[GitHub/mt8127/android_kernel_alcatel_ttab.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;
	int result;
	void (*callback)(struct pcf50633 *, void *, int);
	void *callback_param;

	/* Used in case of sync requests */
	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_request *req = param;

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

int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
{
	struct pcf50633_adc_request *req;
	int err;

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

	req->mux = mux;
	req->avg = avg;
	req->callback =  pcf50633_adc_sync_read_callback;
	req->callback_param = req;

	init_completion(&req->completion);
	err = adc_enqueue_request(pcf, req);
	if (err)
		return err;

	wait_for_completion(&req->completion);

	/* FIXME by this time req might be already freed */
	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;
	33	int result;
	34	void (callback)(struct pcf50633 , void *, int);
	35	void *callback_param;
	36
	37	/* Used in case of sync requests */
	38	struct completion completion;
	39
	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
	112	static void
	113	pcf50633_adc_sync_read_callback(struct pcf50633 pcf, void param, int result)
	114	{
	115	struct pcf50633_adc_request *req = param;
	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	{
	123	struct pcf50633_adc_request *req;
bd8ef102	124	int err;
08c3e06a BR	125
	126	/* req is freed when the result is ready, in interrupt handler */
	127	req = kzalloc(sizeof(*req), GFP_KERNEL);
	128	if (!req)
	129	return -ENOMEM;
	130
	131	req->mux = mux;
	132	req->avg = avg;
	133	req->callback = pcf50633_adc_sync_read_callback;
	134	req->callback_param = req;
	135
	136	init_completion(&req->completion);
bd8ef102 PF	137	err = adc_enqueue_request(pcf, req);
	138	if (err)
	139	return err;
	140
08c3e06a BR	141	wait_for_completion(&req->completion);
08c3e06a BR	142
bd8ef102	143	/* FIXME by this time req might be already freed */
08c3e06a BR	144	return req->result;
	145	}
	146	EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read);
	147
	148	int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
	149	void (callback)(struct pcf50633 , void *, int),
	150	void *callback_param)
	151	{
	152	struct pcf50633_adc_request *req;
	153
	154	/* req is freed when the result is ready, in interrupt handler */
	155	req = kmalloc(sizeof(*req), GFP_KERNEL);
	156	if (!req)
	157	return -ENOMEM;
	158
	159	req->mux = mux;
	160	req->avg = avg;
	161	req->callback = callback;
	162	req->callback_param = callback_param;
	163
bd8ef102	164	return adc_enqueue_request(pcf, req);
08c3e06a BR	165	}
	166	EXPORT_SYMBOL_GPL(pcf50633_adc_async_read);
	167
	168	static int adc_result(struct pcf50633 *pcf)
	169	{
	170	u8 adcs1, adcs3;
	171	u16 result;
	172
	173	adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1);
	174	adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3);
	175	result = (adcs1 << 2) \| (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK);
	176
	177	dev_dbg(pcf->dev, "adc result = %d\n", result);
	178
	179	return result;
	180	}
	181
	182	static void pcf50633_adc_irq(int irq, void *data)
	183	{
	184	struct pcf50633_adc *adc = data;
	185	struct pcf50633 *pcf = adc->pcf;
	186	struct pcf50633_adc_request *req;
bd8ef102	187	int head, res;
08c3e06a BR	188
	189	mutex_lock(&adc->queue_mutex);
	190	head = adc->queue_head;
	191
	192	req = adc->queue[head];
	193	if (WARN_ON(!req)) {
	194	dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n");
	195	mutex_unlock(&adc->queue_mutex);
	196	return;
	197	}
	198	adc->queue[head] = NULL;
	199	adc->queue_head = (head + 1) &
	200	(PCF50633_MAX_ADC_FIFO_DEPTH - 1);
	201
bd8ef102 PF	202	res = adc_result(pcf);
	203	trigger_next_adc_job_if_any(pcf);
	204
08c3e06a BR	205	mutex_unlock(&adc->queue_mutex);
08c3e06a BR	206
bd8ef102	207	req->callback(pcf, req->callback_param, res);
08c3e06a	208	kfree(req);
08c3e06a BR	209	}
	210
	211	static int __devinit pcf50633_adc_probe(struct platform_device *pdev)
	212	{
08c3e06a BR	213	struct pcf50633_adc *adc;
	214
	215	adc = kzalloc(sizeof(*adc), GFP_KERNEL);
	216	if (!adc)
	217	return -ENOMEM;
	218
68d641ef	219	adc->pcf = dev_to_pcf50633(pdev->dev.parent);
08c3e06a BR	220	platform_set_drvdata(pdev, adc);
08c3e06a BR	221
68d641ef	222	pcf50633_register_irq(adc->pcf, PCF50633_IRQ_ADCRDY,
08c3e06a BR	223	pcf50633_adc_irq, adc);
	224
	225	mutex_init(&adc->queue_mutex);
	226
	227	return 0;
	228	}
	229
	230	static int __devexit pcf50633_adc_remove(struct platform_device *pdev)
	231	{
	232	struct pcf50633_adc *adc = platform_get_drvdata(pdev);
	233	int i, head;
	234
	235	pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY);
	236
	237	mutex_lock(&adc->queue_mutex);
	238	head = adc->queue_head;
	239
	240	if (WARN_ON(adc->queue[head]))
	241	dev_err(adc->pcf->dev,
	242	"adc driver removed with request pending\n");
	243
	244	for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++)
	245	kfree(adc->queue[i]);
	246
	247	mutex_unlock(&adc->queue_mutex);
	248	kfree(adc);
	249
	250	return 0;
	251	}
	252
	253	static struct platform_driver pcf50633_adc_driver = {
	254	.driver = {
	255	.name = "pcf50633-adc",
	256	},
	257	.probe = pcf50633_adc_probe,
	258	.remove = __devexit_p(pcf50633_adc_remove),
	259	};
	260
	261	static int __init pcf50633_adc_init(void)
	262	{
	263	return platform_driver_register(&pcf50633_adc_driver);
	264	}
	265	module_init(pcf50633_adc_init);
	266
	267	static void __exit pcf50633_adc_exit(void)
	268	{
	269	platform_driver_unregister(&pcf50633_adc_driver);
	270	}
	271	module_exit(pcf50633_adc_exit);
	272
	273	MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>");
	274	MODULE_DESCRIPTION("PCF50633 adc driver");
	275	MODULE_LICENSE("GPL");
	276	MODULE_ALIAS("platform:pcf50633-adc");
	277