1*abd46274SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2df6df93cSAndrew F. Davis /* 3df6df93cSAndrew F. Davis * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/ 4df6df93cSAndrew F. Davis * Andrew F. Davis <afd@ti.com> 5df6df93cSAndrew F. Davis */ 6df6df93cSAndrew F. Davis 740bb5d72SMorten Hein Tiljeset #include <linux/bitmap.h> 840bb5d72SMorten Hein Tiljeset #include <linux/bitops.h> 9df6df93cSAndrew F. Davis #include <linux/delay.h> 10df6df93cSAndrew F. Davis #include <linux/gpio/consumer.h> 11df6df93cSAndrew F. Davis #include <linux/gpio/driver.h> 12df6df93cSAndrew F. Davis #include <linux/module.h> 13df6df93cSAndrew F. Davis #include <linux/mutex.h> 14df6df93cSAndrew F. Davis #include <linux/spi/spi.h> 15df6df93cSAndrew F. Davis 16df6df93cSAndrew F. Davis #define DEFAULT_NGPIO 8 17df6df93cSAndrew F. Davis 18df6df93cSAndrew F. Davis /** 19df6df93cSAndrew F. Davis * struct pisosr_gpio - GPIO driver data 20df6df93cSAndrew F. Davis * @chip: GPIO controller chip 21df6df93cSAndrew F. Davis * @spi: SPI device pointer 22df6df93cSAndrew F. Davis * @buffer: Buffer for device reads 23df6df93cSAndrew F. Davis * @buffer_size: Size of buffer 24df6df93cSAndrew F. Davis * @load_gpio: GPIO pin used to load input into device 25df6df93cSAndrew F. Davis * @lock: Protects read sequences 26df6df93cSAndrew F. Davis */ 27df6df93cSAndrew F. Davis struct pisosr_gpio { 28df6df93cSAndrew F. Davis struct gpio_chip chip; 29df6df93cSAndrew F. Davis struct spi_device *spi; 30df6df93cSAndrew F. Davis u8 *buffer; 31df6df93cSAndrew F. Davis size_t buffer_size; 32df6df93cSAndrew F. Davis struct gpio_desc *load_gpio; 33df6df93cSAndrew F. Davis struct mutex lock; 34df6df93cSAndrew F. Davis }; 35df6df93cSAndrew F. Davis 36df6df93cSAndrew F. Davis static int pisosr_gpio_refresh(struct pisosr_gpio *gpio) 37df6df93cSAndrew F. Davis { 38df6df93cSAndrew F. Davis int ret; 39df6df93cSAndrew F. Davis 40df6df93cSAndrew F. Davis mutex_lock(&gpio->lock); 41df6df93cSAndrew F. Davis 42df6df93cSAndrew F. Davis if (gpio->load_gpio) { 43ea04a7caSAxel Lin gpiod_set_value_cansleep(gpio->load_gpio, 1); 44df6df93cSAndrew F. Davis udelay(1); /* registers load time (~10ns) */ 45ea04a7caSAxel Lin gpiod_set_value_cansleep(gpio->load_gpio, 0); 46df6df93cSAndrew F. Davis udelay(1); /* registers recovery time (~5ns) */ 47df6df93cSAndrew F. Davis } 48df6df93cSAndrew F. Davis 49df6df93cSAndrew F. Davis ret = spi_read(gpio->spi, gpio->buffer, gpio->buffer_size); 50df6df93cSAndrew F. Davis 51df6df93cSAndrew F. Davis mutex_unlock(&gpio->lock); 52df6df93cSAndrew F. Davis 533e089d9fSSudip Mukherjee return ret; 54df6df93cSAndrew F. Davis } 55df6df93cSAndrew F. Davis 56df6df93cSAndrew F. Davis static int pisosr_gpio_get_direction(struct gpio_chip *chip, 57df6df93cSAndrew F. Davis unsigned offset) 58df6df93cSAndrew F. Davis { 59df6df93cSAndrew F. Davis /* This device always input */ 60e42615ecSMatti Vaittinen return GPIO_LINE_DIRECTION_IN; 61df6df93cSAndrew F. Davis } 62df6df93cSAndrew F. Davis 63df6df93cSAndrew F. Davis static int pisosr_gpio_direction_input(struct gpio_chip *chip, 64df6df93cSAndrew F. Davis unsigned offset) 65df6df93cSAndrew F. Davis { 66df6df93cSAndrew F. Davis /* This device always input */ 67df6df93cSAndrew F. Davis return 0; 68df6df93cSAndrew F. Davis } 