Re: [PATCH v11 3/3] Input: Add TouchNetix axiom i2c touchscreen driver

[Kamel BOUHARA <kamel.bouhara@bootlin.com>]

Le 2024-05-02 10:59, Kamel Bouhara a écrit :
> Le Fri, Apr 19, 2024 at 02:38:27PM +0200, Kamel Bouhara a écrit :
>> Add a new driver for the TouchNetix's axiom family of
>> touchscreen controllers. This driver only supports i2c
>> and can be later adapted for SPI and USB support.
>> 
> 
> Hello Dmitry,
> 
> I'm reaching out to follow up on my previous submission.
> 
> I understand you're likely busy, but I wanted to ensure that my series
> didn't get lost in the shuffle.
> 
> I've put significant effort into ensuring that each patch in the series
> aligns with the reviews and comments received.
> 
> If there are any concerns or additional changes needed before merging,
> please don't hesitate to let me know.
> 

Hello,

I haven't received any comments since v11. I'm just checking if there's 
any chance this series could be merged for v6.10?

> Greetings,
> Kamel
> 
>> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
>> ---
>>  MAINTAINERS                                  |   2 +
>>  drivers/input/touchscreen/Kconfig            |  12 +
>>  drivers/input/touchscreen/Makefile           |   1 +
>>  drivers/input/touchscreen/touchnetix_axiom.c | 657 
>> +++++++++++++++++++
>>  4 files changed, 672 insertions(+)
>>  create mode 100644 drivers/input/touchscreen/touchnetix_axiom.c
>> 
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index d8208dc23a98..6b9790414c55 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -22416,9 +22416,11 @@ F:	drivers/platform/x86/toshiba-wmi.c
>> 
>>  TOUCHNETIX AXIOM I2C TOUCHSCREEN DRIVER
>>  M:	Kamel Bouhara <kamel.bouhara@bootlin.com>
>> +M:	bsp-development.geo@leica-geosystems.com
>>  L:	linux-input@vger.kernel.org
>>  S:	Maintained
>>  
>> F:	Documentation/devicetree/bindings/input/touchscreen/touchnetix,ax54a.yaml
>> +F:	drivers/input/touchscreen/touchnetix_axiom.c
>> 
>>  TPM DEVICE DRIVER
>>  M:	Peter Huewe <peterhuewe@gmx.de>
>> diff --git a/drivers/input/touchscreen/Kconfig 
>> b/drivers/input/touchscreen/Kconfig
>> index c821fe3ee794..503ccea5c1b0 100644
>> --- a/drivers/input/touchscreen/Kconfig
>> +++ b/drivers/input/touchscreen/Kconfig
>> @@ -834,6 +834,18 @@ config TOUCHSCREEN_MIGOR
>>  	  To compile this driver as a module, choose M here: the
>>  	  module will be called migor_ts.
>> 
>> +config TOUCHSCREEN_TOUCHNETIX_AXIOM
>> +	tristate "TouchNetix AXIOM based touchscreen controllers"
>> +	depends on I2C
>> +	help
>> +	  Say Y here if you have a axiom touchscreen connected to
>> +	  your system.
>> +
>> +	  If unsure, say N.
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called axiom.
>> +
>>  config TOUCHSCREEN_TOUCHRIGHT
>>  	tristate "Touchright serial touchscreen"
>>  	select SERIO
>> diff --git a/drivers/input/touchscreen/Makefile 
>> b/drivers/input/touchscreen/Makefile
>> index a81cb5aa21a5..6ce7b804adc7 100644
>> --- a/drivers/input/touchscreen/Makefile
>> +++ b/drivers/input/touchscreen/Makefile
>> @@ -91,6 +91,7 @@ obj-$(CONFIG_TOUCHSCREEN_SUR40)		+= sur40.o
>>  obj-$(CONFIG_TOUCHSCREEN_SURFACE3_SPI)	+= surface3_spi.o
>>  obj-$(CONFIG_TOUCHSCREEN_TI_AM335X_TSC)	+= ti_am335x_tsc.o
>>  obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213)	+= touchit213.o
>> +obj-$(CONFIG_TOUCHSCREEN_TOUCHNETIX_AXIOM)	+= touchnetix_axiom.o
>>  obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT)	+= touchright.o
>>  obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN)	+= touchwin.o
>>  obj-$(CONFIG_TOUCHSCREEN_TS4800)	+= ts4800-ts.o
>> diff --git a/drivers/input/touchscreen/touchnetix_axiom.c 
>> b/drivers/input/touchscreen/touchnetix_axiom.c
>> new file mode 100644
>> index 000000000000..09550847392e
>> --- /dev/null
>> +++ b/drivers/input/touchscreen/touchnetix_axiom.c
>> @@ -0,0 +1,657 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * TouchNetix axiom Touchscreen Driver
>> + *
>> + * Copyright (C) 2020-2023 TouchNetix Ltd.
