[linux-block.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/of.h>
#include <linux/of_device.h>
#include <linux/iio/machine.h>
#include <linux/iio/driver.h>

#include <linux/mfd/ti_am335x_tscadc.h>

struct tiadc_device {
	struct ti_tscadc_dev *mfd_tscadc;
	int channels;
	u8 channel_line[8];
	u8 channel_step[8];
};

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 u32 get_adc_step_mask(struct tiadc_device *adc_dev)
{
	u32 step_en;

	step_en = ((1 << adc_dev->channels) - 1);
	step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
	return step_en;
}

static void tiadc_step_config(struct tiadc_device *adc_dev)
{
	unsigned int stepconfig;
	int i, steps;
	u32 step_en;

	/*
	 * 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;
	stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;

	for (i = 0; i < adc_dev->channels; i++) {
		int chan;

		chan = adc_dev->channel_line[i];
		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
				stepconfig | STEPCONFIG_INP(chan));
		tiadc_writel(adc_dev, REG_STEPDELAY(steps),
				STEPCONFIG_OPENDLY);
		adc_dev->channel_step[i] = steps;
		steps++;
	}
	step_en = get_adc_step_mask(adc_dev);
	am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
}

static const char * const chan_name_ain[] = {
	"AIN0",
	"AIN1",
	"AIN2",
	"AIN3",
	"AIN4",
	"AIN5",
	"AIN6",
	"AIN7",
};

static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct iio_chan_spec *chan_array;
	struct iio_chan_spec *chan;
	int i;

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

	chan = chan_array;
	for (i = 0; i < channels; i++, chan++) {

		chan->type = IIO_VOLTAGE;
		chan->indexed = 1;
		chan->channel = adc_dev->channel_line[i];
		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
		chan->datasheet_name = chan_name_ain[chan->channel];
		chan->scan_type.sign = 'u';
		chan->scan_type.realbits = 12;
		chan->scan_type.storagebits = 32;
	}

	indio_dev->channels = chan_array;

	return 0;
}

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, read;
	u32 step = UINT_MAX;
	bool found = false;

	/*
	 * 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.
	 */

	for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
		if (chan->channel == adc_dev->channel_line[i]) {
			step = adc_dev->channel_step[i];
			break;
		}
	}
	if (WARN_ON_ONCE(step == UINT_MAX))
		return -EINVAL;

	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	for (i = 0; i < fifo1count; i++) {
		read = tiadc_readl(adc_dev, REG_FIFO1);
		if (read >> 16 == step) {
			*val = read & 0xfff;
			found = true;
		}
	}
	am335x_tsc_se_update(adc_dev->mfd_tscadc);
	if (found == false)
		return -EBUSY;
	return IIO_VAL_INT;
}

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

static int tiadc_probe(struct platform_device *pdev)
{
	struct iio_dev		*indio_dev;
	struct tiadc_device	*adc_dev;
	struct device_node	*node = pdev->dev.of_node;
	struct property		*prop;
	const __be32		*cur;
	int			err;
	u32			val;
	int			channels = 0;

	if (!node) {
		dev_err(&pdev->dev, "Could not find valid DT 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 = ti_tscadc_dev_get(pdev);

	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
		adc_dev->channel_line[channels] = val;
		channels++;
	}
	adc_dev->channels = 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);
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	u32 step_en;

	iio_device_unregister(indio_dev);
	tiadc_channels_remove(indio_dev);

	step_en = get_adc_step_mask(adc_dev);
	am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);

