diff options
Diffstat (limited to 'drivers/gpio/gpio-moxtet.c')
| -rw-r--r-- | drivers/gpio/gpio-moxtet.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-moxtet.c b/drivers/gpio/gpio-moxtet.c new file mode 100644 index 0000000000..61f9efd6c6 --- /dev/null +++ b/drivers/gpio/gpio-moxtet.c @@ -0,0 +1,179 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Turris Mox Moxtet GPIO expander + * + * Copyright (C) 2018 Marek Behún <kabel@kernel.org> + */ + +#include <linux/bitops.h> +#include <linux/gpio/driver.h> +#include <linux/moxtet.h> +#include <linux/module.h> + +#define MOXTET_GPIO_NGPIOS 12 +#define MOXTET_GPIO_INPUTS 4 + +struct moxtet_gpio_desc { + u16 in_mask; + u16 out_mask; +}; + +static const struct moxtet_gpio_desc descs[] = { + [TURRIS_MOX_MODULE_SFP] = { + .in_mask = GENMASK(2, 0), + .out_mask = GENMASK(5, 4), + }, +}; + +struct moxtet_gpio_chip { + struct device *dev; + struct gpio_chip gpio_chip; + const struct moxtet_gpio_desc *desc; +}; + +static int moxtet_gpio_get_value(struct gpio_chip *gc, unsigned int offset) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + int ret; + + if (chip->desc->in_mask & BIT(offset)) { + ret = moxtet_device_read(chip->dev); + } else if (chip->desc->out_mask & BIT(offset)) { + ret = moxtet_device_written(chip->dev); + if (ret >= 0) + ret <<= MOXTET_GPIO_INPUTS; + } else { + return -EINVAL; + } + + if (ret < 0) + return ret; + + return !!(ret & BIT(offset)); +} + +static void moxtet_gpio_set_value(struct gpio_chip *gc, unsigned int offset, + int val) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + int state; + + state = moxtet_device_written(chip->dev); + if (state < 0) + return; + + offset -= MOXTET_GPIO_INPUTS; + + if (val) + state |= BIT(offset); + else + state &= ~BIT(offset); + + moxtet_device_write(chip->dev, state); +} + +static int moxtet_gpio_get_direction(struct gpio_chip *gc, unsigned int offset) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + + /* All lines are hard wired to be either input or output, not both. */ + if (chip->desc->in_mask & BIT(offset)) + return GPIO_LINE_DIRECTION_IN; + else if (chip->desc->out_mask & BIT(offset)) + return GPIO_LINE_DIRECTION_OUT; + else + return -EINVAL; +} + +static int moxtet_gpio_direction_input(struct gpio_chip *gc, + unsigned int offset) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + + if (chip->desc->in_mask & BIT(offset)) + return 0; + else if (chip->desc->out_mask & BIT(offset)) + return -ENOTSUPP; + else + return -EINVAL; +} + +static int moxtet_gpio_direction_output(struct gpio_chip *gc, + unsigned int offset, int val) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + + if (chip->desc->out_mask & BIT(offset)) + moxtet_gpio_set_value(gc, offset, val); + else if (chip->desc->in_mask & BIT(offset)) + return -ENOTSUPP; + else + return -EINVAL; + + return 0; +} + +static int moxtet_gpio_probe(struct device *dev) +{ + struct moxtet_gpio_chip *chip; + struct device_node *nc = dev->of_node; + int id; + + id = to_moxtet_device(dev)->id; + + if (id >= ARRAY_SIZE(descs)) { + dev_err(dev, "%pOF Moxtet device id 0x%x is not supported by gpio-moxtet driver\n", + nc, id); + return -ENOTSUPP; + } + + chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + chip->dev = dev; + chip->gpio_chip.parent = dev; + chip->desc = &descs[id]; + + dev_set_drvdata(dev, chip); + + chip->gpio_chip.label = dev_name(dev); + chip->gpio_chip.get_direction = moxtet_gpio_get_direction; + chip->gpio_chip.direction_input = moxtet_gpio_direction_input; + chip->gpio_chip.direction_output = moxtet_gpio_direction_output; + chip->gpio_chip.get = moxtet_gpio_get_value; + chip->gpio_chip.set = moxtet_gpio_set_value; + chip->gpio_chip.base = -1; + + chip->gpio_chip.ngpio = MOXTET_GPIO_NGPIOS; + + chip->gpio_chip.can_sleep = true; + chip->gpio_chip.owner = THIS_MODULE; + + return devm_gpiochip_add_data(dev, &chip->gpio_chip, chip); +} + +static const struct of_device_id moxtet_gpio_dt_ids[] = { + { .compatible = "cznic,moxtet-gpio", }, + {}, +}; +MODULE_DEVICE_TABLE(of, moxtet_gpio_dt_ids); + +static const enum turris_mox_module_id moxtet_gpio_module_table[] = { + TURRIS_MOX_MODULE_SFP, + 0, +}; + +static struct moxtet_driver moxtet_gpio_driver = { + .driver = { + .name = "moxtet-gpio", + .of_match_table = moxtet_gpio_dt_ids, + .probe = moxtet_gpio_probe, + }, + .id_table = moxtet_gpio_module_table, +}; +module_moxtet_driver(moxtet_gpio_driver); + +MODULE_AUTHOR("Marek Behun <kabel@kernel.org>"); +MODULE_DESCRIPTION("Turris Mox Moxtet GPIO expander"); +MODULE_LICENSE("GPL v2"); |