>> + *
>> + * Author(s): Bart Prescott <bartp@baasheep.co.uk>
>> + *            Pedro Torruella <pedro.torruella@touchnetix.com>
>> + *            Mark Satterthwaite <mark.satterthwaite@touchnetix.com>
>> + *            Hannah Rossiter <hannah.rossiter@touchnetix.com>
>> + *            Kamel Bouhara <kamel.bouhara@bootlin.com>
>> + *
>> + */
>> +#include <linux/bitfield.h>
>> +#include <linux/crc16.h>
>> +#include <linux/delay.h>
>> +#include <linux/device.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/i2c.h>
>> +#include <linux/input.h>
>> +#include <linux/input/mt.h>
>> +#include <linux/input/touchscreen.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/regmap.h>
>> +
>> +#include <asm/unaligned.h>
>> +#define AXIOM_PROX_LEVEL		-128
>> +#define AXIOM_DMA_OPS_DELAY_USEC	250
>> +#define AXIOM_STARTUP_TIME_MS		110
>> +/*
>> + * Register group u31 has 2 pages for usage table entries.
>> + */
>> +#define AXIOM_U31_MAX_USAGES		0xff
>> +#define AXIOM_U31_BYTES_PER_USAGE	6
>> +#define AXIOM_U31_PAGE0_LENGTH		0x0C
>> +#define AXIOM_U31_BOOTMODE_MASK		BIT(7)
>> +#define AXIOM_U31_DEVID_MASK		GENMASK(14, 0)
>> +
>> +#define AXIOM_MAX_REPORT_LEN		0x7f
>> +
>> +#define AXIOM_CMD_HEADER_READ_MASK	BIT(15)
>> +#define AXIOM_U41_MAX_TARGETS		10
>> +
>> +#define AXIOM_U46_AUX_CHANNELS		4
>> +#define AXIOM_U46_AUX_MASK		GENMASK(11, 0)
>> +
>> +#define AXIOM_COMMS_MAX_USAGE_PAGES	3
>> +#define AXIOM_COMMS_PAGE_SIZE		256
>> +#define AXIOM_COMMS_REPORT_LEN_MASK	GENMASK(6, 0)
>> +
>> +#define AXIOM_REPORT_USAGE_ID		0x34
>> +#define AXIOM_DEVINFO_USAGE_ID		0x31
>> +#define AXIOM_USAGE_2HB_REPORT_ID	0x01
>> +#define AXIOM_USAGE_2AUX_REPORT_ID	0x46
>> +#define AXIOM_USAGE_2DCTS_REPORT_ID	0x41
>> +
>> +#define AXIOM_PAGE_OFFSET_MASK		GENMASK(6, 0)
>> +
>> +struct axiom_devinfo {
>> +	__le16 device_id;
>> +	u8 fw_minor;
>> +	u8 fw_major;
>> +	u8 fw_info_extra;
>> +	u8 tcp_revision;
>> +	u8 bootloader_fw_minor;
>> +	u8 bootloader_fw_major;
>> +	__le16 jedec_id;
>> +	u8 num_usages;
>> +} __packed;
>> +
>> +/*
>> + * Describes parameters of a specific usage, essentially a single 
>> element of
>> + * the "Usage Table"
>> + */
>> +struct axiom_usage_entry {
>> +	u8 id;
>> +	u8 is_report;
>> +	u8 start_page;
>> +	u8 num_pages;
>> +};
>> +
>> +/*
>> + * Represents state of a touch or target when detected prior to a 
>> touch (eg.
>> + * hover or proximity events).