	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 const struct of_device_id ti_adc_dt_ids[] = {
	{ .compatible = "ti,am3359-adc", },
	{ }
};
MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);

static struct platform_driver tiadc_driver = {
	.driver = {
		.name   = "TI-am335x-adc",
		.owner	= THIS_MODULE,
		.pm	= TIADC_PM_OPS,
		.of_match_table = of_match_ptr(ti_adc_dt_ids),
	},
	.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>
6f39ac4e PR	25	#include <linux/of.h>
6f39ac4e PR	26	#include <linux/of_device.h>
c80df483 PA	27	#include <linux/iio/machine.h>
c80df483 PA	28	#include <linux/iio/driver.h>
5e53a69b PR	29
5e53a69b PR	30	#include <linux/mfd/ti_am335x_tscadc.h>
5e53a69b PR	31
	32	struct tiadc_device {
	33	struct ti_tscadc_dev *mfd_tscadc;
	34	int channels;
18926ede SAS	35	u8 channel_line[8];
18926ede SAS	36	u8 channel_step[8];
5e53a69b PR	37	};
	38
	39	static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
	40	{
	41	return readl(adc->mfd_tscadc->tscadc_base + reg);
	42	}
	43
	44	static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
	45	unsigned int val)
	46	{
	47	writel(val, adc->mfd_tscadc->tscadc_base + reg);
	48	}
	49
abeccee4 PR	50	static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
	51	{
	52	u32 step_en;
	53
	54	step_en = ((1 << adc_dev->channels) - 1);
	55	step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
	56	return step_en;
	57	}
	58
5e53a69b PR	59	static void tiadc_step_config(struct tiadc_device *adc_dev)
	60	{
	61	unsigned int stepconfig;
18926ede	62	int i, steps;
abeccee4	63	u32 step_en;
5e53a69b PR	64
	65	/*
	66	* There are 16 configurable steps and 8 analog input
	67	* lines available which are shared between Touchscreen and ADC.
	68	*
	69	* Steps backwards i.e. from 16 towards 0 are used by ADC
	70	* depending on number of input lines needed.
	71	* Channel would represent which analog input
	72	* needs to be given to ADC to digitalize data.
	73	*/
	74
	75	steps = TOTAL_STEPS - adc_dev->channels;
5e53a69b PR	76	stepconfig = STEPCONFIG_AVG_16 \| STEPCONFIG_FIFO1;
5e53a69b PR	77
18926ede SAS	78	for (i = 0; i < adc_dev->channels; i++) {
	79	int chan;
	80
	81	chan = adc_dev->channel_line[i];
	82	tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
	83	stepconfig \| STEPCONFIG_INP(chan));
	84	tiadc_writel(adc_dev, REG_STEPDELAY(steps),
5e53a69b	85	STEPCONFIG_OPENDLY);
18926ede SAS	86	adc_dev->channel_step[i] = steps;
18926ede SAS	87	steps++;
5e53a69b	88	}
abeccee4 PR	89	step_en = get_adc_step_mask(adc_dev);
abeccee4 PR	90	am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
5e53a69b PR	91	}
5e53a69b PR	92
c80df483 PA	93	static const char * const chan_name_ain[] = {
	94	"AIN0",
	95	"AIN1",
	96	"AIN2",
	97	"AIN3",
	98	"AIN4",
	99	"AIN5",
	100	"AIN6",
	101	"AIN7",
	102	};
	103
5e53a69b PR	104	static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
5e53a69b PR	105	{
c80df483	106	struct tiadc_device *adc_dev = iio_priv(indio_dev);
5e53a69b	107	struct iio_chan_spec *chan_array;
c80df483	108	struct iio_chan_spec *chan;
5e53a69b PR	109	int i;
	110
	111	indio_dev->num_channels = channels;
c80df483	112	chan_array = kcalloc(channels,
5e53a69b	113	sizeof(struct iio_chan_spec), GFP_KERNEL);
5e53a69b PR	114	if (chan_array == NULL)
	115	return -ENOMEM;
	116
c80df483 PA	117	chan = chan_array;
