/*
 * Driver for Motorola PCAP2 as present in EZX phones
 *
 * Copyright (C) 2006 Harald Welte <laforge@openezx.org>
 * Copyright (C) 2009 Daniel Ribeiro <drwyrm@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/mfd/ezx-pcap.h>
#include <linux/spi/spi.h>

#define PCAP_ADC_MAXQ           8
struct pcap_adc_request {
        u8 bank;
        u8 ch[2];
        u32 flags;
        void (*callback)(void *, u16[]);
        void *data;
};

struct pcap_adc_sync_request {
        u16 res[2];
        struct completion completion;
};

struct pcap_chip {
        struct spi_device *spi;

        /* IO */
        u32 buf;
        struct mutex io_mutex;

        /* IRQ */
        unsigned int irq_base;
        u32 msr;
        struct work_struct isr_work;
        struct work_struct msr_work;
        struct workqueue_struct *workqueue;

        /* ADC */
        struct pcap_adc_request *adc_queue[PCAP_ADC_MAXQ];
        u8 adc_head;
        u8 adc_tail;
        struct mutex adc_mutex;
};

/* IO */
static int ezx_pcap_putget(struct pcap_chip *pcap, u32 *data)
{
        struct spi_transfer t;
        struct spi_message m;
        int status;

        memset(&t, 0, sizeof t);
        spi_message_init(&m);
        t.len = sizeof(u32);
        spi_message_add_tail(&t, &m);

        pcap->buf = *data;
        t.tx_buf = (u8 *) &pcap->buf;
        t.rx_buf = (u8 *) &pcap->buf;
        status = spi_sync(pcap->spi, &m);

        if (status == 0)
                *data = pcap->buf;

        return status;
}

int ezx_pcap_write(struct pcap_chip *pcap, u8 reg_num, u32 value)
{
        int ret;

        mutex_lock(&pcap->io_mutex);
        value &= PCAP_REGISTER_VALUE_MASK;
        value |= PCAP_REGISTER_WRITE_OP_BIT
                | (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
        ret = ezx_pcap_putget(pcap, &value);
        mutex_unlock(&pcap->io_mutex);

        return ret;
}
EXPORT_SYMBOL_GPL(ezx_pcap_write);

int ezx_pcap_read(struct pcap_chip *pcap, u8 reg_num, u32 *value)
{
        int ret;

        mutex_lock(&pcap->io_mutex);
        *value = PCAP_REGISTER_READ_OP_BIT
                | (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);

        ret = ezx_pcap_putget(pcap, value);
        mutex_unlock(&pcap->io_mutex);

        return ret;
}
EXPORT_SYMBOL_GPL(ezx_pcap_read);

/* IRQ */
static inline unsigned int irq2pcap(struct pcap_chip *pcap, int irq)
{
        return 1 << (irq - pcap->irq_base);
}

int pcap_to_irq(struct pcap_chip *pcap, int irq)
{
        return pcap->irq_base + irq;
}
EXPORT_SYMBOL_GPL(pcap_to_irq);

static void pcap_mask_irq(unsigned int irq)
{
        struct pcap_chip *pcap = get_irq_chip_data(irq);

        pcap->msr |= irq2pcap(pcap, irq);
        queue_work(pcap->workqueue, &pcap->msr_work);
}

static void pcap_unmask_irq(unsigned int irq)
{
        struct pcap_chip *pcap = get_irq_chip_data(irq);

        pcap->msr &= ~irq2pcap(pcap, irq);
        queue_work(pcap->workqueue, &pcap->msr_work);
}

static struct irq_chip pcap_irq_chip = {
        .name   = "pcap",
        .mask   = pcap_mask_irq,
        .unmask = pcap_unmask_irq,
};

static void pcap_msr_work(struct work_struct *work)
{
        struct pcap_chip *pcap = container_of(work, struct pcap_chip, msr_work);

        ezx_pcap_write(pcap, PCAP_REG_MSR, pcap->msr);
}

static void pcap_isr_work(struct work_struct *work)
{
        struct pcap_chip *pcap = container_of(work, struct pcap_chip, isr_work);
        struct pcap_platform_data *pdata = pcap->spi->dev.platform_data;
        u32 msr, isr, int_sel, service;
        int irq;

        ezx_pcap_read(pcap, PCAP_REG_MSR, &msr);
        ezx_pcap_read(pcap, PCAP_REG_ISR, &isr);