>> + */
>> +enum axiom_target_state {
>> +	AXIOM_TARGET_STATE_NOT_PRESENT = 0,
>> +	AXIOM_TARGET_STATE_PROX = 1,
>> +	AXIOM_TARGET_STATE_HOVER = 2,
>> +	AXIOM_TARGET_STATE_TOUCHING = 3,
>> +};
>> +
>> +struct axiom_u41_target {
>> +	enum axiom_target_state state;
>> +	u16 x;
>> +	u16 y;
>> +	s8 z;
>> +	bool insert;
>> +	bool touch;
>> +};
>> +
>> +struct axiom_target_report {
>> +	u8 index;
>> +	u8 present;
>> +	u16 x;
>> +	u16 y;
>> +	s8 z;
>> +};
>> +
>> +struct axiom_cmd_header {
>> +	__le16 target_address;
>> +	__le16 length;
>> +} __packed;
>> +
>> +struct axiom_data {
>> +	struct axiom_devinfo devinfo;
>> +	struct device *dev;
>> +	struct gpio_desc *reset_gpio;
>> +	struct i2c_client *client;
>> +	struct input_dev *input_dev;
>> +	u32 max_report_len;
>> +	u8 rx_buf[AXIOM_COMMS_MAX_USAGE_PAGES * AXIOM_COMMS_PAGE_SIZE];
>> +	struct axiom_u41_target targets[AXIOM_U41_MAX_TARGETS];
>> +	struct axiom_usage_entry usage_table[AXIOM_U31_MAX_USAGES];
>> +	bool usage_table_populated;
>> +	struct regmap *regmap;
>> +	struct touchscreen_properties	prop;
>> +};
>> +
>> +static const struct regmap_config axiom_i2c_regmap_config = {
>> +	.reg_bits = 32,
>> +	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
>> +	.val_bits = 8,
>> +	.val_format_endian = REGMAP_ENDIAN_LITTLE,
>> +};
>> +
>> +/*
>> + * axiom devices are typically configured to report touches at a rate
>> + * of 100Hz (10ms) for systems that require polling for reports.
>> + * When reports are polled, it will be expected to occasionally
>> + * observe the overflow bit being set in the reports.
>> + * This indicates that reports are not being read fast enough.
>> + */
>> +#define POLL_INTERVAL_DEFAULT_MS 10
>> +
>> +/* Translate usage/page/offset triplet into physical address. */
>> +static u16 axiom_usage_to_target_address(struct axiom_data *ts, u8 
>> usage, u8 page,
>> +					 char offset)
>> +{
>> +	/* At the moment the convention is that u31 is always at physical 
>> address 0x0 */
>> +	if (!ts->usage_table_populated) {
>> +		if (usage == AXIOM_DEVINFO_USAGE_ID)
>> +			return ((page << 8) + offset);
>> +		else
>> +			return 0xffff;
>> +	}
>> +
>> +	if (page >= ts->usage_table[usage].num_pages) {
>> +		dev_err(ts->dev, "Invalid usage table! usage: u%02x, page: %02x, 
>> offset: %02x\n",
>> +			usage, page, offset);
>> +		return 0xffff;
>> +	}
>> +
>> +	return ((ts->usage_table[usage].start_page + page) << 8) + offset;
>> +}
>> +
>> +static int axiom_read(struct axiom_data *ts, u8 usage, u8 page, void 
>> *buf, u16 len)
>> +{
>> +	struct axiom_cmd_header cmd_header;
>> +	u32 preamble;
>> +	int ret;
>> +
>> +	cmd_header.target_address = 
>> cpu_to_le16(axiom_usage_to_target_address(ts, usage, page, 0));
>> +	cmd_header.length = cpu_to_le16(len | AXIOM_CMD_HEADER_READ_MASK);
>> +
>> +	preamble = get_unaligned_le32(&cmd_header);
>> +
>> +	ret = regmap_write(ts->regmap, preamble, 0);
>> +	if (ret) {
>> +		dev_err(ts->dev, "failed to write preamble, error %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = regmap_raw_read(ts->regmap, 0, buf, len);
>> +	if (ret) {
>> +		dev_err(ts->dev, "failed to read target address %04x, error %d\n",
>> +			cmd_header.target_address, ret);
>> +		return ret;
>> +	}
>> +
>> +	/* Wait device's DMA operations */
>> +	usleep_range(AXIOM_DMA_OPS_DELAY_USEC, AXIOM_DMA_OPS_DELAY_USEC + 
>> 50);
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * One of the main purposes for reading the usage table is to 
>> identify
>> + * which usages reside at which target address.
