus_reg)
+ return 0;
+
+ ret = regulator_get_error_flags(da8xx_ohci->vbus_reg, &flags);
+ if (ret)
+ return ret;
+
+ if (flags & REGULATOR_ERROR_OVER_CURRENT)
+ return 1;
+
return 0;
}

static int ohci_da8xx_has_set_power(struct usb_hcd *hcd)
{
+ struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
struct device *dev = hcd->self.controller;
struct da8xx_ohci_root_hub *hub = dev_get_platdata(dev);

if (hub && hub->set_power)
return 1;

+ if (da8xx_ohci->vbus_reg)
+ return 1;
+
return 0;
}

static int ohci_da8xx_has_oci(struct usb_hcd *hcd)
{
+ struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
struct device *dev = hcd->self.controller;
struct da8xx_ohci_root_hub *hub = dev_get_platdata(dev);

if (hub && hub->get_oci)
return 1;

+ if (da8xx_ohci->vbus_reg)
+ return 1;
+
return 0;
}

@@ -160,15 +212,41 @@ static void ohci_da8xx_ocic_handler(struct da8xx_ohci_root_hub *hub,
hub->set_power(port, 0);
}

+static int ohci_da8xx_regulator_event(struct notifier_block *nb,
+ unsigned long event, void *data)
+{
+ struct da8xx_ohci_hcd *da8xx_ohci =
+ container_of(nb, struct da8xx_ohci_hcd, nb);
+ struct device *dev = da8xx_ohci->hcd->self.controller;
+
+ if (event & REGULATOR_EVENT_OVER_CURRENT) {
+ dev_warn(dev, "over current event\n");
+ ocic_mask |= 1;

Following up from a v5 thread that is still applicable here, Axel said:

> I did a couple of tests, and i don't get those prints do you get them?.

The problem here is that ocic_mask |= 1; is wrong. It needs to be...

ocic_mask |= (1 << 1);

If you look at the other uses of ocic_mask, you will see why this it needs to be this way. Once you make this change, then you will see this in the kernel log:

usb 1-1: USB disconnect, device number 2
usb 1-1: may be reset is needed?..
ohci ohci: over current event
usb usb1-port1: over-current condition

So, we don't need the dev_warn() here.


More from Axel:

> What i understand is that they happen when we get a hub event that is
> reporting the over current. Which is what the root hub of the davinci system
> does not have, and why we use gpios instead).

Even though the hardware is not capable of detecting the overcurrent by itself, we are poking the registers in ohci_da8xx_hub_control(), so the core hub driver sees it just the same as if the hardware itself changed the register.


+ ohci_da8xx_set_power(da8xx_ohci->hcd, 0);
+ }
+
+ return 0;
+}
+
static int ohci_da8xx_register_notify(struct usb_hcd *hcd)
{
+ struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
struct device *dev = hcd->self.controller;
struct da8xx_ohci_root_hub *hub = dev_get_platdata(dev);
+ int ret = 0;
+
+ if (hub && hub->ocic_notify) {
+ ret = hub->ocic_notify(ohci_da8xx_ocic_handler);
+ } else if (da8xx_ohci->vbus_reg) {
+ da8xx_ohci->nb.notifier_call = ohci_da8xx_regulator_event;
+ ret = devm_regulator_register_notifier(da8xx_ohci->vbus_reg,
+ &da8xx_ohci->nb);
+ }

- if (hub && hub->ocic_notify)
- return hub->ocic_notify(ohci_da8xx_ocic_handler);
+ if (ret)
+ dev_err(dev, "Failed to register notifier: %d\n", ret);

- return 0;
+ return ret;
}

static void ohci_da8xx_unregister_notify(struct usb_hcd *hcd)
@@ -331,6 +409,7 @@ static int ohci_da8xx_probe(struct platform_device *pdev)
return -ENOMEM;

da8xx_ohci = to_da8xx_ohci(hcd);
+ da8xx_ohci->hcd = hcd;

da8xx_ohci->usb11_clk = devm_clk_get(&pdev->dev, "usb11");
if (IS_ERR(da8xx_ohci->usb11_clk)) {
@@ -348,6 +427,18 @@ static int ohci_da8xx_probe(struct platform_device *pdev)
goto err;
}

+ da8xx_ohci->vbus_reg = devm_regulator_get_optional(&pdev->dev, "vbus");
+ if (IS_ERR(da8xx_ohci->vbus_reg)) {
+ error = PTR_ERR(da8xx_ohci->vbus_reg);
+ if (error == -ENODEV) {
+ da8xx_ohci->vbus_reg = NULL;
+ } else {

It might be good to skip the dev_err() if we get -EPROBE_DEFER

+ dev_err(&pdev->dev,
+ "Failed to get regulator\n");
+ goto err;
+ }
+ }
+
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
hcd->regs = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(hcd->regs)) {