/*
 * Functions to access the TSC2000 controller on TRAB board (used for scanning
 * thermo sensors)
 *
 * Copyright (C) 2003 Martin Krause, TQ-Systems GmbH, martin.krause@tqs.de
 *
 * Copyright (C) 2002 DENX Software Engineering, Wolfgang Denk, wd@denx.de
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <asm/arch/s3c24x0_cpu.h>
#include <asm/io.h>
#include <div64.h>
#include "tsc2000.h"

#include "Pt1000_temp_data.h"

/* helper function */
#define abs(value) (((value) < 0) ? ((value)*-1) : (value))

/*
 * Maximal allowed deviation between two immediate meassurments of an analog
 * thermo channel. 1 DIGIT = 0.0276 °C. This is used to filter sporadic
 * "jumps" in measurment.
 */
#define MAX_DEVIATION   18      /* unit: DIGITs of adc; 18 DIGIT = 0.5 °C */

void tsc2000_spi_init(void)
{
        struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();
        struct s3c24x0_spi * const spi = s3c24x0_get_base_spi();
        int i;

        /* Configure I/O ports. */
        gpio->pdcon = (gpio->pdcon & 0xF3FFFF) | 0x040000;
        gpio->pgcon = (gpio->pgcon & 0x0F3FFF) | 0x008000;
        gpio->pgcon = (gpio->pgcon & 0x0CFFFF) | 0x020000;
        gpio->pgcon = (gpio->pgcon & 0x03FFFF) | 0x080000;

        CLR_CS_TOUCH();

        spi->ch[0].sppre = 0x1F; /* Baud-rate ca. 514kHz */
        spi->ch[0].sppin = 0x01; /* SPI-MOSI holds Level after last bit */
        spi->ch[0].spcon = 0x1A; /* Polling, Prescaler, Master, CPOL=0,
                                    CPHA=1 */

        /* Dummy byte ensures clock to be low. */
        for (i = 0; i < 10; i++) {
                spi->ch[0].sptdat = 0xFF;
        }
        spi_wait_transmit_done();
}


void spi_wait_transmit_done(void)
{
        struct s3c24x0_spi * const spi = s3c24x0_get_base_spi();

        while (!(spi->ch[0].spsta & 0x01)) /* wait until transfer is done */
                ;
}


void tsc2000_write(unsigned short reg, unsigned short data)
{
        struct s3c24x0_spi * const spi = s3c24x0_get_base_spi();
        unsigned int command;

        SET_CS_TOUCH();
        command = reg;
        spi->ch[0].sptdat = (command & 0xFF00) >> 8;
        spi_wait_transmit_done();
        spi->ch[0].sptdat = (command & 0x00FF);
        spi_wait_transmit_done();
        spi->ch[0].sptdat = (data & 0xFF00) >> 8;
        spi_wait_transmit_done();
        spi->ch[0].sptdat = (data & 0x00FF);
        spi_wait_transmit_done();

        CLR_CS_TOUCH();
}


unsigned short tsc2000_read (unsigned short reg)
{
        unsigned short command, data;
        struct s3c24x0_spi * const spi = s3c24x0_get_base_spi();

        SET_CS_TOUCH();
        command = 0x8000 | reg;

        spi->ch[0].sptdat = (command & 0xFF00) >> 8;
        spi_wait_transmit_done();
        spi->ch[0].sptdat = (command & 0x00FF);
        spi_wait_transmit_done();

        spi->ch[0].sptdat = 0xFF;
        spi_wait_transmit_done();
        data = spi->ch[0].sprdat;
        spi->ch[0].sptdat = 0xFF;
        spi_wait_transmit_done();

        CLR_CS_TOUCH();
        return (spi->ch[0].sprdat & 0x0FF) | (data << 8);
}


void tsc2000_set_mux (unsigned int channel)
{
        struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();

        CLR_MUX1_ENABLE; CLR_MUX2_ENABLE;
        CLR_MUX3_ENABLE; CLR_MUX4_ENABLE;
        switch (channel) {
        case 0:
                CLR_MUX0; CLR_MUX1;
                SET_MUX1_ENABLE;
                break;
        case 1:
                SET_MUX0; CLR_MUX1;
                SET_MUX1_ENABLE;
                break;
        case 2:
                CLR_MUX0; SET_MUX1;
                SET_MUX1_ENABLE;
                break;
        case 3:
                SET_MUX0; SET_MUX1;
                SET_MUX1_ENABLE;
                break;
        case 4:
                CLR_MUX0; CLR_MUX1;
                SET_MUX2_ENABLE;
                break;
        case 5:
                SET_MUX0; CLR_MUX1;
                SET_MUX2_ENABLE;
                break;
        case 6:
                CLR_MUX0; SET_MUX1;
                SET_MUX2_ENABLE;
                break;
        case 7:
                SET_MUX0; SET_MUX1;
                SET_MUX2_ENABLE;
                break;
        case 8:
                CLR_MUX0; CLR_MUX1;
                SET_MUX3_ENABLE;
                break;
        case 9:
                SET_MUX0; CLR_MUX1;
                SET_MUX3_ENABLE;
                break;
        case 10:
                CLR_MUX0; SET_MUX1;
                SET_MUX3_ENABLE;
                break;
        case 11:
                SET_MUX0; SET_MUX1;
                SET_MUX3_ENABLE;
                break;
        case 12:
                CLR_MUX0; CLR_MUX1;
                SET_MUX4_ENABLE;
                break;
        case 13:
                SET_MUX0; CLR_MUX1;
                SET_MUX4_ENABLE;
                break;
        case 14:
                CLR_MUX0; SET_MUX1;
                SET_MUX4_ENABLE;
                break;
        case 15:
                SET_MUX0; SET_MUX1;
                SET_MUX4_ENABLE;
                break;
        default:
                CLR_MUX0; CLR_MUX1;
        }
}


