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Message-ID: <CAH=2Ntz8JEGp_Atsv3iToUG1WdLKvdt5GYu7a=LwgmgY7v0rvw@mail.gmail.com>
Date: Wed, 12 Jul 2023 23:52:45 +0530
From: Bhupesh Sharma <bhupesh.sharma@...aro.org>
To: Souradeep Chowdhury <quic_schowdhu@...cinc.com>
Cc: linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
Andy Gross <agross@...nel.org>,
Konrad Dybcio <konrad.dybcio@...ainline.org>,
Bjorn Andersson <andersson@...nel.org>,
gregkh@...uxfoundation.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, Sibi Sankar <quic_sibis@...cinc.com>,
Rajendra Nayak <quic_rjendra@...cinc.com>
Subject: Re: [PATCH V1 2/3] usb: misc: Add notifier call chain to Embedded USB
Debug(EUD) driver
Hi Souradeep,
On Wed, 12 Jul 2023 at 13:58, Souradeep Chowdhury
<quic_schowdhu@...cinc.com> wrote:
>
> Add the notifier call chain to EUD driver. The notifier call chain
> is added to check the role-switch status of EUD. When multiple
> modules are switching roles on the same port, they need to call this
> notifier to check the role-switch status of EUD. If EUD is disabled,
> then the modules can go for the role-switch, otherwise it needs to
> be blocked. The notifier chain can be used to link multiple modules
> switching roles on the same port and create a ordering, priority and
> conflict resolution among them. The wrapper functions are defined here
> which can be used to register a notifier block to the chain, deregister
> it and also call the chain.
>
> Signed-off-by: Souradeep Chowdhury <quic_schowdhu@...cinc.com>
> ---
> drivers/usb/misc/qcom_eud.c | 52 +++++++++++++++++++++++++++++++++++--
> 1 file changed, 50 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
> index 7f371ea1248c..e6c97a2cf2df 100644
> --- a/drivers/usb/misc/qcom_eud.c
> +++ b/drivers/usb/misc/qcom_eud.c
> @@ -11,10 +11,13 @@
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_platform.h>
> #include <linux/platform_device.h>
> #include <linux/slab.h>
> #include <linux/sysfs.h>
> #include <linux/usb/role.h>
> +#include "qcom_eud_notifier.h"
>
> #define EUD_REG_INT1_EN_MASK 0x0024
> #define EUD_REG_INT_STATUS_1 0x0044
> @@ -22,14 +25,16 @@
> #define EUD_REG_VBUS_INT_CLR 0x0080
> #define EUD_REG_CSR_EUD_EN 0x1014
> #define EUD_REG_SW_ATTACH_DET 0x1018
> -#define EUD_REG_EUD_EN2 0x0000
> +#define EUD_REG_EUD_EN2 0x0000
>
> #define EUD_ENABLE BIT(0)
> -#define EUD_INT_PET_EUD BIT(0)
These indentation issues are already addressed in my EUD patches.
Please rebase your patches on the same to reuse those.
> +#define EUD_INT_PET_EUD BIT(0)
> #define EUD_INT_VBUS BIT(2)
> #define EUD_INT_SAFE_MODE BIT(4)
> #define EUD_INT_ALL (EUD_INT_VBUS | EUD_INT_SAFE_MODE)
>
> +static RAW_NOTIFIER_HEAD(eud_nh);
> +
> struct eud_chip {
> struct device *dev;
> struct usb_role_switch *role_sw;
> @@ -41,6 +46,42 @@ struct eud_chip {
> bool usb_attached;
> };
>
> +int eud_register_notify(struct notifier_block *nb)
> +{
> + return raw_notifier_chain_register(&eud_nh, nb);
> +}
> +EXPORT_SYMBOL_GPL(eud_register_notify);
> +
> +void eud_unregister_notify(struct notifier_block *nb)
> +{
> + raw_notifier_chain_unregister(&eud_nh, nb);
> +}
> +EXPORT_SYMBOL_GPL(eud_unregister_notify);
> +
> +void eud_notifier_call_chain(unsigned long role_switch_state)
> +{
> + raw_notifier_call_chain(&eud_nh, role_switch_state, NULL);
> +}
> +EXPORT_SYMBOL_GPL(eud_notifier_call_chain);
Probably I missed it, but you have not provided any example users of
these APIs in the patchset or reference to another one which shows how
these APIs are used.
> +static int eud_vbus_spoof_attach_detach(struct notifier_block *nb, unsigned long event,
> + void *data)
> +{
> + struct device_node *eud = of_find_compatible_node(NULL, NULL, "qcom,eud");
> + struct device *eud_device = bus_find_device_by_of_node(&platform_bus_type, eud);
> + struct eud_chip *eud_data = dev_get_drvdata(eud_device);
> +
> + if (eud_data->enabled && event != USB_ROLE_DEVICE)
> + return NOTIFY_BAD;
> + else
> + return NOTIFY_OK;
> +}
> +
> +static struct notifier_block eud_notifier = {
> + .notifier_call = eud_vbus_spoof_attach_detach,
> + .priority = 1,
Why do you need a 'priority = 1' here, it can be 0 or even lower?
Thanks,
Bhupesh
> +};
> +
> static int enable_eud(struct eud_chip *priv)
> {
> writel(EUD_ENABLE, priv->base + EUD_REG_CSR_EUD_EN);
> @@ -196,6 +237,10 @@ static int eud_probe(struct platform_device *pdev)
> return dev_err_probe(chip->dev, ret,
> "failed to add role switch release action\n");
>
> + ret = eud_register_notify(&eud_notifier);
> + if (ret)
> + return dev_err_probe(chip->dev, ret, "failed to register notifier\n");
> +
> chip->base = devm_platform_ioremap_resource(pdev, 0);
> if (IS_ERR(chip->base))
> return PTR_ERR(chip->base);
> @@ -226,6 +271,9 @@ static void eud_remove(struct platform_device *pdev)
>
> device_init_wakeup(&pdev->dev, false);
> disable_irq_wake(chip->irq);
> + eud_unregister_notify(&eud_notifier);
> +
> + return 0;
> }
>
> static const struct of_device_id eud_dt_match[] = {
> --
> 2.17.1
>
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