[mirror_ubuntu-focal-kernel.git] / drivers / iio / adc / at91-sama5d2_adc.c

/*
 * Atmel ADC driver for SAMA5D2 devices and compatible.
 *
 * Copyright (C) 2015 Atmel,
 *               2015 Ludovic Desroches <ludovic.desroches@atmel.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/regulator/consumer.h>

/* Control Register */
#define AT91_SAMA5D2_CR		0x00
/* Software Reset */
#define	AT91_SAMA5D2_CR_SWRST		BIT(0)
/* Start Conversion */
#define	AT91_SAMA5D2_CR_START		BIT(1)
/* Touchscreen Calibration */
#define	AT91_SAMA5D2_CR_TSCALIB		BIT(2)
/* Comparison Restart */
#define	AT91_SAMA5D2_CR_CMPRST		BIT(4)

/* Mode Register */
#define AT91_SAMA5D2_MR		0x04
/* Trigger Selection */
#define	AT91_SAMA5D2_MR_TRGSEL(v)	((v) << 1)
/* ADTRG */
#define	AT91_SAMA5D2_MR_TRGSEL_TRIG0	0
/* TIOA0 */
#define	AT91_SAMA5D2_MR_TRGSEL_TRIG1	1
/* TIOA1 */
#define	AT91_SAMA5D2_MR_TRGSEL_TRIG2	2
/* TIOA2 */
#define	AT91_SAMA5D2_MR_TRGSEL_TRIG3	3
/* PWM event line 0 */
#define	AT91_SAMA5D2_MR_TRGSEL_TRIG4	4
/* PWM event line 1 */
#define	AT91_SAMA5D2_MR_TRGSEL_TRIG5	5
/* TIOA3 */
#define	AT91_SAMA5D2_MR_TRGSEL_TRIG6	6
/* RTCOUT0 */
#define	AT91_SAMA5D2_MR_TRGSEL_TRIG7	7
/* Sleep Mode */
#define	AT91_SAMA5D2_MR_SLEEP		BIT(5)
/* Fast Wake Up */
#define	AT91_SAMA5D2_MR_FWUP		BIT(6)
/* Prescaler Rate Selection */
#define	AT91_SAMA5D2_MR_PRESCAL(v)	((v) << AT91_SAMA5D2_MR_PRESCAL_OFFSET)
#define	AT91_SAMA5D2_MR_PRESCAL_OFFSET	8
#define	AT91_SAMA5D2_MR_PRESCAL_MAX	0xff
/* Startup Time */
#define	AT91_SAMA5D2_MR_STARTUP(v)	((v) << 16)
/* Analog Change */
#define	AT91_SAMA5D2_MR_ANACH		BIT(23)
/* Tracking Time */
#define	AT91_SAMA5D2_MR_TRACKTIM(v)	((v) << 24)
#define	AT91_SAMA5D2_MR_TRACKTIM_MAX	0xff
/* Transfer Time */
#define	AT91_SAMA5D2_MR_TRANSFER(v)	((v) << 28)
#define	AT91_SAMA5D2_MR_TRANSFER_MAX	0x3
/* Use Sequence Enable */
#define	AT91_SAMA5D2_MR_USEQ		BIT(31)

