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Date: Thu, 12 May 2016 12:16:13 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Benjamin Tissoires <benjamin.tissoires@...hat.com>
Cc: Bastien Nocera <hadess@...ess.net>, linux-input@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Input - ntrig_spi: add new driver for the Surface 3
Hi Benjamin,
On Thu, May 12, 2016 at 05:07:54PM +0200, Benjamin Tissoires wrote:
> This is a basic driver for the Surface 3. I am not so sure it will work
> with any firmwares as most values are encoded, but given that I only have
> access to my current device with its firmware and I don't have the
> datasheet, it should be OK for now.
>
> The Surface Pen is not supported (if it is supposed to be). I'll work on
> this when I get one.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
> ---
> drivers/input/touchscreen/Kconfig | 11 ++
> drivers/input/touchscreen/Makefile | 1 +
> drivers/input/touchscreen/ntrig_spi.c | 339 ++++++++++++++++++++++++++++++++++
> 3 files changed, 351 insertions(+)
> create mode 100644 drivers/input/touchscreen/ntrig_spi.c
>
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 8ecdc38..22296a4 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -561,6 +561,17 @@ config TOUCHSCREEN_MK712
> To compile this driver as a module, choose M here: the
> module will be called mk712.
>
> +config TOUCHSCREEN_NTRIG_SPI
> + tristate "Ntrig/Microsoft SPI touchscreen"
> + help
> + Say Y here if you have the Ntrig/Microsoft SPI touchscreen
> + controller chip as found on the Surface 3 in your system.
> +
> + If unsure, say N.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called ntrig_spi.
> +
> config TOUCHSCREEN_HP600
> tristate "HP Jornada 6xx touchscreen"
> depends on SH_HP6XX && SH_ADC
> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> index f42975e..8e04ad1 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -54,6 +54,7 @@ obj-$(CONFIG_TOUCHSCREEN_MIGOR) += migor_ts.o
> obj-$(CONFIG_TOUCHSCREEN_MMS114) += mms114.o
> obj-$(CONFIG_TOUCHSCREEN_MTOUCH) += mtouch.o
> obj-$(CONFIG_TOUCHSCREEN_MK712) += mk712.o
> +obj-$(CONFIG_TOUCHSCREEN_NTRIG_SPI) += ntrig_spi.o
> obj-$(CONFIG_TOUCHSCREEN_HP600) += hp680_ts_input.o
> obj-$(CONFIG_TOUCHSCREEN_HP7XX) += jornada720_ts.o
> obj-$(CONFIG_TOUCHSCREEN_IPAQ_MICRO) += ipaq-micro-ts.o
> diff --git a/drivers/input/touchscreen/ntrig_spi.c b/drivers/input/touchscreen/ntrig_spi.c
> new file mode 100644
> index 0000000..0d61fc0
> --- /dev/null
> +++ b/drivers/input/touchscreen/ntrig_spi.c
> @@ -0,0 +1,339 @@
> +/*
> + * Driver for Ntrig/Microsoft Touchscreens over SPI
> + *
> + * Copyright (c) 2016 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 as published by the Free
> + * Software Foundation; version 2 of the License.
> + */
> +
> +#include <linux/kernel.h>
> +
> +#include <asm/unaligned.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/input.h>
> +#include <linux/input/mt.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/spi/spi.h>
> +#include <linux/acpi.h>
> +
> +#define NTRIG_PACKET_SIZE 264
> +
> +struct ntrig {
> + struct spi_device *spi;
> + struct gpio_desc *gpiod_int;
> + struct gpio_desc *gpiod_rst[2];
> + struct input_dev *input_dev;
> +};
> +
> +struct ntrig_finger {
> + u8 status;
> + u16 tracking_id;
Can we annotate it with __leXX/__beXX as needed to make sure we do not
accidentally use the structure directly.
> + u16 x;
> + u16 cx;
> + u16 y;
> + u16 cy;
> + u16 width;
> + u16 height;
> + u32 padding;
> +} __packed;
> +
> +static ssize_t ntrig_spi_read(struct spi_device *spi, char *rxbuf, size_t len)
> +{
> + struct spi_message msg;
> + struct spi_transfer xfer;
> + u8 rd_buf[NTRIG_PACKET_SIZE];
> + int err = 0;
> +
> + if (!spi)
> + return 0;
How?
> +
> + memset(&xfer, 0, sizeof(xfer));
> + memset(rd_buf, 0, sizeof(rd_buf));
> + spi_message_init(&msg);
> +
> + xfer.tx_buf = NULL;
> + xfer.len = len;
> + xfer.rx_buf = rd_buf;
SPI (like USB) required buffers to be DMA-able, so they can not be on
stack. Either allocate with kmalloc or put as __cacheline__aligned in
ntrig structure.
> + spi_message_add_tail(&xfer, &msg);
> +
> + err = spi_sync(spi, &msg);
> + memcpy(rxbuf, rd_buf, xfer.len);
BTW, why exactly we use local buffer? And why not simply use spi_read()?
