drivers/mfd/ezx-pcap.c - kernel/common - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Driver for Motorola PCAP2 as present in EZX phones
  *
  * Copyright (C) 2006 Harald Welte <[email protected]>
  * Copyright (C) 2009 Daniel Ribeiro <[email protected]>
  */

 #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>
 #include <linux/gpio.h>
 #include <linux/slab.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;
 	spinlock_t io_lock;

 	/* 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;
 	spinlock_t adc_lock;
 };

 /* 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)
 {
 	unsigned long flags;
 	int ret;

 	spin_lock_irqsave(&pcap->io_lock, flags);
 	value &= PCAP_REGISTER_VALUE_MASK;
 	value |= PCAP_REGISTER_WRITE_OP_BIT
 		| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
 	ret = ezx_pcap_putget(pcap, &value);
 	spin_unlock_irqrestore(&pcap->io_lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(ezx_pcap_write);

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

 	spin_lock_irqsave(&pcap->io_lock, flags);
 	*value = PCAP_REGISTER_READ_OP_BIT
 		| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);

 	ret = ezx_pcap_putget(pcap, value);
 	spin_unlock_irqrestore(&pcap->io_lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(ezx_pcap_read);

 int ezx_pcap_set_bits(struct pcap_chip *pcap, u8 reg_num, u32 mask, u32 val)
 {
 	unsigned long flags;
 	int ret;
 	u32 tmp = PCAP_REGISTER_READ_OP_BIT |
 		(reg_num << PCAP_REGISTER_ADDRESS_SHIFT);

 	spin_lock_irqsave(&pcap->io_lock, flags);
 	ret = ezx_pcap_putget(pcap, &tmp);
 	if (ret)
 		goto out_unlock;

 	tmp &= (PCAP_REGISTER_VALUE_MASK & ~mask);
 	tmp |= (val & mask) | PCAP_REGISTER_WRITE_OP_BIT |
 		(reg_num << PCAP_REGISTER_ADDRESS_SHIFT);

 	ret = ezx_pcap_putget(pcap, &tmp);
 out_unlock:
 	spin_unlock_irqrestore(&pcap->io_lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(ezx_pcap_set_bits);

 /* IRQ */
 int irq_to_pcap(struct pcap_chip *pcap, int irq)
 {
 	return irq - pcap->irq_base;
 }
 EXPORT_SYMBOL_GPL(irq_to_pcap);

 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(struct irq_data *d)
 {
 	struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);

 	pcap->msr |= 1 << irq_to_pcap(pcap, d->irq);
 	queue_work(pcap->workqueue, &pcap->msr_work);
 }

 static void pcap_unmask_irq(struct irq_data *d)
 {
 	struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);

 	pcap->msr &= ~(1 << irq_to_pcap(pcap, d->irq));
 	queue_work(pcap->workqueue, &pcap->msr_work);
 }

 static struct irq_chip pcap_irq_chip = {
 	.name		= "pcap",
 	.irq_disable	= pcap_mask_irq,
 	.irq_mask	= pcap_mask_irq,
 	.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 = dev_get_platdata(&pcap->spi->dev);
 	u32 msr, isr, int_sel, service;
 	int irq;

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

 		/* We can't 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_MSR, isr | msr);
 		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)
 				generic_handle_irq(irq);
 		}
 		local_irq_enable();
 		ezx_pcap_write(pcap, PCAP_REG_MSR, pcap->msr);
 	} while (gpio_get_value(pdata->gpio));
 }

 static void pcap_irq_handler(struct irq_desc *desc)
 {
 	struct pcap_chip *pcap = irq_desc_get_handler_data(desc);

 	desc->irq_data.chip->irq_ack(&desc->irq_data);
 	queue_work(pcap->workqueue, &pcap->isr_work);
 }

 /* ADC */
 void pcap_set_ts_bits(struct pcap_chip *pcap, u32 bits)
 {
 	unsigned long flags;
 	u32 tmp;

 	spin_lock_irqsave(&pcap->adc_lock, flags);
 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
 	tmp &= ~(PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
 	tmp |= bits & (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
 	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
 	spin_unlock_irqrestore(&pcap->adc_lock, flags);
 }
 EXPORT_SYMBOL_GPL(pcap_set_ts_bits);

