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Message-ID: <2b876ece-3b02-493e-ab1d-e5acc40c5d88@redhat.com>
Date: Sat, 1 Jun 2024 19:07:26 +0200
From: Hans de Goede <hdegoede@...hat.com>
To: joelselvaraj.oss@...il.com, Dmitry Torokhov <dmitry.torokhov@...il.com>,
Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: linux-input@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org
Subject: Re: [PATCH v4 3/3] Input: novatek-nvt-ts: add support for NT36672A
touchscreen
Hi Joel,
Thank you for the new version.
On 6/1/24 5:30 PM, Joel Selvaraj via B4 Relay wrote:
> From: Joel Selvaraj <joelselvaraj.oss@...il.com>
>
> Extend the novatek touchscreen driver to support NT36672A chip which
> is found in phones like qcom/sdm845-xiaomi-beryllium-tianma.dts.
> Added devicetree support for the driver and used i2c chip data to handle
> the variation in chip id and wake type. Also added vcc and iovcc
> regulators which are used to power the touchscreen hardware.
>
> Signed-off-by: Joel Selvaraj <joelselvaraj.oss@...il.com>
> ---
> drivers/input/touchscreen/novatek-nvt-ts.c | 70 +++++++++++++++++++++++++++---
> 1 file changed, 64 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/input/touchscreen/novatek-nvt-ts.c b/drivers/input/touchscreen/novatek-nvt-ts.c
> index 9bee3a0c122fb..c24c33f609eb8 100644
> --- a/drivers/input/touchscreen/novatek-nvt-ts.c
> +++ b/drivers/input/touchscreen/novatek-nvt-ts.c
> @@ -31,9 +31,6 @@
> #define NVT_TS_PARAMS_CHIP_ID 0x0e
> #define NVT_TS_PARAMS_SIZE 0x0f
>
> -#define NVT_TS_SUPPORTED_WAKE_TYPE 0x05
> -#define NVT_TS_SUPPORTED_CHIP_ID 0x05
> -
> #define NVT_TS_MAX_TOUCHES 10
> #define NVT_TS_MAX_SIZE 4096
>
> @@ -51,11 +48,18 @@ static const int nvt_ts_irq_type[4] = {
> IRQF_TRIGGER_HIGH
> };
>
> +struct nvt_ts_i2c_chip_data {
> + u8 wake_type;
> + u8 chip_id;
> +};
> +
> struct nvt_ts_data {
> struct i2c_client *client;
> struct input_dev *input;
> struct gpio_desc *reset_gpio;
> + struct regulator_bulk_data regulators[2];
> struct touchscreen_properties prop;
> + const struct nvt_ts_i2c_chip_data *chip;
Almost there. I have one remark which requires fixing below,
so since a v5 will be necessary anyways I also spotted another
small possible improvement:
Since you only use chip->wake_type and chip->chip_id
inside probe() you can make this chip pointer a local
variable in probe(). This saves having this stored
on the kernel heap even though it is never used again.
> int max_touches;
> u8 buf[NVT_TS_TOUCH_SIZE * NVT_TS_MAX_TOUCHES];
> };
> @@ -142,6 +146,13 @@ static irqreturn_t nvt_ts_irq(int irq, void *dev_id)
> static int nvt_ts_start(struct input_dev *dev)
> {
> struct nvt_ts_data *data = input_get_drvdata(dev);
> + int error;
> +
> + error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
> + if (error) {
> + dev_err(&data->client->dev, "failed to enable regulators\n");
> + return error;
> + }
>
> enable_irq(data->client->irq);
> gpiod_set_value_cansleep(data->reset_gpio, 0);
> @@ -155,6 +166,7 @@ static void nvt_ts_stop(struct input_dev *dev)
>
> disable_irq(data->client->irq);
> gpiod_set_value_cansleep(data->reset_gpio, 1);
> + regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
> }
>
> static int nvt_ts_suspend(struct device *dev)
> @@ -199,9 +211,31 @@ static int nvt_ts_probe(struct i2c_client *client)
> if (!data)
> return -ENOMEM;
>
> + data->chip = device_get_match_data(&client->dev);
> + if (!data->chip)
> + return -EINVAL;
> +
As mentioned above instead of data->chip you can use a local
"chip" variable here.