/* Channel Sequence Register 1 */
#define AT91_SAMA5D2_SEQR1	0x08
/* Channel Sequence Register 2 */
#define AT91_SAMA5D2_SEQR2	0x0c
/* Channel Enable Register */
#define AT91_SAMA5D2_CHER	0x10
/* Channel Disable Register */
#define AT91_SAMA5D2_CHDR	0x14
/* Channel Status Register */
#define AT91_SAMA5D2_CHSR	0x18
/* Last Converted Data Register */
#define AT91_SAMA5D2_LCDR	0x20
/* Interrupt Enable Register */
#define AT91_SAMA5D2_IER		0x24
/* Interrupt Disable Register */
#define AT91_SAMA5D2_IDR		0x28
/* Interrupt Mask Register */
#define AT91_SAMA5D2_IMR		0x2c
/* Interrupt Status Register */
#define AT91_SAMA5D2_ISR		0x30
/* Last Channel Trigger Mode Register */
#define AT91_SAMA5D2_LCTMR	0x34
/* Last Channel Compare Window Register */
#define AT91_SAMA5D2_LCCWR	0x38
/* Overrun Status Register */
#define AT91_SAMA5D2_OVER	0x3c
/* Extended Mode Register */
#define AT91_SAMA5D2_EMR		0x40
/* Compare Window Register */
#define AT91_SAMA5D2_CWR		0x44
/* Channel Gain Register */
#define AT91_SAMA5D2_CGR		0x48
/* Channel Offset Register */
#define AT91_SAMA5D2_COR		0x4c
/* Channel Data Register 0 */
#define AT91_SAMA5D2_CDR0	0x50
/* Analog Control Register */
#define AT91_SAMA5D2_ACR		0x94
/* Touchscreen Mode Register */
#define AT91_SAMA5D2_TSMR	0xb0
/* Touchscreen X Position Register */
#define AT91_SAMA5D2_XPOSR	0xb4
/* Touchscreen Y Position Register */
#define AT91_SAMA5D2_YPOSR	0xb8
/* Touchscreen Pressure Register */
#define AT91_SAMA5D2_PRESSR	0xbc
/* Trigger Register */
#define AT91_SAMA5D2_TRGR	0xc0
/* Correction Select Register */
#define AT91_SAMA5D2_COSR	0xd0
/* Correction Value Register */
#define AT91_SAMA5D2_CVR		0xd4
/* Channel Error Correction Register */
#define AT91_SAMA5D2_CECR	0xd8
/* Write Protection Mode Register */
#define AT91_SAMA5D2_WPMR	0xe4
/* Write Protection Status Register */
#define AT91_SAMA5D2_WPSR	0xe8
/* Version Register */
#define AT91_SAMA5D2_VERSION	0xfc

#define AT91_AT91_SAMA5D2_CHAN(num, addr)				\
	{								\
		.type = IIO_VOLTAGE,					\
		.channel = num,						\
		.address = addr,					\
		.scan_type = {						\
			.sign = 'u',					\
			.realbits = 12,					\
		},							\
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
		.datasheet_name = "CH"#num,				\
		.indexed = 1,						\
	}

#define at91_adc_readl(st, reg)		readl_relaxed(st->base + reg)
#define at91_adc_writel(st, reg, val)	writel_relaxed(val, st->base + reg)

struct at91_adc_soc_info {
	unsigned			startup_time;
	unsigned			min_sample_rate;
	unsigned			max_sample_rate;
};

struct at91_adc_state {
	void __iomem			*base;
	int				irq;
	struct clk			*per_clk;
	struct regulator		*reg;
	struct regulator		*vref;
	u32				vref_uv;
	const struct iio_chan_spec	*chan;
	bool				conversion_done;
	u32				conversion_value;
	struct at91_adc_soc_info	soc_info;
	wait_queue_head_t		wq_data_available;
	/*
	 * lock to prevent concurrent 'single conversion' requests through
	 * sysfs.
	 */
	struct mutex			lock;
};

static const struct iio_chan_spec at91_adc_channels[] = {
	AT91_AT91_SAMA5D2_CHAN(0, 0x50),
	AT91_AT91_SAMA5D2_CHAN(1, 0x54),
	AT91_AT91_SAMA5D2_CHAN(2, 0x58),
	AT91_AT91_SAMA5D2_CHAN(3, 0x5c),
	AT91_AT91_SAMA5D2_CHAN(4, 0x60),
	AT91_AT91_SAMA5D2_CHAN(5, 0x64),
	AT91_AT91_SAMA5D2_CHAN(6, 0x68),
	AT91_AT91_SAMA5D2_CHAN(7, 0x6c),
	AT91_AT91_SAMA5D2_CHAN(8, 0x70),
	AT91_AT91_SAMA5D2_CHAN(9, 0x74),
	AT91_AT91_SAMA5D2_CHAN(10, 0x78),
	AT91_AT91_SAMA5D2_CHAN(11, 0x7c),
};

static unsigned at91_adc_startup_time(unsigned startup_time_min,
				      unsigned adc_clk_khz)
{
	const unsigned startup_lookup[] = {
		  0,   8,  16,  24,
		 64,  80,  96, 112,
		512, 576, 640, 704,
		768, 832, 896, 960
		};
	unsigned ticks_min, i;