>> + * When performing subsequent reads or writes to AXIOM, the target 
>> address
>> + * is used to specify which usage is being accessed.
>> + * Consider the following discovery code which will build up the 
>> usage table.
>> + */
>> +static u32 axiom_populate_usage_table(struct axiom_data *ts)
>> +{
>> +	struct axiom_usage_entry *usage_table;
>> +	u8 *rx_data = ts->rx_buf;
>> +	u32 max_report_len = 0;
>> +	u32 usage_id;
>> +	int error;
>> +
>> +	usage_table = ts->usage_table;
>> +
>> +	/* Read the second page of usage u31 to get the usage table */
>> +	error = axiom_read(ts, AXIOM_DEVINFO_USAGE_ID, 1, rx_data,
>> +			   (AXIOM_U31_BYTES_PER_USAGE * ts->devinfo.num_usages));
>> +
>> +	if (error)
>> +		return error;
>> +
>> +	for (usage_id = 0; usage_id < ts->devinfo.num_usages; usage_id++) {
>> +		u16 offset = (usage_id * AXIOM_U31_BYTES_PER_USAGE);
>> +		u8 id = rx_data[offset + 0];
>> +		u8 start_page = rx_data[offset + 1];
>> +		u8 num_pages = rx_data[offset + 2];
>> +		u32 max_offset = ((rx_data[offset + 3] & AXIOM_PAGE_OFFSET_MASK) + 
>> 1) * 2;
>> +
>> +		usage_table[id].is_report = !num_pages;
>> +
>> +		/* Store the entry into the usage table */
>> +		usage_table[id].id = id;
>> +		usage_table[id].start_page = start_page;
>> +		usage_table[id].num_pages = num_pages;
>> +
>> +		dev_dbg(ts->dev, "Usage u%02x Info: %*ph\n", id, 
>> AXIOM_U31_BYTES_PER_USAGE,
>> +			&rx_data[offset]);
>> +
>> +		/* Identify the max report length the module will receive */
>> +		if (usage_table[id].is_report && max_offset > max_report_len)
>> +			max_report_len = max_offset;
>> +	}
>> +
>> +	ts->usage_table_populated = true;
>> +
>> +	return max_report_len;
>> +}
>> +
>> +static int axiom_discover(struct axiom_data *ts)
>> +{
>> +	int error;
>> +
>> +	/*
>> +	 * Fetch the first page of usage u31 to get the
>> +	 * device information and the number of usages
>> +	 */
>> +	error = axiom_read(ts, AXIOM_DEVINFO_USAGE_ID, 0, &ts->devinfo, 
>> AXIOM_U31_PAGE0_LENGTH);
>> +	if (error)
>> +		return error;
>> +
>> +	dev_dbg(ts->dev, "  Boot Mode      : %s\n",
>> +		FIELD_GET(AXIOM_U31_BOOTMODE_MASK,
>> +			  le16_to_cpu(ts->devinfo.device_id)) ? "BLP" : "TCP");
>> +	dev_dbg(ts->dev, "  Device ID      : %04lx\n",
>> +		FIELD_GET(AXIOM_U31_DEVID_MASK, 
>> le16_to_cpu(ts->devinfo.device_id)));
>> +	dev_dbg(ts->dev, "  Firmware Rev   : %02x.%02x\n", 
>> ts->devinfo.fw_major,
>> +		ts->devinfo.fw_minor);
>> +	dev_dbg(ts->dev, "  Bootloader Rev : %02x.%02x\n", 
>> ts->devinfo.bootloader_fw_major,
>> +		ts->devinfo.bootloader_fw_minor);
>> +	dev_dbg(ts->dev, "  FW Extra Info  : %04x\n", 
>> ts->devinfo.fw_info_extra);
>> +	dev_dbg(ts->dev, "  Silicon        : %04x\n", 
>> le16_to_cpu(ts->devinfo.jedec_id));
>> +	dev_dbg(ts->dev, "  Number usages        : %04x\n", 
>> ts->devinfo.num_usages);
>> +
>> +	ts->max_report_len = axiom_populate_usage_table(ts);
>> +	if (!ts->max_report_len || !ts->devinfo.num_usages ||
>> +	    ts->max_report_len > AXIOM_MAX_REPORT_LEN) {
>> +		dev_err(ts->dev, "Invalid report length or usages number");
>> +		return -EINVAL;
>> +	}
>> +
>> +	dev_dbg(ts->dev, "Max Report Length: %u\n", ts->max_report_len);
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * Support function to axiom_process_u41_report.
