| /* |
| * GPIO Greybus driver. |
| * |
| * Copyright 2014 Google Inc. |
| * Copyright 2014 Linaro Ltd. |
| * |
| * Released under the GPLv2 only. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/gpio.h> |
| #include "greybus.h" |
| |
| struct gb_gpio_line { |
| /* The following has to be an array of line_max entries */ |
| /* --> make them just a flags field */ |
| u8 active: 1, |
| direction: 1, /* 0 = output, 1 = input */ |
| value: 1; /* 0 = low, 1 = high */ |
| u16 debounce_usec; |
| }; |
| |
| struct gb_gpio_controller { |
| struct gb_connection *connection; |
| u8 version_major; |
| u8 version_minor; |
| u8 line_max; /* max line number */ |
| struct gb_gpio_line *lines; |
| |
| struct gpio_chip chip; |
| }; |
| #define gpio_chip_to_gb_gpio_controller(chip) \ |
| container_of(chip, struct gb_gpio_controller, chip) |
| |
| /* Version of the Greybus GPIO protocol we support */ |
| #define GB_GPIO_VERSION_MAJOR 0x00 |
| #define GB_GPIO_VERSION_MINOR 0x01 |
| |
| /* Greybus GPIO request types */ |
| #define GB_GPIO_TYPE_INVALID 0x00 |
| #define GB_GPIO_TYPE_PROTOCOL_VERSION 0x01 |
| #define GB_GPIO_TYPE_LINE_COUNT 0x02 |
| #define GB_GPIO_TYPE_ACTIVATE 0x03 |
| #define GB_GPIO_TYPE_DEACTIVATE 0x04 |
| #define GB_GPIO_TYPE_GET_DIRECTION 0x05 |
| #define GB_GPIO_TYPE_DIRECTION_IN 0x06 |
| #define GB_GPIO_TYPE_DIRECTION_OUT 0x07 |
| #define GB_GPIO_TYPE_GET_VALUE 0x08 |
| #define GB_GPIO_TYPE_SET_VALUE 0x09 |
| #define GB_GPIO_TYPE_SET_DEBOUNCE 0x0a |
| #define GB_GPIO_TYPE_RESPONSE 0x80 /* OR'd with rest */ |
| |
| #define GB_GPIO_DEBOUNCE_USEC_DEFAULT 0 /* microseconds */ |
| |
| /* line count request has no payload */ |
| struct gb_gpio_line_count_response { |
| __u8 count; |
| }; |
| |
| struct gb_gpio_activate_request { |
| __u8 which; |
| }; |
| /* activate response has no payload */ |
| |
| struct gb_gpio_deactivate_request { |
| __u8 which; |
| }; |
| /* deactivate response has no payload */ |
| |
| struct gb_gpio_get_direction_request { |
| __u8 which; |
| }; |
| struct gb_gpio_get_direction_response { |
| __u8 direction; |
| }; |
| |
| struct gb_gpio_direction_in_request { |
| __u8 which; |
| }; |
| /* direction in response has no payload */ |
| |
| struct gb_gpio_direction_out_request { |
| __u8 which; |
| __u8 value; |
| }; |
| /* direction out response has no payload */ |
| |
| struct gb_gpio_get_value_request { |
| __u8 which; |
| }; |
| struct gb_gpio_get_value_response { |
| __u8 value; |
| }; |
| |
| struct gb_gpio_set_value_request { |
| __u8 which; |
| __u8 value; |
| }; |
| /* set value response has no payload */ |
| |
| struct gb_gpio_set_debounce_request { |
| __u8 which; |
| __le16 usec; |
| }; |
| /* debounce response has no payload */ |
| |
| |
| /* Define get_version() routine */ |
| define_get_version(gb_gpio_controller, GPIO); |
| |
| static int gb_gpio_line_count_operation(struct gb_gpio_controller *ggc) |
| { |
| struct gb_gpio_line_count_response response; |
| int ret; |
| |
| ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_LINE_COUNT, |
| NULL, 0, &response, sizeof(response)); |
| if (!ret) |
| ggc->line_max = response.count; |
| return ret; |
| } |
| |
| static int gb_gpio_activate_operation(struct gb_gpio_controller *ggc, u8 which) |
| { |
| struct gb_gpio_activate_request request; |
| int ret; |
| |
| if (which > ggc->line_max) |
| return -EINVAL; |
| |
| request.which = which; |
| ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_ACTIVATE, |
| &request, sizeof(request), NULL, 0); |
| if (!ret) |