	/*
	 * Since the adc frequency is checked before, there is no reason
	 * to not meet the startup time constraint.
	 */

	ticks_min = startup_time_min * adc_clk_khz / 1000;
	for (i = 0; i < ARRAY_SIZE(startup_lookup); i++)
		if (startup_lookup[i] > ticks_min)
			break;

	return i;
}

static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
{
	struct iio_dev *indio_dev = iio_priv_to_dev(st);
	unsigned f_per, prescal, startup;

	f_per = clk_get_rate(st->per_clk);
	prescal = (f_per / (2 * freq)) - 1;

	startup = at91_adc_startup_time(st->soc_info.startup_time,
					freq / 1000);

	at91_adc_writel(st, AT91_SAMA5D2_MR,
			AT91_SAMA5D2_MR_TRANSFER(2)
			| AT91_SAMA5D2_MR_STARTUP(startup)
			| AT91_SAMA5D2_MR_PRESCAL(prescal));

	dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
		freq, startup, prescal);
}

static unsigned at91_adc_get_sample_freq(struct at91_adc_state *st)
{
	unsigned f_adc, f_per = clk_get_rate(st->per_clk);
	unsigned mr, prescal;

	mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
	prescal = (mr >> AT91_SAMA5D2_MR_PRESCAL_OFFSET)
		  & AT91_SAMA5D2_MR_PRESCAL_MAX;
	f_adc = f_per / (2 * (prescal + 1));

	return f_adc;
}

static irqreturn_t at91_adc_interrupt(int irq, void *private)
{
	struct iio_dev *indio = private;
	struct at91_adc_state *st = iio_priv(indio);
	u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
	u32 imr = at91_adc_readl(st, AT91_SAMA5D2_IMR);

	if (status & imr) {
		st->conversion_value = at91_adc_readl(st, st->chan->address);
		st->conversion_done = true;
		wake_up_interruptible(&st->wq_data_available);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int at91_adc_read_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int *val, int *val2, long mask)
{
	struct at91_adc_state *st = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		mutex_lock(&st->lock);

		st->chan = chan;

		at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
		at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel));
		at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);

		ret = wait_event_interruptible_timeout(st->wq_data_available,
						       st->conversion_done,
						       msecs_to_jiffies(1000));
		if (ret == 0)
			ret = -ETIMEDOUT;

		if (ret > 0) {
			*val = st->conversion_value;
			ret = IIO_VAL_INT;
			st->conversion_done = false;
		}

		at91_adc_writel(st, AT91_SAMA5D2_IDR, BIT(chan->channel));
		at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));

		mutex_unlock(&st->lock);
		return ret;

	case IIO_CHAN_INFO_SCALE:
		*val = st->vref_uv / 1000;
		*val2 = chan->scan_type.realbits;
		return IIO_VAL_FRACTIONAL_LOG2;

	case IIO_CHAN_INFO_SAMP_FREQ:
		*val = at91_adc_get_sample_freq(st);
		return IIO_VAL_INT;

	default:
		return -EINVAL;
	}
}

static int at91_adc_write_raw(struct iio_dev *indio_dev,
			      struct iio_chan_spec const *chan,
			      int val, int val2, long mask)
{
	struct at91_adc_state *st = iio_priv(indio_dev);

	if (mask != IIO_CHAN_INFO_SAMP_FREQ)
		return -EINVAL;

	if (val < st->soc_info.min_sample_rate ||
	    val > st->soc_info.max_sample_rate)
		return -EINVAL;

	at91_adc_setup_samp_freq(st, val);

	return 0;
}

static const struct iio_info at91_adc_info = {
	.read_raw = &at91_adc_read_raw,
	.write_raw = &at91_adc_write_raw,
	.driver_module = THIS_MODULE,
};

static int at91_adc_probe(struct platform_device *pdev)
{
	struct iio_dev *indio_dev;
	struct at91_adc_state *st;
	struct resource	*res;
	int ret;

	indio_dev = devm_iio_device_alloc(&pdev->dev,
					  sizeof(struct at91_adc_state));
	if (!indio_dev)
		return -ENOMEM;

	indio_dev->dev.parent = &pdev->dev;
	indio_dev->name = dev_name(&pdev->dev);
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &at91_adc_info;
	indio_dev->channels = at91_adc_channels;
	indio_dev->num_channels = ARRAY_SIZE(at91_adc_channels);

	st = iio_priv(indio_dev);

	ret = of_property_read_u32(pdev->dev.of_node,
				   "atmel,min-sample-rate-hz",
				   &st->soc_info.min_sample_rate);
	if (ret) {
		dev_err(&pdev->dev,
			"invalid or missing value for atmel,min-sample-rate-hz\n");
		return ret;
	}

	ret = of_property_read_u32(pdev->dev.of_node,
				   "atmel,max-sample-rate-hz",
				   &st->soc_info.max_sample_rate);
	if (ret) {
		dev_err(&pdev->dev,
			"invalid or missing value for atmel,max-sample-rate-hz\n");
		return ret;
	}

