[net-next-2.6.git] / drivers / mfd / pcf50633-adc.c

/* NXP PCF50633 ADC Driver
 *
 * (C) 2006-2008 by Openmoko, Inc.
 * Author: Balaji Rao <balajirrao@openmoko.org>
 * All rights reserved.
 *
 * Broken down from monstrous PCF50633 driver mainly by
 * Harald Welte, Andy Green and Werner Almesberger
 *
 *  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.
 *
 *  NOTE: This driver does not yet support subtractive ADC mode, which means
 *  you can do only one measurement per read request.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/completion.h>

#include <linux/mfd/pcf50633/core.h>
#include <linux/mfd/pcf50633/adc.h>

struct pcf50633_adc_request {
	int mux;
	int avg;
	void (*callback)(struct pcf50633 *, void *, int);
	void *callback_param;
};

struct pcf50633_adc_sync_request {
	int result;
	struct completion completion;
};

#define PCF50633_MAX_ADC_FIFO_DEPTH 8

struct pcf50633_adc {
	struct pcf50633 *pcf;

	/* Private stuff */
	struct pcf50633_adc_request *queue[PCF50633_MAX_ADC_FIFO_DEPTH];
	int queue_head;
	int queue_tail;
	struct mutex queue_mutex;
};

static inline struct pcf50633_adc *__to_adc(struct pcf50633 *pcf)
{
	return platform_get_drvdata(pcf->adc_pdev);
}

static void adc_setup(struct pcf50633 *pcf, int channel, int avg)
{
	channel &= PCF50633_ADCC1_ADCMUX_MASK;

	/* kill ratiometric, but enable ACCSW biasing */
	pcf50633_reg_write(pcf, PCF50633_REG_ADCC2, 0x00);
	pcf50633_reg_write(pcf, PCF50633_REG_ADCC3, 0x01);

	/* start ADC conversion on selected channel */
	pcf50633_reg_write(pcf, PCF50633_REG_ADCC1, channel | avg |
		    PCF50633_ADCC1_ADCSTART | PCF50633_ADCC1_RES_10BIT);
}

static void trigger_next_adc_job_if_any(struct pcf50633 *pcf)
{
	struct pcf50633_adc *adc = __to_adc(pcf);
	int head;

	head = adc->queue_head;

	if (!adc->queue[head])
		return;

	adc_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg);
}

static int
adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req)
{
	struct pcf50633_adc *adc = __to_adc(pcf);
	int head, tail;

	mutex_lock(&adc->queue_mutex);

	head = adc->queue_head;
	tail = adc->queue_tail;

	if (adc->queue[tail]) {
		mutex_unlock(&adc->queue_mutex);
		dev_err(pcf->dev, "ADC queue is full, dropping request\n");
		return -EBUSY;
	}

	adc->queue[tail] = req;
	if (head == tail)
		trigger_next_adc_job_if_any(pcf);
	adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1);

	mutex_unlock(&adc->queue_mutex);

	return 0;
}

static void pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param,
	int result)
{
	struct pcf50633_adc_sync_request *req = param;

	req->result = result;
	complete(&req->completion);
}

int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
{
	struct pcf50633_adc_sync_request req;
	int ret;

	init_completion(&req.completion);

	ret = pcf50633_adc_async_read(pcf, mux, avg,
		pcf50633_adc_sync_read_callback, &req);
	if (ret)
		return ret;

	wait_for_completion(&req.completion);

	return req.result;
}
EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read);

int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
			     void (*callback)(struct pcf50633 *, void *, int),
			     void *callback_param)
{
	struct pcf50633_adc_request *req;

	/* req is freed when the result is ready, in interrupt handler */
	req = kmalloc(sizeof(*req), GFP_KERNEL);
	if (!req)
		return -ENOMEM;

	req->mux = mux;
	req->avg = avg;
	req->callback = callback;
	req->callback_param = callback_param;

	return adc_enqueue_request(pcf, req);
}
EXPORT_SYMBOL_GPL(pcf50633_adc_async_read);

static int adc_result(struct pcf50633 *pcf)
{
	u8 adcs1, adcs3;
	u16 result;

	adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1);
	adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3);
	result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK);

	dev_dbg(pcf->dev, "adc result = %d\n", result);

