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Date: Wed, 18 Jan 2017 09:05:34 +0100
From: Benjamin Tissoires <benjamin.tissoires@...il.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: KT Liao <kt.liao@....com.tw>,
Andrew Duggan <aduggan@...aptics.com>,
Adrian Alves <aalves@...il.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
linux-input <linux-input@...r.kernel.org>
Subject: Re: [PATCH 08/10] Input: add a PS/2 to SMBus platform module
On Tue, Jan 10, 2017 at 5:11 PM, Benjamin Tissoires
<benjamin.tissoires@...hat.com> wrote:
> This driver is a glue between PS/2 devices that enumerate
> the RMI4 devices and Elan touchpads to the RMI4 (or Elan)
> SMBus driver.
>
> We use an intermediate platform device to not add a
> dependency between psmouse and I2C. It also handles
> the subtleties of going around the serio mutex lock by
> deferring the i2c creation/destruction in a separate
> thread.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
> ---
> drivers/input/misc/Kconfig | 11 ++
> drivers/input/misc/Makefile | 1 +
> drivers/input/misc/ps2_smbus.c | 255 +++++++++++++++++++++++++++++++++++++++++
> drivers/input/rmi4/Kconfig | 1 +
> 4 files changed, 268 insertions(+)
> create mode 100644 drivers/input/misc/ps2_smbus.c
>
> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> index 1ae4d96..e0dfefc 100644
> --- a/drivers/input/misc/Kconfig
> +++ b/drivers/input/misc/Kconfig
> @@ -832,4 +832,15 @@ config INPUT_HISI_POWERKEY
> To compile this driver as a module, choose M here: the
> module will be called hisi_powerkey.
>
> +config PS2_SMBUS
> + tristate "Platform Support for PS/2 Nodes also connected over SMBus"
> + depends on I2C
> + help
> + Say Y here if you want to support RMI4 or Elan devices connected to
> + an SMB bus but enumerated through PS/2.
> +
> + if unsure, say N.
> + To compile this driver as a module, choose M here: the module will be
> + called ps2_smbus.
> +
> endif
> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
> index 0b6d025..094a911 100644
> --- a/drivers/input/misc/Makefile
> +++ b/drivers/input/misc/Makefile
> @@ -57,6 +57,7 @@ obj-$(CONFIG_INPUT_PCSPKR) += pcspkr.o
> obj-$(CONFIG_INPUT_PM8941_PWRKEY) += pm8941-pwrkey.o
> obj-$(CONFIG_INPUT_PM8XXX_VIBRATOR) += pm8xxx-vibrator.o
> obj-$(CONFIG_INPUT_PMIC8XXX_PWRKEY) += pmic8xxx-pwrkey.o
> +obj-$(CONFIG_PS2_SMBUS) += ps2_smbus.o
> obj-$(CONFIG_INPUT_POWERMATE) += powermate.o
> obj-$(CONFIG_INPUT_PWM_BEEPER) += pwm-beeper.o
> obj-$(CONFIG_INPUT_RB532_BUTTON) += rb532_button.o
> diff --git a/drivers/input/misc/ps2_smbus.c b/drivers/input/misc/ps2_smbus.c
> new file mode 100644
> index 0000000..d1f27ed
> --- /dev/null
> +++ b/drivers/input/misc/ps2_smbus.c
> @@ -0,0 +1,255 @@
> +/*
> + * Copyright (c) 2017 Red Hat, Inc
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/platform_device.h>
> +#include <linux/rmi.h>
> +#include <linux/serio.h>
> +#include <linux/slab.h>
> +
> +MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@...hat.com>");
> +MODULE_DESCRIPTION("Platform PS/2 - SMBus bridge driver");
> +MODULE_LICENSE("GPL");
> +
> +static struct workqueue_struct *kps2smbus_wq;
> +DEFINE_MUTEX(ps2smbus_mutex);
> +
> +enum ps2smbus_type {
> + PS2SMBUS_SYNAPTICS_RMI4,
> +};
> +
