[linux-2.6-block.git] / drivers / gpio / gpio-max3191x.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * gpio-max3191x.c - GPIO driver for Maxim MAX3191x industrial serializer
 *
 * Copyright (C) 2017 KUNBUS GmbH
 *
 * The MAX3191x makes 8 digital 24V inputs available via SPI.
 * Multiple chips can be daisy-chained, the spec does not impose
 * a limit on the number of chips and neither does this driver.
 *
 * Either of two modes is selectable: In 8-bit mode, only the state
 * of the inputs is clocked out to achieve high readout speeds;
 * In 16-bit mode, an additional status byte is clocked out with
 * a CRC and indicator bits for undervoltage and overtemperature.
 * The driver returns an error instead of potentially bogus data
 * if any of these fault conditions occur.  However it does allow
 * readout of non-faulting chips in the same daisy-chain.
 *
 * MAX3191x supports four debounce settings and the driver is
 * capable of configuring these differently for each chip in the
 * daisy-chain.
 *
 * If the chips are hardwired to 8-bit mode ("modesel" pulled high),
 * gpio-pisosr.c can be used alternatively to this driver.
 *
 * https://datasheets.maximintegrated.com/en/ds/MAX31910.pdf
 * https://datasheets.maximintegrated.com/en/ds/MAX31911.pdf
 * https://datasheets.maximintegrated.com/en/ds/MAX31912.pdf
 * https://datasheets.maximintegrated.com/en/ds/MAX31913.pdf
 * https://datasheets.maximintegrated.com/en/ds/MAX31953-MAX31963.pdf
 */

#include <linux/bitmap.h>
#include <linux/crc8.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/module.h>
#include <linux/spi/spi.h>

enum max3191x_mode {
	STATUS_BYTE_ENABLED,
	STATUS_BYTE_DISABLED,
};

/**
 * struct max3191x_chip - max3191x daisy-chain
 * @gpio: GPIO controller struct
 * @lock: protects read sequences
 * @nchips: number of chips in the daisy-chain
 * @mode: current mode, 0 for 16-bit, 1 for 8-bit;
 *	for simplicity, all chips in the daisy-chain are assumed
 *	to use the same mode
 * @modesel_pins: GPIO pins to configure modesel of each chip
 * @fault_pins: GPIO pins to detect fault of each chip
 * @db0_pins: GPIO pins to configure debounce of each chip
 * @db1_pins: GPIO pins to configure debounce of each chip
 * @mesg: SPI message to perform a readout
 * @xfer: SPI transfer used by @mesg
 * @crc_error: bitmap signaling CRC error for each chip
 * @overtemp: bitmap signaling overtemperature alarm for each chip
 * @undervolt1: bitmap signaling undervoltage alarm for each chip
 * @undervolt2: bitmap signaling undervoltage warning for each chip
 * @fault: bitmap signaling assertion of @fault_pins for each chip
 * @ignore_uv: whether to ignore undervoltage alarms;
 *	set by a device property if the chips are powered through
 *	5VOUT instead of VCC24V, in which case they will constantly
 *	signal undervoltage;
 *	for simplicity, all chips in the daisy-chain are assumed
 *	to be powered the same way
 */
struct max3191x_chip {
	struct gpio_chip gpio;
	struct mutex lock;
	u32 nchips;
	enum max3191x_mode mode;
	struct gpio_descs *modesel_pins;
	struct gpio_descs *fault_pins;
	struct gpio_descs *db0_pins;
	struct gpio_descs *db1_pins;
	struct spi_message mesg;
	struct spi_transfer xfer;
	unsigned long *crc_error;
	unsigned long *overtemp;
	unsigned long *undervolt1;
	unsigned long *undervolt2;
	unsigned long *fault;
	bool ignore_uv;
};

#define MAX3191X_NGPIO 8
#define MAX3191X_CRC8_POLYNOMIAL 0xa8 /* (x^5) + x^4 + x^2 + x^0 */

DECLARE_CRC8_TABLE(max3191x_crc8);

static int max3191x_get_direction(struct gpio_chip *gpio, unsigned int offset)
{
	return 1; /* always in */
}

static int max3191x_direction_input(struct gpio_chip *gpio, unsigned int offset)
{
	return 0;
}

static int max3191x_direction_output(struct gpio_chip *gpio,
				     unsigned int offset, int value)
{
	return -EINVAL;
}

static void max3191x_set(struct gpio_chip *gpio, unsigned int offset, int value)
{ }

static void max3191x_set_multiple(struct gpio_chip *gpio, unsigned long *mask,
				  unsigned long *bits)
{ }

static unsigned int max3191x_wordlen(struct max3191x_chip *max3191x)
{
	return max3191x->mode == STATUS_BYTE_ENABLED ? 2 : 1;
}