 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)
 {
 	unsigned long flags;
 	u32 tmp;
 	u8 head;

 	spin_lock_irqsave(&pcap->adc_lock, flags);
 	head = pcap->adc_head;
 	if (!pcap->adc_queue[head]) {
 		/* queue is empty, save power */
 		pcap_disable_adc(pcap);
 		spin_unlock_irqrestore(&pcap->adc_lock, flags);
 		return;
 	}
 	/* start conversion on requested bank, save TS_M bits */
 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
 	tmp &= (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
 	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);
 	spin_unlock_irqrestore(&pcap->adc_lock, flags);
 	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;

 	spin_lock(&pcap->adc_lock);
 	req = pcap->adc_queue[pcap->adc_head];

 	if (WARN(!req, "adc irq without pending request\n")) {
 		spin_unlock(&pcap->adc_lock);
 		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);
 	spin_unlock(&pcap->adc_lock);

 	/* 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;
 	unsigned long irq_flags;

 	/* 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;

 	spin_lock_irqsave(&pcap->adc_lock, irq_flags);
 	if (pcap->adc_queue[pcap->adc_tail]) {
 		spin_unlock_irqrestore(&pcap->adc_lock, irq_flags);
 		kfree(req);
 		return -EBUSY;
 	}
 	pcap->adc_queue[pcap->adc_tail] = req;
 	pcap->adc_tail = (pcap->adc_tail + 1) & (PCAP_ADC_MAXQ - 1);
 	spin_unlock_irqrestore(&pcap->adc_lock, irq_flags);

 	/* 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 pcap_add_subdev(struct pcap_chip *pcap,
 						struct pcap_subdev *subdev)
 {
 	struct platform_device *pdev;
 	int ret;

 	pdev = platform_device_alloc(subdev->name, subdev->id);
 	if (!pdev)
 		return -ENOMEM;

 	pdev->dev.parent = &pcap->spi->dev;
 	pdev->dev.platform_data = subdev->platform_data;

 	ret = platform_device_add(pdev);
 	if (ret)
 		platform_device_put(pdev);

 	return ret;
 }

 static int ezx_pcap_remove(struct spi_device *spi)
 {
 	struct pcap_chip *pcap = spi_get_drvdata(spi);
 	unsigned long flags;
 	int i;

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

 	/* cleanup ADC */
 	spin_lock_irqsave(&pcap->adc_lock, flags);
 	for (i = 0; i < PCAP_ADC_MAXQ; i++)
 		kfree(pcap->adc_queue[i]);
 	spin_unlock_irqrestore(&pcap->adc_lock, flags);

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

 	destroy_workqueue(pcap->workqueue);

 	return 0;
 }

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

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

 	pcap = devm_kzalloc(&spi->dev, sizeof(*pcap), GFP_KERNEL);
 	if (!pcap) {
 		ret = -ENOMEM;
 		goto ret;
 	}

 	spin_lock_init(&pcap->io_lock);
 	spin_lock_init(&pcap->adc_lock);
 	INIT_WORK(&pcap->isr_work, pcap_isr_work);
 	INIT_WORK(&pcap->msr_work, pcap_msr_work);
 	spi_set_drvdata(spi, 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 ret;

 	pcap->spi = spi;

 	/* setup irq */
 	pcap->irq_base = pdata->irq_base;
 	pcap->workqueue = create_singlethread_workqueue("pcapd");
 	if (!pcap->workqueue) {
 		ret = -ENOMEM;
 		dev_err(&spi->dev, "can't create pcap thread\n");
 		goto ret;
 	}

 	/* 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++) {
 		irq_set_chip_and_handler(i, &pcap_irq_chip, handle_simple_irq);
 		irq_set_chip_data(i, pcap);
 		irq_clear_status_flags(i, IRQ_NOREQUEST | IRQ_NOPROBE);
 	}

 	/* 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;

 	irq_set_irq_type(spi->irq, IRQ_TYPE_EDGE_RISING);
 	irq_set_chained_handler_and_data(spi->irq, pcap_irq_handler, pcap);
 	irq_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 = devm_request_irq(&spi->dev, 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_irqchip:
 	for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
 		irq_set_chip_and_handler(i, NULL, NULL);
 /* destroy_workqueue: */
 	destroy_workqueue(pcap->workqueue);
 ret:
 	return ret;
 }

