[deliverable/linux.git] / drivers / iio / adc / ti_am335x_adc.c

/*
 * TI ADC MFD driver
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
 *
 * 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 version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/iio/iio.h>

#include <linux/mfd/ti_am335x_tscadc.h>
#include <linux/platform_data/ti_am335x_adc.h>

struct tiadc_device {
	struct ti_tscadc_dev *mfd_tscadc;
	int channels;
};

static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
{
	return readl(adc->mfd_tscadc->tscadc_base + reg);
}

static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
					unsigned int val)
{
	writel(val, adc->mfd_tscadc->tscadc_base + reg);
}

static void tiadc_step_config(struct tiadc_device *adc_dev)
{
	unsigned int stepconfig;
	int i, channels = 0, steps;

	/*
	 * There are 16 configurable steps and 8 analog input
	 * lines available which are shared between Touchscreen and ADC.
	 *
	 * Steps backwards i.e. from 16 towards 0 are used by ADC
	 * depending on number of input lines needed.
	 * Channel would represent which analog input
	 * needs to be given to ADC to digitalize data.
	 */

	steps = TOTAL_STEPS - adc_dev->channels;
	channels = TOTAL_CHANNELS - adc_dev->channels;

	stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;

	for (i = (steps + 1); i <= TOTAL_STEPS; i++) {
		tiadc_writel(adc_dev, REG_STEPCONFIG(i),
				stepconfig | STEPCONFIG_INP(channels));
		tiadc_writel(adc_dev, REG_STEPDELAY(i),
				STEPCONFIG_OPENDLY);
		channels++;
	}
	tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
}

static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
{
	struct iio_chan_spec *chan_array;
	int i;

	indio_dev->num_channels = channels;
	chan_array = kcalloc(indio_dev->num_channels,
			sizeof(struct iio_chan_spec), GFP_KERNEL);

	if (chan_array == NULL)
		return -ENOMEM;

	for (i = 0; i < (indio_dev->num_channels); i++) {
		struct iio_chan_spec *chan = chan_array + i;
		chan->type = IIO_VOLTAGE;
		chan->indexed = 1;
		chan->channel = i;
		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
	}

	indio_dev->channels = chan_array;

	return indio_dev->num_channels;
}

static void tiadc_channels_remove(struct iio_dev *indio_dev)
{
	kfree(indio_dev->channels);
}

static int tiadc_read_raw(struct iio_dev *indio_dev,
		struct iio_chan_spec const *chan,
		int *val, int *val2, long mask)
{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	int i;
	unsigned int fifo1count, readx1;

	/*
	 * When the sub-system is first enabled,
	 * the sequencer will always start with the
	 * lowest step (1) and continue until step (16).
	 * For ex: If we have enabled 4 ADC channels and
	 * currently use only 1 out of them, the
	 * sequencer still configures all the 4 steps,
	 * leading to 3 unwanted data.
	 * Hence we need to flush out this data.
	 */

	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	for (i = 0; i < fifo1count; i++) {
		readx1 = tiadc_readl(adc_dev, REG_FIFO1);
		if (i == chan->channel)
			*val = readx1 & 0xfff;
	}
	tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);

	return IIO_VAL_INT;
}

static const struct iio_info tiadc_info = {
	.read_raw = &tiadc_read_raw,
};

static int tiadc_probe(struct platform_device *pdev)
{
	struct iio_dev		*indio_dev;
	struct tiadc_device	*adc_dev;
	struct ti_tscadc_dev	*tscadc_dev = ti_tscadc_dev_get(pdev);
	struct mfd_tscadc_board	*pdata;
	int			err;

	pdata = tscadc_dev->dev->platform_data;
	if (!pdata || !pdata->adc_init) {
		dev_err(&pdev->dev, "Could not find platform data\n");
		return -EINVAL;
	}

	indio_dev = iio_device_alloc(sizeof(struct tiadc_device));
	if (indio_dev == NULL) {
		dev_err(&pdev->dev, "failed to allocate iio device\n");
		err = -ENOMEM;
		goto err_ret;
	}
	adc_dev = iio_priv(indio_dev);

	adc_dev->mfd_tscadc = tscadc_dev;
	adc_dev->channels = pdata->adc_init->adc_channels;

	indio_dev->dev.parent = &pdev->dev;
	indio_dev->name = dev_name(&pdev->dev);
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &tiadc_info;

	tiadc_step_config(adc_dev);

	err = tiadc_channel_init(indio_dev, adc_dev->channels);
	if (err < 0)
		goto err_free_device;

	err = iio_device_register(indio_dev);
	if (err)
		goto err_free_channels;

	platform_set_drvdata(pdev, indio_dev);

	return 0;

err_free_channels:
	tiadc_channels_remove(indio_dev);
err_free_device:
	iio_device_free(indio_dev);
err_ret:
	return err;
}

static int tiadc_remove(struct platform_device *pdev)
{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);

	iio_device_unregister(indio_dev);
	tiadc_channels_remove(indio_dev);

	iio_device_free(indio_dev);

	return 0;
}

#ifdef CONFIG_PM
static int tiadc_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct ti_tscadc_dev *tscadc_dev;
	unsigned int idle;

	tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
	if (!device_may_wakeup(tscadc_dev->dev)) {
		idle = tiadc_readl(adc_dev, REG_CTRL);
		idle &= ~(CNTRLREG_TSCSSENB);
		tiadc_writel(adc_dev, REG_CTRL, (idle |
				CNTRLREG_POWERDOWN));
	}

	return 0;
}

static int tiadc_resume(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	unsigned int restore;