>> + * Generates input-subsystem events for every target.
>> + * After calling this function the caller shall issue
>> + * a Sync to the input sub-system.
>> + */
>> +static bool axiom_process_u41_report_target(struct axiom_data *ts,
>> +					    struct axiom_target_report *target)
>> +{
>> +	struct input_dev *input_dev = ts->input_dev;
>> +	struct axiom_u41_target *target_prev_state;
>> +	enum axiom_target_state current_state;
>> +	int id;
>> +
>> +	/* Verify the target index */
>> +	if (target->index >= AXIOM_U41_MAX_TARGETS) {
>> +		dev_err(ts->dev, "Invalid target index! %u\n", target->index);
>> +		return false;
>> +	}
>> +
>> +	target_prev_state = &ts->targets[target->index];
>> +
>> +	current_state = AXIOM_TARGET_STATE_NOT_PRESENT;
>> +
>> +	if (target->present) {
>> +		if (target->z >= 0)
>> +			current_state = AXIOM_TARGET_STATE_TOUCHING;
>> +		else if (target->z > AXIOM_PROX_LEVEL && target->z < 0)
>> +			current_state = AXIOM_TARGET_STATE_HOVER;
>> +		else if (target->z == AXIOM_PROX_LEVEL)
>> +			current_state = AXIOM_TARGET_STATE_PROX;
>> +	}
>> +
>> +	if (target_prev_state->state == current_state &&
>> +	    target_prev_state->x == target->x &&
>> +	    target_prev_state->y == target->y &&
>> +	    target_prev_state->z == target->z)
>> +		return false;
>> +
>> +	id = target->index;
>> +
>> +	dev_dbg(ts->dev, "U41 Target T%u, present:%u, x:%u, y:%u, z:%d\n",
>> +		target->index, target->present,
>> +		target->x, target->y, target->z);
>> +
>> +	switch (current_state) {
>> +	case AXIOM_TARGET_STATE_NOT_PRESENT:
>> +	case AXIOM_TARGET_STATE_PROX:
>> +		if (!target_prev_state->insert)
>> +			break;
>> +		target_prev_state->insert = false;
>> +
>> +		if (!id)
>> +			input_report_key(input_dev, BTN_TOUCH, 0);
>> +
>> +		input_mt_report_slot_inactive(input_dev);
>> +		/*
>> +		 * make sure the previous coordinates are
>> +		 * all off screen when the finger comes back
>> +		 */
>> +		target->x = 65535;
>> +		target->y = 65535;
>> +		target->z = AXIOM_PROX_LEVEL;
>> +		break;
>> +	case AXIOM_TARGET_STATE_HOVER:
>> +	case AXIOM_TARGET_STATE_TOUCHING:
>> +		target_prev_state->insert = true;
>> +		input_report_abs(input_dev, ABS_MT_TRACKING_ID, id);
>> +		input_report_abs(input_dev, ABS_MT_POSITION_X, target->x);
>> +		input_report_abs(input_dev, ABS_MT_POSITION_Y, target->y);
>> +
>> +		if (current_state == AXIOM_TARGET_STATE_TOUCHING) {
>> +			input_report_abs(input_dev, ABS_MT_DISTANCE, 0);
>> +			input_report_abs(input_dev, ABS_DISTANCE, 0);
>> +			input_report_abs(input_dev, ABS_MT_PRESSURE, target->z);
>> +			input_report_abs(input_dev, ABS_PRESSURE, target->z);
>> +		} else {
>> +			input_report_abs(input_dev, ABS_MT_DISTANCE, -target->z);
>> +			input_report_abs(input_dev, ABS_DISTANCE, -target->z);
>> +			input_report_abs(input_dev, ABS_MT_PRESSURE, 0);
>> +			input_report_abs(input_dev, ABS_PRESSURE, 0);
>> +		}
>> +
>> +		if (!id)
>> +			input_report_key(input_dev, BTN_TOUCH, (current_state ==
>> +					 AXIOM_TARGET_STATE_TOUCHING));
>> +		break;
>> +	default:
>> +		break;
>> +	}
>> +
>> +	target_prev_state->state = current_state;
>> +	target_prev_state->x = target->x;
>> +	target_prev_state->y = target->y;
>> +	target_prev_state->z = target->z;
>> +
>> +	return true;
>> +}
>> +
>> +/*
>> + * U41 is the output report of the 2D CTS and contains the status of 
>> targets
>> + * (including contacts and pre-contacts) along with their X,Y,Z 
>> values.
