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Message-ID: <20161201144126.GE1280@mail.corp.redhat.com>
Date: Thu, 1 Dec 2016 15:41:26 +0100
From: Benjamin Tissoires <benjamin.tissoires@...hat.com>
To: Brian Norris <briannorris@...omium.org>
Cc: Jiri Kosina <jikos@...nel.org>, Caesar Wang <wxt@...k-chips.com>,
linux-rockchip@...ts.infradead.org,
Rob Herring <robh+dt@...nel.org>, linux-input@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Mark Rutland <mark.rutland@....com>,
Doug Anderson <dianders@...omium.org>
Subject: Re: [PATCH v2 2/2] HID: i2c-hid: support Wacom digitizer + regulator
On Nov 30 2016 or thereabouts, Brian Norris wrote:
> We need to power on the digitizer before using it, and it's also nice to
> save power in suspend by disabling it. Support an optional "vdd-supply"
> and wire it up for the new Wacom device.
>
> Wacom recommended waiting up to 100ms after powering on before trying to
> access this device.
>
> Signed-off-by: Brian Norris <briannorris@...omium.org>
> Signed-off-by: Caesar Wang <wxt@...k-chips.com>
> Cc: Jiri Kosina <jikos@...nel.org>
> Cc: linux-input@...r.kernel.org
> ---
> v1 was a few months back. I finally got around to rewriting it based on
> DT binding feedback.
>
> v2:
> * support compatible property for wacom, with specific "vdd-supply" name
> * support the 100ms delay needed for this digitizer
> * target regulator support only at specific device
>
> Documentation/devicetree/bindings/input/hid-over-i2c.txt | 6 +++++-
> drivers/hid/i2c-hid/i2c-hid.c | 70 ++++++++++++++++++++++++++++++++++++++++++-
> include/linux/i2c/i2c-hid.h | 6 ++++
> 2 files changed, 75 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index b3ec4f2de875..1bc174f3a788 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -37,7 +37,9 @@
> #include <linux/mutex.h>
> #include <linux/acpi.h>
> #include <linux/of.h>
> +#include <linux/of_device.h>
> #include <linux/gpio/consumer.h>
> +#include <linux/regulator/consumer.h>
>
> #include <linux/i2c/i2c-hid.h>
>
> @@ -918,10 +920,25 @@ static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
> #endif
>
> #ifdef CONFIG_OF
> +
> +/* of_device_id match data */
> +struct i2c_hid_of_data {
> + /* Name of supply regulator. */
> + const char *supply_name;
> + /* Delay required after powering on device before it is usable. */
> + int init_delay_ms;
> +};
> +
> +static const struct i2c_hid_of_data wacom_w9013_data = {
Why is the struct "wacom" specific?
If the vdd line is required, I don't see why there is a need to specify
that this is a Wacom specifics. Then Elan, SYnaptics will want the same
and we won't be able to to follow.
> + .supply_name = "vdd",
> + .init_delay_ms = 100,
If the purpose of this declaration is to set the delay, why isn't this
something provided by the device tree?
> +};
> +
> static int i2c_hid_of_probe(struct i2c_client *client,
> struct i2c_hid_platform_data *pdata)
> {
> struct device *dev = &client->dev;
> + const struct i2c_hid_of_data *data = of_device_get_match_data(dev);
> u32 val;
> int ret;
>
> @@ -937,10 +954,33 @@ static int i2c_hid_of_probe(struct i2c_client *client,
> }
> pdata->hid_descriptor_address = val;
>
> + if (data) {
> + pdata->init_delay_ms = data->init_delay_ms;
> + if (data->supply_name) {
> + pdata->supply = devm_regulator_get_optional(&client->dev,
> + data->supply_name);
> + if (IS_ERR(pdata->supply)) {
> + ret = PTR_ERR(pdata->supply);
> + pdata->supply = NULL;
> + if (ret == -EPROBE_DEFER)
> + return ret;
> + if (ret == -ENODEV)
> + return 0;
> + dev_err(dev, "Failed to get %s regulator: %d\n",
> + data->supply_name, ret);
> + return ret;
> + }
> + }
> + }
> +
> return 0;
> }
>
> static const struct of_device_id i2c_hid_of_match[] = {
> + {
> + .compatible = "wacom,w9013",
> + .data = &wacom_w9013_data,
> + },
NACK, see 1/2
I don't really like the v2. IMO, v1 was less intrusive (though it was
missing the init_delay_ms).