static int max3191x_readout_locked(struct max3191x_chip *max3191x)
{
	struct device *dev = max3191x->gpio.parent;
	struct spi_device *spi = to_spi_device(dev);
	int val, i, ot = 0, uv1 = 0;

	val = spi_sync(spi, &max3191x->mesg);
	if (val) {
		dev_err_ratelimited(dev, "SPI receive error %d\n", val);
		return val;
	}

	for (i = 0; i < max3191x->nchips; i++) {
		if (max3191x->mode == STATUS_BYTE_ENABLED) {
			u8 in	  = ((u8 *)max3191x->xfer.rx_buf)[i * 2];
			u8 status = ((u8 *)max3191x->xfer.rx_buf)[i * 2 + 1];

			val = (status & 0xf8) != crc8(max3191x_crc8, &in, 1, 0);
			__assign_bit(i, max3191x->crc_error, val);
			if (val)
				dev_err_ratelimited(dev,
					"chip %d: CRC error\n", i);

			ot  = (status >> 1) & 1;
			__assign_bit(i, max3191x->overtemp, ot);
			if (ot)
				dev_err_ratelimited(dev,
					"chip %d: overtemperature\n", i);

			if (!max3191x->ignore_uv) {
				uv1 = !((status >> 2) & 1);
				__assign_bit(i, max3191x->undervolt1, uv1);
				if (uv1)
					dev_err_ratelimited(dev,
						"chip %d: undervoltage\n", i);

				val = !(status & 1);
				__assign_bit(i, max3191x->undervolt2, val);
				if (val && !uv1)
					dev_warn_ratelimited(dev,
						"chip %d: voltage warn\n", i);
			}
		}

		if (max3191x->fault_pins && !max3191x->ignore_uv) {
			/* fault pin shared by all chips or per chip */
			struct gpio_desc *fault_pin =
				(max3191x->fault_pins->ndescs == 1)
					? max3191x->fault_pins->desc[0]
					: max3191x->fault_pins->desc[i];

			val = gpiod_get_value_cansleep(fault_pin);
			if (val < 0) {
				dev_err_ratelimited(dev,
					"GPIO read error %d\n", val);
				return val;
			}
			__assign_bit(i, max3191x->fault, val);
			if (val && !uv1 && !ot)
				dev_err_ratelimited(dev,
					"chip %d: fault\n", i);
		}
	}

	return 0;
}

static bool max3191x_chip_is_faulting(struct max3191x_chip *max3191x,
				      unsigned int chipnum)
{
	/* without status byte the only diagnostic is the fault pin */
	if (!max3191x->ignore_uv && test_bit(chipnum, max3191x->fault))
		return true;

	if (max3191x->mode == STATUS_BYTE_DISABLED)
		return false;

	return test_bit(chipnum, max3191x->crc_error) ||
	       test_bit(chipnum, max3191x->overtemp)  ||
	       (!max3191x->ignore_uv &&
		test_bit(chipnum, max3191x->undervolt1));
}

static int max3191x_get(struct gpio_chip *gpio, unsigned int offset)
{
	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);
	int ret, chipnum, wordlen = max3191x_wordlen(max3191x);
	u8 in;

	mutex_lock(&max3191x->lock);
	ret = max3191x_readout_locked(max3191x);
	if (ret)
		goto out_unlock;

	chipnum = offset / MAX3191X_NGPIO;
	if (max3191x_chip_is_faulting(max3191x, chipnum)) {
		ret = -EIO;
		goto out_unlock;
	}

	in = ((u8 *)max3191x->xfer.rx_buf)[chipnum * wordlen];
	ret = (in >> (offset % MAX3191X_NGPIO)) & 1;

out_unlock:
	mutex_unlock(&max3191x->lock);
	return ret;
}

static int max3191x_get_multiple(struct gpio_chip *gpio, unsigned long *mask,
				 unsigned long *bits)
{
	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);
	int ret, bit = 0, wordlen = max3191x_wordlen(max3191x);

	mutex_lock(&max3191x->lock);
	ret = max3191x_readout_locked(max3191x);
	if (ret)
		goto out_unlock;

	while ((bit = find_next_bit(mask, gpio->ngpio, bit)) != gpio->ngpio) {
		unsigned int chipnum = bit / MAX3191X_NGPIO;
		unsigned long in, shift, index;

		if (max3191x_chip_is_faulting(max3191x, chipnum)) {
			ret = -EIO;
			goto out_unlock;
		}

		in = ((u8 *)max3191x->xfer.rx_buf)[chipnum * wordlen];
		shift = round_down(bit % BITS_PER_LONG, MAX3191X_NGPIO);
		index = bit / BITS_PER_LONG;
		bits[index] &= ~(mask[index] & (0xff << shift));
		bits[index] |= mask[index] & (in << shift); /* copy bits */