void tsc2000_set_range (unsigned int range)
{
        struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();

        switch (range) {
        case 1:
                CLR_SEL_TEMP_V_0; SET_SEL_TEMP_V_1;
                CLR_SEL_TEMP_V_2; CLR_SEL_TEMP_V_3;
                break;
        case 2:
                CLR_SEL_TEMP_V_0; CLR_SEL_TEMP_V_1;
                CLR_SEL_TEMP_V_2; SET_SEL_TEMP_V_3;
                break;
        case 3:
                SET_SEL_TEMP_V_0; CLR_SEL_TEMP_V_1;
                SET_SEL_TEMP_V_2; CLR_SEL_TEMP_V_3;
                break;
        }
}


u16 tsc2000_read_channel (unsigned int channel)
{
        u16 res;

        tsc2000_set_mux(channel);
        udelay(20 * TSC2000_DELAY_BASE);

        tsc2000_write(TSC2000_REG_ADC, 0x2036);
        adc_wait_conversion_done ();
        res = tsc2000_read(TSC2000_REG_AUX1);
        return res;
}


s32 tsc2000_contact_temp (void)
{
        long adc_pt1000, offset;
        long u_pt1000;
        long contact_temp;
        long temp1, temp2;

        tsc2000_reg_init ();
        tsc2000_set_range (3);

        /*
         * Because of sporadic "jumps" in the measured adc values every
         * channel is read two times. If there is a significant difference
         * between the two measurements, then print an error and do a third
         * measurement, because it is very unlikely that a successive third
         * measurement goes also wrong.
         */
        temp1 = tsc2000_read_channel (14);
        temp2 = tsc2000_read_channel (14);
        if (abs(temp2 - temp1) < MAX_DEVIATION)
                adc_pt1000 = temp2;
        else {
                printf ("%s: read adc value (channel 14) exceeded max allowed "
                        "deviation: %d * 0.0276 °C\n",
                        __FUNCTION__, MAX_DEVIATION);
                printf ("adc value 1: %ld DIGITs\nadc value 2: %ld DIGITs\n",
                        temp1, temp2);
                adc_pt1000 = tsc2000_read_channel (14);
                printf ("use (third read) adc value: adc_pt1000 = "
                        "%ld DIGITs\n", adc_pt1000);
        }
        debug ("read channel 14 (pt1000 adc value): %ld\n", adc_pt1000);

        temp1 = tsc2000_read_channel (15);
        temp2 = tsc2000_read_channel (15);
        if (abs(temp2 - temp1) < MAX_DEVIATION)
                offset = temp2;
        else {
                printf ("%s: read adc value (channel 15) exceeded max allowed "
                        "deviation: %d * 0.0276 °C\n",
                        __FUNCTION__, MAX_DEVIATION);
                printf ("adc value 1: %ld DIGITs\nadc value 2: %ld DIGITs\n",
                        temp1, temp2);
                offset = tsc2000_read_channel (15);
                printf ("use (third read) adc value: offset = %ld DIGITs\n",
                        offset);
        }
        debug ("read channel 15 (offset): %ld\n", offset);

        /*
         * Formula for calculating voltage drop on PT1000 resistor: u_pt1000 =
         * x_range3 * (adc_raw - offset) / 10. Formula to calculate x_range3:
         * x_range3 = (2500 * (1000000 + err_vref + err_amp3)) / (4095*6). The
         * error correction Values err_vref and err_amp3 are assumed as 0 in
         * u-boot, because this could cause only a very small error (< 1%).
         */
        u_pt1000 = (101750 * (adc_pt1000 - offset)) / 10;
        debug ("u_pt1000: %ld\n", u_pt1000);

        if (tsc2000_interpolate(u_pt1000, Pt1000_temp_table,
                                &contact_temp) == -1) {
                printf ("%s: error interpolating PT1000 vlaue\n",
                         __FUNCTION__);
                return (-1000);
        }
        debug ("contact_temp: %ld\n", contact_temp);

        return contact_temp;
}


void tsc2000_reg_init (void)
{
        struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();

        tsc2000_write(TSC2000_REG_ADC, 0x2036);
        tsc2000_write(TSC2000_REG_REF, 0x0011);
        tsc2000_write(TSC2000_REG_DACCTL, 0x0000);

        CON_MUX0;
        CON_MUX1;

        CON_MUX1_ENABLE;
        CON_MUX2_ENABLE;
        CON_MUX3_ENABLE;
        CON_MUX4_ENABLE;

        CON_SEL_TEMP_V_0;
        CON_SEL_TEMP_V_1;
        CON_SEL_TEMP_V_2;
        CON_SEL_TEMP_V_3;

        tsc2000_set_mux(0);
        tsc2000_set_range(0);
}


int tsc2000_interpolate(long value, long data[][2], long *result)
{
        int i;
        unsigned long long val;

        /* the data is sorted and the first element is upper
         * limit so we can easily check for out-of-band values
         */
        if (data[0][0] < value || data[1][0] > value)
                return -1;

        i = 1;
        while (data[i][0] < value)
                i++;

        /* To prevent overflow we have to store the intermediate
           result in 'long long'.
        */

        val = ((unsigned long long)(data[i][1] - data[i-1][1])
                   * (unsigned long long)(value - data[i-1][0]));
        do_div(val, (data[i][0] - data[i-1][0]));
        *result = data[i-1][1] + val;

        return 0;
}


void adc_wait_conversion_done(void)
{
        while (!(tsc2000_read(TSC2000_REG_ADC) & (1 << 14)));
}