69df6df93cSAndrew F. Davis 70df6df93cSAndrew F. Davis static int pisosr_gpio_direction_output(struct gpio_chip *chip, 71df6df93cSAndrew F. Davis unsigned offset, int value) 72df6df93cSAndrew F. Davis { 73df6df93cSAndrew F. Davis /* This device is input only */ 74df6df93cSAndrew F. Davis return -EINVAL; 75df6df93cSAndrew F. Davis } 76df6df93cSAndrew F. Davis 77df6df93cSAndrew F. Davis static int pisosr_gpio_get(struct gpio_chip *chip, unsigned offset) 78df6df93cSAndrew F. Davis { 79df6df93cSAndrew F. Davis struct pisosr_gpio *gpio = gpiochip_get_data(chip); 80df6df93cSAndrew F. Davis 81df6df93cSAndrew F. Davis /* Refresh may not always be needed */ 82df6df93cSAndrew F. Davis pisosr_gpio_refresh(gpio); 83df6df93cSAndrew F. Davis 84df6df93cSAndrew F. Davis return (gpio->buffer[offset / 8] >> (offset % 8)) & 0x1; 85df6df93cSAndrew F. Davis } 86df6df93cSAndrew F. Davis 8740bb5d72SMorten Hein Tiljeset static int pisosr_gpio_get_multiple(struct gpio_chip *chip, 8840bb5d72SMorten Hein Tiljeset unsigned long *mask, unsigned long *bits) 8940bb5d72SMorten Hein Tiljeset { 9040bb5d72SMorten Hein Tiljeset struct pisosr_gpio *gpio = gpiochip_get_data(chip); 91608bd5fdSWilliam Breathitt Gray unsigned long offset; 92608bd5fdSWilliam Breathitt Gray unsigned long gpio_mask; 93608bd5fdSWilliam Breathitt Gray unsigned long buffer_state; 9440bb5d72SMorten Hein Tiljeset 9540bb5d72SMorten Hein Tiljeset pisosr_gpio_refresh(gpio); 9640bb5d72SMorten Hein Tiljeset 9740bb5d72SMorten Hein Tiljeset bitmap_zero(bits, chip->ngpio); 98608bd5fdSWilliam Breathitt Gray for_each_set_clump8(offset, gpio_mask, mask, chip->ngpio) { 99608bd5fdSWilliam Breathitt Gray buffer_state = gpio->buffer[offset / 8] & gpio_mask; 100608bd5fdSWilliam Breathitt Gray bitmap_set_value8(bits, buffer_state, offset); 10140bb5d72SMorten Hein Tiljeset } 10240bb5d72SMorten Hein Tiljeset 10340bb5d72SMorten Hein Tiljeset return 0; 10440bb5d72SMorten Hein Tiljeset } 10540bb5d72SMorten Hein Tiljeset 106e35b5ab0SJulia Lawall static const struct gpio_chip template_chip = { 107df6df93cSAndrew F. Davis .label = "pisosr-gpio", 108df6df93cSAndrew F. Davis .owner = THIS_MODULE, 109df6df93cSAndrew F. Davis .get_direction = pisosr_gpio_get_direction, 110df6df93cSAndrew F. Davis .direction_input = pisosr_gpio_direction_input, 111df6df93cSAndrew F. Davis .direction_output = pisosr_gpio_direction_output, 112df6df93cSAndrew F. Davis .get = pisosr_gpio_get, 11340bb5d72SMorten Hein Tiljeset .get_multiple = pisosr_gpio_get_multiple, 114df6df93cSAndrew F. Davis .base = -1, 115df6df93cSAndrew F. Davis .ngpio = DEFAULT_NGPIO, 116df6df93cSAndrew F. Davis .can_sleep = true, 117df6df93cSAndrew F. Davis }; 118df6df93cSAndrew F. Davis 119df6df93cSAndrew F. Davis static int pisosr_gpio_probe(struct spi_device *spi) 120df6df93cSAndrew F. Davis { 121df6df93cSAndrew F. Davis struct device *dev = &spi->dev; 122df6df93cSAndrew F. Davis struct pisosr_gpio *gpio; 123df6df93cSAndrew F. Davis int ret; 124df6df93cSAndrew F. Davis 125df6df93cSAndrew F. Davis gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL); 126df6df93cSAndrew F. Davis if (!gpio) 127df6df93cSAndrew F. Davis return -ENOMEM; 128df6df93cSAndrew F. Davis 129df6df93cSAndrew F. Davis spi_set_drvdata(spi, gpio); 130df6df93cSAndrew F. Davis 131df6df93cSAndrew