		bit = (chipnum + 1) * MAX3191X_NGPIO; /* go to next chip */
	}

out_unlock:
	mutex_unlock(&max3191x->lock);
	return ret;
}

static int max3191x_set_config(struct gpio_chip *gpio, unsigned int offset,
			       unsigned long config)
{
	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);
	u32 debounce, chipnum, db0_val, db1_val;

	if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)
		return -ENOTSUPP;

	if (!max3191x->db0_pins || !max3191x->db1_pins)
		return -EINVAL;

	debounce = pinconf_to_config_argument(config);
	switch (debounce) {
	case 0:
		db0_val = 0;
		db1_val = 0;
		break;
	case 1 ... 25:
		db0_val = 0;
		db1_val = 1;
		break;
	case 26 ... 750:
		db0_val = 1;
		db1_val = 0;
		break;
	case 751 ... 3000:
		db0_val = 1;
		db1_val = 1;
		break;
	default:
		return -EINVAL;
	}

	if (max3191x->db0_pins->ndescs == 1)
		chipnum = 0; /* all chips use the same pair of debounce pins */
	else
		chipnum = offset / MAX3191X_NGPIO; /* per chip debounce pins */

	mutex_lock(&max3191x->lock);
	gpiod_set_value_cansleep(max3191x->db0_pins->desc[chipnum], db0_val);
	gpiod_set_value_cansleep(max3191x->db1_pins->desc[chipnum], db1_val);
	mutex_unlock(&max3191x->lock);
	return 0;
}

static void gpiod_set_array_single_value_cansleep(unsigned int ndescs,
						  struct gpio_desc **desc,
						  struct gpio_array *info,
						  int value)
{
	unsigned long *values;

	values = bitmap_alloc(ndescs, GFP_KERNEL);
	if (!values)
		return;

	if (value)
		bitmap_fill(values, ndescs);
	else
		bitmap_zero(values, ndescs);

	gpiod_set_array_value_cansleep(ndescs, desc, info, values);
	kfree(values);
}

static struct gpio_descs *devm_gpiod_get_array_optional_count(
				struct device *dev, const char *con_id,
				enum gpiod_flags flags, unsigned int expected)
{
	struct gpio_descs *descs;
	int found = gpiod_count(dev, con_id);

	if (found == -ENOENT)
		return NULL;

	if (found != expected && found != 1) {
		dev_err(dev, "ignoring %s-gpios: found %d, expected %u or 1\n",
			con_id, found, expected);
		return NULL;
	}

	descs = devm_gpiod_get_array_optional(dev, con_id, flags);

	if (IS_ERR(descs)) {
		dev_err(dev, "failed to get %s-gpios: %ld\n",
			con_id, PTR_ERR(descs));
		return NULL;
	}

	return descs;
}

static int max3191x_probe(struct spi_device *spi)
{
	struct device *dev = &spi->dev;
	struct max3191x_chip *max3191x;
	int n, ret;

	max3191x = devm_kzalloc(dev, sizeof(*max3191x), GFP_KERNEL);
	if (!max3191x)
		return -ENOMEM;
	spi_set_drvdata(spi, max3191x);

	max3191x->nchips = 1;
	device_property_read_u32(dev, "#daisy-chained-devices",
				 &max3191x->nchips);

	n = BITS_TO_LONGS(max3191x->nchips);
	max3191x->crc_error   = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	max3191x->undervolt1  = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	max3191x->undervolt2  = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	max3191x->overtemp    = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	max3191x->fault       = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	max3191x->xfer.rx_buf = devm_kcalloc(dev, max3191x->nchips,
								2, GFP_KERNEL);
	if (!max3191x->crc_error || !max3191x->undervolt1 ||
	    !max3191x->overtemp  || !max3191x->undervolt2 ||
	    !max3191x->fault     || !max3191x->xfer.rx_buf)
		return -ENOMEM;

	max3191x->modesel_pins = devm_gpiod_get_array_optional_count(dev,
				 "maxim,modesel", GPIOD_ASIS, max3191x->nchips);
	max3191x->fault_pins   = devm_gpiod_get_array_optional_count(dev,
				 "maxim,fault", GPIOD_IN, max3191x->nchips);
	max3191x->db0_pins     = devm_gpiod_get_array_optional_count(dev,
				 "maxim,db0", GPIOD_OUT_LOW, max3191x->nchips);
	max3191x->db1_pins     = devm_gpiod_get_array_optional_count(dev,
				 "maxim,db1", GPIOD_OUT_LOW, max3191x->nchips);

	max3191x->mode = device_property_read_bool(dev, "maxim,modesel-8bit")
				 ? STATUS_BYTE_DISABLED : STATUS_BYTE_ENABLED;
	if (max3191x->modesel_pins)
		gpiod_set_array_single_value_cansleep(
				 max3191x->modesel_pins->ndescs,
				 max3191x->modesel_pins->desc,
				 max3191x->modesel_pins->info, max3191x->mode);

	max3191x->ignore_uv = device_property_read_bool(dev,
						  "maxim,ignore-undervoltage");