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

 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);
 }

 subsys_initcall(ezx_pcap_init);
 module_exit(ezx_pcap_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
 MODULE_DESCRIPTION("Motorola PCAP2 ASIC Driver");
 MODULE_ALIAS("spi:ezx-pcap");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Driver for Motorola PCAP2 as present in EZX phones
	*
	* Copyright (C) 2006 Harald Welte <[email protected]>
	* Copyright (C) 2009 Daniel Ribeiro <[email protected]>
	*/

	#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>
	#include <linux/gpio.h>
	#include <linux/slab.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;
	spinlock_t io_lock;

	/* 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;
	spinlock_t adc_lock;
	};

	/* 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)
	{
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&pcap->io_lock, flags);
	value &= PCAP_REGISTER_VALUE_MASK;
	value \|= PCAP_REGISTER_WRITE_OP_BIT
	\| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
	ret = ezx_pcap_putget(pcap, &value);
	spin_unlock_irqrestore(&pcap->io_lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(ezx_pcap_write);

	int ezx_pcap_read(struct pcap_chip pcap, u8 reg_num, u32 value)
	{
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&pcap->io_lock, flags);
	*value = PCAP_REGISTER_READ_OP_BIT
	\| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);

	ret = ezx_pcap_putget(pcap, value);
	spin_unlock_irqrestore(&pcap->io_lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(ezx_pcap_read);

	int ezx_pcap_set_bits(struct pcap_chip *pcap, u8 reg_num, u32 mask, u32 val)
	{
	unsigned long flags;
	int ret;
	u32 tmp = PCAP_REGISTER_READ_OP_BIT \|
	(reg_num << PCAP_REGISTER_ADDRESS_SHIFT);

	spin_lock_irqsave(&pcap->io_lock, flags);
	ret = ezx_pcap_putget(pcap, &tmp);
	if (ret)
	goto out_unlock;

	tmp &= (PCAP_REGISTER_VALUE_MASK & ~mask);
	tmp \|= (val & mask) \| PCAP_REGISTER_WRITE_OP_BIT \|
	(reg_num << PCAP_REGISTER_ADDRESS_SHIFT);

	ret = ezx_pcap_putget(pcap, &tmp);
	out_unlock:
	spin_unlock_irqrestore(&pcap->io_lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(ezx_pcap_set_bits);

	/* IRQ */
	int irq_to_pcap(struct pcap_chip *pcap, int irq)
	{
	return irq - pcap->irq_base;
	}
	EXPORT_SYMBOL_GPL(irq_to_pcap);

	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(struct irq_data *d)
	{
	struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);

	pcap->msr \|= 1 << irq_to_pcap(pcap, d->irq);
	queue_work(pcap->workqueue, &pcap->msr_work);
	}

	static void pcap_unmask_irq(struct irq_data *d)
	{
	struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);

	pcap->msr &= ~(1 << irq_to_pcap(pcap, d->irq));
	queue_work(pcap->workqueue, &pcap->msr_work);
	}

	static struct irq_chip pcap_irq_chip = {
	.name = "pcap",
	.irq_disable = pcap_mask_irq,
	.irq_mask = pcap_mask_irq,
	.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 = dev_get_platdata(&pcap->spi->dev);
	u32 msr, isr, int_sel, service;
	int irq;

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

	/* We can't 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_MSR, isr \| msr);
	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)
	generic_handle_irq(irq);
	}
	local_irq_enable();
	ezx_pcap_write(pcap, PCAP_REG_MSR, pcap->msr);
	} while (gpio_get_value(pdata->gpio));
	}

	static void pcap_irq_handler(struct irq_desc *desc)
	{
	struct pcap_chip *pcap = irq_desc_get_handler_data(desc);

	desc->irq_data.chip->irq_ack(&desc->irq_data);
	queue_work(pcap->workqueue, &pcap->isr_work);
	}

	/* ADC */
	void pcap_set_ts_bits(struct pcap_chip *pcap, u32 bits)
	{
	unsigned long flags;
	u32 tmp;

	spin_lock_irqsave(&pcap->adc_lock, flags);
	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
	tmp &= ~(PCAP_ADC_TS_M_MASK \| PCAP_ADC_TS_REF_LOWPWR);
	tmp \|= bits & (PCAP_ADC_TS_M_MASK \| PCAP_ADC_TS_REF_LOWPWR);
	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
	spin_unlock_irqrestore(&pcap->adc_lock, flags);
	}
	EXPORT_SYMBOL_GPL(pcap_set_ts_bits);