        /* We cant service/ack irqs that are assigned to port 2 */
        if (!(pdata->config & PCAP_SECOND_PORT)) {
                ezx_pcap_read(pcap, PCAP_REG_INT_SEL, &int_sel);
                isr &= ~int_sel;
        }
        ezx_pcap_write(pcap, PCAP_REG_ISR, isr);

        local_irq_disable();
        service = isr & ~msr;

        for (irq = pcap->irq_base; service; service >>= 1, irq++) {
                if (service & 1) {
                        struct irq_desc *desc = irq_to_desc(irq);

                        if (WARN(!desc, KERN_WARNING
                                        "Invalid PCAP IRQ %d\n", irq))
                                break;

                        if (desc->status & IRQ_DISABLED)
                                note_interrupt(irq, desc, IRQ_NONE);
                        else
                                desc->handle_irq(irq, desc);
                }
        }
        local_irq_enable();
}

static void pcap_irq_handler(unsigned int irq, struct irq_desc *desc)
{
        struct pcap_chip *pcap = get_irq_data(irq);

        desc->chip->ack(irq);
        queue_work(pcap->workqueue, &pcap->isr_work);
        return;
}

/* ADC */
static void pcap_disable_adc(struct pcap_chip *pcap)
{
        u32 tmp;

        ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
        tmp &= ~(PCAP_ADC_ADEN|PCAP_ADC_BATT_I_ADC|PCAP_ADC_BATT_I_POLARITY);
        ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
}

static void pcap_adc_trigger(struct pcap_chip *pcap)
{
        u32 tmp;
        u8 head;

        mutex_lock(&pcap->adc_mutex);
        head = pcap->adc_head;
        if (!pcap->adc_queue[head]) {
                /* queue is empty, save power */
                pcap_disable_adc(pcap);
                mutex_unlock(&pcap->adc_mutex);
                return;
        }
        mutex_unlock(&pcap->adc_mutex);

        /* start conversion on requested bank */
        tmp = pcap->adc_queue[head]->flags | PCAP_ADC_ADEN;

        if (pcap->adc_queue[head]->bank == PCAP_ADC_BANK_1)
                tmp |= PCAP_ADC_AD_SEL1;

        ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
        ezx_pcap_write(pcap, PCAP_REG_ADR, PCAP_ADR_ASC);
}

static irqreturn_t pcap_adc_irq(int irq, void *_pcap)
{
        struct pcap_chip *pcap = _pcap;
        struct pcap_adc_request *req;
        u16 res[2];
        u32 tmp;

        mutex_lock(&pcap->adc_mutex);
        req = pcap->adc_queue[pcap->adc_head];

        if (WARN(!req, KERN_WARNING "adc irq without pending request\n"))
                return IRQ_HANDLED;

        /* read requested channels results */
        ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
        tmp &= ~(PCAP_ADC_ADA1_MASK | PCAP_ADC_ADA2_MASK);
        tmp |= (req->ch[0] << PCAP_ADC_ADA1_SHIFT);
        tmp |= (req->ch[1] << PCAP_ADC_ADA2_SHIFT);
        ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
        ezx_pcap_read(pcap, PCAP_REG_ADR, &tmp);
        res[0] = (tmp & PCAP_ADR_ADD1_MASK) >> PCAP_ADR_ADD1_SHIFT;
        res[1] = (tmp & PCAP_ADR_ADD2_MASK) >> PCAP_ADR_ADD2_SHIFT;

        pcap->adc_queue[pcap->adc_head] = NULL;
        pcap->adc_head = (pcap->adc_head + 1) & (PCAP_ADC_MAXQ - 1);
        mutex_unlock(&pcap->adc_mutex);

