[mirror_ubuntu-hirsute-kernel.git] / drivers / input / keyboard / sun4i-lradc-keys.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Allwinner sun4i low res adc attached tablet keys driver
 *
 * Copyright (C) 2014 Hans de Goede <hdegoede@redhat.com>
 */

/*
 * Allwinnner sunxi SoCs have a lradc which is specifically designed to have
 * various (tablet) keys (ie home, back, search, etc). attached to it using
 * a resistor network. This driver is for the keys on such boards.
 *
 * There are 2 channels, currently this driver only supports channel 0 since
 * there are no boards known to use channel 1.
 */

#include <linux/err.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

#define LRADC_CTRL		0x00
#define LRADC_INTC		0x04
#define LRADC_INTS		0x08
#define LRADC_DATA0		0x0c
#define LRADC_DATA1		0x10

/* LRADC_CTRL bits */
#define FIRST_CONVERT_DLY(x)	((x) << 24) /* 8 bits */
#define CHAN_SELECT(x)		((x) << 22) /* 2 bits */
#define CONTINUE_TIME_SEL(x)	((x) << 16) /* 4 bits */
#define KEY_MODE_SEL(x)		((x) << 12) /* 2 bits */
#define LEVELA_B_CNT(x)		((x) << 8)  /* 4 bits */
#define HOLD_KEY_EN(x)		((x) << 7)
#define HOLD_EN(x)		((x) << 6)
#define LEVELB_VOL(x)		((x) << 4)  /* 2 bits */
#define SAMPLE_RATE(x)		((x) << 2)  /* 2 bits */
#define ENABLE(x)		((x) << 0)

/* LRADC_INTC and LRADC_INTS bits */
#define CHAN1_KEYUP_IRQ		BIT(12)
#define CHAN1_ALRDY_HOLD_IRQ	BIT(11)
#define CHAN1_HOLD_IRQ		BIT(10)
#define	CHAN1_KEYDOWN_IRQ	BIT(9)
#define CHAN1_DATA_IRQ		BIT(8)
#define CHAN0_KEYUP_IRQ		BIT(4)
#define CHAN0_ALRDY_HOLD_IRQ	BIT(3)
#define CHAN0_HOLD_IRQ		BIT(2)
#define	CHAN0_KEYDOWN_IRQ	BIT(1)
#define CHAN0_DATA_IRQ		BIT(0)

/* struct lradc_variant - Describe sun4i-a10-lradc-keys hardware variant
 * @divisor_numerator:		The numerator of lradc Vref internally divisor
 * @divisor_denominator:	The denominator of lradc Vref internally divisor
 */
struct lradc_variant {
	u8 divisor_numerator;
	u8 divisor_denominator;
};

static const struct lradc_variant lradc_variant_a10 = {
	.divisor_numerator = 2,
	.divisor_denominator = 3
};

static const struct lradc_variant r_lradc_variant_a83t = {
	.divisor_numerator = 3,
	.divisor_denominator = 4
};

struct sun4i_lradc_keymap {
	u32 voltage;
	u32 keycode;
};

struct sun4i_lradc_data {
	struct device *dev;
	struct input_dev *input;
	void __iomem *base;
	struct regulator *vref_supply;
	struct sun4i_lradc_keymap *chan0_map;
	const struct lradc_variant *variant;
	u32 chan0_map_count;
	u32 chan0_keycode;
	u32 vref;
};

static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
{
	struct sun4i_lradc_data *lradc = dev_id;
	u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;

	ints  = readl(lradc->base + LRADC_INTS);

	/*
	 * lradc supports only one keypress at a time, release does not give
	 * any info as to which key was released, so we cache the keycode.
	 */

	if (ints & CHAN0_KEYUP_IRQ) {
		input_report_key(lradc->input, lradc->chan0_keycode, 0);
		lradc->chan0_keycode = 0;
	}

	if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
		val = readl(lradc->base + LRADC_DATA0) & 0x3f;
		voltage = val * lradc->vref / 63;

		for (i = 0; i < lradc->chan0_map_count; i++) {
			diff = abs(lradc->chan0_map[i].voltage - voltage);
			if (diff < closest) {
				closest = diff;
				keycode = lradc->chan0_map[i].keycode;
			}
		}

		lradc->chan0_keycode = keycode;
		input_report_key(lradc->input, lradc->chan0_keycode, 1);
	}

	input_sync(lradc->input);