	ret = of_property_read_u32(pdev->dev.of_node, "atmel,startup-time-ms",
				   &st->soc_info.startup_time);
	if (ret) {
		dev_err(&pdev->dev,
			"invalid or missing value for atmel,startup-time-ms\n");
		return ret;
	}

	init_waitqueue_head(&st->wq_data_available);
	mutex_init(&st->lock);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -EINVAL;

	st->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(st->base))
		return PTR_ERR(st->base);

	st->irq = platform_get_irq(pdev, 0);
	if (st->irq <= 0) {
		if (!st->irq)
			st->irq = -ENXIO;

		return st->irq;
	}

	st->per_clk = devm_clk_get(&pdev->dev, "adc_clk");
	if (IS_ERR(st->per_clk))
		return PTR_ERR(st->per_clk);

	st->reg = devm_regulator_get(&pdev->dev, "vddana");
	if (IS_ERR(st->reg))
		return PTR_ERR(st->reg);

	st->vref = devm_regulator_get(&pdev->dev, "vref");
	if (IS_ERR(st->vref))
		return PTR_ERR(st->vref);

	ret = devm_request_irq(&pdev->dev, st->irq, at91_adc_interrupt, 0,
			       pdev->dev.driver->name, indio_dev);
	if (ret)
		return ret;

	ret = regulator_enable(st->reg);
	if (ret)
		return ret;

	ret = regulator_enable(st->vref);
	if (ret)
		goto reg_disable;

	st->vref_uv = regulator_get_voltage(st->vref);
	if (st->vref_uv <= 0) {
		ret = -EINVAL;
		goto vref_disable;
	}

	at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
	at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);

	at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);

	ret = clk_prepare_enable(st->per_clk);
	if (ret)
		goto vref_disable;

	ret = iio_device_register(indio_dev);
	if (ret < 0)
		goto per_clk_disable_unprepare;

	dev_info(&pdev->dev, "version: %x\n",
		 readl_relaxed(st->base + AT91_SAMA5D2_VERSION));

	return 0;

per_clk_disable_unprepare:
	clk_disable_unprepare(st->per_clk);
vref_disable:
	regulator_disable(st->vref);
reg_disable:
	regulator_disable(st->reg);
	return ret;
}

static int at91_adc_remove(struct platform_device *pdev)
{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
	struct at91_adc_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);

	clk_disable_unprepare(st->per_clk);

	regulator_disable(st->vref);
	regulator_disable(st->reg);

	return 0;
}

static const struct of_device_id at91_adc_dt_match[] = {
	{
		.compatible = "atmel,sama5d2-adc",
	}, {
		/* sentinel */
	}
};
MODULE_DEVICE_TABLE(of, at91_adc_dt_match);

static struct platform_driver at91_adc_driver = {
	.probe = at91_adc_probe,
	.remove = at91_adc_remove,
	.driver = {
		.name = "at91-sama5d2_adc",
		.of_match_table = at91_adc_dt_match,
	},
};
module_platform_driver(at91_adc_driver)

MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
MODULE_DESCRIPTION("Atmel AT91 SAMA5D2 ADC");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
27e17719 LD	1	/*
	2	* Atmel ADC driver for SAMA5D2 devices and compatible.
	3	*
	4	* Copyright (C) 2015 Atmel,
	5	* 2015 Ludovic Desroches <ludovic.desroches@atmel.com>
	6	*
	7	* This software is licensed under the terms of the GNU General Public
	8	* License version 2, as published by the Free Software Foundation, and
	9	* may be copied, distributed, and modified under those terms.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*/
	16
	17	#include <linux/bitops.h>
	18	#include <linux/clk.h>
	19	#include <linux/interrupt.h>
	20	#include <linux/io.h>
	21	#include <linux/module.h>
	22	#include <linux/of_device.h>
	23	#include <linux/platform_device.h>
	24	#include <linux/sched.h>
	25	#include <linux/wait.h>
	26	#include <linux/iio/iio.h>
	27	#include <linux/iio/sysfs.h>
	28	#include <linux/regulator/consumer.h>
	29
	30	/* Control Register */
	31	#define AT91_SAMA5D2_CR 0x00
	32	/* Software Reset */
	33	#define AT91_SAMA5D2_CR_SWRST BIT(0)
	34	/* Start Conversion */
	35	#define AT91_SAMA5D2_CR_START BIT(1)
	36	/* Touchscreen Calibration */
	37	#define AT91_SAMA5D2_CR_TSCALIB BIT(2)
	38	/* Comparison Restart */
	39	#define AT91_SAMA5D2_CR_CMPRST BIT(4)
	40
	41	/* Mode Register */
	42	#define AT91_SAMA5D2_MR 0x04
	43	/* Trigger Selection */
	44	#define AT91_SAMA5D2_MR_TRGSEL(v) ((v) << 1)
	45	/* ADTRG */
	46	#define AT91_SAMA5D2_MR_TRGSEL_TRIG0 0
	47	/* TIOA0 */
	48	#define AT91_SAMA5D2_MR_TRGSEL_TRIG1 1
	49	/* TIOA1 */
	50	#define AT91_SAMA5D2_MR_TRGSEL_TRIG2 2
	51	/* TIOA2 */
	52	#define AT91_SAMA5D2_MR_TRGSEL_TRIG3 3
	53	/* PWM event line 0 */
	54	#define AT91_SAMA5D2_MR_TRGSEL_TRIG4 4
	55	/* PWM event line 1 */
	56	#define AT91_SAMA5D2_MR_TRGSEL_TRIG5 5
	57	/* TIOA3 */
	58	#define AT91_SAMA5D2_MR_TRGSEL_TRIG6 6
	59	/* RTCOUT0 */
	60	#define AT91_SAMA5D2_MR_TRGSEL_TRIG7 7
	61	/* Sleep Mode */
	62	#define AT91_SAMA5D2_MR_SLEEP BIT(5)
	63	/* Fast Wake Up */
	64	#define AT91_SAMA5D2_MR_FWUP BIT(6)
65	/* Prescaler Rate Selection */
66	#define AT91_SAMA5D2_MR_PRESCAL(v) ((v) << AT91_SAMA5D2_MR_PRESCAL_OFFSET)
67	#define AT91_SAMA5D2_MR_PRESCAL_OFFSET 8
68	#define AT91_SAMA5D2_MR_PRESCAL_MAX 0xff
69	/* Startup Time */
70	#define AT91_SAMA5D2_MR_STARTUP(v) ((v) << 16)
71	/* Analog Change */
72	#define AT91_SAMA5D2_MR_ANACH BIT(23)
73	/* Tracking Time */
74	#define AT91_SAMA5D2_MR_TRACKTIM(v) ((v) << 24)
75	#define AT91_SAMA5D2_MR_TRACKTIM_MAX 0xff
76	/* Transfer Time */
77	#define AT91_SAMA5D2_MR_TRANSFER(v) ((v) << 28)
78	#define AT91_SAMA5D2_MR_TRANSFER_MAX 0x3
79	/* Use Sequence Enable */
80	#define AT91_SAMA5D2_MR_USEQ BIT(31)
81
82	/* Channel Sequence Register 1 */
83	#define AT91_SAMA5D2_SEQR1 0x08
84	/* Channel Sequence Register 2 */
85	#define AT91_SAMA5D2_SEQR2 0x0c
86	/* Channel Enable Register */
87	#define AT91_SAMA5D2_CHER 0x10
88	/* Channel Disable Register */
89	#define AT91_SAMA5D2_CHDR 0x14
90	/* Channel Status Register */
91	#define AT91_SAMA5D2_CHSR 0x18
92	/* Last Converted Data Register */
93	#define AT91_SAMA5D2_LCDR 0x20
94	/* Interrupt Enable Register */
95	#define AT91_SAMA5D2_IER 0x24
96	/* Interrupt Disable Register */
97	#define AT91_SAMA5D2_IDR 0x28
98	/* Interrupt Mask Register */
99	#define AT91_SAMA5D2_IMR 0x2c
100	/* Interrupt Status Register */
101	#define AT91_SAMA5D2_ISR 0x30
102	/* Last Channel Trigger Mode Register */
103	#define AT91_SAMA5D2_LCTMR 0x34
104	/* Last Channel Compare Window Register */
105	#define AT91_SAMA5D2_LCCWR 0x38
106	/* Overrun Status Register */
107	#define AT91_SAMA5D2_OVER 0x3c
108	/* Extended Mode Register */