	if (max3191x->db0_pins && max3191x->db1_pins &&
	    max3191x->db0_pins->ndescs != max3191x->db1_pins->ndescs) {
		dev_err(dev, "ignoring maxim,db*-gpios: array len mismatch\n");
		devm_gpiod_put_array(dev, max3191x->db0_pins);
		devm_gpiod_put_array(dev, max3191x->db1_pins);
		max3191x->db0_pins = NULL;
		max3191x->db1_pins = NULL;
	}

	max3191x->xfer.len = max3191x->nchips * max3191x_wordlen(max3191x);
	spi_message_init_with_transfers(&max3191x->mesg, &max3191x->xfer, 1);

	max3191x->gpio.label = spi->modalias;
	max3191x->gpio.owner = THIS_MODULE;
	max3191x->gpio.parent = dev;
	max3191x->gpio.base = -1;
	max3191x->gpio.ngpio = max3191x->nchips * MAX3191X_NGPIO;
	max3191x->gpio.can_sleep = true;

	max3191x->gpio.get_direction = max3191x_get_direction;
	max3191x->gpio.direction_input = max3191x_direction_input;
	max3191x->gpio.direction_output = max3191x_direction_output;
	max3191x->gpio.set = max3191x_set;
	max3191x->gpio.set_multiple = max3191x_set_multiple;
	max3191x->gpio.get = max3191x_get;
	max3191x->gpio.get_multiple = max3191x_get_multiple;
	max3191x->gpio.set_config = max3191x_set_config;

	mutex_init(&max3191x->lock);

	ret = gpiochip_add_data(&max3191x->gpio, max3191x);
	if (ret) {
		mutex_destroy(&max3191x->lock);
		return ret;
	}

	return 0;
}

static int max3191x_remove(struct spi_device *spi)
{
	struct max3191x_chip *max3191x = spi_get_drvdata(spi);

	gpiochip_remove(&max3191x->gpio);
	mutex_destroy(&max3191x->lock);

	return 0;
}

static int __init max3191x_register_driver(struct spi_driver *sdrv)
{
	crc8_populate_msb(max3191x_crc8, MAX3191X_CRC8_POLYNOMIAL);
	return spi_register_driver(sdrv);
}

#ifdef CONFIG_OF
static const struct of_device_id max3191x_of_id[] = {
	{ .compatible = "maxim,max31910" },
	{ .compatible = "maxim,max31911" },
	{ .compatible = "maxim,max31912" },
	{ .compatible = "maxim,max31913" },
	{ .compatible = "maxim,max31953" },
	{ .compatible = "maxim,max31963" },
	{ }
};
MODULE_DEVICE_TABLE(of, max3191x_of_id);
#endif

static const struct spi_device_id max3191x_spi_id[] = {
	{ "max31910" },
	{ "max31911" },
	{ "max31912" },
	{ "max31913" },
	{ "max31953" },
	{ "max31963" },
	{ }
};
MODULE_DEVICE_TABLE(spi, max3191x_spi_id);

static struct spi_driver max3191x_driver = {
	.driver = {
		.name		= "max3191x",
		.of_match_table	= of_match_ptr(max3191x_of_id),
	},
	.probe	  = max3191x_probe,
	.remove	  = max3191x_remove,
	.id_table = max3191x_spi_id,
};
module_driver(max3191x_driver, max3191x_register_driver, spi_unregister_driver);

