/*
 * isl6421.h - driver for lnb supply and control ic ISL6421
 *
 * Copyright (C) 2006 Andrew de Quincey
 * Copyright (C) 2006 Oliver Endriss
 *
 * 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.
 *
 * To obtain the license, point your browser to
 * http://www.gnu.org/copyleft/gpl.html
 *
 *
 * the project's page is at https://linuxtv.org
 */
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/slab.h>

#include <media/dvb_frontend.h>
#include "isl6421.h"

struct isl6421 {
        u8                      config;
        u8                      override_or;
        u8                      override_and;
        struct i2c_adapter      *i2c;
        u8                      i2c_addr;
        bool                    is_off;
};

static int isl6421_set_voltage(struct dvb_frontend *fe,
                               enum fe_sec_voltage voltage)
{
        int ret;
        u8 buf;
        bool is_off;
        struct isl6421 *isl6421 = (struct isl6421 *) fe->sec_priv;
        struct i2c_msg msg[2] = {
                {
                  .addr = isl6421->i2c_addr,
                  .flags = 0,
                  .buf = &isl6421->config,
                  .len = 1,
                }, {
                  .addr = isl6421->i2c_addr,
                  .flags = I2C_M_RD,
                  .buf = &buf,
                  .len = 1,
                }

        };

        isl6421->config &= ~(ISL6421_VSEL1 | ISL6421_EN1);

        switch(voltage) {
        case SEC_VOLTAGE_OFF:
                is_off = true;
                break;
        case SEC_VOLTAGE_13:
                is_off = false;
                isl6421->config |= ISL6421_EN1;
                break;
        case SEC_VOLTAGE_18:
                is_off = false;
                isl6421->config |= (ISL6421_EN1 | ISL6421_VSEL1);
                break;
        default:
                return -EINVAL;
        }

        /*
         * If LNBf were not powered on, disable dynamic current limit, as,
         * according with datasheet, highly capacitive load on the output may
         * cause a difficult start-up.
         */
        if (isl6421->is_off && !is_off)
                isl6421->config |= ISL6421_DCL;

        isl6421->config |= isl6421->override_or;
        isl6421->config &= isl6421->override_and;

        ret = i2c_transfer(isl6421->i2c, msg, 2);
        if (ret < 0)
                return ret;
        if (ret != 2)
                return -EIO;

        /* Store off status now incase future commands fail */
        isl6421->is_off = is_off;

        /* On overflow, the device will try again after 900 ms (typically) */
        if (!is_off && (buf & ISL6421_OLF1))
                msleep(1000);

        /* Re-enable dynamic current limit */
        if ((isl6421->config & ISL6421_DCL) &&
            !(isl6421->override_or & ISL6421_DCL)) {
                isl6421->config &= ~ISL6421_DCL;

                ret = i2c_transfer(isl6421->i2c, msg, 2);
                if (ret < 0)
                        return ret;
                if (ret != 2)
                        return -EIO;
        }

        /* Check if overload flag is active. If so, disable power */
        if (!is_off && (buf & ISL6421_OLF1)) {
                isl6421->config &= ~(ISL6421_VSEL1 | ISL6421_EN1);
                ret = i2c_transfer(isl6421->i2c, msg, 1);
                if (ret < 0)
                        return ret;
                if (ret != 1)
                        return -EIO;
                isl6421->is_off = true;

                dev_warn(&isl6421->i2c->dev,
                         "Overload current detected. disabling LNBf power\n");
                return -EINVAL;
        }

        return 0;
}

static int isl6421_enable_high_lnb_voltage(struct dvb_frontend *fe, long arg)
{
        struct isl6421 *isl6421 = (struct isl6421 *) fe->sec_priv;
        struct i2c_msg msg = {  .addr = isl6421->i2c_addr, .flags = 0,
                                .buf = &isl6421->config,
                                .len = sizeof(isl6421->config) };

        if (arg)
                isl6421->config |= ISL6421_LLC1;
        else
                isl6421->config &= ~ISL6421_LLC1;

        isl6421->config |= isl6421->override_or;
        isl6421->config &= isl6421->override_and;

        return (i2c_transfer(isl6421->i2c, &msg, 1) == 1) ? 0 : -EIO;
}

static int isl6421_set_tone(struct dvb_frontend *fe,
                            enum fe_sec_tone_mode tone)
{
        struct isl6421 *isl6421 = (struct isl6421 *) fe->sec_priv;
        struct i2c_msg msg = { .addr = isl6421->i2c_addr, .flags = 0,
                               .buf = &isl6421->config,
                               .len = sizeof(isl6421->config) };

        switch (tone) {
        case SEC_TONE_ON:
                isl6421->config |= ISL6421_ENT1;
                break;
        case SEC_TONE_OFF:
                isl6421->config &= ~ISL6421_ENT1;
                break;
        default:
                return -EINVAL;
        }

        isl6421->config |= isl6421->override_or;
        isl6421->config &= isl6421->override_and;

        return (i2c_transfer(isl6421->i2c, &msg, 1) == 1) ? 0 : -EIO;
}

static void isl6421_release(struct dvb_frontend *fe)
{
        /* power off */
        isl6421_set_voltage(fe, SEC_VOLTAGE_OFF);

        /* free */
        kfree(fe->sec_priv);
        fe->sec_priv = NULL;
}

struct dvb_frontend *isl6421_attach(struct dvb_frontend *fe, struct i2c_adapter *i2c, u8 i2c_addr,
                   u8 override_set, u8 override_clear, bool override_tone)
{
        struct isl6421 *isl6421 = kmalloc(sizeof(struct isl6421), GFP_KERNEL);
        if (!isl6421)
                return NULL;

        /* default configuration */
        isl6421->config = ISL6421_ISEL1;
        isl6421->i2c = i2c;
        isl6421->i2c_addr = i2c_addr;
        fe->sec_priv = isl6421;

        /* bits which should be forced to '1' */
        isl6421->override_or = override_set;

        /* bits which should be forced to '0' */
        isl6421->override_and = ~override_clear;

        /* detect if it is present or not */
        if (isl6421_set_voltage(fe, SEC_VOLTAGE_OFF)) {
                kfree(isl6421);
                fe->sec_priv = NULL;
                return NULL;
        }

        isl6421->is_off = true;

        /* install release callback */
        fe->ops.release_sec = isl6421_release;

        /* override frontend ops */
        fe->ops.set_voltage = isl6421_set_voltage;
        fe->ops.enable_high_lnb_voltage = isl6421_enable_high_lnb_voltage;
        if (override_tone)
                fe->ops.set_tone = isl6421_set_tone;

        return fe;
}
EXPORT_SYMBOL(isl6421_attach);

MODULE_DESCRIPTION("Driver for lnb supply and control ic isl6421");
MODULE_AUTHOR("Andrew de Quincey & Oliver Endriss");
MODULE_LICENSE("GPL");