> +struct ps2smbus {
> + struct i2c_client *smbus_client;
> + struct notifier_block i2c_notifier;
> + enum ps2smbus_type type;
> + void *pdata;
> +};
> +
> +enum ps2smbus_event_type {
> + PS2SMBUS_REGISTER_DEVICE,
> + PS2SMBUS_UNREGISTER_DEVICE,
> +};
> +
> +struct ps2smbus_work {
> + struct work_struct work;
> + enum ps2smbus_event_type type;
> + struct ps2smbus *ps2smbus;
> + struct i2c_adapter *adap;
> +};
> +
> +static void ps2smbus_create_rmi4(struct ps2smbus *ps2smbus,
> + struct i2c_adapter *adap)
> +{
> + const struct i2c_board_info i2c_info = {
> + I2C_BOARD_INFO("rmi4_smbus", 0x2c),
> + .platform_data = ps2smbus->pdata,
> + .flags = I2C_CLIENT_HOST_NOTIFY,
> + };
> +
> + ps2smbus->smbus_client = i2c_new_device(adap, &i2c_info);
> +}
> +
> +static void ps2smbus_worker(struct work_struct *work)
> +{
> + struct ps2smbus_work *ps2smbus_work;
> + struct i2c_client *client;
> +
> + ps2smbus_work = container_of(work, struct ps2smbus_work, work);
> + client = ps2smbus_work->ps2smbus->smbus_client;
> +
> + mutex_lock(&ps2smbus_mutex);
> +
> + switch (ps2smbus_work->type) {
> + case PS2SMBUS_REGISTER_DEVICE:
> + if (ps2smbus_work->ps2smbus->type == PS2SMBUS_SYNAPTICS_RMI4)
> + ps2smbus_create_rmi4(ps2smbus_work->ps2smbus,
> + ps2smbus_work->adap);
> + break;
> + case PS2SMBUS_UNREGISTER_DEVICE:
> + if (client)
> + i2c_unregister_device(client);
> + break;
> + }
> +
> + kfree(ps2smbus_work);
> +
> + mutex_unlock(&ps2smbus_mutex);
> +}
> +
> +static int ps2smbus_schedule_work(enum ps2smbus_event_type type,
> + struct ps2smbus *ps2smbus,
> + struct i2c_adapter *adap)
> +{
> + struct ps2smbus_work *ps2smbus_work;
> +
> + ps2smbus_work = kzalloc(sizeof(*ps2smbus_work), GFP_KERNEL);
> + if (!ps2smbus_work)
> + return -ENOMEM;
> +
> + ps2smbus_work->type = type;
> + ps2smbus_work->ps2smbus = ps2smbus;
> + ps2smbus_work->adap = adap;
> +
> + INIT_WORK(&ps2smbus_work->work, ps2smbus_worker);
> +
> + queue_work(kps2smbus_wq, &ps2smbus_work->work);
> +
> + return 0;
> +}
> +
> +static int ps2smbus_attach_i2c_device(struct device *dev, void *data)
> +{
> + struct ps2smbus *ps2smbus = data;
> + struct i2c_adapter *adap;
> +
> + if (dev->type != &i2c_adapter_type)
> + return 0;
> +
> + adap = to_i2c_adapter(dev);
> +
> + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
> + return 0;
> +
> + if (ps2smbus->smbus_client)
> + return 0;
> +
> + ps2smbus_schedule_work(PS2SMBUS_REGISTER_DEVICE, ps2smbus, adap);
> +
> + pr_debug("ps2smbus: adapter [%s] registered\n", adap->name);
> + return 0;
> +}
> +
> +static int ps2smbus_detach_i2c_device(struct device *dev,
> + struct ps2smbus *ps2smbus)
> +{
> + struct i2c_client *client;
> +
> + if (dev->type == &i2c_adapter_type)
> + return 0;
> +
> + mutex_lock(&ps2smbus_mutex);
> +
> + client = to_i2c_client(dev);
> + if (client == ps2smbus->smbus_client)
> + ps2smbus->smbus_client = NULL;
> +
> + mutex_unlock(&ps2smbus_mutex);
> +
> + pr_debug("ps2smbus: client [%s] unregistered\n", client->name);
> + return 0;
> +}
> +
> +static int ps2smbus_notifier_call(struct notifier_block *nb,
> + unsigned long action, void *data)
> +{
> + struct device *dev = data;
> + struct ps2smbus *ps2smbus;
> +
> + ps2smbus = container_of(nb, struct ps2smbus, i2c_notifier);