109	#define AT91_SAMA5D2_EMR 0x40
110	/* Compare Window Register */
111	#define AT91_SAMA5D2_CWR 0x44
112	/* Channel Gain Register */
113	#define AT91_SAMA5D2_CGR 0x48
114	/* Channel Offset Register */
115	#define AT91_SAMA5D2_COR 0x4c
116	/* Channel Data Register 0 */
117	#define AT91_SAMA5D2_CDR0 0x50
118	/* Analog Control Register */
119	#define AT91_SAMA5D2_ACR 0x94
120	/* Touchscreen Mode Register */
121	#define AT91_SAMA5D2_TSMR 0xb0
122	/* Touchscreen X Position Register */
123	#define AT91_SAMA5D2_XPOSR 0xb4
124	/* Touchscreen Y Position Register */
125	#define AT91_SAMA5D2_YPOSR 0xb8
126	/* Touchscreen Pressure Register */
127	#define AT91_SAMA5D2_PRESSR 0xbc
128	/* Trigger Register */
129	#define AT91_SAMA5D2_TRGR 0xc0
130	/* Correction Select Register */
131	#define AT91_SAMA5D2_COSR 0xd0
132	/* Correction Value Register */
133	#define AT91_SAMA5D2_CVR 0xd4
134	/* Channel Error Correction Register */
135	#define AT91_SAMA5D2_CECR 0xd8
136	/* Write Protection Mode Register */
137	#define AT91_SAMA5D2_WPMR 0xe4
138	/* Write Protection Status Register */
139	#define AT91_SAMA5D2_WPSR 0xe8
140	/* Version Register */
141	#define AT91_SAMA5D2_VERSION 0xfc
142
143	#define AT91_AT91_SAMA5D2_CHAN(num, addr) \
144	{ \
145	.type = IIO_VOLTAGE, \
146	.channel = num, \
147	.address = addr, \
148	.scan_type = { \
149	.sign = 'u', \
150	.realbits = 12, \
151	}, \
152	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
153	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
154	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
155	.datasheet_name = "CH"#num, \
156	.indexed = 1, \
157	}
158
159	#define at91_adc_readl(st, reg) readl_relaxed(st->base + reg)
160	#define at91_adc_writel(st, reg, val) writel_relaxed(val, st->base + reg)
161
162	struct at91_adc_soc_info {
163	unsigned startup_time;
164	unsigned min_sample_rate;
165	unsigned max_sample_rate;
166	};
167
168	struct at91_adc_state {
169	void __iomem *base;
170	int irq;
171	struct clk *per_clk;
172	struct regulator *reg;
173	struct regulator *vref;
174	u32 vref_uv;
175	const struct iio_chan_spec *chan;
176	bool conversion_done;
177	u32 conversion_value;
178	struct at91_adc_soc_info soc_info;
179	wait_queue_head_t wq_data_available;
180	/*
181	* lock to prevent concurrent 'single conversion' requests through
182	* sysfs.
183	*/
184	struct mutex lock;
185	};
186
187	static const struct iio_chan_spec at91_adc_channels[] = {
188	AT91_AT91_SAMA5D2_CHAN(0, 0x50),
189	AT91_AT91_SAMA5D2_CHAN(1, 0x54),
190	AT91_AT91_SAMA5D2_CHAN(2, 0x58),
191	AT91_AT91_SAMA5D2_CHAN(3, 0x5c),
192	AT91_AT91_SAMA5D2_CHAN(4, 0x60),
193	AT91_AT91_SAMA5D2_CHAN(5, 0x64),
194	AT91_AT91_SAMA5D2_CHAN(6, 0x68),
195	AT91_AT91_SAMA5D2_CHAN(7, 0x6c),
196	AT91_AT91_SAMA5D2_CHAN(8, 0x70),
197	AT91_AT91_SAMA5D2_CHAN(9, 0x74),
198	AT91_AT91_SAMA5D2_CHAN(10, 0x78),
199	AT91_AT91_SAMA5D2_CHAN(11, 0x7c),
200	};
201
202	static unsigned at91_adc_startup_time(unsigned startup_time_min,
203	unsigned adc_clk_khz)
204	{
205	const unsigned startup_lookup[] = {
206	0, 8, 16, 24,
207	64, 80, 96, 112,
208	512, 576, 640, 704,
209	768, 832, 896, 960
210	};
211	unsigned ticks_min, i;
212
213	/*
214	* Since the adc frequency is checked before, there is no reason
215	* to not meet the startup time constraint.
216	*/
217
218	ticks_min = startup_time_min * adc_clk_khz / 1000;
219	for (i = 0; i < ARRAY_SIZE(startup_lookup); i++)
220	if (startup_lookup[i] > ticks_min)
221	break;
222
223	return i;
224	}
225
226	static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
227	{
228	struct iio_dev *indio_dev = iio_priv_to_dev(st);
229	unsigned f_per, prescal, startup;
230
231	f_per = clk_get_rate(st->per_clk);