MODULE_AUTHOR("Lukas Wunner <lukas@wunner.de>");
MODULE_DESCRIPTION("GPIO driver for Maxim MAX3191x industrial serializer");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
b2f68edf LW	2	/*
	3	* gpio-max3191x.c - GPIO driver for Maxim MAX3191x industrial serializer
	4	*
	5	* Copyright (C) 2017 KUNBUS GmbH
	6	*
	7	* The MAX3191x makes 8 digital 24V inputs available via SPI.
	8	* Multiple chips can be daisy-chained, the spec does not impose
	9	* a limit on the number of chips and neither does this driver.
	10	*
	11	* Either of two modes is selectable: In 8-bit mode, only the state
	12	* of the inputs is clocked out to achieve high readout speeds;
	13	* In 16-bit mode, an additional status byte is clocked out with
	14	* a CRC and indicator bits for undervoltage and overtemperature.
	15	* The driver returns an error instead of potentially bogus data
	16	* if any of these fault conditions occur. However it does allow
	17	* readout of non-faulting chips in the same daisy-chain.
	18	*
	19	* MAX3191x supports four debounce settings and the driver is
	20	* capable of configuring these differently for each chip in the
	21	* daisy-chain.
	22	*
	23	* If the chips are hardwired to 8-bit mode ("modesel" pulled high),
	24	* gpio-pisosr.c can be used alternatively to this driver.
	25	*
	26	* https://datasheets.maximintegrated.com/en/ds/MAX31910.pdf
	27	* https://datasheets.maximintegrated.com/en/ds/MAX31911.pdf
	28	* https://datasheets.maximintegrated.com/en/ds/MAX31912.pdf
	29	* https://datasheets.maximintegrated.com/en/ds/MAX31913.pdf
	30	* https://datasheets.maximintegrated.com/en/ds/MAX31953-MAX31963.pdf
b2f68edf LW	31	*/
	32
	33	#include <linux/bitmap.h>
	34	#include <linux/crc8.h>
	35	#include <linux/gpio/consumer.h>
	36	#include <linux/gpio/driver.h>
	37	#include <linux/module.h>
	38	#include <linux/spi/spi.h>
	39
	40	enum max3191x_mode {
	41	STATUS_BYTE_ENABLED,
	42	STATUS_BYTE_DISABLED,
	43	};
	44
	45	/**
	46	* struct max3191x_chip - max3191x daisy-chain
	47	* @gpio: GPIO controller struct
	48	* @lock: protects read sequences
	49	* @nchips: number of chips in the daisy-chain
	50	* @mode: current mode, 0 for 16-bit, 1 for 8-bit;
	51	* for simplicity, all chips in the daisy-chain are assumed
	52	* to use the same mode
	53	* @modesel_pins: GPIO pins to configure modesel of each chip
	54	* @fault_pins: GPIO pins to detect fault of each chip
	55	* @db0_pins: GPIO pins to configure debounce of each chip
	56	* @db1_pins: GPIO pins to configure debounce of each chip
	57	* @mesg: SPI message to perform a readout
	58	* @xfer: SPI transfer used by @mesg
	59	* @crc_error: bitmap signaling CRC error for each chip
	60	* @overtemp: bitmap signaling overtemperature alarm for each chip
	61	* @undervolt1: bitmap signaling undervoltage alarm for each chip
	62	* @undervolt2: bitmap signaling undervoltage warning for each chip
	63	* @fault: bitmap signaling assertion of @fault_pins for each chip
	64	* @ignore_uv: whether to ignore undervoltage alarms;
	65	* set by a device property if the chips are powered through
	66	* 5VOUT instead of VCC24V, in which case they will constantly
	67	* signal undervoltage;
	68	* for simplicity, all chips in the daisy-chain are assumed
	69	* to be powered the same way
	70	*/
	71	struct max3191x_chip {
	72	struct gpio_chip gpio;
	73	struct mutex lock;
	74	u32 nchips;
	75	enum max3191x_mode mode;
	76	struct gpio_descs *modesel_pins;
	77	struct gpio_descs *fault_pins;
	78	struct gpio_descs *db0_pins;
	79	struct gpio_descs *db1_pins;
	80	struct spi_message mesg;
	81	struct spi_transfer xfer;
	82	unsigned long *crc_error;
	83	unsigned long *overtemp;
	84	unsigned long *undervolt1;
	85	unsigned long *undervolt2;
	86	unsigned long *fault;
	87	bool ignore_uv;
	88	};
	89
	90	#define MAX3191X_NGPIO 8
	91	#define MAX3191X_CRC8_POLYNOMIAL 0xa8 /* (x^5) + x^4 + x^2 + x^0 */
	92
	93	DECLARE_CRC8_TABLE(max3191x_crc8);
	94
95	static int max3191x_get_direction(struct gpio_chip *gpio, unsigned int offset)
96	{
97	return 1; /* always in */
98	}
99
100	static int max3191x_direction_input(struct gpio_chip *gpio, unsigned int offset)
