Release 4.11 drivers/staging/iio/adc/spear_adc.c

/*
 * ST SPEAr ADC driver
 *
 * Copyright 2012 Stefan Roese <sr@denx.de>
 *
 * Licensed under the GPL-2.
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/completion.h>
#include <linux/of.h>
#include <linux/of_address.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

/* SPEAR registers definitions */

#define SPEAR600_ADC_SCAN_RATE_LO(x)	((x) & 0xFFFF)

#define SPEAR600_ADC_SCAN_RATE_HI(x)	(((x) >> 0x10) & 0xFFFF)

#define SPEAR_ADC_CLK_LOW(x)		(((x) & 0xf) << 0)

#define SPEAR_ADC_CLK_HIGH(x)		(((x) & 0xf) << 4)

/* Bit definitions for SPEAR_ADC_STATUS */

#define SPEAR_ADC_STATUS_START_CONVERSION	BIT(0)

#define SPEAR_ADC_STATUS_CHANNEL_NUM(x)		((x) << 1)

#define SPEAR_ADC_STATUS_ADC_ENABLE		BIT(4)

#define SPEAR_ADC_STATUS_AVG_SAMPLE(x)		((x) << 5)

#define SPEAR_ADC_STATUS_VREF_INTERNAL		BIT(9)


#define SPEAR_ADC_DATA_MASK		0x03ff

#define SPEAR_ADC_DATA_BITS		10


#define SPEAR_ADC_MOD_NAME "spear-adc"


#define SPEAR_ADC_CHANNEL_NUM		8


#define SPEAR_ADC_CLK_MIN			2500000

#define SPEAR_ADC_CLK_MAX			20000000


struct adc_regs_spear3xx {
	
u32 status;
	
u32 average;
	
u32 scan_rate;
	
u32 clk;	/* Not avail for 1340 & 1310 */
	
u32 ch_ctrl[SPEAR_ADC_CHANNEL_NUM];
	
u32 ch_data[SPEAR_ADC_CHANNEL_NUM];
};


struct chan_data {
	
u32 lsb;
	
u32 msb;
};


struct adc_regs_spear6xx {
	
u32 status;
	
u32 pad[2];
	
u32 clk;
	
u32 ch_ctrl[SPEAR_ADC_CHANNEL_NUM];
	
struct chan_data ch_data[SPEAR_ADC_CHANNEL_NUM];
	
u32 scan_rate_lo;
	
u32 scan_rate_hi;
	
struct chan_data average;
};


struct spear_adc_state {
	
struct device_node *np;
	
struct adc_regs_spear3xx __iomem *adc_base_spear3xx;
	
struct adc_regs_spear6xx __iomem *adc_base_spear6xx;
	
struct clk *clk;
	
struct completion completion;
	
u32 current_clk;
	
u32 sampling_freq;
	
u32 avg_samples;
	
u32 vref_external;
	
u32 value;
};

/*
 * Functions to access some SPEAr ADC register. Abstracted into
 * static inline functions, because of different register offsets
 * on different SoC variants (SPEAr300 vs SPEAr600 etc).
 */


static void spear_adc_set_status(struct spear_adc_state *st, u32 val)
{
	__raw_writel(val, &st->adc_base_spear6xx->status);
}

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2
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static void spear_adc_set_clk(struct spear_adc_state *st, u32 val)
{
	u32 clk_high, clk_low, count;
	u32 apb_clk = clk_get_rate(st->clk);

	count = DIV_ROUND_UP(apb_clk, val);
	clk_low = count / 2;
	clk_high = count - clk_low;
	st->current_clk = apb_clk / count;

	__raw_writel(SPEAR_ADC_CLK_LOW(clk_low) | SPEAR_ADC_CLK_HIGH(clk_high),
		     &st->adc_base_spear6xx->clk);
}

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8.75%
2
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Tapasweni Pathak
4
5.00%
1
25.00%
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80
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4
100.00%



static void spear_adc_set_ctrl(struct spear_adc_state *st, int n,
			       u32 val)
{
	__raw_writel(val, &st->adc_base_spear6xx->ch_ctrl[n]);
}

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2
100.00%



static u32 spear_adc_get_average(struct spear_adc_state *st)
{
	if (of_device_is_compatible(st->np, "st,spear600-adc")) {
		return __raw_readl(&st->adc_base_spear6xx->average.msb) &
			SPEAR_ADC_DATA_MASK;
	} else {
		return __raw_readl(&st->adc_base_spear3xx->average) &
			SPEAR_ADC_DATA_MASK;
	}
}

