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Date: Wed, 4 Nov 2020 13:09:40 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Douglas Anderson <dianders@...omium.org>, jkosina@...e.cz,
benjamin.tissoires@...hat.com, gregkh@...uxfoundation.org,
Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: linux-input@...r.kernel.org, swboyd@...omium.org,
andrea@...gia.bo.it, kai.heng.feng@...onical.com,
robh+dt@...nel.org, Jiri Kosina <jikos@...nel.org>,
Masahiro Yamada <masahiroy@...nel.org>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 4/4] HID: i2c-hid: Introduce goodix-i2c-hid as a
subclass of i2c-hid
Hi,
On 11/4/20 2:29 AM, Douglas Anderson wrote:
> Goodix i2c-hid touchscreens are mostly i2c-hid compliant but have some
> special power sequencing requirements, including the need to drive a
> reset line during the sequencing.
>
> Let's use the new ability of i2c-hid to have subclasses for power
> sequencing to support the first Goodix i2c-hid touchscreen: GT7375P
>
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> ---
>
> Changes in v4:
> - Totally redid based on the new subclass system.
Again just my 2 cents, but I'm not sure if this should be an
entirely separate driver, or just something added to the
generic drivers/hid/i2c-hid/i2c-hid-of.c code.
I have no real preference either way, just asking the
question to make sure both options are considered.
Regards,
Hans
> Changes in v3:
> - Rework to use subclassing.
>
> drivers/hid/i2c-hid/Kconfig | 19 +++-
> drivers/hid/i2c-hid/Makefile | 1 +
> drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 120 ++++++++++++++++++++++++
> 3 files changed, 138 insertions(+), 2 deletions(-)
> create mode 100644 drivers/hid/i2c-hid/i2c-hid-of-goodix.c
>
> diff --git a/drivers/hid/i2c-hid/Kconfig b/drivers/hid/i2c-hid/Kconfig
> index 819b7521c182..a16c6a69680b 100644
> --- a/drivers/hid/i2c-hid/Kconfig
> +++ b/drivers/hid/i2c-hid/Kconfig
> @@ -32,10 +32,25 @@ config I2C_HID_OF
> will be called i2c-hid-of. It will also build/depend on the
> module i2c-hid.
>
> +config I2C_HID_OF_GOODIX
> + tristate "Driver for Goodix hid-i2c based devices on OF systems"
> + default n
> + depends on I2C && INPUT && OF
> + help
> + Say Y here if you want support for Goodix i2c devices that use
> + the i2c-hid protocol on Open Firmware (Device Tree)-based
> + systems.
> +
> + If unsure, say N.
> +
> + This support is also available as a module. If so, the module
> + will be called i2c-hid-of-goodix. It will also build/depend on
> + the module i2c-hid.
> +
> endmenu
>
> config I2C_HID_CORE
> tristate
> - default y if I2C_HID_ACPI=y || I2C_HID_OF=y
> - default m if I2C_HID_ACPI=m || I2C_HID_OF=m
> + default y if I2C_HID_ACPI=y || I2C_HID_OF=y || I2C_HID_OF_GOODIX=y
> + default m if I2C_HID_ACPI=m || I2C_HID_OF=m || I2C_HID_OF_GOODIX=m
> select HID
> diff --git a/drivers/hid/i2c-hid/Makefile b/drivers/hid/i2c-hid/Makefile
> index 9b4a73446841..302545a771f3 100644
> --- a/drivers/hid/i2c-hid/Makefile
> +++ b/drivers/hid/i2c-hid/Makefile
> @@ -10,3 +10,4 @@ i2c-hid-$(CONFIG_DMI) += i2c-hid-dmi-quirks.o
>
> obj-$(CONFIG_I2C_HID_ACPI) += i2c-hid-acpi.o
> obj-$(CONFIG_I2C_HID_OF) += i2c-hid-of.o
> +obj-$(CONFIG_I2C_HID_OF_GOODIX) += i2c-hid-of-goodix.o
> diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c
> new file mode 100644
> index 000000000000..7b27fd8b7401
> --- /dev/null
> +++ b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c
> @@ -0,0 +1,120 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for Goodix touchscreens that use the i2c-hid protocol.
