// SPDX-License-Identifier: GPL-2.0-only
/*
 * drivers/media/i2c/ccs/ccs-reg-access.c
 *
 * Generic driver for MIPI CCS/SMIA/SMIA++ compliant camera sensors
 *
 * Copyright (C) 2020 Intel Corporation
 * Copyright (C) 2011--2012 Nokia Corporation
 * Contact: Sakari Ailus <sakari.ailus@linux.intel.com>
 */

#include <linux/unaligned.h>

#include <linux/delay.h>
#include <linux/i2c.h>

#include "ccs.h"
#include "ccs-limits.h"

static u32 float_to_u32_mul_1000000(struct i2c_client *client, u32 phloat)
{
	s32 exp;
	u64 man;

	if (phloat >= 0x80000000) {
		dev_err(&client->dev, "this is a negative number\n");
		return 0;
	}

	if (phloat == 0x7f800000)
		return ~0; /* Inf. */

	if ((phloat & 0x7f800000) == 0x7f800000) {
		dev_err(&client->dev, "NaN or other special number\n");
		return 0;
	}

	/* Valid cases begin here */
	if (phloat == 0)
		return 0; /* Valid zero */

	if (phloat > 0x4f800000)
		return ~0; /* larger than 4294967295 */

	/*
	 * Unbias exponent (note how phloat is now guaranteed to
	 * have 0 in the high bit)
	 */
	exp = ((int32_t)phloat >> 23) - 127;

	/* Extract mantissa, add missing '1' bit and it's in MHz */
	man = ((phloat & 0x7fffff) | 0x800000) * 1000000ULL;

	if (exp < 0)
		man >>= -exp;
	else
		man <<= exp;

	man >>= 23; /* Remove mantissa bias */

	return man & 0xffffffff;
}


static u32 ireal32_to_u32_mul_1000000(struct i2c_client *client, u32 val)
{
	if (val >> 10 > U32_MAX / 15625) {
		dev_warn(&client->dev, "value %u overflows!\n", val);
		return U32_MAX;
	}

	return ((val >> 10) * 15625) +
		(val & GENMASK(9, 0)) * 15625 / 1024;
}

u32 ccs_reg_conv(struct ccs_sensor *sensor, u32 reg, u32 val)
{
	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);

	if (reg & CCS_FL_FLOAT_IREAL) {
		if (CCS_LIM(sensor, CLOCK_CAPA_TYPE_CAPABILITY) &
		    CCS_CLOCK_CAPA_TYPE_CAPABILITY_IREAL)
			val = ireal32_to_u32_mul_1000000(client, val);
		else
			val = float_to_u32_mul_1000000(client, val);
	} else if (reg & CCS_FL_IREAL) {
		val = ireal32_to_u32_mul_1000000(client, val);
	}

	return val;
}

/*
 * Read a 8/16/32-bit i2c register.  The value is returned in 'val'.
 * Returns zero if successful, or non-zero otherwise.
 */
static int __ccs_read_addr(struct ccs_sensor *sensor, u32 reg, u32 *val,
			   bool only8, bool conv)
{
	u64 __val;
	int rval;

	rval = cci_read(sensor->regmap, reg, &__val, NULL);
	if (rval < 0)
		return rval;

	*val = conv ? ccs_reg_conv(sensor, reg, __val) : __val;

	return 0;
}

static int __ccs_static_data_read_ro_reg(struct ccs_reg *regs, size_t num_regs,
					 u32 reg, u32 *val)
{
	unsigned int width = CCI_REG_WIDTH_BYTES(reg);
	size_t i;

	for (i = 0; i < num_regs; i++, regs++) {
		u8 *data;

		if (regs->addr + regs->len < CCS_REG_ADDR(reg) + width)
			continue;

		if (regs->addr > CCS_REG_ADDR(reg))
			break;

		data = &regs->value[CCS_REG_ADDR(reg) - regs->addr];