>> + * When a target has been removed (no longer detected),
>> + * the corresponding X,Y,Z values will be zeroed.
>> + */
>> +static bool axiom_process_u41_report(struct axiom_data *ts, u8 
>> *rx_buf)
>> +{
>> +	struct axiom_target_report target;
>> +	bool update_done = false;
>> +	u16 target_status;
>> +	int i;
>> +
>> +	target_status = get_unaligned_le16(rx_buf + 1);
>> +
>> +	for (i = 0; i < AXIOM_U41_MAX_TARGETS; i++) {
>> +		u8 *target_step = &rx_buf[i * 4];
>> +
>> +		target.index = i;
>> +		input_mt_slot(ts->input_dev, i);
>> +		input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, true);
>> +		target.present = ((target_status & (1 << i)) != 0) ? 1 : 0;
>> +		target.x = get_unaligned_le16(target_step + 3);
>> +		target.y = get_unaligned_le16(target_step + 5);
>> +		target.z = (s8)(rx_buf[i + 43]);
>> +		touchscreen_report_pos(ts->input_dev, &ts->prop, target.x, 
>> target.y, true);
>> +		update_done |= axiom_process_u41_report_target(ts, &target);
>> +	}
>> +
>> +	return update_done;
>> +}
>> +
>> +/*
>> + * U46 report contains a low level measurement data generated by the 
>> capacitive
>> + * displacement sensor (CDS) algorithms from the auxiliary channels.
>> + * This information is useful when tuning multi-press to assess 
>> mechanical
>> + * consistency in the unit's construction.
>> + */
>> +static void axiom_process_u46_report(struct axiom_data *ts, u8 
>> *rx_buf)
>> +{
>> +	struct input_dev *input_dev = ts->input_dev;
>> +	u32 event_value;
>> +	u16 aux_value;
>> +	int i;
>> +
>> +	for (i = 0; i < AXIOM_U46_AUX_CHANNELS; i++) {
>> +		u8 *target_step = &rx_buf[i * 2];
>> +
>> +		input_mt_slot(input_dev, i);
>> +		input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, true);
>> +		aux_value = get_unaligned_le16(target_step + 1) & 
>> AXIOM_U46_AUX_MASK;
>> +		event_value = (i << 16) | (aux_value);
>> +		input_event(input_dev, EV_MSC, MSC_RAW, event_value);
>> +	}
>> +}
>> +
>> +/*
>> + * Validates the crc and demultiplexes the axiom reports to the 
>> appropriate
>> + * report handler
>> + */
>> +static int axiom_handle_events(struct axiom_data *ts)
>> +{
>> +	struct input_dev *input_dev = ts->input_dev;
>> +	u8 *report_data = ts->rx_buf;
>> +	struct device *dev = ts->dev;
>> +	u16 crc_report;
>> +	u8 *crc_bytes;
>> +	u16 crc_calc;
>> +	int error;
>> +	u8 len;
>> +
>> +	error = axiom_read(ts, AXIOM_REPORT_USAGE_ID, 0, report_data, 
>> ts->max_report_len);
>> +	if (error)
>> +		return error;
>> +
>> +	len = (report_data[0] & AXIOM_COMMS_REPORT_LEN_MASK) << 1;
>> +	if (len <= 2) {
>> +		dev_err(dev, "Zero length report discarded.\n");
>> +		return -ENODATA;
>> +	}
>> +
>> +	/* Validate the report CRC */
>> +	crc_bytes = &report_data[len];
>> +
>> +	crc_report = get_unaligned_le16(crc_bytes - 2);
>> +	/* Length is in 16 bit words and remove the size of the CRC16 itself 
>> */
>> +	crc_calc = crc16(0, report_data, (len - 2));
>> +
>> +	if (crc_calc != crc_report) {
>> +		dev_err(dev,
>> +			"CRC mismatch! Expected: %#x, Calculated CRC: %#x.\n",