> +
> + return err;
> +}
> +
> +static void ntrig_spi_report_touch(struct ntrig *ntr,
> + struct ntrig_finger *finger)
> +{
> + int st = finger->status & 0x01;
> + int id = get_unaligned_le16(&finger->tracking_id);
> + int x = get_unaligned_le16(&finger->x);
> + int y = get_unaligned_le16(&finger->y);
> + int w = get_unaligned_le16(&finger->width);
> + int h = get_unaligned_le16(&finger->height);
> + int slot;
> +
> + slot = input_mt_get_slot_by_key(ntr->input_dev, id);
> + if (slot < 0)
> + return;
> +
> + input_mt_slot(ntr->input_dev, slot);
> + input_mt_report_slot_state(ntr->input_dev, MT_TOOL_FINGER, st);
> + if (st) {
Maybe do the le->cpu conversions only when we have active touch?
> + input_report_abs(ntr->input_dev, ABS_MT_POSITION_X, x);
> + input_report_abs(ntr->input_dev, ABS_MT_POSITION_Y, y);
> + input_report_abs(ntr->input_dev, ABS_MT_TOUCH_MAJOR, w);
> + input_report_abs(ntr->input_dev, ABS_MT_WIDTH_MAJOR, w);
> + input_report_abs(ntr->input_dev, ABS_MT_TOUCH_MINOR, h);
> + input_report_abs(ntr->input_dev, ABS_MT_WIDTH_MINOR, h);
Do we need to report WIDTH if it is same as TOUCH? BTW, you do not seem
to declare TOUCH in input devoice capabilities.
> + }
> +}
> +
> +static int ntrig_spi_process(struct ntrig *ntr, const char *data)
> +{
> + const char header[] = {0xff, 0xff, 0xff, 0xff, 0xa5, 0x5a, 0xe7, 0x7e,
> + 0x01, 0xd2, 0x00, 0x80, 0x01, 0x03, 0x03};
> + u16 timestamp;
> + unsigned int i;
> +
> + if (memcmp(header, data, sizeof(header)))
> + dev_err(&ntr->spi->dev, "%s header error: %15ph, ignoring... %s:%d\n",
Use %*ph and then (int)sizeof(header) ?
> + __func__, data, __FILE__, __LINE__);
Do we really need FILE/LINE?
> +
> + timestamp = get_unaligned_le16(&data[15]);
> +
> + for (i = 0; i < 13; i++) {
> + struct ntrig_finger *finger;
> +
> + finger = (struct ntrig_finger *)&data[17 +
> + i * sizeof(struct ntrig_finger)];
> +
> + if (finger->status & 0x10)
> + break;
Comment why we are breaking out?
> +
> + ntrig_spi_report_touch(ntr, finger);
> + }
> +
> + input_mt_sync_frame(ntr->input_dev);
> + input_sync(ntr->input_dev);
> + return 0;
> +}
> +
> +static irqreturn_t ntrig_spi_irq_handler(int irq, void *dev_id)
> +{
> + struct ntrig *data = dev_id;
> + char spiRxbuf[NTRIG_PACKET_SIZE];
> +
> + while (gpiod_get_value(data->gpiod_int)) {
What if interrupt line is not described as GPIO?
> + memset(spiRxbuf, 0x00, NTRIG_PACKET_SIZE);
No camel casing (or local buffers either).
> + ntrig_spi_read(data->spi, spiRxbuf, NTRIG_PACKET_SIZE);
Handle failures?
> + dev_dbg(&data->spi->dev, "%s received -> %*ph %s:%d\n",
> + __func__, NTRIG_PACKET_SIZE, spiRxbuf,
> + __FILE__, __LINE__);
> + ntrig_spi_process(data, spiRxbuf);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static void ntrig_spi_power(struct ntrig *data, unsigned int value)
"bool on"?
> +{
> + gpiod_set_value(data->gpiod_rst[0], value);
> + gpiod_set_value(data->gpiod_rst[1], value);
Does it require any timing considerations?
> +}
> +
> +/**
> + * ntrig_spi_get_gpio_config - Get GPIO config from ACPI/DT
> + *
> + * @ts: ntrig_spi_ts_data pointer
> + */
> +static int ntrig_spi_get_gpio_config(struct ntrig *data)
> +{
> + int error;
> + struct device *dev;
> + struct gpio_desc *gpiod;
> + int i;
> +
> + if (!data->spi)
> + return -EINVAL;
How?
> +
> + dev = &data->spi->dev;
> +
> + /* Get the interrupt GPIO pin number */
> + gpiod = devm_gpiod_get_index(dev, NULL, 2, GPIOD_IN);
> + if (IS_ERR(gpiod)) {
> + error = PTR_ERR(gpiod);
> + if (error != -EPROBE_DEFER)
> + dev_err(dev, "Failed to get int GPIO: %d\n", error);
> + return error;
> + }
Can this made optional?