	118	for (i = 0; i < channels; i++, chan++) {
	119
5e53a69b PR	120	chan->type = IIO_VOLTAGE;
5e53a69b PR	121	chan->indexed = 1;
18926ede	122	chan->channel = adc_dev->channel_line[i];
6c572522	123	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
18926ede	124	chan->datasheet_name = chan_name_ain[chan->channel];
c80df483 PA	125	chan->scan_type.sign = 'u';
	126	chan->scan_type.realbits = 12;
	127	chan->scan_type.storagebits = 32;
5e53a69b PR	128	}
	129
	130	indio_dev->channels = chan_array;
	131
c80df483	132	return 0;
5e53a69b PR	133	}
	134
	135	static void tiadc_channels_remove(struct iio_dev *indio_dev)
	136	{
	137	kfree(indio_dev->channels);
	138	}
	139
	140	static int tiadc_read_raw(struct iio_dev *indio_dev,
	141	struct iio_chan_spec const *chan,
	142	int val, int val2, long mask)
	143	{
	144	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	145	int i;
18926ede SAS	146	unsigned int fifo1count, read;
18926ede SAS	147	u32 step = UINT_MAX;
1460c152	148	bool found = false;
5e53a69b PR	149
	150	/*
	151	* When the sub-system is first enabled,
	152	* the sequencer will always start with the
	153	* lowest step (1) and continue until step (16).
	154	* For ex: If we have enabled 4 ADC channels and
	155	* currently use only 1 out of them, the
	156	* sequencer still configures all the 4 steps,
	157	* leading to 3 unwanted data.
	158	* Hence we need to flush out this data.
	159	*/
	160
18926ede SAS	161	for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
	162	if (chan->channel == adc_dev->channel_line[i]) {
	163	step = adc_dev->channel_step[i];
	164	break;
	165	}
	166	}
	167	if (WARN_ON_ONCE(step == UINT_MAX))
	168	return -EINVAL;
	169
5e53a69b PR	170	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
5e53a69b PR	171	for (i = 0; i < fifo1count; i++) {
18926ede	172	read = tiadc_readl(adc_dev, REG_FIFO1);
1460c152	173	if (read >> 16 == step) {
18926ede	174	*val = read & 0xfff;
1460c152 SAS	175	found = true;
1460c152 SAS	176	}
5e53a69b	177	}
abeccee4	178	am335x_tsc_se_update(adc_dev->mfd_tscadc);
1460c152 SAS	179	if (found == false)
1460c152 SAS	180	return -EBUSY;
5e53a69b PR	181	return IIO_VAL_INT;
	182	}
	183
	184	static const struct iio_info tiadc_info = {
	185	.read_raw = &tiadc_read_raw,
bc93aa76	186	.driver_module = THIS_MODULE,
5e53a69b PR	187	};
5e53a69b PR	188
fc52692c	189	static int tiadc_probe(struct platform_device *pdev)
5e53a69b PR	190	{
	191	struct iio_dev *indio_dev;
	192	struct tiadc_device *adc_dev;
6f39ac4e	193	struct device_node *node = pdev->dev.of_node;
18926ede SAS	194	struct property *prop;
18926ede SAS	195	const __be32 *cur;
5e53a69b	196	int err;
18926ede SAS	197	u32 val;
18926ede SAS	198	int channels = 0;
5e53a69b	199
0ead4fb2 SAS	200	if (!node) {
0ead4fb2 SAS	201	dev_err(&pdev->dev, "Could not find valid DT data.\n");
5e53a69b PR	202	return -EINVAL;
	203	}
	204
	205	indio_dev = iio_device_alloc(sizeof(struct tiadc_device));
	206	if (indio_dev == NULL) {
	207	dev_err(&pdev->dev, "failed to allocate iio device\n");
	208	err = -ENOMEM;
	209	goto err_ret;
	210	}
	211	adc_dev = iio_priv(indio_dev);
	212
6f39ac4e PR	213	adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
6f39ac4e PR	214
18926ede SAS	215	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
	216	adc_dev->channel_line[channels] = val;