101	{
102	return 0;
103	}
104
105	static int max3191x_direction_output(struct gpio_chip *gpio,
106	unsigned int offset, int value)
107	{
108	return -EINVAL;
109	}
110
111	static void max3191x_set(struct gpio_chip *gpio, unsigned int offset, int value)
112	{ }
113
114	static void max3191x_set_multiple(struct gpio_chip gpio, unsigned long mask,
115	unsigned long *bits)
116	{ }
117
118	static unsigned int max3191x_wordlen(struct max3191x_chip *max3191x)
119	{
120	return max3191x->mode == STATUS_BYTE_ENABLED ? 2 : 1;
121	}
122
123	static int max3191x_readout_locked(struct max3191x_chip *max3191x)
124	{
125	struct device *dev = max3191x->gpio.parent;
126	struct spi_device *spi = to_spi_device(dev);
127	int val, i, ot = 0, uv1 = 0;
128
129	val = spi_sync(spi, &max3191x->mesg);
130	if (val) {
131	dev_err_ratelimited(dev, "SPI receive error %d\n", val);
132	return val;
133	}
134
135	for (i = 0; i < max3191x->nchips; i++) {
136	if (max3191x->mode == STATUS_BYTE_ENABLED) {
137	u8 in = ((u8 )max3191x->xfer.rx_buf)[i 2];
138	u8 status = ((u8 )max3191x->xfer.rx_buf)[i 2 + 1];
139
140	val = (status & 0xf8) != crc8(max3191x_crc8, &in, 1, 0);
141	__assign_bit(i, max3191x->crc_error, val);
142	if (val)
143	dev_err_ratelimited(dev,
144	"chip %d: CRC error\n", i);
145
146	ot = (status >> 1) & 1;
147	__assign_bit(i, max3191x->overtemp, ot);
148	if (ot)
149	dev_err_ratelimited(dev,
150	"chip %d: overtemperature\n", i);
151
152	if (!max3191x->ignore_uv) {
153	uv1 = !((status >> 2) & 1);
154	__assign_bit(i, max3191x->undervolt1, uv1);
155	if (uv1)
156	dev_err_ratelimited(dev,
157	"chip %d: undervoltage\n", i);
158
159	val = !(status & 1);
160	__assign_bit(i, max3191x->undervolt2, val);
161	if (val && !uv1)
162	dev_warn_ratelimited(dev,
163	"chip %d: voltage warn\n", i);
164	}
165	}
166
167	if (max3191x->fault_pins && !max3191x->ignore_uv) {
168	/* fault pin shared by all chips or per chip */
169	struct gpio_desc *fault_pin =
170	(max3191x->fault_pins->ndescs == 1)
171	? max3191x->fault_pins->desc[0]
172	: max3191x->fault_pins->desc[i];
173
174	val = gpiod_get_value_cansleep(fault_pin);
175	if (val < 0) {
176	dev_err_ratelimited(dev,
177	"GPIO read error %d\n", val);
178	return val;
179	}
180	__assign_bit(i, max3191x->fault, val);
181	if (val && !uv1 && !ot)
182	dev_err_ratelimited(dev,
183	"chip %d: fault\n", i);
184	}
185	}
186
187	return 0;
188	}
189
190	static bool max3191x_chip_is_faulting(struct max3191x_chip *max3191x,
191	unsigned int chipnum)
192	{
193	/* without status byte the only diagnostic is the fault pin */
194	if (!max3191x->ignore_uv && test_bit(chipnum, max3191x->fault))
195	return true;
196
197	if (max3191x->mode == STATUS_BYTE_DISABLED)
198	return false;
199
200	return test_bit(chipnum, max3191x->crc_error) \|\|
201	test_bit(chipnum, max3191x->overtemp) \|\|
202	(!max3191x->ignore_uv &&
203	test_bit(chipnum, max3191x->undervolt1));
204	}
205
206	static int max3191x_get(struct gpio_chip *gpio, unsigned int offset)
207	{
208	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);
209	int ret, chipnum, wordlen = max3191x_wordlen(max3191x);
210	u8 in;
211
212	mutex_lock(&max3191x->lock);
213	ret = max3191x_readout_locked(max3191x);
214	if (ret)
215	goto out_unlock;
216
217	chipnum = offset / MAX3191X_NGPIO;
218	if (max3191x_chip_is_faulting(max3191x, chipnum)) {
219	ret = -EIO;
220	goto out_unlock;
221	}
222
223	in = ((u8 )max3191x->xfer.rx_buf)[chipnum wordlen];
224	ret = (in >> (offset % MAX3191X_NGPIO)) & 1;
225
226	out_unlock:
227	mutex_unlock(&max3191x->lock);
228	return ret;
229	}
230
231	static int max3191x_get_multiple(struct gpio_chip gpio, unsigned long mask,
232	unsigned long *bits)
233	{
234	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);
235	int ret, bit = 0, wordlen = max3191x_wordlen(max3191x);
236
237	mutex_lock(&max3191x->lock);
238	ret = max3191x_readout_locked(max3191x);
239	if (ret)
240	goto out_unlock;
241
242	while ((bit = find_next_bit(mask, gpio->ngpio, bit)) != gpio->ngpio) {
243	unsigned int chipnum = bit / MAX3191X_NGPIO;