> +
> + data->gpiod_int = gpiod;
> +
> + /* Get the reset lines GPIO pin number */
> + for (i = 0; i < 2; i++) {
> + gpiod = devm_gpiod_get_index(dev, NULL, i, GPIOD_OUT_LOW);
> + if (IS_ERR(gpiod)) {
> + error = PTR_ERR(gpiod);
> + if (error != -EPROBE_DEFER)
> + dev_err(dev,
> + "Failed to get power GPIO %d: %d\n",
> + i,
> + error);
> + return error;
> + }
> +
> + data->gpiod_rst[i] = gpiod;
> + }
> +
> + return 0;
> +}
> +
> +static int ntrig_spi_create_input(struct ntrig *data)
> +{
> + struct input_dev *input;
> + int error;
> +
> + input = devm_input_allocate_device(&data->spi->dev);
> + if (IS_ERR(input))
> + return PTR_ERR(input);
devm_input_allocate_device does not return ERR_PTR-encoded pointers.
> +
> + data->input_dev = input;
> +
> + input_set_abs_params(input, ABS_MT_POSITION_X, 0, 9600, 0, 0);
> + input_abs_set_res(input, ABS_MT_POSITION_X, 40);
> + input_set_abs_params(input, ABS_MT_POSITION_Y, 0, 7200, 0, 0);
> + input_abs_set_res(input, ABS_MT_POSITION_Y, 48);
> + input_set_abs_params(input, ABS_MT_WIDTH_MAJOR, 0, 1024, 0, 0);
> + input_set_abs_params(input, ABS_MT_WIDTH_MINOR, 0, 1024, 0, 0);
> + input_mt_init_slots(input, 10, INPUT_MT_DIRECT);
> +
> + input->name = "Ntrig Capacitive TouchScreen";
> + input->phys = "input/ts";
> + input->id.bustype = BUS_SPI;
> + input->id.vendor = 0x1b96;
> + input->id.product = 0x0000;
> + input->id.version = 0x0000;
> +
> + error = input_register_device(input);
> + if (error) {
> + dev_err(&data->spi->dev,
> + "Failed to register input device: %d", error);
> + return error;
> + }
> +
> + return 0;
> +}
> +
> +static void ntrig_spi_free_irq(struct ntrig *data)
> +{
> + devm_free_irq(&data->spi->dev, data->spi->irq, data);
> +}
> +
> +static int ntrig_spi_request_irq(struct ntrig *data)
> +{
> + struct spi_device *spi = data->spi;
> +
> + return devm_request_threaded_irq(&spi->dev, spi->irq,
> + NULL, ntrig_spi_irq_handler,
> + IRQ_TYPE_EDGE_RISING | IRQF_ONESHOT,
> + "Ntrig-irq", data);
> +}
> +
> +static int ntrig_spi_probe(struct spi_device *spi)
> +{
> + struct ntrig *data = NULL;
Why do you initialize this?
> + int error;
> +
> + /* Set up SPI*/
> + spi->bits_per_word = 8;
> + spi->mode = SPI_MODE_0;
> + error = spi_setup(spi);
> + if (error)
> + return error;
> +
> + data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
Error handling?
> +
> + data->spi = spi;
> + spi_set_drvdata(spi, data);
> +
> + error = ntrig_spi_get_gpio_config(data);
> + if (error)
> + return error;
> +
> + ntrig_spi_power(data, 1);
> + msleep(20);
> + ntrig_spi_power(data, 0);
> + msleep(20);
> + ntrig_spi_power(data, 1);
> +
> + error = ntrig_spi_create_input(data);
> + if (error)
> + return error;
> +
> + error = ntrig_spi_request_irq(data);
> + if (error)
> + return error;
> +
> + return PTR_ERR_OR_ZERO(data);
Why on earth???
> +}
> +
> +static int __maybe_unused ntrig_spi_suspend(struct device *dev)
> +{
> + struct spi_device *spi = to_spi_device(dev);
> + struct ntrig *data = spi_get_drvdata(spi);
> +
> + ntrig_spi_free_irq(data);
Why?
> +
> + ntrig_spi_power(data, 0);
false?
> +
> + return 0;
> +}
> +
> +static int __maybe_unused ntrig_spi_resume(struct device *dev)
> +{
> + struct spi_device *spi = to_spi_device(dev);
> + struct ntrig *data = spi_get_drvdata(spi);
> + int error;
> +
> + ntrig_spi_power(data, 1);
true?
> +
> + error = ntrig_spi_request_irq(data);
> + if (error)
> + return error;
Again, why?
> +
> + return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(ntrig_spi_pm_ops, ntrig_spi_suspend, ntrig_spi_resume);
> +
> +#ifdef CONFIG_ACPI
> +static const struct acpi_device_id ntrig_spi_acpi_match[] = {
> + { "MSHW0037", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(acpi, ntrig_spi_acpi_match);
> +#endif
> +
> +static struct spi_driver ntrig_spi_driver = {
> + .driver = {
> + .name = "Ntrig-spi",
> + .acpi_match_table = ACPI_PTR(ntrig_spi_acpi_match),
> + .pm = &ntrig_spi_pm_ops,
> + },
> + .probe = ntrig_spi_probe,
> +};
> +
> +module_spi_driver(ntrig_spi_driver);
> +
> +MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@...il.com>");
> +MODULE_DESCRIPTION("Ntrig SPI touchscreen driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.5.0
>
--
Dmitry
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