	writel(ints, lradc->base + LRADC_INTS);

	return IRQ_HANDLED;
}

static int sun4i_lradc_open(struct input_dev *dev)
{
	struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
	int error;

	error = regulator_enable(lradc->vref_supply);
	if (error)
		return error;

	lradc->vref = regulator_get_voltage(lradc->vref_supply) *
		      lradc->variant->divisor_numerator /
		      lradc->variant->divisor_denominator;
	/*
	 * Set sample time to 4 ms / 250 Hz. Wait 2 * 4 ms for key to
	 * stabilize on press, wait (1 + 1) * 4 ms for key release
	 */
	writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
		SAMPLE_RATE(0) | ENABLE(1), lradc->base + LRADC_CTRL);

	writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);

	return 0;
}

static void sun4i_lradc_close(struct input_dev *dev)
{
	struct sun4i_lradc_data *lradc = input_get_drvdata(dev);

	/* Disable lradc, leave other settings unchanged */
	writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
		SAMPLE_RATE(2), lradc->base + LRADC_CTRL);
	writel(0, lradc->base + LRADC_INTC);

	regulator_disable(lradc->vref_supply);
}

static int sun4i_lradc_load_dt_keymap(struct device *dev,
				      struct sun4i_lradc_data *lradc)
{
	struct device_node *np, *pp;
	int i;
	int error;

	np = dev->of_node;
	if (!np)
		return -EINVAL;

	lradc->chan0_map_count = of_get_child_count(np);
	if (lradc->chan0_map_count == 0) {
		dev_err(dev, "keymap is missing in device tree\n");
		return -EINVAL;
	}

	lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count,
					      sizeof(struct sun4i_lradc_keymap),
					      GFP_KERNEL);
	if (!lradc->chan0_map)
		return -ENOMEM;

	i = 0;
	for_each_child_of_node(np, pp) {
		struct sun4i_lradc_keymap *map = &lradc->chan0_map[i];
		u32 channel;

		error = of_property_read_u32(pp, "channel", &channel);
		if (error || channel != 0) {
			dev_err(dev, "%pOFn: Inval channel prop\n", pp);
			return -EINVAL;
		}

		error = of_property_read_u32(pp, "voltage", &map->voltage);
		if (error) {
			dev_err(dev, "%pOFn: Inval voltage prop\n", pp);
			return -EINVAL;
		}

		error = of_property_read_u32(pp, "linux,code", &map->keycode);
		if (error) {
			dev_err(dev, "%pOFn: Inval linux,code prop\n", pp);
			return -EINVAL;
		}

		i++;
	}

	return 0;
}

static int sun4i_lradc_probe(struct platform_device *pdev)
{
	struct sun4i_lradc_data *lradc;
	struct device *dev = &pdev->dev;
	int i;
	int error;

	lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
	if (!lradc)
		return -ENOMEM;

	error = sun4i_lradc_load_dt_keymap(dev, lradc);
	if (error)
		return error;

	lradc->variant = of_device_get_match_data(&pdev->dev);
	if (!lradc->variant) {
		dev_err(&pdev->dev, "Missing sun4i-a10-lradc-keys variant\n");
		return -EINVAL;
	}

	lradc->vref_supply = devm_regulator_get(dev, "vref");
	if (IS_ERR(lradc->vref_supply))
		return PTR_ERR(lradc->vref_supply);

	lradc->dev = dev;
	lradc->input = devm_input_allocate_device(dev);
	if (!lradc->input)
		return -ENOMEM;

	lradc->input->name = pdev->name;
	lradc->input->phys = "sun4i_lradc/input0";
	lradc->input->open = sun4i_lradc_open;
	lradc->input->close = sun4i_lradc_close;
	lradc->input->id.bustype = BUS_HOST;
	lradc->input->id.vendor = 0x0001;
	lradc->input->id.product = 0x0001;
	lradc->input->id.version = 0x0100;