	return result;
}

static void pcf50633_adc_irq(int irq, void *data)
{
	struct pcf50633_adc *adc = data;
	struct pcf50633 *pcf = adc->pcf;
	struct pcf50633_adc_request *req;
	int head, res;

	mutex_lock(&adc->queue_mutex);
	head = adc->queue_head;

	req = adc->queue[head];
	if (WARN_ON(!req)) {
		dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n");
		mutex_unlock(&adc->queue_mutex);
		return;
	}
	adc->queue[head] = NULL;
	adc->queue_head = (head + 1) &
				      (PCF50633_MAX_ADC_FIFO_DEPTH - 1);

	res = adc_result(pcf);
	trigger_next_adc_job_if_any(pcf);

	mutex_unlock(&adc->queue_mutex);

	req->callback(pcf, req->callback_param, res);
	kfree(req);
}

static int __devinit pcf50633_adc_probe(struct platform_device *pdev)
{
	struct pcf50633_adc *adc;

	adc = kzalloc(sizeof(*adc), GFP_KERNEL);
	if (!adc)
		return -ENOMEM;

	adc->pcf = dev_to_pcf50633(pdev->dev.parent);
	platform_set_drvdata(pdev, adc);

	pcf50633_register_irq(adc->pcf, PCF50633_IRQ_ADCRDY,
					pcf50633_adc_irq, adc);

	mutex_init(&adc->queue_mutex);

	return 0;
}

static int __devexit pcf50633_adc_remove(struct platform_device *pdev)
{
	struct pcf50633_adc *adc = platform_get_drvdata(pdev);
	int i, head;

	pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY);

	mutex_lock(&adc->queue_mutex);
	head = adc->queue_head;

	if (WARN_ON(adc->queue[head]))
		dev_err(adc->pcf->dev,
			"adc driver removed with request pending\n");

	for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++)
		kfree(adc->queue[i]);

	mutex_unlock(&adc->queue_mutex);
	kfree(adc);

	return 0;
}

static struct platform_driver pcf50633_adc_driver = {
	.driver = {
		.name = "pcf50633-adc",
	},
	.probe = pcf50633_adc_probe,
	.remove = __devexit_p(pcf50633_adc_remove),
};

static int __init pcf50633_adc_init(void)
{
	return platform_driver_register(&pcf50633_adc_driver);
}
module_init(pcf50633_adc_init);

static void __exit pcf50633_adc_exit(void)
{
	platform_driver_unregister(&pcf50633_adc_driver);
}
module_exit(pcf50633_adc_exit);

MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>");
MODULE_DESCRIPTION("PCF50633 adc driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pcf50633-adc");
Commit	Line	Data
08c3e06a BR	1	/* NXP PCF50633 ADC Driver
	2	*
	3	* (C) 2006-2008 by Openmoko, Inc.
	4	* Author: Balaji Rao <balajirrao@openmoko.org>
	5	* All rights reserved.
	6	*
	7	* Broken down from monstrous PCF50633 driver mainly by
	8	* Harald Welte, Andy Green and Werner Almesberger
	9	*
	10	* This program is free software; you can redistribute it and/or modify it
	11	* under the terms of the GNU General Public License as published by the
	12	* Free Software Foundation; either version 2 of the License, or (at your
	13	* option) any later version.
	14	*
	15	* NOTE: This driver does not yet support subtractive ADC mode, which means
	16	* you can do only one measurement per read request.
	17	*/
	18
	19	#include <linux/kernel.h>
5a0e3ad6	20	#include <linux/slab.h>
08c3e06a BR	21	#include <linux/module.h>
	22	#include <linux/init.h>
	23	#include <linux/device.h>
	24	#include <linux/platform_device.h>
	25	#include <linux/completion.h>
	26
	27	#include <linux/mfd/pcf50633/core.h>
	28	#include <linux/mfd/pcf50633/adc.h>
	29
	30	struct pcf50633_adc_request {
	31	int mux;
	32	int avg;
08c3e06a BR	33	void (callback)(struct pcf50633 , void *, int);
08c3e06a BR	34	void *callback_param;
6438a694	35	};
08c3e06a	36
6438a694 LPC	37	struct pcf50633_adc_sync_request {
6438a694 LPC	38	int result;
08c3e06a	39	struct completion completion;
08c3e06a BR	40	};
	41
	42	#define PCF50633_MAX_ADC_FIFO_DEPTH 8
	43
	44	struct pcf50633_adc {
	45	struct pcf50633 *pcf;
	46
	47	/* Private stuff */
	48	struct pcf50633_adc_request *queue[PCF50633_MAX_ADC_FIFO_DEPTH];
	49	int queue_head;
	50	int queue_tail;
	51	struct mutex queue_mutex;
	52	};
	53
	54	static inline struct pcf50633_adc __to_adc(struct pcf50633 pcf)
	55	{
	56	return platform_get_drvdata(pcf->adc_pdev);
	57	}
	58
	59	static void adc_setup(struct pcf50633 *pcf, int channel, int avg)
	60	{
	61	channel &= PCF50633_ADCC1_ADCMUX_MASK;
	62
	63	/* kill ratiometric, but enable ACCSW biasing */
	64	pcf50633_reg_write(pcf, PCF50633_REG_ADCC2, 0x00);
	65	pcf50633_reg_write(pcf, PCF50633_REG_ADCC3, 0x01);
	66
	67	/* start ADC conversion on selected channel */
	68	pcf50633_reg_write(pcf, PCF50633_REG_ADCC1, channel \| avg \|
	69	PCF50633_ADCC1_ADCSTART \| PCF50633_ADCC1_RES_10BIT);
	70	}
	71
	72	static void trigger_next_adc_job_if_any(struct pcf50633 *pcf)
	73	{
	74	struct pcf50633_adc *adc = __to_adc(pcf);
	75	int head;
	76
08c3e06a BR	77	head = adc->queue_head;
08c3e06a BR	78
bd8ef102	79	if (!adc->queue[head])
08c3e06a	80	return;
08c3e06a BR	81
	82	adc_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg);
	83	}
	84
	85	static int
	86	adc_enqueue_request(struct pcf50633 pcf, struct pcf50633_adc_request req)
	87	{
	88	struct pcf50633_adc *adc = __to_adc(pcf);
	89	int head, tail;
	90
	91	mutex_lock(&adc->queue_mutex);
	92
	93	head = adc->queue_head;
	94	tail = adc->queue_tail;
	95
	96	if (adc->queue[tail]) {
	97	mutex_unlock(&adc->queue_mutex);
bd8ef102	98	dev_err(pcf->dev, "ADC queue is full, dropping request\n");
08c3e06a BR	99	return -EBUSY;
	100	}
	101
	102	adc->queue[tail] = req;
bd8ef102 PF	103	if (head == tail)
bd8ef102 PF	104	trigger_next_adc_job_if_any(pcf);
08c3e06a BR	105	adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
	106
	107	mutex_unlock(&adc->queue_mutex);
	108
08c3e06a BR	109	return 0;
	110	}
	111
6438a694 LPC	112	static void pcf50633_adc_sync_read_callback(struct pcf50633 pcf, void param,
6438a694 LPC	113	int result)
08c3e06a	114	{
6438a694	115	struct pcf50633_adc_sync_request *req = param;
08c3e06a BR	116
	117	req->result = result;
	118	complete(&req->completion);
	119	}
	120
	121	int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
	122	{
6438a694 LPC	123	struct pcf50633_adc_sync_request req;
6438a694 LPC	124	int ret;
08c3e06a	125
6438a694	126	init_completion(&req.completion);
08c3e06a	127