> + *
> + * Copyright 2020 Google LLC
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/pm.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include "i2c-hid.h"
> +
> +struct goodix_i2c_hid_timing_data {
> + unsigned int post_gpio_reset_delay_ms;
> + unsigned int post_power_delay_ms;
> +};
> +
> +struct i2c_hid_of_goodix {
> + struct i2chid_subclass_data subclass;
> +
> + struct regulator *vdd;
> + struct gpio_desc *reset_gpio;
> + const struct goodix_i2c_hid_timing_data *timings;
> +};
> +
> +static int goodix_i2c_hid_power_up_device(struct i2chid_subclass_data *subclass)
> +{
> + struct i2c_hid_of_goodix *ihid_goodix =
> + container_of(subclass, struct i2c_hid_of_goodix, subclass);
> + int ret;
> +
> + ret = regulator_enable(ihid_goodix->vdd);
> + if (ret)
> + return ret;
> +
> + if (ihid_goodix->timings->post_power_delay_ms)
> + msleep(ihid_goodix->timings->post_power_delay_ms);
> +
> + gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 0);
> + if (ihid_goodix->timings->post_gpio_reset_delay_ms)
> + msleep(ihid_goodix->timings->post_gpio_reset_delay_ms);
> +
> + return 0;
> +}
> +
> +static void goodix_i2c_hid_power_down_device(struct i2chid_subclass_data *subclass)
> +{
> + struct i2c_hid_of_goodix *ihid_goodix =
> + container_of(subclass, struct i2c_hid_of_goodix, subclass);
> +
> + gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
> + regulator_disable(ihid_goodix->vdd);
> +}
> +
> +static int i2c_hid_of_goodix_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct i2c_hid_of_goodix *ihid_goodix;
> +
> + ihid_goodix = devm_kzalloc(&client->dev, sizeof(*ihid_goodix),
> + GFP_KERNEL);
> + if (!ihid_goodix)
> + return -ENOMEM;
> +
> + ihid_goodix->subclass.power_up_device = goodix_i2c_hid_power_up_device;
> + ihid_goodix->subclass.power_down_device = goodix_i2c_hid_power_down_device;
> +
> + /* Start out with reset asserted */
> + ihid_goodix->reset_gpio =
> + devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
> + if (IS_ERR(ihid_goodix->reset_gpio))
> + return PTR_ERR(ihid_goodix->reset_gpio);
> +
> + ihid_goodix->vdd = devm_regulator_get(&client->dev, "vdd");
> + if (IS_ERR(ihid_goodix->vdd))
> + return PTR_ERR(ihid_goodix->vdd);
> +
> + ihid_goodix->timings = device_get_match_data(&client->dev);
> +
> + return i2c_hid_core_probe(client, &ihid_goodix->subclass, 0x0001);
> +}
> +
> +static const struct goodix_i2c_hid_timing_data goodix_gt7375p_timing_data = {
> + .post_power_delay_ms = 10,
> + .post_gpio_reset_delay_ms = 120,
> +};
> +
> +static const struct of_device_id goodix_i2c_hid_of_match[] = {
> + { .compatible = "goodix,gt7375p", .data = &goodix_gt7375p_timing_data },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, goodix_i2c_hid_of_match);
> +
> +static const struct dev_pm_ops goodix_i2c_hid_pm = {
> + SET_SYSTEM_SLEEP_PM_OPS(i2c_hid_core_suspend, i2c_hid_core_resume)
> +};
> +
> +static struct i2c_driver goodix_i2c_hid_ts_driver = {
> + .driver = {
> + .name = "i2c_hid_of_goodix",
> + .pm = &goodix_i2c_hid_pm,
> + .probe_type = PROBE_PREFER_ASYNCHRONOUS,
> + .of_match_table = of_match_ptr(goodix_i2c_hid_of_match),
> + },
> + .probe = i2c_hid_of_goodix_probe,
> + .remove = i2c_hid_core_remove,
> + .shutdown = i2c_hid_core_shutdown,
> +};
> +module_i2c_driver(goodix_i2c_hid_ts_driver);
> +
> +MODULE_AUTHOR("Douglas Anderson <dianders@...omium.org>");
> +MODULE_DESCRIPTION("Goodix i2c-hid touchscreen driver");
> +MODULE_LICENSE("GPL v2");
>
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