        /* pass the results and release memory */
        req->callback(req->data, res);
        kfree(req);

        /* trigger next conversion (if any) on queue */
        pcap_adc_trigger(pcap);

        return IRQ_HANDLED;
}

int pcap_adc_async(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
                                                void *callback, void *data)
{
        struct pcap_adc_request *req;

        /* This will be freed after we have a result */
        req = kmalloc(sizeof(struct pcap_adc_request), GFP_KERNEL);
        if (!req)
                return -ENOMEM;

        req->bank = bank;
        req->flags = flags;
        req->ch[0] = ch[0];
        req->ch[1] = ch[1];
        req->callback = callback;
        req->data = data;

        mutex_lock(&pcap->adc_mutex);
        if (pcap->adc_queue[pcap->adc_tail]) {
                mutex_unlock(&pcap->adc_mutex);
                kfree(req);
                return -EBUSY;
        }
        pcap->adc_queue[pcap->adc_tail] = req;
        pcap->adc_tail = (pcap->adc_tail + 1) & (PCAP_ADC_MAXQ - 1);
        mutex_unlock(&pcap->adc_mutex);

        /* start conversion */
        pcap_adc_trigger(pcap);

        return 0;
}
EXPORT_SYMBOL_GPL(pcap_adc_async);

static void pcap_adc_sync_cb(void *param, u16 res[])
{
        struct pcap_adc_sync_request *req = param;

        req->res[0] = res[0];
        req->res[1] = res[1];
        complete(&req->completion);
}

int pcap_adc_sync(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
                                                                u16 res[])
{
        struct pcap_adc_sync_request sync_data;
        int ret;

        init_completion(&sync_data.completion);
        ret = pcap_adc_async(pcap, bank, flags, ch, pcap_adc_sync_cb,
                                                                &sync_data);
        if (ret)
                return ret;
        wait_for_completion(&sync_data.completion);
        res[0] = sync_data.res[0];
        res[1] = sync_data.res[1];

        return 0;
}
EXPORT_SYMBOL_GPL(pcap_adc_sync);

/* subdevs */
static int pcap_remove_subdev(struct device *dev, void *unused)
{
        platform_device_unregister(to_platform_device(dev));
        return 0;
}

static int __devinit pcap_add_subdev(struct pcap_chip *pcap,
                                                struct pcap_subdev *subdev)
{
        struct platform_device *pdev;

        pdev = platform_device_alloc(subdev->name, subdev->id);
        pdev->dev.parent = &pcap->spi->dev;
        pdev->dev.platform_data = subdev->platform_data;
        platform_set_drvdata(pdev, pcap);

        return platform_device_add(pdev);
}

static int __devexit ezx_pcap_remove(struct spi_device *spi)
{
        struct pcap_chip *pcap = dev_get_drvdata(&spi->dev);
        struct pcap_platform_data *pdata = spi->dev.platform_data;
        int i, adc_irq;

        /* remove all registered subdevs */
        device_for_each_child(&spi->dev, NULL, pcap_remove_subdev);

        /* cleanup ADC */
        adc_irq = pcap_to_irq(pcap, (pdata->config & PCAP_SECOND_PORT) ?
                                PCAP_IRQ_ADCDONE2 : PCAP_IRQ_ADCDONE);
        free_irq(adc_irq, pcap);
        mutex_lock(&pcap->adc_mutex);
        for (i = 0; i < PCAP_ADC_MAXQ; i++)
                kfree(pcap->adc_queue[i]);
        mutex_unlock(&pcap->adc_mutex);

        /* cleanup irqchip */
        for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
                set_irq_chip_and_handler(i, NULL, NULL);

        destroy_workqueue(pcap->workqueue);

        kfree(pcap);

        return 0;
}

static int __devinit ezx_pcap_probe(struct spi_device *spi)
{
        struct pcap_platform_data *pdata = spi->dev.platform_data;
        struct pcap_chip *pcap;
        int i, adc_irq;
        int ret = -ENODEV;