| ggc->lines[which].active = true; |
| return ret; |
| } |
| |
| static int gb_gpio_deactivate_operation(struct gb_gpio_controller *ggc, |
| u8 which) |
| { |
| struct gb_gpio_deactivate_request request; |
| int ret; |
| |
| if (which > ggc->line_max) |
| return -EINVAL; |
| |
| request.which = which; |
| ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DEACTIVATE, |
| &request, sizeof(request), NULL, 0); |
| if (!ret) |
| ggc->lines[which].active = false; |
| return ret; |
| } |
| |
| static int gb_gpio_get_direction_operation(struct gb_gpio_controller *ggc, |
| u8 which) |
| { |
| struct gb_gpio_get_direction_request request; |
| struct gb_gpio_get_direction_response response; |
| int ret; |
| u8 direction; |
| |
| if (which > ggc->line_max) |
| return -EINVAL; |
| |
| request.which = which; |
| ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_DIRECTION, |
| &request, sizeof(request), |
| &response, sizeof(response)); |
| if (ret) |
| return ret; |
| |
| direction = response.direction; |
| if (direction && direction != 1) |
| pr_warn("gpio %u direction was %u (should be 0 or 1)\n", |
| which, direction); |
| ggc->lines[which].direction = direction ? 1 : 0; |
| return 0; |
| } |
| |
| static int gb_gpio_direction_in_operation(struct gb_gpio_controller *ggc, |
| u8 which) |
| { |
| struct gb_gpio_direction_in_request request; |
| int ret; |
| |
| if (which > ggc->line_max) |
| return -EINVAL; |
| |
| request.which = which; |
| ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_IN, |
| &request, sizeof(request), NULL, 0); |
| if (!ret) |
| ggc->lines[which].direction = 1; |
| return ret; |
| } |
| |
| static int gb_gpio_direction_out_operation(struct gb_gpio_controller *ggc, |
| u8 which, bool value_high) |
| { |
| struct gb_gpio_direction_out_request request; |
| int ret; |
| |
| if (which > ggc->line_max) |
| return -EINVAL; |
| |
| request.which = which; |
| request.value = value_high ? 1 : 0; |
| ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_OUT, |
| &request, sizeof(request), NULL, 0); |
| if (!ret) |
| ggc->lines[which].direction = 0; |
| return ret; |
| } |
| |
| static int gb_gpio_get_value_operation(struct gb_gpio_controller *ggc, |
| u8 which) |
| { |
| struct gb_gpio_get_value_request request; |
| struct gb_gpio_get_value_response response; |
| int ret; |
| u8 value; |
| |
| if (which > ggc->line_max) |
| return -EINVAL; |
| |
| request.which = which; |
| ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_VALUE, |
| &request, sizeof(request), |
| &response, sizeof(response)); |
| if (ret) |
| return ret; |
| |
| value = response.value; |
| if (value && value != 1) |
| pr_warn("gpio %u value was %u (should be 0 or 1)\n", |
| which, value); |
| ggc->lines[which].value = value ? 1 : 0; |
| return 0; |
| } |
| |
| static int gb_gpio_set_value_operation(struct gb_gpio_controller *ggc, |
| u8 which, bool value_high) |
| { |
| struct gb_gpio_set_value_request request; |
| int ret; |
| |
| if (which > ggc->line_max) |
| return -EINVAL; |
| |
| request.which = which; |
| request.value = value_high ? 1 : 0; |
| ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_VALUE, |
| &request, sizeof(request), NULL, 0); |
| if (!ret) { |
| /* XXX should this set direction to out? */ |
| ggc->lines[which].value = request.value; |
| } |
| return ret; |
| } |
| |
| static int gb_gpio_set_debounce_operation(struct gb_gpio_controller *ggc, |
| u8 which, u16 debounce_usec) |
| { |
| struct gb_gpio_set_debounce_request request; |
