1 // SPDX-License-Identifier: GPL-2.0-only
3  * gpio-max3191x.c - GPIO driver for Maxim MAX3191x industrial serializer
7  * The MAX3191x makes 8 digital 24V inputs available via SPI.
8  * Multiple chips can be daisy-chained, the spec does not impose
11  * Either of two modes is selectable: In 8-bit mode, only the state
13  * In 16-bit mode, an additional status byte is clocked out with
17  * readout of non-faulting chips in the same daisy-chain.
21  * daisy-chain.
23  * If the chips are hardwired to 8-bit mode ("modesel" pulled high),
24  * gpio-pisosr.c can be used alternatively to this driver.
30  * https://datasheets.maximintegrated.com/en/ds/MAX31953-MAX31963.pdf
36 #include <linux/gpio/consumer.h>
37 #include <linux/gpio/driver.h>
39 #include <linux/spi/spi.h>
47  * struct max3191x_chip - max3191x daisy-chain
48  * @gpio: GPIO controller struct
50  * @nchips: number of chips in the daisy-chain
51  * @mode: current mode, 0 for 16-bit, 1 for 8-bit;
52  *	for simplicity, all chips in the daisy-chain are assumed
54  * @modesel_pins: GPIO pins to configure modesel of each chip
55  * @fault_pins: GPIO pins to detect fault of each chip
56  * @db0_pins: GPIO pins to configure debounce of each chip
57  * @db1_pins: GPIO pins to configure debounce of each chip
58  * @mesg: SPI message to perform a readout
59  * @xfer: SPI transfer used by @mesg
69  *	for simplicity, all chips in the daisy-chain are assumed
73 	struct gpio_chip gpio;  member
96 static int max3191x_get_direction(struct gpio_chip *gpio, unsigned int offset)  in max3191x_get_direction()  argument
101 static int max3191x_direction_input(struct gpio_chip *gpio, unsigned int offset)  in max3191x_direction_input()  argument
106 static int max3191x_direction_output(struct gpio_chip *gpio,  in max3191x_direction_output()  argument
109 	return -EINVAL;  in max3191x_direction_output()
112 static void max3191x_set(struct gpio_chip *gpio, unsigned int offset, int value)  in max3191x_set()  argument
115 static void max3191x_set_multiple(struct gpio_chip *gpio, unsigned long *mask,  in max3191x_set_multiple()  argument
121 	return max3191x->mode == STATUS_BYTE_ENABLED ? 2 : 1;  in max3191x_wordlen()
126 	struct device *dev = max3191x->gpio.parent;  in max3191x_readout_locked()
127 	struct spi_device *spi = to_spi_device(dev);  in max3191x_readout_locked()  local
130 	val = spi_sync(spi, &max3191x->mesg);  in max3191x_readout_locked()
132 		dev_err_ratelimited(dev, "SPI receive error %d\n", val);  in max3191x_readout_locked()
136 	for (i = 0; i < max3191x->nchips; i++) {  in max3191x_readout_locked()
137 		if (max3191x->mode == STATUS_BYTE_ENABLED) {  in max3191x_readout_locked()
138 			u8 in	  = ((u8 *)max3191x->xfer.rx_buf)[i * 2];  in max3191x_readout_locked()
139 			u8 status = ((u8 *)max3191x->xfer.rx_buf)[i * 2 + 1];  in max3191x_readout_locked()
142 			__assign_bit(i, max3191x->crc_error, val);  in max3191x_readout_locked()
148 			__assign_bit(i, max3191x->overtemp, ot);  in max3191x_readout_locked()
153 			if (!max3191x->ignore_uv) {  in max3191x_readout_locked()
155 				__assign_bit(i, max3191x->undervolt1, uv1);  in max3191x_readout_locked()
161 				__assign_bit(i, max3191x->undervolt2, val);  in max3191x_readout_locked()
168 		if (max3191x->fault_pins && !max3191x->ignore_uv) {  in max3191x_readout_locked()
171 				(max3191x->fault_pins->ndescs == 1)  in max3191x_readout_locked()
172 					? max3191x->fault_pins->desc[0]  in max3191x_readout_locked()
173 					: max3191x->fault_pins->desc[i];  in max3191x_readout_locked()
178 					"GPIO read error %d\n", val);  in max3191x_readout_locked()
181 			__assign_bit(i, max3191x->fault, val);  in max3191x_readout_locked()