	217	channels++;
	218	}
	219	adc_dev->channels = channels;
5e53a69b PR	220
	221	indio_dev->dev.parent = &pdev->dev;
	222	indio_dev->name = dev_name(&pdev->dev);
	223	indio_dev->modes = INDIO_DIRECT_MODE;
	224	indio_dev->info = &tiadc_info;
	225
	226	tiadc_step_config(adc_dev);
	227
	228	err = tiadc_channel_init(indio_dev, adc_dev->channels);
	229	if (err < 0)
	230	goto err_free_device;
	231
	232	err = iio_device_register(indio_dev);
	233	if (err)
	234	goto err_free_channels;
	235
	236	platform_set_drvdata(pdev, indio_dev);
	237
	238	return 0;
	239
	240	err_free_channels:
	241	tiadc_channels_remove(indio_dev);
	242	err_free_device:
	243	iio_device_free(indio_dev);
	244	err_ret:
	245	return err;
	246	}
	247
fc52692c	248	static int tiadc_remove(struct platform_device *pdev)
5e53a69b PR	249	{
5e53a69b PR	250	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
abeccee4 PR	251	struct tiadc_device *adc_dev = iio_priv(indio_dev);
abeccee4 PR	252	u32 step_en;
5e53a69b PR	253
	254	iio_device_unregister(indio_dev);
	255	tiadc_channels_remove(indio_dev);
	256
abeccee4 PR	257	step_en = get_adc_step_mask(adc_dev);
	258	am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
	259
5e53a69b PR	260	iio_device_free(indio_dev);
	261
	262	return 0;
	263	}
	264
	265	#ifdef CONFIG_PM
	266	static int tiadc_suspend(struct device *dev)
	267	{
	268	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	269	struct tiadc_device *adc_dev = iio_priv(indio_dev);
a9bce1b0	270	struct ti_tscadc_dev *tscadc_dev;
5e53a69b PR	271	unsigned int idle;
5e53a69b PR	272
a9bce1b0	273	tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
5e53a69b PR	274	if (!device_may_wakeup(tscadc_dev->dev)) {
	275	idle = tiadc_readl(adc_dev, REG_CTRL);
	276	idle &= ~(CNTRLREG_TSCSSENB);
	277	tiadc_writel(adc_dev, REG_CTRL, (idle \|
	278	CNTRLREG_POWERDOWN));
	279	}
	280
	281	return 0;
	282	}
	283
	284	static int tiadc_resume(struct device *dev)
	285	{
	286	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	287	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	288	unsigned int restore;
	289
	290	/* Make sure ADC is powered up */
	291	restore = tiadc_readl(adc_dev, REG_CTRL);
	292	restore &= ~(CNTRLREG_POWERDOWN);
	293	tiadc_writel(adc_dev, REG_CTRL, restore);
	294
	295	tiadc_step_config(adc_dev);
	296
	297	return 0;
	298	}
	299
	300	static const struct dev_pm_ops tiadc_pm_ops = {
	301	.suspend = tiadc_suspend,
	302	.resume = tiadc_resume,
	303	};
	304	#define TIADC_PM_OPS (&tiadc_pm_ops)
	305	#else
	306	#define TIADC_PM_OPS NULL
	307	#endif
	308
6f39ac4e PR	309	static const struct of_device_id ti_adc_dt_ids[] = {
	310	{ .compatible = "ti,am3359-adc", },
	311	{ }
	312	};
	313	MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
	314
5e53a69b PR	315	static struct platform_driver tiadc_driver = {
5e53a69b PR	316	.driver = {
9f99928f	317	.name = "TI-am335x-adc",
5e53a69b PR	318	.owner = THIS_MODULE,
5e53a69b PR	319	.pm = TIADC_PM_OPS,
6f39ac4e	320	.of_match_table = of_match_ptr(ti_adc_dt_ids),
5e53a69b PR	321	},
5e53a69b PR	322	.probe = tiadc_probe,
fc52692c	323	.remove = tiadc_remove,
5e53a69b	324	};
5e53a69b PR	325	module_platform_driver(tiadc_driver);
	326
	327	MODULE_DESCRIPTION("TI ADC controller driver");
	328	MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
	329	MODULE_LICENSE("GPL");