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55
100.00%
3
100.00%



static void spear_adc_set_scanrate(struct spear_adc_state *st, u32 rate)
{
	if (of_device_is_compatible(st->np, "st,spear600-adc")) {
		__raw_writel(SPEAR600_ADC_SCAN_RATE_LO(rate),
			     &st->adc_base_spear6xx->scan_rate_lo);
		__raw_writel(SPEAR600_ADC_SCAN_RATE_HI(rate),
			     &st->adc_base_spear6xx->scan_rate_hi);
	} else {
		__raw_writel(rate, &st->adc_base_spear3xx->scan_rate);
	}
}

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11.11%
2
66.67%
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72
100.00%
3
100.00%



static int spear_adc_read_raw(struct iio_dev *indio_dev,
			      struct iio_chan_spec const *chan,
			      int *val,
			      int *val2,
			      long mask)
{
	struct spear_adc_state *st = iio_priv(indio_dev);
	u32 status;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		mutex_lock(&indio_dev->mlock);

		status = SPEAR_ADC_STATUS_CHANNEL_NUM(chan->channel) |
			SPEAR_ADC_STATUS_AVG_SAMPLE(st->avg_samples) |
			SPEAR_ADC_STATUS_START_CONVERSION |
			SPEAR_ADC_STATUS_ADC_ENABLE;
		if (st->vref_external == 0)
			status |= SPEAR_ADC_STATUS_VREF_INTERNAL;

		spear_adc_set_status(st, status);
		wait_for_completion(&st->completion); /* set by ISR */
		*val = st->value;

		mutex_unlock(&indio_dev->mlock);

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:
		*val = st->vref_external;
		*val2 = SPEAR_ADC_DATA_BITS;
		return IIO_VAL_FRACTIONAL_LOG2;
	case IIO_CHAN_INFO_SAMP_FREQ:
		*val = st->current_clk;
		return IIO_VAL_INT;
	}

	return -EINVAL;
}

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14.29%
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29
18.24%
5
71.43%
Lars-Peter Clausen
3
1.89%
1
14.29%
Total
159
100.00%
7
100.00%



static int spear_adc_write_raw(struct iio_dev *indio_dev,
			       struct iio_chan_spec const *chan,
			       int val,
			       int val2,
			       long mask)
{
	struct spear_adc_state *st = iio_priv(indio_dev);
	int ret = 0;

	if (mask != IIO_CHAN_INFO_SAMP_FREQ)
		return -EINVAL;

	mutex_lock(&indio_dev->mlock);

	if ((val < SPEAR_ADC_CLK_MIN) ||
	    (val > SPEAR_ADC_CLK_MAX) ||
	    (val2 != 0)) {
		ret = -EINVAL;
		goto out;
	}

	spear_adc_set_clk(st, val);

out:
	mutex_unlock(&indio_dev->mlock);
	return ret;
}

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#define SPEAR_ADC_CHAN(idx) {                               \
        .type = IIO_VOLTAGE,                            \
        .indexed = 1,                                   \
        .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),\
        .channel = idx,                                 \
}


static const struct iio_chan_spec spear_adc_iio_channels[] = {
	SPEAR_ADC_CHAN(0),
	SPEAR_ADC_CHAN(1),
	SPEAR_ADC_CHAN(2),
	SPEAR_ADC_CHAN(3),
	SPEAR_ADC_CHAN(4),
	SPEAR_ADC_CHAN(5),
	SPEAR_ADC_CHAN(6),
	SPEAR_ADC_CHAN(7),
};



static irqreturn_t spear_adc_isr(int irq, void *dev_id)
{
	struct spear_adc_state *st = dev_id;

	/* Read value to clear IRQ */
	st->value = spear_adc_get_average(st);
	complete(&st->completion);

	return IRQ_HANDLED;
}

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41
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2
100.00%



static int spear_adc_configure(struct spear_adc_state *st)
{
	int i;

	/* Reset ADC core */
	spear_adc_set_status(st, 0);
	__raw_writel(0, &st->adc_base_spear6xx->clk);
	for (i = 0; i < 8; i++)
		spear_adc_set_ctrl(st, i, 0);
	spear_adc_set_scanrate(st, 0);

	spear_adc_set_clk(st, st->sampling_freq);

	return 0;
}

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2
100.00%


static const struct iio_info spear_adc_info = {
	.read_raw = &spear_adc_read_raw,
	.write_raw = &spear_adc_write_raw,
	.driver_module = THIS_MODULE,
};



static int spear_adc_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct device *dev = &pdev->dev;
	struct spear_adc_state *st;
	struct resource *res;
	struct iio_dev *indio_dev = NULL;
	int ret = -ENODEV;
	int irq;

	indio_dev = devm_iio_device_alloc(dev, sizeof(struct spear_adc_state));
	if (!indio_dev) {
		dev_err(dev, "failed allocating iio device\n");
		return -ENOMEM;
	}

	st = iio_priv(indio_dev);
	st->np = np;