232	prescal = (f_per / (2 * freq)) - 1;
233
234	startup = at91_adc_startup_time(st->soc_info.startup_time,
235	freq / 1000);
236
237	at91_adc_writel(st, AT91_SAMA5D2_MR,
238	AT91_SAMA5D2_MR_TRANSFER(2)
239	\| AT91_SAMA5D2_MR_STARTUP(startup)
240	\| AT91_SAMA5D2_MR_PRESCAL(prescal));
241
242	dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
243	freq, startup, prescal);
244	}
245
246	static unsigned at91_adc_get_sample_freq(struct at91_adc_state *st)
247	{
248	unsigned f_adc, f_per = clk_get_rate(st->per_clk);
249	unsigned mr, prescal;
250
251	mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
252	prescal = (mr >> AT91_SAMA5D2_MR_PRESCAL_OFFSET)
253	& AT91_SAMA5D2_MR_PRESCAL_MAX;
254	f_adc = f_per / (2 * (prescal + 1));
255
256	return f_adc;
257	}
258
259	static irqreturn_t at91_adc_interrupt(int irq, void *private)
260	{
261	struct iio_dev *indio = private;
262	struct at91_adc_state *st = iio_priv(indio);
263	u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
264	u32 imr = at91_adc_readl(st, AT91_SAMA5D2_IMR);
265
266	if (status & imr) {
267	st->conversion_value = at91_adc_readl(st, st->chan->address);
268	st->conversion_done = true;
269	wake_up_interruptible(&st->wq_data_available);
270	return IRQ_HANDLED;
271	}
272
273	return IRQ_NONE;
274	}
275
276	static int at91_adc_read_raw(struct iio_dev *indio_dev,
277	struct iio_chan_spec const *chan,
278	int val, int val2, long mask)
279	{
280	struct at91_adc_state *st = iio_priv(indio_dev);
281	int ret;
282
283	switch (mask) {
284	case IIO_CHAN_INFO_RAW:
285	mutex_lock(&st->lock);
286
287	st->chan = chan;
288
289	at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
290	at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel));
291	at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);
292
293	ret = wait_event_interruptible_timeout(st->wq_data_available,
294	st->conversion_done,
295	msecs_to_jiffies(1000));
296	if (ret == 0)
297	ret = -ETIMEDOUT;
298
299	if (ret > 0) {
300	*val = st->conversion_value;
301	ret = IIO_VAL_INT;
302	st->conversion_done = false;
303	}
304
305	at91_adc_writel(st, AT91_SAMA5D2_IDR, BIT(chan->channel));
306	at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
307
308	mutex_unlock(&st->lock);
309	return ret;
310
311	case IIO_CHAN_INFO_SCALE:
312	*val = st->vref_uv / 1000;
313	*val2 = chan->scan_type.realbits;
314	return IIO_VAL_FRACTIONAL_LOG2;
315
316	case IIO_CHAN_INFO_SAMP_FREQ:
317	*val = at91_adc_get_sample_freq(st);
318	return IIO_VAL_INT;
319
320	default:
321	return -EINVAL;
322	}
323	}
324
325	static int at91_adc_write_raw(struct iio_dev *indio_dev,
326	struct iio_chan_spec const *chan,
327	int val, int val2, long mask)
328	{
329	struct at91_adc_state *st = iio_priv(indio_dev);
330
331	if (mask != IIO_CHAN_INFO_SAMP_FREQ)
332	return -EINVAL;
333
334	if (val < st->soc_info.min_sample_rate \|\|
335	val > st->soc_info.max_sample_rate)
336	return -EINVAL;
337
338	at91_adc_setup_samp_freq(st, val);
339
340	return 0;
341	}
342
343	static const struct iio_info at91_adc_info = {
344	.read_raw = &at91_adc_read_raw,
345	.write_raw = &at91_adc_write_raw,
346	.driver_module = THIS_MODULE,
347	};
348
349	static int at91_adc_probe(struct platform_device *pdev)
350	{
351	struct iio_dev *indio_dev;
352	struct at91_adc_state *st;
353	struct resource *res;
354	int ret;
355
356	indio_dev = devm_iio_device_alloc(&pdev->dev,
357	sizeof(struct at91_adc_state));
358	if (!indio_dev)
359	return -ENOMEM;
360
361	indio_dev->dev.parent = &pdev->dev;
362	indio_dev->name = dev_name(&pdev->dev);
363	indio_dev->modes = INDIO_DIRECT_MODE;
364	indio_dev->info = &at91_adc_info;
365	indio_dev->channels = at91_adc_channels;