>> +			crc_report, crc_calc);
>> +		return -EINVAL;
>> +	}
>> +
>> +	switch (report_data[1]) {
>> +	case AXIOM_USAGE_2DCTS_REPORT_ID:
>> +		if (axiom_process_u41_report(ts, &report_data[1])) {
>> +			input_mt_sync_frame(input_dev);
>> +			input_sync(input_dev);
>> +		}
>> +		break;
>> +
>> +	case AXIOM_USAGE_2AUX_REPORT_ID:
>> +		/* This is an aux report (force) */
>> +		axiom_process_u46_report(ts, &report_data[1]);
>> +		input_mt_sync(input_dev);
>> +		input_sync(input_dev);
>> +		break;
>> +
>> +	case AXIOM_USAGE_2HB_REPORT_ID:
>> +		/* This is a heartbeat report */
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static void axiom_i2c_poll(struct input_dev *input_dev)
>> +{
>> +	struct axiom_data *ts = input_get_drvdata(input_dev);
>> +
>> +	axiom_handle_events(ts);
>> +}
>> +
>> +static irqreturn_t axiom_irq(int irq, void *dev_id)
>> +{
>> +	struct axiom_data *ts = dev_id;
>> +
>> +	axiom_handle_events(ts);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static void axiom_reset(struct gpio_desc *reset_gpio)
>> +{
>> +	gpiod_set_value_cansleep(reset_gpio, 1);
>> +	usleep_range(1000, 2000);
>> +	gpiod_set_value_cansleep(reset_gpio, 0);
>> +	msleep(AXIOM_STARTUP_TIME_MS);
>> +}
>> +
>> +static int axiom_i2c_probe(struct i2c_client *client)
>> +{
>> +	struct device *dev = &client->dev;
>> +	struct input_dev *input_dev;
>> +	struct axiom_data *ts;
>> +	u32 poll_interval;
>> +	int target;
>> +	int error;
>> +
>> +	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
>> +	if (!ts)
>> +		return -ENOMEM;
>> +
>> +	i2c_set_clientdata(client, ts);
>> +	ts->client = client;
>> +	ts->dev = dev;
>> +
>> +	ts->regmap = devm_regmap_init_i2c(client, &axiom_i2c_regmap_config);
>> +	error = PTR_ERR_OR_ZERO(ts->regmap);
>> +	if (error) {
>> +		dev_err(dev, "Failed to initialize regmap: %d\n", error);
>> +		return error;
>> +	}
>> +
>> +	error = devm_regulator_get_enable(dev, "vddi");
>> +	if (error)
>> +		return dev_err_probe(&client->dev, error,
>> +				     "Failed to enable VDDI regulator\n");
>> +
>> +	error = devm_regulator_get_enable(dev, "vdda");
>> +	if (error)
>> +		return dev_err_probe(&client->dev, error,
>> +				     "Failed to enable VDDA regulator\n");
>> +
>> +	ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", 
>> GPIOD_OUT_HIGH);
>> +	if (IS_ERR(ts->reset_gpio))
>> +		return dev_err_probe(dev, PTR_ERR(ts->reset_gpio), "failed to get 
>> reset GPIO\n");
>> +
>> +	if (ts->reset_gpio)
>> +		axiom_reset(ts->reset_gpio);
>> +	else
>> +		msleep(AXIOM_STARTUP_TIME_MS);
>> +
>> +	error = axiom_discover(ts);
>> +	if (error)
>> +		return dev_err_probe(dev, error, "Failed touchscreen discover\n");
>> +
>> +	input_dev = devm_input_allocate_device(ts->dev);
>> +	if (!input_dev)
>> +		return -ENOMEM;
>> +
>> +	input_dev->name = "TouchNetix axiom Touchscreen";
>> +	input_dev->phys = "input/axiom_ts";
>> +
>> +	input_set_abs_params(input_dev, ABS_MT_POSITION_X, 0, 65535, 0, 0);
>> +	input_set_abs_params(input_dev, ABS_MT_POSITION_Y, 0, 65535, 0, 0);