195 	if (!max3191x->ignore_uv && test_bit(chipnum, max3191x->fault))  in max3191x_chip_is_faulting()
198 	if (max3191x->mode == STATUS_BYTE_DISABLED)  in max3191x_chip_is_faulting()
201 	return test_bit(chipnum, max3191x->crc_error) ||  in max3191x_chip_is_faulting()
202 	       test_bit(chipnum, max3191x->overtemp)  ||  in max3191x_chip_is_faulting()
203 	       (!max3191x->ignore_uv &&  in max3191x_chip_is_faulting()
204 		test_bit(chipnum, max3191x->undervolt1));  in max3191x_chip_is_faulting()
207 static int max3191x_get(struct gpio_chip *gpio, unsigned int offset)  in max3191x_get()  argument
209 	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);  in max3191x_get()
213 	mutex_lock(&max3191x->lock);  in max3191x_get()
220 		ret = -EIO;  in max3191x_get()
224 	in = ((u8 *)max3191x->xfer.rx_buf)[chipnum * wordlen];  in max3191x_get()
228 	mutex_unlock(&max3191x->lock);  in max3191x_get()
232 static int max3191x_get_multiple(struct gpio_chip *gpio, unsigned long *mask,  in max3191x_get_multiple()  argument
235 	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);  in max3191x_get_multiple()
242 	mutex_lock(&max3191x->lock);  in max3191x_get_multiple()
247 	bitmap_zero(bits, gpio->ngpio);  in max3191x_get_multiple()
248 	for_each_set_clump8(bit, gpio_mask, mask, gpio->ngpio) {  in max3191x_get_multiple()
252 			ret = -EIO;  in max3191x_get_multiple()
256 		in = ((u8 *)max3191x->xfer.rx_buf)[chipnum * wordlen];  in max3191x_get_multiple()
262 	mutex_unlock(&max3191x->lock);  in max3191x_get_multiple()
266 static int max3191x_set_config(struct gpio_chip *gpio, unsigned int offset,  in max3191x_set_config()  argument
269 	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);  in max3191x_set_config()
273 		return -ENOTSUPP;  in max3191x_set_config()
275 	if (!max3191x->db0_pins || !max3191x->db1_pins)  in max3191x_set_config()
276 		return -EINVAL;  in max3191x_set_config()
297 		return -EINVAL;  in max3191x_set_config()
300 	if (max3191x->db0_pins->ndescs == 1)  in max3191x_set_config()
305 	mutex_lock(&max3191x->lock);  in max3191x_set_config()
306 	gpiod_set_value_cansleep(max3191x->db0_pins->desc[chipnum], db0_val);  in max3191x_set_config()
307 	gpiod_set_value_cansleep(max3191x->db1_pins->desc[chipnum], db1_val);  in max3191x_set_config()
308 	mutex_unlock(&max3191x->lock);  in max3191x_set_config()
339 	if (found == -ENOENT)  in devm_gpiod_get_array_optional_count()
343 		dev_err(dev, "ignoring %s-gpios: found %d, expected %u or 1\n",  in devm_gpiod_get_array_optional_count()
351 		dev_err(dev, "failed to get %s-gpios: %ld\n",  in devm_gpiod_get_array_optional_count()
359 static int max3191x_probe(struct spi_device *spi)  in max3191x_probe()  argument
361 	struct device *dev = &spi->dev;  in max3191x_probe()
367 		return -ENOMEM;  in max3191x_probe()
368 	spi_set_drvdata(spi, max3191x);  in max3191x_probe()
370 	max3191x->nchips = 1;  in max3191x_probe()
371 	device_property_read_u32(dev, "#daisy-chained-devices",  in max3191x_probe()
372 				 &max3191x->nchips);  in max3191x_probe()
374 	n = BITS_TO_LONGS(max3191x->nchips);  in max3191x_probe()
375 	max3191x->crc_error   = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);  in max3191x_probe()
376 	max3191x->undervolt1  = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);  in max3191x_probe()
377 	max3191x->undervolt2  = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);  in max3191x_probe()
378 	max3191x->overtemp    = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);  in max3191x_probe()
379 	max3191x->fault       = devm_kcalloc(dev, n, sizeof(long), GFP_KERNEL);  in max3191x_probe()
380 	max3191x->xfer.rx_buf = devm_kcalloc(dev, max3191x->nchips,  in max3191x_probe()