	__set_bit(EV_KEY, lradc->input->evbit);
	for (i = 0; i < lradc->chan0_map_count; i++)
		__set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit);

	input_set_drvdata(lradc->input, lradc);

	lradc->base = devm_ioremap_resource(dev,
			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
	if (IS_ERR(lradc->base))
		return PTR_ERR(lradc->base);

	error = devm_request_irq(dev, platform_get_irq(pdev, 0),
				 sun4i_lradc_irq, 0,
				 "sun4i-a10-lradc-keys", lradc);
	if (error)
		return error;

	error = input_register_device(lradc->input);
	if (error)
		return error;

	return 0;
}

static const struct of_device_id sun4i_lradc_of_match[] = {
	{ .compatible = "allwinner,sun4i-a10-lradc-keys",
		.data = &lradc_variant_a10 },
	{ .compatible = "allwinner,sun8i-a83t-r-lradc",
		.data = &r_lradc_variant_a83t },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);

static struct platform_driver sun4i_lradc_driver = {
	.driver = {
		.name	= "sun4i-a10-lradc-keys",
		.of_match_table = of_match_ptr(sun4i_lradc_of_match),
	},
	.probe	= sun4i_lradc_probe,
};

module_platform_driver(sun4i_lradc_driver);

MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
c942fddf	1	// SPDX-License-Identifier: GPL-2.0-or-later
af6a5af8 HG	2	/*
	3	* Allwinner sun4i low res adc attached tablet keys driver
	4	*
	5	* Copyright (C) 2014 Hans de Goede <hdegoede@redhat.com>
af6a5af8 HG	6	*/
	7
	8	/*
	9	* Allwinnner sunxi SoCs have a lradc which is specifically designed to have
	10	* various (tablet) keys (ie home, back, search, etc). attached to it using
	11	* a resistor network. This driver is for the keys on such boards.
	12	*
	13	* There are 2 channels, currently this driver only supports channel 0 since
	14	* there are no boards known to use channel 1.
	15	*/
	16
	17	#include <linux/err.h>
	18	#include <linux/init.h>
	19	#include <linux/input.h>
	20	#include <linux/interrupt.h>
	21	#include <linux/io.h>
	22	#include <linux/module.h>
	23	#include <linux/of_platform.h>
	24	#include <linux/platform_device.h>
	25	#include <linux/regulator/consumer.h>
	26	#include <linux/slab.h>
	27
	28	#define LRADC_CTRL 0x00
	29	#define LRADC_INTC 0x04
	30	#define LRADC_INTS 0x08
	31	#define LRADC_DATA0 0x0c
	32	#define LRADC_DATA1 0x10
	33
	34	/* LRADC_CTRL bits */
	35	#define FIRST_CONVERT_DLY(x) ((x) << 24) /* 8 bits */
	36	#define CHAN_SELECT(x) ((x) << 22) /* 2 bits */
	37	#define CONTINUE_TIME_SEL(x) ((x) << 16) /* 4 bits */
	38	#define KEY_MODE_SEL(x) ((x) << 12) /* 2 bits */
	39	#define LEVELA_B_CNT(x) ((x) << 8) /* 4 bits */
4c459117	40	#define HOLD_KEY_EN(x) ((x) << 7)
af6a5af8 HG	41	#define HOLD_EN(x) ((x) << 6)
	42	#define LEVELB_VOL(x) ((x) << 4) /* 2 bits */
	43	#define SAMPLE_RATE(x) ((x) << 2) /* 2 bits */
	44	#define ENABLE(x) ((x) << 0)
	45
	46	/* LRADC_INTC and LRADC_INTS bits */
	47	#define CHAN1_KEYUP_IRQ BIT(12)
	48	#define CHAN1_ALRDY_HOLD_IRQ BIT(11)
	49	#define CHAN1_HOLD_IRQ BIT(10)
	50	#define CHAN1_KEYDOWN_IRQ BIT(9)
	51	#define CHAN1_DATA_IRQ BIT(8)
	52	#define CHAN0_KEYUP_IRQ BIT(4)
	53	#define CHAN0_ALRDY_HOLD_IRQ BIT(3)
	54	#define CHAN0_HOLD_IRQ BIT(2)
	55	#define CHAN0_KEYDOWN_IRQ BIT(1)
	56	#define CHAN0_DATA_IRQ BIT(0)
	57
4c459117 ZC	58	/* struct lradc_variant - Describe sun4i-a10-lradc-keys hardware variant
	59	* @divisor_numerator: The numerator of lradc Vref internally divisor
	60	* @divisor_denominator: The denominator of lradc Vref internally divisor
	61	*/
	62	struct lradc_variant {
	63	u8 divisor_numerator;
	64	u8 divisor_denominator;
	65	};
	66