6438a694 LPC	128	ret = pcf50633_adc_async_read(pcf, mux, avg,
	129	pcf50633_adc_sync_read_callback, &req);
	130	if (ret)
	131	return ret;
bd8ef102	132
6438a694	133	wait_for_completion(&req.completion);
08c3e06a	134
6438a694	135	return req.result;
08c3e06a BR	136	}
	137	EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read);
	138
	139	int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
	140	void (callback)(struct pcf50633 , void *, int),
	141	void *callback_param)
	142	{
	143	struct pcf50633_adc_request *req;
	144
	145	/* req is freed when the result is ready, in interrupt handler */
	146	req = kmalloc(sizeof(*req), GFP_KERNEL);
	147	if (!req)
	148	return -ENOMEM;
	149
	150	req->mux = mux;
	151	req->avg = avg;
	152	req->callback = callback;
	153	req->callback_param = callback_param;
	154
bd8ef102	155	return adc_enqueue_request(pcf, req);
08c3e06a BR	156	}
	157	EXPORT_SYMBOL_GPL(pcf50633_adc_async_read);
	158
	159	static int adc_result(struct pcf50633 *pcf)
	160	{
	161	u8 adcs1, adcs3;
	162	u16 result;
	163
	164	adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1);
	165	adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3);
	166	result = (adcs1 << 2) \| (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK);
	167
	168	dev_dbg(pcf->dev, "adc result = %d\n", result);
	169
	170	return result;
	171	}
	172
	173	static void pcf50633_adc_irq(int irq, void *data)
	174	{
	175	struct pcf50633_adc *adc = data;
	176	struct pcf50633 *pcf = adc->pcf;
	177	struct pcf50633_adc_request *req;
bd8ef102	178	int head, res;
08c3e06a BR	179
	180	mutex_lock(&adc->queue_mutex);
	181	head = adc->queue_head;
	182
	183	req = adc->queue[head];
	184	if (WARN_ON(!req)) {
	185	dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n");
	186	mutex_unlock(&adc->queue_mutex);
	187	return;
	188	}
	189	adc->queue[head] = NULL;
	190	adc->queue_head = (head + 1) &
	191	(PCF50633_MAX_ADC_FIFO_DEPTH - 1);
	192
bd8ef102 PF	193	res = adc_result(pcf);
	194	trigger_next_adc_job_if_any(pcf);
	195
08c3e06a BR	196	mutex_unlock(&adc->queue_mutex);
08c3e06a BR	197
bd8ef102	198	req->callback(pcf, req->callback_param, res);
08c3e06a	199	kfree(req);
08c3e06a BR	200	}
	201
	202	static int __devinit pcf50633_adc_probe(struct platform_device *pdev)
	203	{
08c3e06a BR	204	struct pcf50633_adc *adc;
	205
	206	adc = kzalloc(sizeof(*adc), GFP_KERNEL);
	207	if (!adc)
	208	return -ENOMEM;
	209
68d641ef	210	adc->pcf = dev_to_pcf50633(pdev->dev.parent);
08c3e06a BR	211	platform_set_drvdata(pdev, adc);
08c3e06a BR	212
68d641ef	213	pcf50633_register_irq(adc->pcf, PCF50633_IRQ_ADCRDY,
08c3e06a BR	214	pcf50633_adc_irq, adc);
	215
	216	mutex_init(&adc->queue_mutex);
	217
	218	return 0;
	219	}
	220
	221	static int __devexit pcf50633_adc_remove(struct platform_device *pdev)
	222	{
	223	struct pcf50633_adc *adc = platform_get_drvdata(pdev);
	224	int i, head;
	225
	226	pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY);
	227
	228	mutex_lock(&adc->queue_mutex);
	229	head = adc->queue_head;
	230
	231	if (WARN_ON(adc->queue[head]))
	232	dev_err(adc->pcf->dev,
	233	"adc driver removed with request pending\n");
	234
	235	for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++)
	236	kfree(adc->queue[i]);
	237
	238	mutex_unlock(&adc->queue_mutex);
	239	kfree(adc);
	240
	241	return 0;
	242	}
	243
	244	static struct platform_driver pcf50633_adc_driver = {
	245	.driver = {
	246	.name = "pcf50633-adc",
	247	},
	248	.probe = pcf50633_adc_probe,
	249	.remove = __devexit_p(pcf50633_adc_remove),
	250	};
	251
	252	static int __init pcf50633_adc_init(void)
	253	{
	254	return platform_driver_register(&pcf50633_adc_driver);
	255	}
	256	module_init(pcf50633_adc_init);
	257
	258	static void __exit pcf50633_adc_exit(void)
	259	{
	260	platform_driver_unregister(&pcf50633_adc_driver);
	261	}
	262	module_exit(pcf50633_adc_exit);
	263
	264	MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>");
	265	MODULE_DESCRIPTION("PCF50633 adc driver");
	266	MODULE_LICENSE("GPL");
	267	MODULE_ALIAS("platform:pcf50633-adc");
	268