> data->client = client;
> i2c_set_clientdata(client, data);
>
> + /*
> + * VCC is the analog voltage supply
> + * IOVCC is the digital voltage supply
> + */
> + data->regulators[0].supply = "vcc";
> + data->regulators[1].supply = "iovcc";
> + error = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->regulators), data->regulators);
> + if (error) {
> + dev_err(dev, "cannot get regulators: %d\n", error);
> + return error;
> + }
> +
> + error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
> + if (error) {
> + dev_err(dev, "failed to enable regulators: %d\n", error);
> + return error;
> + }
> +
> data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> error = PTR_ERR_OR_ZERO(data->reset_gpio);
> if (error) {
Almost there. You need to disable the regulators when probe fails to
avoid an error from the regulator core about unbalanced enable/disable
of the regulators when the devm framework releases them.
So you need to add a regulator_bulk_disable() call in
the "if (error) {" branch here:
data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
error = PTR_ERR_OR_ZERO(data->reset_gpio);
if (error) {
regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
dev_err(dev, "failed to request reset GPIO: %d\n", error);
return error;
}
And ... (continued below)
> @@ -216,6 +250,11 @@ static int nvt_ts_probe(struct i2c_client *client)
> gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
> if (error)
> return error;
> + error = regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
I would not error check this, just like how it is not error checked
in void nvt_ts_stop() and then I would move it to above the error
checking for the nvt_ts_read_data(...NVT_TS_PARAMETERS...), to avoid
the need for an extra regulator_bulk_disable() call in the if (error)
path for the nvt_ts_read_data() call.
So make the code look like this:
error = nvt_ts_read_data(data->client, NVT_TS_PARAMETERS_START,
data->buf, NVT_TS_PARAMS_SIZE);
gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
if (error)
return error;
width = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_WIDTH]);
height = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_HEIGHT]);
...
This way you only need one extra regulator_bulk_disable() call for
error-exit paths in the case of devm_gpiod_get(dev, "reset", ...)
failing.
Regards,
Hans
> @@ -225,8 +264,8 @@ static int nvt_ts_probe(struct i2c_client *client)
> if (width > NVT_TS_MAX_SIZE || height >= NVT_TS_MAX_SIZE ||
> data->max_touches > NVT_TS_MAX_TOUCHES ||
> irq_type >= ARRAY_SIZE(nvt_ts_irq_type) ||
> - data->buf[NVT_TS_PARAMS_WAKE_TYPE] != NVT_TS_SUPPORTED_WAKE_TYPE ||
> - data->buf[NVT_TS_PARAMS_CHIP_ID] != NVT_TS_SUPPORTED_CHIP_ID) {
> + data->buf[NVT_TS_PARAMS_WAKE_TYPE] != data->chip->wake_type ||
> + data->buf[NVT_TS_PARAMS_CHIP_ID] != data->chip->chip_id) {
> dev_err(dev, "Unsupported touchscreen parameters: %*ph\n",
> NVT_TS_PARAMS_SIZE, data->buf);
> return -EIO;
> @@ -277,8 +316,26 @@ static int nvt_ts_probe(struct i2c_client *client)
> return 0;
> }
>
> +static const struct nvt_ts_i2c_chip_data nvt_nt11205_ts_data = {
> + .wake_type = 0x05,
> + .chip_id = 0x05,
> +};
> +
> +static const struct nvt_ts_i2c_chip_data nvt_nt36672a_ts_data = {
> + .wake_type = 0x01,
> + .chip_id = 0x08,
> +};
> +
> +static const struct of_device_id nvt_ts_of_match[] = {
> + { .compatible = "novatek,nt11205-ts", .data = &nvt_nt11205_ts_data },
> + { .compatible = "novatek,nt36672a-ts", .data = &nvt_nt36672a_ts_data },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, nvt_ts_of_match);
> +
> static const struct i2c_device_id nvt_ts_i2c_id[] = {
> - { "nt11205-ts" },
> + { "nt11205-ts", (unsigned long) &nvt_nt11205_ts_data },
> + { "nt36672a-ts", (unsigned long) &nvt_nt36672a_ts_data },
> { }
> };
> MODULE_DEVICE_TABLE(i2c, nvt_ts_i2c_id);
> @@ -287,6 +344,7 @@ static struct i2c_driver nvt_ts_driver = {
> .driver = {
> .name = "novatek-nvt-ts",
> .pm = pm_sleep_ptr(&nvt_ts_pm_ops),
> + .of_match_table = nvt_ts_of_match,
> },
> .probe = nvt_ts_probe,
> .id_table = nvt_ts_i2c_id,
>
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