	67	static const struct lradc_variant lradc_variant_a10 = {
	68	.divisor_numerator = 2,
	69	.divisor_denominator = 3
	70	};
	71
	72	static const struct lradc_variant r_lradc_variant_a83t = {
	73	.divisor_numerator = 3,
	74	.divisor_denominator = 4
	75	};
	76
af6a5af8 HG	77	struct sun4i_lradc_keymap {
	78	u32 voltage;
	79	u32 keycode;
	80	};
	81
	82	struct sun4i_lradc_data {
	83	struct device *dev;
	84	struct input_dev *input;
	85	void __iomem *base;
	86	struct regulator *vref_supply;
	87	struct sun4i_lradc_keymap *chan0_map;
4c459117	88	const struct lradc_variant *variant;
af6a5af8 HG	89	u32 chan0_map_count;
	90	u32 chan0_keycode;
	91	u32 vref;
	92	};
	93
	94	static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
	95	{
	96	struct sun4i_lradc_data *lradc = dev_id;
	97	u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;
	98
	99	ints = readl(lradc->base + LRADC_INTS);
	100
	101	/*
	102	* lradc supports only one keypress at a time, release does not give
	103	* any info as to which key was released, so we cache the keycode.
	104	*/
	105
	106	if (ints & CHAN0_KEYUP_IRQ) {
	107	input_report_key(lradc->input, lradc->chan0_keycode, 0);
	108	lradc->chan0_keycode = 0;
	109	}
	110
	111	if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
	112	val = readl(lradc->base + LRADC_DATA0) & 0x3f;
	113	voltage = val * lradc->vref / 63;
	114
	115	for (i = 0; i < lradc->chan0_map_count; i++) {
	116	diff = abs(lradc->chan0_map[i].voltage - voltage);
	117	if (diff < closest) {
	118	closest = diff;
	119	keycode = lradc->chan0_map[i].keycode;
	120	}
	121	}
	122
	123	lradc->chan0_keycode = keycode;
	124	input_report_key(lradc->input, lradc->chan0_keycode, 1);
	125	}
	126
	127	input_sync(lradc->input);
	128
	129	writel(ints, lradc->base + LRADC_INTS);
	130
	131	return IRQ_HANDLED;
	132	}
	133
	134	static int sun4i_lradc_open(struct input_dev *dev)
	135	{
	136	struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
	137	int error;
	138
	139	error = regulator_enable(lradc->vref_supply);
	140	if (error)
	141	return error;
	142
4c459117 ZC	143	lradc->vref = regulator_get_voltage(lradc->vref_supply) *
	144	lradc->variant->divisor_numerator /
	145	lradc->variant->divisor_denominator;
af6a5af8 HG	146	/*
	147	* Set sample time to 4 ms / 250 Hz. Wait 2 * 4 ms for key to
	148	* stabilize on press, wait (1 + 1) * 4 ms for key release
	149	*/
	150	writel(FIRST_CONVERT_DLY(2) \| LEVELA_B_CNT(1) \| HOLD_EN(1) \|
	151	SAMPLE_RATE(0) \| ENABLE(1), lradc->base + LRADC_CTRL);
	152
	153	writel(CHAN0_KEYUP_IRQ \| CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);
	154
	155	return 0;
	156	}
	157
	158	static void sun4i_lradc_close(struct input_dev *dev)
	159	{
	160	struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
	161
	162	/* Disable lradc, leave other settings unchanged */
	163	writel(FIRST_CONVERT_DLY(2) \| LEVELA_B_CNT(1) \| HOLD_EN(1) \|
	164	SAMPLE_RATE(2), lradc->base + LRADC_CTRL);
	165	writel(0, lradc->base + LRADC_INTC);
	166
	167	regulator_disable(lradc->vref_supply);
	168	}
	169
	170	static int sun4i_lradc_load_dt_keymap(struct device *dev,
	171	struct sun4i_lradc_data *lradc)
	172	{
	173	struct device_node np, pp;
	174	int i;
	175	int error;
	176
	177	np = dev->of_node;
	178	if (!np)
	179	return -EINVAL;
	180
	181	lradc->chan0_map_count = of_get_child_count(np);
	182	if (lradc->chan0_map_count == 0) {
	183	dev_err(dev, "keymap is missing in device tree\n");
	184	return -EINVAL;
	185	}
	186
	187	lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count,
	188	sizeof(struct sun4i_lradc_keymap),