	/*
         * SPEAr600 has a different register layout than other SPEAr SoC's
         * (e.g. SPEAr3xx). Let's provide two register base addresses
         * to support multi-arch kernels.
         */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	st->adc_base_spear6xx = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(st->adc_base_spear6xx))
		return PTR_ERR(st->adc_base_spear6xx);

	st->adc_base_spear3xx =
		(struct adc_regs_spear3xx __iomem *)st->adc_base_spear6xx;

	st->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(st->clk)) {
		dev_err(dev, "failed getting clock\n");
		return PTR_ERR(st->clk);
	}

	ret = clk_prepare_enable(st->clk);
	if (ret) {
		dev_err(dev, "failed enabling clock\n");
		return ret;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq <= 0) {
		dev_err(dev, "failed getting interrupt resource\n");
		ret = -EINVAL;
		goto errout2;
	}

	ret = devm_request_irq(dev, irq, spear_adc_isr, 0, SPEAR_ADC_MOD_NAME,
			       st);
	if (ret < 0) {
		dev_err(dev, "failed requesting interrupt\n");
		goto errout2;
	}

	if (of_property_read_u32(np, "sampling-frequency",
				 &st->sampling_freq)) {
		dev_err(dev, "sampling-frequency missing in DT\n");
		ret = -EINVAL;
		goto errout2;
	}

	/*
         * Optional avg_samples defaults to 0, resulting in single data
         * conversion
         */
	of_property_read_u32(np, "average-samples", &st->avg_samples);

	/*
         * Optional vref_external defaults to 0, resulting in internal vref
         * selection
         */
	of_property_read_u32(np, "vref-external", &st->vref_external);

	spear_adc_configure(st);

	platform_set_drvdata(pdev, indio_dev);

	init_completion(&st->completion);

	indio_dev->name = SPEAR_ADC_MOD_NAME;
	indio_dev->dev.parent = dev;
	indio_dev->info = &spear_adc_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = spear_adc_iio_channels;
	indio_dev->num_channels = ARRAY_SIZE(spear_adc_iio_channels);

	ret = iio_device_register(indio_dev);
	if (ret)
		goto errout2;

	dev_info(dev, "SPEAR ADC driver loaded, IRQ %d\n", irq);

	return 0;

errout2:
	clk_disable_unprepare(st->clk);
	return ret;
}

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9.21%
1
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Jonathan Cameron
34
7.64%
3
30.00%
Sachin Kamat
7
1.57%
1
10.00%
Hari Prasath Gujulan Elango
6
1.35%
1
10.00%
Lars-Peter Clausen
2
0.45%
2
20.00%
Julia Lawall
1
0.22%
1
10.00%
Total
445
100.00%
10
100.00%



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

	iio_device_unregister(indio_dev);
	clk_disable_unprepare(st->clk);

	return 0;
}

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Julia Lawall
1
2.17%
1
25.00%
Total
46
100.00%
4
100.00%

#ifdef CONFIG_OF

static const struct of_device_id spear_adc_dt_ids[] = {
	{ .compatible = "st,spear600-adc", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, spear_adc_dt_ids);
#endif


static struct platform_driver spear_adc_driver = {
	.probe		= spear_adc_probe,
	.remove		= spear_adc_remove,
	.driver		= {
		.name	= SPEAR_ADC_MOD_NAME,
		.of_match_table = of_match_ptr(spear_adc_dt_ids),
        },
};


module_platform_driver(spear_adc_driver);

MODULE_AUTHOR("Stefan Roese <sr@denx.de>");
MODULE_DESCRIPTION("SPEAr ADC driver");
MODULE_LICENSE("GPL");
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15.91%
7
36.84%
Amitoj Kaur Chawla
41
2.63%
1
5.26%
Sachin Kamat
12
0.77%
2
10.53%
Lars-Peter Clausen
6
0.38%
4
21.05%
Hari Prasath Gujulan Elango
6
0.38%
1
5.26%
Tapasweni Pathak
4
0.26%
1
5.26%
Haneen Mohammed
3
0.19%
1
5.26%
Julia Lawall
2
0.13%
1
5.26%
Total
1559
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19
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Directory: drivers/staging/iio/adc

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