	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)
	{
	unsigned long flags;
	u32 tmp;
	u8 head;

	spin_lock_irqsave(&pcap->adc_lock, flags);
	head = pcap->adc_head;
	if (!pcap->adc_queue[head]) {
	/* queue is empty, save power */
	pcap_disable_adc(pcap);
	spin_unlock_irqrestore(&pcap->adc_lock, flags);
	return;
	}
	/* start conversion on requested bank, save TS_M bits */
	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
	tmp &= (PCAP_ADC_TS_M_MASK \| PCAP_ADC_TS_REF_LOWPWR);
	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);
	spin_unlock_irqrestore(&pcap->adc_lock, flags);
	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;

	spin_lock(&pcap->adc_lock);
	req = pcap->adc_queue[pcap->adc_head];

	if (WARN(!req, "adc irq without pending request\n")) {
	spin_unlock(&pcap->adc_lock);
	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);
	spin_unlock(&pcap->adc_lock);

	/* 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;
	unsigned long irq_flags;

	/* 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;

	spin_lock_irqsave(&pcap->adc_lock, irq_flags);
	if (pcap->adc_queue[pcap->adc_tail]) {
	spin_unlock_irqrestore(&pcap->adc_lock, irq_flags);
	kfree(req);
	return -EBUSY;
	}
	pcap->adc_queue[pcap->adc_tail] = req;
	pcap->adc_tail = (pcap->adc_tail + 1) & (PCAP_ADC_MAXQ - 1);
	spin_unlock_irqrestore(&pcap->adc_lock, irq_flags);

	/* 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 pcap_add_subdev(struct pcap_chip *pcap,
	struct pcap_subdev *subdev)
	{
	struct platform_device *pdev;
	int ret;

	pdev = platform_device_alloc(subdev->name, subdev->id);
	if (!pdev)
	return -ENOMEM;

	pdev->dev.parent = &pcap->spi->dev;
	pdev->dev.platform_data = subdev->platform_data;

	ret = platform_device_add(pdev);
	if (ret)
	platform_device_put(pdev);

	return ret;
	}

	static int ezx_pcap_remove(struct spi_device *spi)
	{
	struct pcap_chip *pcap = spi_get_drvdata(spi);
	unsigned long flags;
	int i;

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

	/* cleanup ADC */
	spin_lock_irqsave(&pcap->adc_lock, flags);
	for (i = 0; i < PCAP_ADC_MAXQ; i++)
	kfree(pcap->adc_queue[i]);
	spin_unlock_irqrestore(&pcap->adc_lock, flags);

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

	destroy_workqueue(pcap->workqueue);

	return 0;
	}

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

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

	pcap = devm_kzalloc(&spi->dev, sizeof(*pcap), GFP_KERNEL);
	if (!pcap) {
	ret = -ENOMEM;
	goto ret;
	}

	spin_lock_init(&pcap->io_lock);
	spin_lock_init(&pcap->adc_lock);
	INIT_WORK(&pcap->isr_work, pcap_isr_work);
	INIT_WORK(&pcap->msr_work, pcap_msr_work);
	spi_set_drvdata(spi, 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 ret;

	pcap->spi = spi;

	/* setup irq */
	pcap->irq_base = pdata->irq_base;
	pcap->workqueue = create_singlethread_workqueue("pcapd");
	if (!pcap->workqueue) {
	ret = -ENOMEM;
	dev_err(&spi->dev, "can't create pcap thread\n");
	goto ret;
	}

	/* 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++) {
	irq_set_chip_and_handler(i, &pcap_irq_chip, handle_simple_irq);
	irq_set_chip_data(i, pcap);
	irq_clear_status_flags(i, IRQ_NOREQUEST \| IRQ_NOPROBE);
	}

	/* 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;

	irq_set_irq_type(spi->irq, IRQ_TYPE_EDGE_RISING);
	irq_set_chained_handler_and_data(spi->irq, pcap_irq_handler, pcap);
	irq_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 = devm_request_irq(&spi->dev, 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_irqchip:
	for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
	irq_set_chip_and_handler(i, NULL, NULL);
	/* destroy_workqueue: */
	destroy_workqueue(pcap->workqueue);
	ret:
	return ret;
	}

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

	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);
	}

	subsys_initcall(ezx_pcap_init);
	module_exit(ezx_pcap_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
	MODULE_DESCRIPTION("Motorola PCAP2 ASIC Driver");
	MODULE_ALIAS("spi:ezx-pcap");