382 	if (!max3191x->crc_error || !max3191x->undervolt1 ||  in max3191x_probe()
383 	    !max3191x->overtemp  || !max3191x->undervolt2 ||  in max3191x_probe()
384 	    !max3191x->fault     || !max3191x->xfer.rx_buf)  in max3191x_probe()
385 		return -ENOMEM;  in max3191x_probe()
387 	max3191x->modesel_pins = devm_gpiod_get_array_optional_count(dev,  in max3191x_probe()
388 				 "maxim,modesel", GPIOD_ASIS, max3191x->nchips);  in max3191x_probe()
389 	max3191x->fault_pins   = devm_gpiod_get_array_optional_count(dev,  in max3191x_probe()
390 				 "maxim,fault", GPIOD_IN, max3191x->nchips);  in max3191x_probe()
391 	max3191x->db0_pins     = devm_gpiod_get_array_optional_count(dev,  in max3191x_probe()
392 				 "maxim,db0", GPIOD_OUT_LOW, max3191x->nchips);  in max3191x_probe()
393 	max3191x->db1_pins     = devm_gpiod_get_array_optional_count(dev,  in max3191x_probe()
394 				 "maxim,db1", GPIOD_OUT_LOW, max3191x->nchips);  in max3191x_probe()
396 	max3191x->mode = device_property_read_bool(dev, "maxim,modesel-8bit")  in max3191x_probe()
398 	if (max3191x->modesel_pins)  in max3191x_probe()
400 				 max3191x->modesel_pins->ndescs,  in max3191x_probe()
401 				 max3191x->modesel_pins->desc,  in max3191x_probe()
402 				 max3191x->modesel_pins->info, max3191x->mode);  in max3191x_probe()
404 	max3191x->ignore_uv = device_property_read_bool(dev,  in max3191x_probe()
405 						  "maxim,ignore-undervoltage");  in max3191x_probe()
407 	if (max3191x->db0_pins && max3191x->db1_pins &&  in max3191x_probe()
408 	    max3191x->db0_pins->ndescs != max3191x->db1_pins->ndescs) {  in max3191x_probe()
409 		dev_err(dev, "ignoring maxim,db*-gpios: array len mismatch\n");  in max3191x_probe()
410 		devm_gpiod_put_array(dev, max3191x->db0_pins);  in max3191x_probe()
411 		devm_gpiod_put_array(dev, max3191x->db1_pins);  in max3191x_probe()
412 		max3191x->db0_pins = NULL;  in max3191x_probe()
413 		max3191x->db1_pins = NULL;  in max3191x_probe()
416 	max3191x->xfer.len = max3191x->nchips * max3191x_wordlen(max3191x);  in max3191x_probe()
417 	spi_message_init_with_transfers(&max3191x->mesg, &max3191x->xfer, 1);  in max3191x_probe()
419 	max3191x->gpio.label = spi->modalias;  in max3191x_probe()
420 	max3191x->gpio.owner = THIS_MODULE;  in max3191x_probe()
421 	max3191x->gpio.parent = dev;  in max3191x_probe()
422 	max3191x->gpio.base = -1;  in max3191x_probe()
423 	max3191x->gpio.ngpio = max3191x->nchips * MAX3191X_NGPIO;  in max3191x_probe()
424 	max3191x->gpio.can_sleep = true;  in max3191x_probe()
426 	max3191x->gpio.get_direction = max3191x_get_direction;  in max3191x_probe()
427 	max3191x->gpio.direction_input = max3191x_direction_input;  in max3191x_probe()
428 	max3191x->gpio.direction_output = max3191x_direction_output;  in max3191x_probe()
429 	max3191x->gpio.set = max3191x_set;  in max3191x_probe()
430 	max3191x->gpio.set_multiple = max3191x_set_multiple;  in max3191x_probe()
431 	max3191x->gpio.get = max3191x_get;  in max3191x_probe()
432 	max3191x->gpio.get_multiple = max3191x_get_multiple;  in max3191x_probe()
433 	max3191x->gpio.set_config = max3191x_set_config;  in max3191x_probe()
435 	mutex_init(&max3191x->lock);  in max3191x_probe()
437 	ret = gpiochip_add_data(&max3191x->gpio, max3191x);  in max3191x_probe()
439 		mutex_destroy(&max3191x->lock);  in max3191x_probe()
446 static void max3191x_remove(struct spi_device *spi)  in max3191x_remove()  argument
448 	struct max3191x_chip *max3191x = spi_get_drvdata(spi);  in max3191x_remove()
450 	gpiochip_remove(&max3191x->gpio);  in max3191x_remove()
451 	mutex_destroy(&max3191x->lock);  in max3191x_remove()
480 MODULE_DEVICE_TABLE(spi, max3191x_spi_id);
494 MODULE_DESCRIPTION("GPIO driver for Maxim MAX3191x industrial serializer");