>> +	input_set_abs_params(input_dev, ABS_MT_TOOL_TYPE, 0, MT_TOOL_MAX, 0, 
>> 0);
>> +	input_set_abs_params(input_dev, ABS_MT_DISTANCE, 0, 127, 0, 0);
>> +	input_set_abs_params(input_dev, ABS_MT_PRESSURE, 0, 127, 0, 0);
>> +
>> +	touchscreen_parse_properties(input_dev, true, &ts->prop);
>> +
>> +	/* Registers the axiom device as a touchscreen instead of a mouse 
>> pointer */
>> +	error = input_mt_init_slots(input_dev, AXIOM_U41_MAX_TARGETS, 
>> INPUT_MT_DIRECT);
>> +	if (error)
>> +		return error;
>> +
>> +	/* Enables the raw data for up to 4 force channels to be sent to the 
>> input subsystem */
>> +	set_bit(EV_REL, input_dev->evbit);
>> +	set_bit(EV_MSC, input_dev->evbit);
>> +	/* Declare that we support "RAW" Miscellaneous events */
>> +	set_bit(MSC_RAW, input_dev->mscbit);
>> +
>> +	ts->input_dev = input_dev;
>> +	input_set_drvdata(ts->input_dev, ts);
>> +
>> +	/* Ensure that all reports are initialised to not be present. */
>> +	for (target = 0; target < AXIOM_U41_MAX_TARGETS; target++)
>> +		ts->targets[target].state = AXIOM_TARGET_STATE_NOT_PRESENT;
>> +
>> +	error = devm_request_threaded_irq(dev, client->irq, NULL,
>> +					  axiom_irq, IRQF_ONESHOT, dev_name(dev), ts);
>> +	if (error) {
>> +		dev_info(dev, "Request irq failed, falling back to polling mode");
>> +
>> +		error = input_setup_polling(input_dev, axiom_i2c_poll);
>> +		if (error)
>> +			return dev_err_probe(ts->dev, error, "Unable to set up polling 
>> mode\n");
>> +
>> +		if (!device_property_read_u32(ts->dev, "poll-interval", 
>> &poll_interval))
>> +			input_set_poll_interval(input_dev, poll_interval);
>> +		else
>> +			input_set_poll_interval(input_dev, POLL_INTERVAL_DEFAULT_MS);
>> +	}
>> +
>> +	return input_register_device(input_dev);
>> +}
>> +
>> +static const struct i2c_device_id axiom_i2c_id_table[] = {
>> +	{ "ax54a" },
>> +	{ },
>> +};
>> +MODULE_DEVICE_TABLE(i2c, axiom_i2c_id_table);
>> +
>> +static const struct of_device_id axiom_i2c_of_match[] = {
>> +	{ .compatible = "touchnetix,ax54a", },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(of, axiom_i2c_of_match);
>> +
>> +static struct i2c_driver axiom_i2c_driver = {
>> +	.driver = {
>> +		   .name = "axiom",
>> +		   .of_match_table = axiom_i2c_of_match,
>> +	},
>> +	.id_table = axiom_i2c_id_table,
>> +	.probe = axiom_i2c_probe,
>> +};
>> +module_i2c_driver(axiom_i2c_driver);
>> +
>> +MODULE_AUTHOR("Bart Prescott <bartp@baasheep.co.uk>");
>> +MODULE_AUTHOR("Pedro Torruella <pedro.torruella@touchnetix.com>");
>> +MODULE_AUTHOR("Mark Satterthwaite 
>> <mark.satterthwaite@touchnetix.com>");
>> +MODULE_AUTHOR("Hannah Rossiter <hannah.rossiter@touchnetix.com>");
>> +MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
>> +MODULE_DESCRIPTION("TouchNetix axiom touchscreen I2C bus driver");
>> +MODULE_LICENSE("GPL");
>> --
>> 2.25.1
>> 
> 
> --
> Kamel Bouhara, Bootlin
> Embedded Linux and kernel engineering
> https://bootlin.com

-- 
--
Kamel Bouhara, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com