> +
> + switch (action) {
> + case BUS_NOTIFY_ADD_DEVICE:
> + return ps2smbus_attach_i2c_device(dev, ps2smbus);
> + case BUS_NOTIFY_DEL_DEVICE:
> + return ps2smbus_detach_i2c_device(dev, ps2smbus);
> + }
> +
> + return 0;
> +}
> +
> +static int ps2smbus_probe(struct platform_device *pdev)
> +{
> + struct rmi_device_platform_data *rmi_pdata = pdev->dev.platform_data;
> + struct serio *parent;
> + struct ps2smbus *ps2smbus;
> + int error;
> +
> + ps2smbus = devm_kzalloc(&pdev->dev, sizeof(struct ps2smbus),
> + GFP_KERNEL);
> + if (!ps2smbus)
> + return -ENOMEM;
> +
> + ps2smbus->i2c_notifier.notifier_call = ps2smbus_notifier_call;
> + ps2smbus->pdata = pdev->dev.platform_data;
> + ps2smbus->type = pdev->id_entry->driver_data;
> + if (pdev->dev.parent) {
> + parent = to_serio_port(pdev->dev.parent);
> + if (ps2smbus->type == PS2SMBUS_SYNAPTICS_RMI4)
> + rmi_pdata->parent = parent;
> + }
> +
> + /* Keep track of adapters which will be added or removed later */
> + error = bus_register_notifier(&i2c_bus_type, &ps2smbus->i2c_notifier);
> + if (error)
> + return error;
> +
> + /* Bind to already existing adapters right away */
> + i2c_for_each_dev(ps2smbus, ps2smbus_attach_i2c_device);
> +
> + platform_set_drvdata(pdev, ps2smbus);
> +
> + return 0;
> +}
> +
> +static int ps2smbus_remove(struct platform_device *pdev)
> +{
> + struct ps2smbus *ps2smbus = platform_get_drvdata(pdev);
> +
> + bus_unregister_notifier(&i2c_bus_type, &ps2smbus->i2c_notifier);
> +
> + if (ps2smbus->smbus_client)
> + ps2smbus_schedule_work(PS2SMBUS_UNREGISTER_DEVICE, ps2smbus,
> + NULL);
> +
> + platform_set_drvdata(pdev, NULL);
> +
> + return 0;
> +}
> +
> +static const struct platform_device_id ps2smbus_id_table[] = {
> + { .name = "rmi4", .driver_data = PS2SMBUS_SYNAPTICS_RMI4 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(platform, ps2smbus_id_table);
> +
> +static struct platform_driver ps2smbus_drv = {
> + .driver = {
> + .name = "ps2smbus",
> + },
> + .probe = ps2smbus_probe,
> + .remove = ps2smbus_remove,
> + .id_table = ps2smbus_id_table,
> +};
> +
> +static int __init ps2smbus_init(void)
> +{
> + int err;
> +
> + kps2smbus_wq = alloc_ordered_workqueue("kps2smbusd", WQ_MEM_RECLAIM);
> + if (!kps2smbus_wq) {
> + pr_err("failed to create kps2smbusd workqueue\n");
> + return -ENOMEM;
> + }
> +
> + err = platform_driver_register(&ps2smbus_drv);
> + if (err)
> + destroy_workqueue(kps2smbus_wq);
> +
> + return err;
> +}
> +
> +static void __exit ps2smbus_exit(void)
> +{
> + platform_driver_unregister(&ps2smbus_drv);
> + destroy_workqueue(kps2smbus_wq);
> +}
> +
> +module_init(ps2smbus_init);
> +module_exit(ps2smbus_exit);
> diff --git a/drivers/input/rmi4/Kconfig b/drivers/input/rmi4/Kconfig
> index 30cc627..eb74678 100644
> --- a/drivers/input/rmi4/Kconfig
> +++ b/drivers/input/rmi4/Kconfig
> @@ -30,6 +30,7 @@ config RMI4_SPI
> config RMI4_SMB
> tristate "RMI4 SMB Support"
> depends on RMI4_CORE && I2C
> + select RMI4_PLATFORM
I realized yesterday that it should be "select PS2_SMBUS" here :/
Other than that, any comments on the series?
Cheers,
Benjamin
> help
> Say Y here if you want to support RMI4 devices connected to an SMB
> bus.
> --
> 2.9.3
>
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