I believe it's possible to have a generic device tree description which
doesn't require us to adapt the driver for each and every device.
Cheers,
Benjamin
> { .compatible = "hid-over-i2c" },
> {},
> };
> @@ -983,6 +1023,17 @@ static int i2c_hid_probe(struct i2c_client *client,
> ihid->pdata = *platform_data;
> }
>
> + if (ihid->pdata.supply) {
> + ret = regulator_enable(ihid->pdata.supply);
> + if (ret < 0) {
> + dev_err(&client->dev, "Failed to enable regulator: %d\n",
> + ret);
> + return ret;
> + }
> + if (ihid->pdata.init_delay_ms)
> + msleep(ihid->pdata.init_delay_ms);
> + }
> +
> if (client->irq > 0) {
> ihid->irq = client->irq;
> } else if (ACPI_COMPANION(&client->dev)) {
> @@ -1100,6 +1151,9 @@ static int i2c_hid_remove(struct i2c_client *client)
> if (ihid->desc)
> gpiod_put(ihid->desc);
>
> + if (ihid->pdata.supply)
> + regulator_disable(ihid->pdata.supply);
> +
> kfree(ihid);
>
> acpi_dev_remove_driver_gpios(ACPI_COMPANION(&client->dev));
> @@ -1152,6 +1206,11 @@ static int i2c_hid_suspend(struct device *dev)
> else
> hid_warn(hid, "Failed to enable irq wake: %d\n",
> wake_status);
> + } else if (ihid->pdata.supply) {
> + ret = regulator_disable(ihid->pdata.supply);
> + if (ret < 0)
> + hid_warn(hid, "Failed to disable supply: %d\n",
> + ret);
> }
>
> return 0;
> @@ -1165,7 +1224,16 @@ static int i2c_hid_resume(struct device *dev)
> struct hid_device *hid = ihid->hid;
> int wake_status;
>
> - if (device_may_wakeup(&client->dev) && ihid->irq_wake_enabled) {
> + if (!device_may_wakeup(&client->dev)) {
> + if (ihid->pdata.supply) {
> + ret = regulator_enable(ihid->pdata.supply);
> + if (ret < 0)
> + hid_warn(hid, "Failed to enable supply: %d\n",
> + ret);
> + if (ihid->pdata.init_delay_ms)
> + msleep(ihid->pdata.init_delay_ms);
> + }
> + } else if (ihid->irq_wake_enabled) {
> wake_status = disable_irq_wake(ihid->irq);
> if (!wake_status)
> ihid->irq_wake_enabled = false;
> diff --git a/include/linux/i2c/i2c-hid.h b/include/linux/i2c/i2c-hid.h
> index 7aa901d92058..97688cde4a91 100644
> --- a/include/linux/i2c/i2c-hid.h
> +++ b/include/linux/i2c/i2c-hid.h
> @@ -14,9 +14,13 @@
>
> #include <linux/types.h>
>
> +struct regulator;
> +
> /**
> * struct i2chid_platform_data - used by hid over i2c implementation.
> * @hid_descriptor_address: i2c register where the HID descriptor is stored.
> + * @supply: regulator for powering on the device.
> + * @init_delay_ms: delay after powering on before device is usable.
> *
> * Note that it is the responsibility of the platform driver (or the acpi 5.0
> * driver, or the flattened device tree) to setup the irq related to the gpio in
> @@ -31,6 +35,8 @@
> */
> struct i2c_hid_platform_data {
> u16 hid_descriptor_address;
> + struct regulator *supply;
> + int init_delay_ms;
> };
>
> #endif /* __LINUX_I2C_HID_H */
> --
> 2.8.0.rc3.226.g39d4020
>
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