244	unsigned long in, shift, index;
245
246	if (max3191x_chip_is_faulting(max3191x, chipnum)) {
247	ret = -EIO;
248	goto out_unlock;
249	}
250
251	in = ((u8 )max3191x->xfer.rx_buf)[chipnum wordlen];
252	shift = round_down(bit % BITS_PER_LONG, MAX3191X_NGPIO);
253	index = bit / BITS_PER_LONG;
254	bits[index] &= ~(mask[index] & (0xff << shift));
255	bits[index] \|= mask[index] & (in << shift); /* copy bits */
256
257	bit = (chipnum + 1) * MAX3191X_NGPIO; /* go to next chip */
258	}
259
260	out_unlock:
261	mutex_unlock(&max3191x->lock);
262	return ret;
263	}
264
265	static int max3191x_set_config(struct gpio_chip *gpio, unsigned int offset,
266	unsigned long config)
267	{
268	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);
269	u32 debounce, chipnum, db0_val, db1_val;
270
271	if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)
272	return -ENOTSUPP;
273
274	if (!max3191x->db0_pins \|\| !max3191x->db1_pins)
275	return -EINVAL;
276
277	debounce = pinconf_to_config_argument(config);
278	switch (debounce) {
279	case 0:
280	db0_val = 0;
281	db1_val = 0;
282	break;
283	case 1 ... 25:
284	db0_val = 0;
285	db1_val = 1;
286	break;
287	case 26 ... 750:
288	db0_val = 1;
289	db1_val = 0;
290	break;
291	case 751 ... 3000:
292	db0_val = 1;
293	db1_val = 1;
294	break;
295	default:
296	return -EINVAL;
297	}
298
299	if (max3191x->db0_pins->ndescs == 1)
300	chipnum = 0; /* all chips use the same pair of debounce pins */
301	else
302	chipnum = offset / MAX3191X_NGPIO; /* per chip debounce pins */
303
304	mutex_lock(&max3191x->lock);
305	gpiod_set_value_cansleep(max3191x->db0_pins->desc[chipnum], db0_val);
306	gpiod_set_value_cansleep(max3191x->db1_pins->desc[chipnum], db1_val);
307	mutex_unlock(&max3191x->lock);
308	return 0;
309	}
310
311	static void gpiod_set_array_single_value_cansleep(unsigned int ndescs,
312	struct gpio_desc **desc,
77588c14	313	struct gpio_array *info,
b2f68edf LW	314	int value)
b2f68edf LW	315	{
b9762beb	316	unsigned long *values;
48da181d	317
b9762beb	318	values = bitmap_alloc(ndescs, GFP_KERNEL);
48da181d LA	319	if (!values)
48da181d LA	320	return;
b2f68edf	321
b9762beb JK	322	if (value)
	323	bitmap_fill(values, ndescs);
	324	else
	325	bitmap_zero(values, ndescs);
b2f68edf	326
77588c14	327	gpiod_set_array_value_cansleep(ndescs, desc, info, values);
48da181d	328	kfree(values);
b2f68edf LW	329	}
	330
	331	static struct gpio_descs *devm_gpiod_get_array_optional_count(
	332	struct device dev, const char con_id,
	333	enum gpiod_flags flags, unsigned int expected)
	334	{
	335	struct gpio_descs *descs;
	336	int found = gpiod_count(dev, con_id);
	337
	338	if (found == -ENOENT)
	339	return NULL;
	340
	341	if (found != expected && found != 1) {
	342	dev_err(dev, "ignoring %s-gpios: found %d, expected %u or 1\n",
	343	con_id, found, expected);
	344	return NULL;
	345	}
	346
	347	descs = devm_gpiod_get_array_optional(dev, con_id, flags);
	348
	349	if (IS_ERR(descs)) {
	350	dev_err(dev, "failed to get %s-gpios: %ld\n",
	351	con_id, PTR_ERR(descs));
	352	return NULL;
	353	}
	354
	355	return descs;
	356	}
	357
	358	static int max3191x_probe(struct spi_device *spi)
	359	{
	360	struct device *dev = &spi->dev;
	361	struct max3191x_chip *max3191x;
	362	int n, ret;
	363
	364	max3191x = devm_kzalloc(dev, sizeof(*max3191x), GFP_KERNEL);
	365	if (!max3191x)
	366	return -ENOMEM;
	367	spi_set_drvdata(spi, max3191x);
	368
	369	max3191x->nchips = 1;
	370	device_property_read_u32(dev, "#daisy-chained-devices",
	371	&max3191x->nchips);
	372
	373	n = BITS_TO_LONGS(max3191x->nchips);
	374	max3191x->crc_error = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	375	max3191x->undervolt1 = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	376	max3191x->undervolt2 = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	377	max3191x->overtemp = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	378	max3191x->fault = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);
	379	max3191x->xfer.rx_buf = devm_kcalloc(dev, max3191x->nchips,
	380	2, GFP_KERNEL);
	381	if (!max3191x->crc_error \|\| !max3191x->undervolt1 \|\|
