// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2012-2025 Synaptics Incorporated
 */

#include <linux/bits.h>
#include <linux/dev_printk.h>
#include <linux/kernel.h>
#include <linux/rmi.h>
#include <linux/input.h>
#include <linux/slab.h>
#include "rmi_driver.h"

#define RMI_F21_SENSOR_COUNT_MASK	GENMASK(3, 0)
#define RMI_F21_FINGER_COUNT_PRESENT	BIT(5)
#define RMI_F21_NEW_REPORT_FORMAT	BIT(6)

#define RMI_F21_FINGER_COUNT_MASK	GENMASK(3, 0)

#define RMI_F21_MAX_SENSORS		16
#define RMI_F21_MAX_FINGERS		16
#define RMI_F21_DATA_REGS_MAX_SIZE	(RMI_F21_MAX_SENSORS * 2 + \
					 RMI_F21_MAX_FINGERS * 2 + 1)

#define RMI_F21_FORCE_CLICK_BIT		BIT(0)

#define RMI_F21_FORCEPAD_BUTTON_COUNT	1

struct f21_data {
	struct input_dev *input;
	u16 key_code;

	unsigned int attn_data_size;
	unsigned int attn_data_button_offset;

	unsigned int data_reg_size;
	unsigned int data_reg_button_offset;
	u8 data_regs[RMI_F21_DATA_REGS_MAX_SIZE];
};

static irqreturn_t rmi_f21_attention(int irq, void *ctx)
{
	struct rmi_function *fn = ctx;
	struct f21_data *f21 = dev_get_drvdata(&fn->dev);
	struct rmi_driver_data *drvdata = dev_get_drvdata(&fn->rmi_dev->dev);
	u8 *pdata;
	int error;
	bool pressed;

	if (drvdata->attn_data.data) {
		if (drvdata->attn_data.size < f21->attn_data_size) {
			dev_warn(&fn->dev, "f21 interrupt, but data is missing\n");
			return IRQ_HANDLED;
		}

		pdata = drvdata->attn_data.data + f21->attn_data_button_offset;

		drvdata->attn_data.data += f21->attn_data_size;
		drvdata->attn_data.size -= f21->attn_data_size;
	} else {
		error = rmi_read_block(fn->rmi_dev, fn->fd.data_base_addr,
				       f21->data_regs, f21->data_reg_size);
		if (error) {
			dev_err(&fn->dev, "failed to read f21 data registers: %d\n",
				error);
			return IRQ_RETVAL(error);
		}

		pdata = f21->data_regs + f21->data_reg_button_offset;
	}

	pressed = *pdata & RMI_F21_FORCE_CLICK_BIT;
	input_report_key(f21->input, f21->key_code, pressed);

	return IRQ_HANDLED;
}

static int rmi_f21_config(struct rmi_function *fn)
{
	struct rmi_driver *drv = fn->rmi_dev->driver;

	drv->set_irq_bits(fn->rmi_dev, fn->irq_mask);

	return 0;
}

static int rmi_f21_initialize(struct rmi_function *fn, struct f21_data *f21)
{
	struct input_dev *input = f21->input;

	f21->key_code = BTN_LEFT;

	input->keycode = &f21->key_code;
	input->keycodesize = sizeof(f21->key_code);
	input->keycodemax = RMI_F21_FORCEPAD_BUTTON_COUNT;

	input_set_capability(input, EV_KEY, f21->key_code);
	__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);

	return 0;
}

static int rmi_f21_probe(struct rmi_function *fn)
{
	struct rmi_device *rmi_dev = fn->rmi_dev;
	struct rmi_driver_data *drv_data = dev_get_drvdata(&rmi_dev->dev);
	struct f21_data *f21;
	unsigned int sensor_count;
	unsigned int max_fingers;
	unsigned int query15_offset;
	u8 query15_data;
	int error;

	if (!drv_data->input) {
		dev_info(&fn->dev, "f21: no input device found, ignoring\n");
		return -ENXIO;
	}

	f21 = devm_kzalloc(&fn->dev, sizeof(*f21), GFP_KERNEL);
	if (!f21)
		return -ENOMEM;

	f21->input = drv_data->input;

	error = rmi_f21_initialize(fn, f21);
	if (error)
		return error;

	dev_set_drvdata(&fn->dev, f21);

	sensor_count = fn->fd.query_base_addr & RMI_F21_SENSOR_COUNT_MASK;
	if (fn->fd.query_base_addr & RMI_F21_FINGER_COUNT_PRESENT) {
		query15_offset = fn->fd.query_base_addr & RMI_F21_NEW_REPORT_FORMAT ? 2 : 1;
		error = rmi_read_block(fn->rmi_dev,
				       fn->fd.query_base_addr + query15_offset,
				       &query15_data, sizeof(query15_data));
		if (error)
			return dev_err_probe(&fn->dev, error,
					     "failed to read 'query15' data");

		max_fingers = query15_data & RMI_F21_FINGER_COUNT_MASK;
	} else {
		max_fingers = 5;
	}

	if (fn->fd.query_base_addr & RMI_F21_NEW_REPORT_FORMAT) {
		/* Each finger uses one byte, and the button state uses one byte.*/
		f21->attn_data_size = max_fingers + 1;
		f21->attn_data_button_offset = f21->attn_data_size - 1;
		/*
		 * Each sensor uses two bytes, the button state uses one byte,
		 * and each finger uses two bytes.
		 */
		f21->data_reg_size = sensor_count * 2 + 1 + max_fingers * 2;
		f21->data_reg_button_offset = sensor_count * 2;
	} else {
		/*
		 * Regardless of the transport each finger uses two bytes,
		 * and the button state uses one byte.
		 */
		f21->attn_data_size = sensor_count * 2 + 1;
		f21->attn_data_button_offset = sensor_count * 2;

		f21->data_reg_size = f21->attn_data_size;
		f21->data_reg_button_offset = f21->attn_data_button_offset;
	}

	return 0;
}

struct rmi_function_handler rmi_f21_handler = {
	.driver = {
		.name = "rmi4_f21",
	},
	.func = 0x21,
	.probe = rmi_f21_probe,
	.config = rmi_f21_config,
	.attention = rmi_f21_attention,
};