| int ret; |
| |
| if (which > ggc->line_max) |
| return -EINVAL; |
| |
| request.which = which; |
| request.usec = cpu_to_le16(debounce_usec); |
| ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_DEBOUNCE, |
| &request, sizeof(request), NULL, 0); |
| if (!ret) |
| ggc->lines[which].debounce_usec = debounce_usec; |
| return ret; |
| } |
| |
| static int gb_gpio_request(struct gpio_chip *chip, unsigned offset) |
| { |
| struct gb_gpio_controller *gb_gpio_controller = gpio_chip_to_gb_gpio_controller(chip); |
| int ret; |
| |
| if (offset >= chip->ngpio) |
| return -EINVAL; |
| ret = gb_gpio_activate_operation(gb_gpio_controller, (u8)offset); |
| if (ret) |
| ; /* return ret; */ |
| return 0; |
| } |
| |
| static void gb_gpio_free(struct gpio_chip *chip, unsigned offset) |
| { |
| struct gb_gpio_controller *gb_gpio_controller = gpio_chip_to_gb_gpio_controller(chip); |
| int ret; |
| |
| if (offset >= chip->ngpio) { |
| pr_err("bad offset %u supplied (must be 0..%u)\n", |
| offset, chip->ngpio - 1); |
| return; |
| } |
| ret = gb_gpio_deactivate_operation(gb_gpio_controller, (u8)offset); |
| if (ret) |
| ; /* return ret; */ |
| } |
| |
| static int gb_gpio_get_direction(struct gpio_chip *chip, unsigned offset) |
| { |
| struct gb_gpio_controller *gb_gpio_controller = gpio_chip_to_gb_gpio_controller(chip); |
| u8 which; |
| int ret; |
| |
| if (offset >= chip->ngpio) |
| return -EINVAL; |
| which = (u8)offset; |
| ret = gb_gpio_get_direction_operation(gb_gpio_controller, which); |
| if (ret) |
| ; /* return ret; */ |
| return gb_gpio_controller->lines[which].direction ? 1 : 0; |
| } |
| |
| static int gb_gpio_direction_input(struct gpio_chip *chip, unsigned offset) |
| { |
| struct gb_gpio_controller *gb_gpio_controller = gpio_chip_to_gb_gpio_controller(chip); |
| int ret; |
| |
| if (offset >= chip->ngpio) |
| return -EINVAL; |
| ret = gb_gpio_direction_in_operation(gb_gpio_controller, (u8)offset); |
| if (ret) |
| ; /* return ret; */ |
| return 0; |
| } |
| |
| static int gb_gpio_direction_output(struct gpio_chip *chip, unsigned offset, |
| int value) |
| { |
| struct gb_gpio_controller *gb_gpio_controller = gpio_chip_to_gb_gpio_controller(chip); |
| int ret; |
| |
| if (offset >= chip->ngpio) |
| return -EINVAL; |
| ret = gb_gpio_direction_out_operation(gb_gpio_controller, (u8)offset, !!value); |
| if (ret) |
| ; /* return ret; */ |
| return 0; |
| } |
| |
| static int gb_gpio_get(struct gpio_chip *chip, unsigned offset) |
| { |
| struct gb_gpio_controller *gb_gpio_controller = gpio_chip_to_gb_gpio_controller(chip); |
| u8 which; |
| int ret; |
| |
| if (offset >= chip->ngpio) |
| return -EINVAL; |
| which = (u8)offset; |
| ret = gb_gpio_get_value_operation(gb_gpio_controller, which); |
| if (ret) |
| return ret; |
| return (int)gb_gpio_controller->lines[which].value; |
| } |
| |
| static void gb_gpio_set(struct gpio_chip *chip, unsigned offset, int value) |
| { |
| struct gb_gpio_controller *gb_gpio_controller = gpio_chip_to_gb_gpio_controller(chip); |
| int ret; |
| |
| if (offset < 0 || offset >= chip->ngpio) { |
| pr_err("bad offset %u supplied (must be 0..%u)\n", |
| offset, chip->ngpio - 1); |
| return; |
| } |
| ret = gb_gpio_set_value_operation(gb_gpio_controller, (u8)offset, !!value); |
| if (ret) |
| ; /* return ret; */ |
| } |
| |
| static int gb_gpio_set_debounce(struct gpio_chip *chip, unsigned offset, |
| unsigned debounce) |
| { |
| struct gb_gpio_controller *gb_gpio_controller = gpio_chip_to_gb_gpio_controller(chip); |