	382	!max3191x->overtemp \|\| !max3191x->undervolt2 \|\|
	383	!max3191x->fault \|\| !max3191x->xfer.rx_buf)
	384	return -ENOMEM;
	385
	386	max3191x->modesel_pins = devm_gpiod_get_array_optional_count(dev,
	387	"maxim,modesel", GPIOD_ASIS, max3191x->nchips);
	388	max3191x->fault_pins = devm_gpiod_get_array_optional_count(dev,
	389	"maxim,fault", GPIOD_IN, max3191x->nchips);
	390	max3191x->db0_pins = devm_gpiod_get_array_optional_count(dev,
	391	"maxim,db0", GPIOD_OUT_LOW, max3191x->nchips);
	392	max3191x->db1_pins = devm_gpiod_get_array_optional_count(dev,
393	"maxim,db1", GPIOD_OUT_LOW, max3191x->nchips);
394
395	max3191x->mode = device_property_read_bool(dev, "maxim,modesel-8bit")
396	? STATUS_BYTE_DISABLED : STATUS_BYTE_ENABLED;
397	if (max3191x->modesel_pins)
398	gpiod_set_array_single_value_cansleep(
399	max3191x->modesel_pins->ndescs,
77588c14 JK	400	max3191x->modesel_pins->desc,
77588c14 JK	401	max3191x->modesel_pins->info, max3191x->mode);
b2f68edf LW	402
	403	max3191x->ignore_uv = device_property_read_bool(dev,
	404	"maxim,ignore-undervoltage");
	405
	406	if (max3191x->db0_pins && max3191x->db1_pins &&
	407	max3191x->db0_pins->ndescs != max3191x->db1_pins->ndescs) {
	408	dev_err(dev, "ignoring maxim,db*-gpios: array len mismatch\n");
	409	devm_gpiod_put_array(dev, max3191x->db0_pins);
	410	devm_gpiod_put_array(dev, max3191x->db1_pins);
	411	max3191x->db0_pins = NULL;
	412	max3191x->db1_pins = NULL;
	413	}
	414
	415	max3191x->xfer.len = max3191x->nchips * max3191x_wordlen(max3191x);
	416	spi_message_init_with_transfers(&max3191x->mesg, &max3191x->xfer, 1);
	417
	418	max3191x->gpio.label = spi->modalias;
	419	max3191x->gpio.owner = THIS_MODULE;
	420	max3191x->gpio.parent = dev;
	421	max3191x->gpio.base = -1;
	422	max3191x->gpio.ngpio = max3191x->nchips * MAX3191X_NGPIO;
	423	max3191x->gpio.can_sleep = true;
	424
	425	max3191x->gpio.get_direction = max3191x_get_direction;
	426	max3191x->gpio.direction_input = max3191x_direction_input;
	427	max3191x->gpio.direction_output = max3191x_direction_output;
	428	max3191x->gpio.set = max3191x_set;
	429	max3191x->gpio.set_multiple = max3191x_set_multiple;
	430	max3191x->gpio.get = max3191x_get;
	431	max3191x->gpio.get_multiple = max3191x_get_multiple;
	432	max3191x->gpio.set_config = max3191x_set_config;
	433
	434	mutex_init(&max3191x->lock);
	435
	436	ret = gpiochip_add_data(&max3191x->gpio, max3191x);
	437	if (ret) {
	438	mutex_destroy(&max3191x->lock);
	439	return ret;
	440	}
	441
	442	return 0;
	443	}
	444
	445	static int max3191x_remove(struct spi_device *spi)
	446	{
	447	struct max3191x_chip *max3191x = spi_get_drvdata(spi);
	448
	449	gpiochip_remove(&max3191x->gpio);
	450	mutex_destroy(&max3191x->lock);
	451
	452	return 0;
	453	}
	454
	455	static int __init max3191x_register_driver(struct spi_driver *sdrv)
	456	{
	457	crc8_populate_msb(max3191x_crc8, MAX3191X_CRC8_POLYNOMIAL);
	458	return spi_register_driver(sdrv);
	459	}
	460
	461	#ifdef CONFIG_OF
	462	static const struct of_device_id max3191x_of_id[] = {
	463	{ .compatible = "maxim,max31910" },
	464	{ .compatible = "maxim,max31911" },
	465	{ .compatible = "maxim,max31912" },
466	{ .compatible = "maxim,max31913" },
467	{ .compatible = "maxim,max31953" },
468	{ .compatible = "maxim,max31963" },
469	{ }
470	};
471	MODULE_DEVICE_TABLE(of, max3191x_of_id);
472	#endif
473
474	static const struct spi_device_id max3191x_spi_id[] = {
475	{ "max31910" },
476	{ "max31911" },
477	{ "max31912" },
478	{ "max31913" },
479	{ "max31953" },
480	{ "max31963" },
481	{ }
482	};
483	MODULE_DEVICE_TABLE(spi, max3191x_spi_id);
484
485	static struct spi_driver max3191x_driver = {
486	.driver = {
487	.name = "max3191x",
488	.of_match_table = of_match_ptr(max3191x_of_id),
489	},
490	.probe = max3191x_probe,
491	.remove = max3191x_remove,
492	.id_table = max3191x_spi_id,
493	};
494	module_driver(max3191x_driver, max3191x_register_driver, spi_unregister_driver);
495
496	MODULE_AUTHOR("Lukas Wunner <lukas@wunner.de>");
497	MODULE_DESCRIPTION("GPIO driver for Maxim MAX3191x industrial serializer");
498	MODULE_LICENSE("GPL v2");