	/* Make sure ADC is powered up */
	restore = tiadc_readl(adc_dev, REG_CTRL);
	restore &= ~(CNTRLREG_POWERDOWN);
	tiadc_writel(adc_dev, REG_CTRL, restore);

	tiadc_step_config(adc_dev);

	return 0;
}

static const struct dev_pm_ops tiadc_pm_ops = {
	.suspend = tiadc_suspend,
	.resume = tiadc_resume,
};
#define TIADC_PM_OPS (&tiadc_pm_ops)
#else
#define TIADC_PM_OPS NULL
#endif

static struct platform_driver tiadc_driver = {
	.driver = {
		.name   = "tiadc",
		.owner	= THIS_MODULE,
		.pm	= TIADC_PM_OPS,
	},
	.probe	= tiadc_probe,
	.remove	= tiadc_remove,
};

module_platform_driver(tiadc_driver);

MODULE_DESCRIPTION("TI ADC controller driver");
MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
5e53a69b PR	1	/*
	2	* TI ADC MFD driver
	3	*
	4	* Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License as
	8	* published by the Free Software Foundation version 2.
	9	*
	10	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	11	* kind, whether express or implied; without even the implied warranty
	12	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*/
	15
	16	#include <linux/init.h>
	17	#include <linux/kernel.h>
	18	#include <linux/err.h>
	19	#include <linux/module.h>
	20	#include <linux/slab.h>
	21	#include <linux/interrupt.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/io.h>
	24	#include <linux/iio/iio.h>
	25
	26	#include <linux/mfd/ti_am335x_tscadc.h>
	27	#include <linux/platform_data/ti_am335x_adc.h>
	28
	29	struct tiadc_device {
	30	struct ti_tscadc_dev *mfd_tscadc;
	31	int channels;
	32	};
	33
	34	static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
	35	{
	36	return readl(adc->mfd_tscadc->tscadc_base + reg);
	37	}
	38
	39	static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
	40	unsigned int val)
	41	{
	42	writel(val, adc->mfd_tscadc->tscadc_base + reg);
	43	}
	44
	45	static void tiadc_step_config(struct tiadc_device *adc_dev)
	46	{
	47	unsigned int stepconfig;
	48	int i, channels = 0, steps;
	49
	50	/*
	51	* There are 16 configurable steps and 8 analog input
	52	* lines available which are shared between Touchscreen and ADC.
	53	*
	54	* Steps backwards i.e. from 16 towards 0 are used by ADC
	55	* depending on number of input lines needed.
	56	* Channel would represent which analog input
	57	* needs to be given to ADC to digitalize data.
	58	*/
	59
	60	steps = TOTAL_STEPS - adc_dev->channels;
	61	channels = TOTAL_CHANNELS - adc_dev->channels;
	62
	63	stepconfig = STEPCONFIG_AVG_16 \| STEPCONFIG_FIFO1;
	64
65	for (i = (steps + 1); i <= TOTAL_STEPS; i++) {
66	tiadc_writel(adc_dev, REG_STEPCONFIG(i),
67	stepconfig \| STEPCONFIG_INP(channels));
68	tiadc_writel(adc_dev, REG_STEPDELAY(i),
69	STEPCONFIG_OPENDLY);
70	channels++;
71	}
72	tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
73	}
74
75	static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
76	{
77	struct iio_chan_spec *chan_array;
78	int i;
79
80	indio_dev->num_channels = channels;
81	chan_array = kcalloc(indio_dev->num_channels,
82	sizeof(struct iio_chan_spec), GFP_KERNEL);
83
84	if (chan_array == NULL)
85	return -ENOMEM;
86
87	for (i = 0; i < (indio_dev->num_channels); i++) {
88	struct iio_chan_spec *chan = chan_array + i;
89	chan->type = IIO_VOLTAGE;
90	chan->indexed = 1;
91	chan->channel = i;
6c572522	92	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
5e53a69b PR	93	}
	94
	95	indio_dev->channels = chan_array;
	96
	97	return indio_dev->num_channels;
	98	}
	99
	100	static void tiadc_channels_remove(struct iio_dev *indio_dev)
	101	{
	102	kfree(indio_dev->channels);
	103	}
	104
	105	static int tiadc_read_raw(struct iio_dev *indio_dev,
	106	struct iio_chan_spec const *chan,
	107	int val, int val2, long mask)
	108	{
	109	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	110	int i;
	111	unsigned int fifo1count, readx1;
	112
	113	/*
	114	* When the sub-system is first enabled,
	115	* the sequencer will always start with the
	116	* lowest step (1) and continue until step (16).
	117	* For ex: If we have enabled 4 ADC channels and
	118	* currently use only 1 out of them, the