366	indio_dev->num_channels = ARRAY_SIZE(at91_adc_channels);
367
368	st = iio_priv(indio_dev);
369
370	ret = of_property_read_u32(pdev->dev.of_node,
371	"atmel,min-sample-rate-hz",
372	&st->soc_info.min_sample_rate);
373	if (ret) {
374	dev_err(&pdev->dev,
375	"invalid or missing value for atmel,min-sample-rate-hz\n");
376	return ret;
377	}
378
379	ret = of_property_read_u32(pdev->dev.of_node,
380	"atmel,max-sample-rate-hz",
381	&st->soc_info.max_sample_rate);
382	if (ret) {
383	dev_err(&pdev->dev,
384	"invalid or missing value for atmel,max-sample-rate-hz\n");
385	return ret;
386	}
387
388	ret = of_property_read_u32(pdev->dev.of_node, "atmel,startup-time-ms",
389	&st->soc_info.startup_time);
390	if (ret) {
391	dev_err(&pdev->dev,
392	"invalid or missing value for atmel,startup-time-ms\n");
393	return ret;
394	}
395
396	init_waitqueue_head(&st->wq_data_available);
397	mutex_init(&st->lock);
398
399	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
400	if (!res)
401	return -EINVAL;
402
403	st->base = devm_ioremap_resource(&pdev->dev, res);
404	if (IS_ERR(st->base))
405	return PTR_ERR(st->base);
406
407	st->irq = platform_get_irq(pdev, 0);
408	if (st->irq <= 0) {
409	if (!st->irq)
410	st->irq = -ENXIO;
411
412	return st->irq;
413	}
414
415	st->per_clk = devm_clk_get(&pdev->dev, "adc_clk");
416	if (IS_ERR(st->per_clk))
417	return PTR_ERR(st->per_clk);
418
419	st->reg = devm_regulator_get(&pdev->dev, "vddana");
420	if (IS_ERR(st->reg))
421	return PTR_ERR(st->reg);
422
423	st->vref = devm_regulator_get(&pdev->dev, "vref");
424	if (IS_ERR(st->vref))
425	return PTR_ERR(st->vref);
426
427	ret = devm_request_irq(&pdev->dev, st->irq, at91_adc_interrupt, 0,
428	pdev->dev.driver->name, indio_dev);
429	if (ret)
430	return ret;
431
432	ret = regulator_enable(st->reg);
433	if (ret)
434	return ret;
435
436	ret = regulator_enable(st->vref);
437	if (ret)
438	goto reg_disable;
439
440	st->vref_uv = regulator_get_voltage(st->vref);
441	if (st->vref_uv <= 0) {
442	ret = -EINVAL;
443	goto vref_disable;
444	}
445
446	at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
447	at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
448
449	at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);
450
451	ret = clk_prepare_enable(st->per_clk);
452	if (ret)
453	goto vref_disable;
454
455	ret = iio_device_register(indio_dev);
456	if (ret < 0)
457	goto per_clk_disable_unprepare;
458
459	dev_info(&pdev->dev, "version: %x\n",
460	readl_relaxed(st->base + AT91_SAMA5D2_VERSION));
461
462	return 0;
463
464	per_clk_disable_unprepare:
465	clk_disable_unprepare(st->per_clk);
466	vref_disable:
467	regulator_disable(st->vref);
468	reg_disable:
469	regulator_disable(st->reg);
470	return ret;
471	}
472
473	static int at91_adc_remove(struct platform_device *pdev)
474	{
475	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
476	struct at91_adc_state *st = iio_priv(indio_dev);
477
478	iio_device_unregister(indio_dev);
479
480	clk_disable_unprepare(st->per_clk);
481
482	regulator_disable(st->vref);
483	regulator_disable(st->reg);
484
485	return 0;
486	}
487
488	static const struct of_device_id at91_adc_dt_match[] = {
489	{
490	.compatible = "atmel,sama5d2-adc",
491	}, {
492	/* sentinel */
493	}
494	};
495	MODULE_DEVICE_TABLE(of, at91_adc_dt_match);
496
497	static struct platform_driver at91_adc_driver = {
498	.probe = at91_adc_probe,
499	.remove = at91_adc_remove,
500	.driver = {
501	.name = "at91-sama5d2_adc",
502	.of_match_table = at91_adc_dt_match,
503	},
504	};
505	module_platform_driver(at91_adc_driver)
506
507	MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
508	MODULE_DESCRIPTION("Atmel AT91 SAMA5D2 ADC");
509	MODULE_LICENSE("GPL v2");