| u16 usec; |
| int ret; |
| |
| if (offset >= chip->ngpio) |
| return -EINVAL; |
| if (debounce > (unsigned int)U16_MAX) |
| return -EINVAL; |
| usec = (u8)debounce; |
| ret = gb_gpio_set_debounce_operation(gb_gpio_controller, (u8)offset, usec); |
| if (ret) |
| ; /* return ret; */ |
| |
| return 0; /* XXX */ |
| } |
| |
| static int gb_gpio_to_irq(struct gpio_chip *chip, unsigned offset) |
| { |
| if (offset >= chip->ngpio) |
| return -EINVAL; |
| |
| return 0; /* XXX */ |
| } |
| |
| static void gb_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip) |
| { |
| return; /* XXX */ |
| } |
| |
| static int gb_gpio_controller_setup(struct gb_gpio_controller *gb_gpio_controller) |
| { |
| u32 line_count; |
| size_t size; |
| int ret; |
| |
| /* First thing we need to do is check the version */ |
| ret = get_version(gb_gpio_controller); |
| if (ret) |
| ; /* return ret; */ |
| |
| /* Now find out how many lines there are */ |
| ret = gb_gpio_line_count_operation(gb_gpio_controller); |
| if (ret) |
| ; /* return ret; */ |
| line_count = (u32)gb_gpio_controller->line_max + 1; |
| size = line_count * sizeof(*gb_gpio_controller->lines); |
| gb_gpio_controller->lines = kzalloc(size, GFP_KERNEL); |
| if (!gb_gpio_controller->lines) |
| return -ENOMEM; |
| |
| return ret; |
| } |
| |
| static int gb_gpio_connection_init(struct gb_connection *connection) |
| { |
| struct gb_gpio_controller *gb_gpio_controller; |
| struct gpio_chip *gpio; |
| int ret; |
| |
| gb_gpio_controller = kzalloc(sizeof(*gb_gpio_controller), GFP_KERNEL); |
| if (!gb_gpio_controller) |
| return -ENOMEM; |
| gb_gpio_controller->connection = connection; |
| connection->private = gb_gpio_controller; |
| |
| ret = gb_gpio_controller_setup(gb_gpio_controller); |
| if (ret) |
| goto out_err; |
| |
| gpio = &gb_gpio_controller->chip; |
| |
| gpio->label = "greybus_gpio"; |
| gpio->owner = THIS_MODULE; /* XXX Module get? */ |
| |
| gpio->request = gb_gpio_request; |
| gpio->free = gb_gpio_free; |
| gpio->get_direction = gb_gpio_get_direction; |
| gpio->direction_input = gb_gpio_direction_input; |
| gpio->direction_output = gb_gpio_direction_output; |
| gpio->get = gb_gpio_get; |
| gpio->set = gb_gpio_set; |
| gpio->set_debounce = gb_gpio_set_debounce; |
| gpio->to_irq = gb_gpio_to_irq; |
| gpio->dbg_show = gb_gpio_dbg_show; |
| |
| gpio->base = -1; /* Allocate base dynamically */ |
| gpio->ngpio = gb_gpio_controller->line_max + 1; |
| gpio->can_sleep = true; /* XXX */ |
| |
| ret = gpiochip_add(gpio); |
| if (ret) { |
| pr_err("Failed to register GPIO\n"); |
| return ret; |
| } |
| |
| return 0; |
| out_err: |
| kfree(gb_gpio_controller); |
| return ret; |
| } |
| |
| static void gb_gpio_connection_exit(struct gb_connection *connection) |
| { |
| struct gb_gpio_controller *gb_gpio_controller = connection->private; |
| |
| if (!gb_gpio_controller) |
| return; |
| |
| gb_gpiochip_remove(&gb_gpio_controller->chip); |
| /* kref_put(gb_gpio_controller->connection) */ |
| kfree(gb_gpio_controller); |
| } |
| |
| static struct gb_protocol gpio_protocol = { |
| .name = "gpio", |
| .id = GREYBUS_PROTOCOL_GPIO, |
| .major = 0, |
| .minor = 1, |
| .connection_init = gb_gpio_connection_init, |
| .connection_exit = gb_gpio_connection_exit, |
| .request_recv = NULL, /* no incoming requests */ |
| }; |
| |
| int gb_gpio_protocol_init(void) |
| { |
| return gb_protocol_register(&gpio_protocol); |
| } |
| |
| void gb_gpio_protocol_exit(void) |
| { |
| gb_protocol_deregister(&gpio_protocol); |
| } |