	119	* sequencer still configures all the 4 steps,
	120	* leading to 3 unwanted data.
	121	* Hence we need to flush out this data.
	122	*/
	123
	124	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	125	for (i = 0; i < fifo1count; i++) {
	126	readx1 = tiadc_readl(adc_dev, REG_FIFO1);
	127	if (i == chan->channel)
	128	*val = readx1 & 0xfff;
	129	}
	130	tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
	131
	132	return IIO_VAL_INT;
	133	}
	134
	135	static const struct iio_info tiadc_info = {
	136	.read_raw = &tiadc_read_raw,
	137	};
	138
fc52692c	139	static int tiadc_probe(struct platform_device *pdev)
5e53a69b PR	140	{
	141	struct iio_dev *indio_dev;
	142	struct tiadc_device *adc_dev;
a9bce1b0	143	struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
5e53a69b PR	144	struct mfd_tscadc_board *pdata;
	145	int err;
	146
	147	pdata = tscadc_dev->dev->platform_data;
	148	if (!pdata \|\| !pdata->adc_init) {
	149	dev_err(&pdev->dev, "Could not find platform data\n");
	150	return -EINVAL;
	151	}
	152
	153	indio_dev = iio_device_alloc(sizeof(struct tiadc_device));
	154	if (indio_dev == NULL) {
	155	dev_err(&pdev->dev, "failed to allocate iio device\n");
	156	err = -ENOMEM;
	157	goto err_ret;
	158	}
	159	adc_dev = iio_priv(indio_dev);
	160
	161	adc_dev->mfd_tscadc = tscadc_dev;
	162	adc_dev->channels = pdata->adc_init->adc_channels;
	163
	164	indio_dev->dev.parent = &pdev->dev;
	165	indio_dev->name = dev_name(&pdev->dev);
	166	indio_dev->modes = INDIO_DIRECT_MODE;
	167	indio_dev->info = &tiadc_info;
	168
	169	tiadc_step_config(adc_dev);
	170
	171	err = tiadc_channel_init(indio_dev, adc_dev->channels);
	172	if (err < 0)
	173	goto err_free_device;
	174
	175	err = iio_device_register(indio_dev);
	176	if (err)
	177	goto err_free_channels;
	178
	179	platform_set_drvdata(pdev, indio_dev);
	180
	181	return 0;
	182
	183	err_free_channels:
	184	tiadc_channels_remove(indio_dev);
	185	err_free_device:
	186	iio_device_free(indio_dev);
	187	err_ret:
	188	return err;
	189	}
	190
fc52692c	191	static int tiadc_remove(struct platform_device *pdev)
5e53a69b PR	192	{
	193	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
	194
	195	iio_device_unregister(indio_dev);
	196	tiadc_channels_remove(indio_dev);
	197
	198	iio_device_free(indio_dev);
	199
	200	return 0;
	201	}
	202
	203	#ifdef CONFIG_PM
	204	static int tiadc_suspend(struct device *dev)
	205	{
	206	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	207	struct tiadc_device *adc_dev = iio_priv(indio_dev);
a9bce1b0	208	struct ti_tscadc_dev *tscadc_dev;
5e53a69b PR	209	unsigned int idle;
5e53a69b PR	210
a9bce1b0	211	tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
5e53a69b PR	212	if (!device_may_wakeup(tscadc_dev->dev)) {
	213	idle = tiadc_readl(adc_dev, REG_CTRL);
	214	idle &= ~(CNTRLREG_TSCSSENB);
	215	tiadc_writel(adc_dev, REG_CTRL, (idle \|
	216	CNTRLREG_POWERDOWN));
	217	}
	218
	219	return 0;
	220	}
	221
	222	static int tiadc_resume(struct device *dev)
	223	{
	224	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	225	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	226	unsigned int restore;
	227
	228	/* Make sure ADC is powered up */
	229	restore = tiadc_readl(adc_dev, REG_CTRL);
	230	restore &= ~(CNTRLREG_POWERDOWN);
	231	tiadc_writel(adc_dev, REG_CTRL, restore);
	232
	233	tiadc_step_config(adc_dev);
	234
	235	return 0;
	236	}
	237
	238	static const struct dev_pm_ops tiadc_pm_ops = {
	239	.suspend = tiadc_suspend,
	240	.resume = tiadc_resume,
	241	};
	242	#define TIADC_PM_OPS (&tiadc_pm_ops)
	243	#else
	244	#define TIADC_PM_OPS NULL
	245	#endif
	246
	247	static struct platform_driver tiadc_driver = {
	248	.driver = {
	249	.name = "tiadc",
	250	.owner = THIS_MODULE,
	251	.pm = TIADC_PM_OPS,
	252	},
	253	.probe = tiadc_probe,
fc52692c	254	.remove = tiadc_remove,
5e53a69b PR	255	};
	256
	257	module_platform_driver(tiadc_driver);
	258
	259	MODULE_DESCRIPTION("TI ADC controller driver");
	260	MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
	261	MODULE_LICENSE("GPL");