F. Davis gpio->chip = template_chip; 132df6df93cSAndrew F. Davis gpio->chip.parent = dev; 133df6df93cSAndrew F. Davis of_property_read_u16(dev->of_node, "ngpios", &gpio->chip.ngpio); 134df6df93cSAndrew F. Davis 135df6df93cSAndrew F. Davis gpio->spi = spi; 136df6df93cSAndrew F. Davis 137df6df93cSAndrew F. Davis gpio->buffer_size = DIV_ROUND_UP(gpio->chip.ngpio, 8); 138df6df93cSAndrew F. Davis gpio->buffer = devm_kzalloc(dev, gpio->buffer_size, GFP_KERNEL); 139df6df93cSAndrew F. Davis if (!gpio->buffer) 140df6df93cSAndrew F. Davis return -ENOMEM; 141df6df93cSAndrew F. Davis 14221d08ab9SAxel Lin gpio->load_gpio = devm_gpiod_get_optional(dev, "load", GPIOD_OUT_LOW); 143308a028dSKrzysztof Kozlowski if (IS_ERR(gpio->load_gpio)) 144308a028dSKrzysztof Kozlowski return dev_err_probe(dev, PTR_ERR(gpio->load_gpio), 145308a028dSKrzysztof Kozlowski "Unable to allocate load GPIO\n"); 146df6df93cSAndrew F. Davis 147df6df93cSAndrew F. Davis mutex_init(&gpio->lock); 148df6df93cSAndrew F. Davis 149df6df93cSAndrew F. Davis ret = gpiochip_add_data(&gpio->chip, gpio); 150df6df93cSAndrew F. Davis if (ret < 0) { 151df6df93cSAndrew F. Davis dev_err(dev, "Unable to register gpiochip\n"); 152df6df93cSAndrew F. Davis return ret; 153df6df93cSAndrew F. Davis } 154df6df93cSAndrew F. Davis 155df6df93cSAndrew F. Davis return 0; 156df6df93cSAndrew F. Davis } 157df6df93cSAndrew F. Davis 158a0386bbaSUwe Kleine-König static void pisosr_gpio_remove(struct spi_device *spi) 159df6df93cSAndrew F. Davis { 160df6df93cSAndrew F. Davis struct pisosr_gpio *gpio = spi_get_drvdata(spi); 161df6df93cSAndrew F. Davis 162df6df93cSAndrew F. Davis gpiochip_remove(&gpio->chip); 163df6df93cSAndrew F. Davis 164df6df93cSAndrew F. Davis mutex_destroy(&gpio->lock); 165df6df93cSAndrew F. Davis } 166df6df93cSAndrew F. Davis 167df6df93cSAndrew F. Davis static const struct spi_device_id pisosr_gpio_id_table[] = { 168df6df93cSAndrew F. Davis { "pisosr-gpio", }, 169df6df93cSAndrew F. Davis { /* sentinel */ } 170df6df93cSAndrew F. Davis }; 171df6df93cSAndrew F. Davis MODULE_DEVICE_TABLE(spi, pisosr_gpio_id_table); 172df6df93cSAndrew F. Davis 173df6df93cSAndrew F. Davis static const struct of_device_id pisosr_gpio_of_match_table[] = { 174df6df93cSAndrew F. Davis { .compatible = "pisosr-gpio", }, 175df6df93cSAndrew F. Davis { /* sentinel */ } 176df6df93cSAndrew F. Davis }; 177df6df93cSAndrew F. Davis MODULE_DEVICE_TABLE(of, pisosr_gpio_of_match_table); 178df6df93cSAndrew F. Davis 179df6df93cSAndrew F. Davis static struct spi_driver pisosr_gpio_driver = { 180df6df93cSAndrew F. Davis .driver = { 181df6df93cSAndrew F. Davis .name = "pisosr-gpio", 182df6df93cSAndrew F. Davis .of_match_table = pisosr_gpio_of_match_table, 183df6df93cSAndrew F. Davis }, 184df6df93cSAndrew F. Davis .probe = pisosr_gpio_probe, 185df6df93cSAndrew F. Davis .remove = pisosr_gpio_remove, 186df6df93cSAndrew F. Davis .id_table = pisosr_gpio_id_table, 187df6df93cSAndrew F. Davis }; 188df6df93cSAndrew F. Davis module_spi_driver(pisosr_gpio_driver); 189df6df93cSAndrew F. Davis 190df6df93cSAndrew F. Davis MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>"); 191df6df93cSAndrew F. Davis MODULE_DESCRIPTION("SPI Compatible PISO Shift Register GPIO Driver"); 192df6df93cSAndrew F. Davis MODULE_LICENSE("GPL v2"); 193