        /* platform data is required */
        if (!pdata)
                goto ret;

        pcap = kzalloc(sizeof(*pcap), GFP_KERNEL);
        if (!pcap) {
                ret = -ENOMEM;
                goto ret;
        }

        mutex_init(&pcap->io_mutex);
        mutex_init(&pcap->adc_mutex);
        INIT_WORK(&pcap->isr_work, pcap_isr_work);
        INIT_WORK(&pcap->msr_work, pcap_msr_work);
        dev_set_drvdata(&spi->dev, pcap);

        /* setup spi */
        spi->bits_per_word = 32;
        spi->mode = SPI_MODE_0 | (pdata->config & PCAP_CS_AH ? SPI_CS_HIGH : 0);
        ret = spi_setup(spi);
        if (ret)
                goto free_pcap;

        pcap->spi = spi;

        /* setup irq */
        pcap->irq_base = pdata->irq_base;
        pcap->workqueue = create_singlethread_workqueue("pcapd");
        if (!pcap->workqueue) {
                dev_err(&spi->dev, "cant create pcap thread\n");
                goto free_pcap;
        }

        /* redirect interrupts to AP, except adcdone2 */
        if (!(pdata->config & PCAP_SECOND_PORT))
                ezx_pcap_write(pcap, PCAP_REG_INT_SEL,
                                        (1 << PCAP_IRQ_ADCDONE2));

        /* setup irq chip */
        for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++) {
                set_irq_chip_and_handler(i, &pcap_irq_chip, handle_simple_irq);
                set_irq_chip_data(i, pcap);
#ifdef CONFIG_ARM
                set_irq_flags(i, IRQF_VALID);
#else
                set_irq_noprobe(i);
#endif
        }

        /* mask/ack all PCAP interrupts */
        ezx_pcap_write(pcap, PCAP_REG_MSR, PCAP_MASK_ALL_INTERRUPT);
        ezx_pcap_write(pcap, PCAP_REG_ISR, PCAP_CLEAR_INTERRUPT_REGISTER);
        pcap->msr = PCAP_MASK_ALL_INTERRUPT;

        set_irq_type(spi->irq, IRQ_TYPE_EDGE_RISING);
        set_irq_data(spi->irq, pcap);
        set_irq_chained_handler(spi->irq, pcap_irq_handler);
        set_irq_wake(spi->irq, 1);

        /* ADC */
        adc_irq = pcap_to_irq(pcap, (pdata->config & PCAP_SECOND_PORT) ?
                                        PCAP_IRQ_ADCDONE2 : PCAP_IRQ_ADCDONE);

        ret = request_irq(adc_irq, pcap_adc_irq, 0, "ADC", pcap);
        if (ret)
                goto free_irqchip;

        /* setup subdevs */
        for (i = 0; i < pdata->num_subdevs; i++) {
                ret = pcap_add_subdev(pcap, &pdata->subdevs[i]);
                if (ret)
                        goto remove_subdevs;
        }

        /* board specific quirks */
        if (pdata->init)
                pdata->init(pcap);

        return 0;

remove_subdevs:
        device_for_each_child(&spi->dev, NULL, pcap_remove_subdev);
/* free_adc: */
        free_irq(adc_irq, pcap);
free_irqchip:
        for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
                set_irq_chip_and_handler(i, NULL, NULL);
/* destroy_workqueue: */
        destroy_workqueue(pcap->workqueue);
free_pcap:
        kfree(pcap);
ret:
        return ret;
}

static struct spi_driver ezxpcap_driver = {
        .probe  = ezx_pcap_probe,
        .remove = __devexit_p(ezx_pcap_remove),
        .driver = {
                .name   = "ezx-pcap",
                .owner  = THIS_MODULE,
        },
};

static int __init ezx_pcap_init(void)
{
        return spi_register_driver(&ezxpcap_driver);
}

static void __exit ezx_pcap_exit(void)
{
        spi_unregister_driver(&ezxpcap_driver);
}

module_init(ezx_pcap_init);
module_exit(ezx_pcap_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
MODULE_DESCRIPTION("Motorola PCAP2 ASIC Driver");