	189	GFP_KERNEL);
	190	if (!lradc->chan0_map)
	191	return -ENOMEM;
	192
	193	i = 0;
	194	for_each_child_of_node(np, pp) {
	195	struct sun4i_lradc_keymap *map = &lradc->chan0_map[i];
	196	u32 channel;
	197
	198	error = of_property_read_u32(pp, "channel", &channel);
	199	if (error \|\| channel != 0) {
b297b728	200	dev_err(dev, "%pOFn: Inval channel prop\n", pp);
af6a5af8 HG	201	return -EINVAL;
	202	}
	203
	204	error = of_property_read_u32(pp, "voltage", &map->voltage);
	205	if (error) {
b297b728	206	dev_err(dev, "%pOFn: Inval voltage prop\n", pp);
af6a5af8 HG	207	return -EINVAL;
	208	}
	209
	210	error = of_property_read_u32(pp, "linux,code", &map->keycode);
	211	if (error) {
b297b728	212	dev_err(dev, "%pOFn: Inval linux,code prop\n", pp);
af6a5af8 HG	213	return -EINVAL;
	214	}
	215
	216	i++;
	217	}
	218
	219	return 0;
	220	}
	221
	222	static int sun4i_lradc_probe(struct platform_device *pdev)
	223	{
	224	struct sun4i_lradc_data *lradc;
	225	struct device *dev = &pdev->dev;
	226	int i;
	227	int error;
	228
	229	lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
	230	if (!lradc)
	231	return -ENOMEM;
	232
	233	error = sun4i_lradc_load_dt_keymap(dev, lradc);
	234	if (error)
	235	return error;
	236
4c459117 ZC	237	lradc->variant = of_device_get_match_data(&pdev->dev);
	238	if (!lradc->variant) {
	239	dev_err(&pdev->dev, "Missing sun4i-a10-lradc-keys variant\n");
	240	return -EINVAL;
	241	}
	242
af6a5af8 HG	243	lradc->vref_supply = devm_regulator_get(dev, "vref");
	244	if (IS_ERR(lradc->vref_supply))
	245	return PTR_ERR(lradc->vref_supply);
	246
	247	lradc->dev = dev;
	248	lradc->input = devm_input_allocate_device(dev);
	249	if (!lradc->input)
	250	return -ENOMEM;
	251
	252	lradc->input->name = pdev->name;
	253	lradc->input->phys = "sun4i_lradc/input0";
	254	lradc->input->open = sun4i_lradc_open;
	255	lradc->input->close = sun4i_lradc_close;
	256	lradc->input->id.bustype = BUS_HOST;
	257	lradc->input->id.vendor = 0x0001;
	258	lradc->input->id.product = 0x0001;
	259	lradc->input->id.version = 0x0100;
	260
	261	__set_bit(EV_KEY, lradc->input->evbit);
	262	for (i = 0; i < lradc->chan0_map_count; i++)
	263	__set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit);
	264
	265	input_set_drvdata(lradc->input, lradc);
	266
	267	lradc->base = devm_ioremap_resource(dev,
	268	platform_get_resource(pdev, IORESOURCE_MEM, 0));
	269	if (IS_ERR(lradc->base))
	270	return PTR_ERR(lradc->base);
	271
	272	error = devm_request_irq(dev, platform_get_irq(pdev, 0),
	273	sun4i_lradc_irq, 0,
	274	"sun4i-a10-lradc-keys", lradc);
	275	if (error)
	276	return error;
	277
	278	error = input_register_device(lradc->input);
	279	if (error)
	280	return error;
	281
af6a5af8 HG	282	return 0;
	283	}
	284
	285	static const struct of_device_id sun4i_lradc_of_match[] = {
4c459117 ZC	286	{ .compatible = "allwinner,sun4i-a10-lradc-keys",
	287	.data = &lradc_variant_a10 },
	288	{ .compatible = "allwinner,sun8i-a83t-r-lradc",
	289	.data = &r_lradc_variant_a83t },
af6a5af8 HG	290	{ /* sentinel */ }
	291	};
	292	MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
	293
	294	static struct platform_driver sun4i_lradc_driver = {
	295	.driver = {
	296	.name = "sun4i-a10-lradc-keys",
	297	.of_match_table = of_match_ptr(sun4i_lradc_of_match),
	298	},
	299	.probe = sun4i_lradc_probe,
	300	};
	301
	302	module_platform_driver(sun4i_lradc_driver);
	303
	304	MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver");
	305	MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
	306	MODULE_LICENSE("GPL");