		switch (width) {
		case sizeof(u8):
			*val = *data;
			break;
		case sizeof(u16):
			*val = get_unaligned_be16(data);
			break;
		case sizeof(u32):
			*val = get_unaligned_be32(data);
			break;
		default:
			WARN_ON(1);
			return -EINVAL;
		}

		return 0;
	}

	return -ENOENT;
}

static int
ccs_static_data_read_ro_reg(struct ccs_sensor *sensor, u32 reg, u32 *val)
{
	if (!__ccs_static_data_read_ro_reg(sensor->sdata.sensor_read_only_regs,
					   sensor->sdata.num_sensor_read_only_regs,
					   reg, val))
		return 0;

	return __ccs_static_data_read_ro_reg(sensor->mdata.module_read_only_regs,
					     sensor->mdata.num_module_read_only_regs,
					     reg, val);
}

static int ccs_read_addr_raw(struct ccs_sensor *sensor, u32 reg, u32 *val,
			     bool force8, bool quirk, bool conv, bool data)
{
	int rval;

	if (data) {
		rval = ccs_static_data_read_ro_reg(sensor, reg, val);
		if (!rval)
			return 0;
	}

	if (quirk) {
		*val = 0;
		rval = ccs_call_quirk(sensor, reg_access, false, &reg, val);
		if (rval == -ENOIOCTLCMD)
			return 0;
		if (rval < 0)
			return rval;

		if (force8)
			return __ccs_read_addr(sensor, reg, val, true, conv);
	}

	return __ccs_read_addr(sensor, reg, val,
			       ccs_needs_quirk(sensor,
					       CCS_QUIRK_FLAG_8BIT_READ_ONLY),
			       conv);
}

int ccs_read_addr(struct ccs_sensor *sensor, u32 reg, u32 *val)
{
	return ccs_read_addr_raw(sensor, reg, val, false, true, true, true);
}

int ccs_read_addr_8only(struct ccs_sensor *sensor, u32 reg, u32 *val)
{
	return ccs_read_addr_raw(sensor, reg, val, true, true, true, true);
}

int ccs_read_addr_noconv(struct ccs_sensor *sensor, u32 reg, u32 *val)
{
	return ccs_read_addr_raw(sensor, reg, val, false, true, false, true);
}

/*
 * Write to a 8/16-bit register.
 * Returns zero if successful, or non-zero otherwise.
 */
int ccs_write_addr(struct ccs_sensor *sensor, u32 reg, u32 val)
{
	unsigned int retries = 10;
	int rval;

	rval = ccs_call_quirk(sensor, reg_access, true, &reg, &val);
	if (rval == -ENOIOCTLCMD)
		return 0;
	if (rval < 0)
		return rval;

	rval = 0;
	do {
		if (cci_write(sensor->regmap, reg, val, &rval))
			fsleep(1000);
	} while (rval && --retries);

	return rval;
}

#define MAX_WRITE_LEN	32U

int ccs_write_data_regs(struct ccs_sensor *sensor, struct ccs_reg *regs,
			size_t num_regs)
{
	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
	size_t i;

	for (i = 0; i < num_regs; i++, regs++) {
		unsigned char *regdata = regs->value;
		unsigned int j;
		int len;

		for (j = 0; j < regs->len; j += len, regdata += len) {
			char printbuf[(MAX_WRITE_LEN << 1) +
				      1 /* \0 */] = { 0 };
			unsigned int retries = 10;
			int rval;

			len = min(regs->len - j, MAX_WRITE_LEN);

			bin2hex(printbuf, regdata, len);
			dev_dbg(&client->dev,
				"writing msr reg 0x%4.4x value 0x%s\n",
				regs->addr + j, printbuf);

			do {
				rval = regmap_bulk_write(sensor->regmap,
							 regs->addr + j,
							 regdata, len);
				if (rval)
					fsleep(1000);
			} while (rval && --retries);

			if (rval) {
				dev_err(&client->dev,
					"error writing %u octets to address 0x%4.4x\n",
					len, regs->addr + j);
				return rval;
			}
		}
	}

	return 0;
}