On 03/02/2020 19:35, Bjorn Andersson wrote:
On Thu 30 Jan 20:43 PST 2020, Avaneesh Kumar Dwivedi wrote:
Hi Avaneesh.
Please aim for keeping the sort order in this file (ignore QCOM_APR
which obviously is in the wrong place)
+ tristate "QTI Embedded USB Debugger (EUD)"
+ depends on ARCH_QCOM
If we persist with the model of EXTCON you should "select EXTCON" here.
+ help
+ The Embedded USB Debugger (EUD) driver is a driver for the
+ control peripheral which waits on events like USB attach/detach
+ and charger enable/disable. The control peripheral further helps
+ support the USB-based debug and trace capabilities.
+ This module enables support for Qualcomm Technologies, Inc.
+ Embedded USB Debugger (EUD).
Suggest.
This module enables support for Qualcomm Technologies, Inc.
Embedded USB Debugger (EUD).
The EUD is a control peripheral which reports VBUS attach/detach,
charger enable/disable and USB-based debug and trace capabilities.
+ * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
2020
+
+static int enable_eud(struct eud_chip *priv)
+{
+ int ret;
+
+ /* write into CSR to enable EUD */
+ writel_relaxed(BIT(0), priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
+ /* Enable vbus, chgr & safe mode warning interrupts */
+ writel_relaxed(EUD_INT_VBUS | EUD_INT_CHGR | EUD_INT_SAFE_MODE,
+ priv->eud_reg_base + EUD_REG_INT1_EN_MASK);
+
+ /* Ensure Register Writes Complete */
So... You are writing a register in an on-chip PMIC. The PMIC is
responsible for detecting USB ID and supplying VBUS as appropriate.
You then get an interrupt to inform you of the state ?
+static ssize_t enable_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct eud_chip *chip = dev_get_drvdata(dev);
+ int enable = 0;
You shouldn't need to initialize this as you're checking the return
value of sscanf().
+ int ret = 0;
+
+ if (sscanf(buf, "%du", &enable) != 1)
+ return -EINVAL;
+
+ if (enable == EUD_ENABLE_CMD)
+ ret = enable_eud(chip);
If ret is !0 you should probably return that, rather than count...
+ else if (enable == EUD_DISABLE_CMD)
+ disable_eud(chip);
+ if (!ret)
...and then you don't need this check, or initialize ret to 0 above.
+ chip->enable = enable;
So if I write 42 to "enable" nothing will change in the hardware, but
chip->enable will be 42...
+ return count;
+}
I was just going to comment on usb_connector but, does the above code
need a synchronization primitive to serialize with the worker and
interrupt handler ?
+static int msm_eud_probe(struct platform_device *pdev)
+{
+ struct eud_chip *chip;
+ struct resource *res;
+ int ret;
+
+ chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->dev = &pdev->dev;
+ platform_set_drvdata(pdev, chip);
+
+ chip->extcon = devm_extcon_dev_allocate(&pdev->dev, eud_extcon_cable);
Aren't we moving away from extcon in favor of the usb role switching
thing?
Yes.
For the VBUS notification you could use
usb-role-switch and model the USB connector as a child-node of the
dual-role controller.
See:
https://patchwork.kernel.org/cover/11346247/
https://patchwork.kernel.org/patch/11346295/
https://patchwork.kernel.org/patch/11346263/
Avaneesh do you have any kernel code that cares about the charger state ?
What we are suggesting here is dropping extcon and using role-switching
but, if you have some other code that cares about EXTCON_CHG_USB_SDP
you'd have to do additional work.
But, if I understood the implication of the code above where you write
to the PMIC and let it handle VBUS/CHARGER on/off and you are just
notified of the state change, you should be fine with usb-role-switching.
---
bod
