diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/gnss/sirf.c | 581 |
1 files changed, 581 insertions, 0 deletions
diff --git a/drivers/gnss/sirf.c b/drivers/gnss/sirf.c new file mode 100644 index 000000000..bcb53ccfe --- /dev/null +++ b/drivers/gnss/sirf.c @@ -0,0 +1,581 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * SiRFstar GNSS receiver driver + * + * Copyright (C) 2018 Johan Hovold <johan@kernel.org> + */ + +#include <linux/errno.h> +#include <linux/gnss.h> +#include <linux/gpio/consumer.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/pm.h> +#include <linux/pm_runtime.h> +#include <linux/regulator/consumer.h> +#include <linux/sched.h> +#include <linux/serdev.h> +#include <linux/slab.h> +#include <linux/wait.h> + +#define SIRF_BOOT_DELAY 500 +#define SIRF_ON_OFF_PULSE_TIME 100 +#define SIRF_ACTIVATE_TIMEOUT 200 +#define SIRF_HIBERNATE_TIMEOUT 200 +/* + * If no data arrives for this time, we assume that the chip is off. + * REVISIT: The report cycle is configurable and can be several minutes long, + * so this will only work reliably if the report cycle is set to a reasonable + * low value. Also power saving settings (like send data only on movement) + * might things work even worse. + * Workaround might be to parse shutdown or bootup messages. + */ +#define SIRF_REPORT_CYCLE 2000 + +struct sirf_data { + struct gnss_device *gdev; + struct serdev_device *serdev; + speed_t speed; + struct regulator *vcc; + struct regulator *lna; + struct gpio_desc *on_off; + struct gpio_desc *wakeup; + int irq; + bool active; + + struct mutex gdev_mutex; + bool open; + + struct mutex serdev_mutex; + int serdev_count; + + wait_queue_head_t power_wait; +}; + +static int sirf_serdev_open(struct sirf_data *data) +{ + int ret = 0; + + mutex_lock(&data->serdev_mutex); + if (++data->serdev_count == 1) { + ret = serdev_device_open(data->serdev); + if (ret) { + data->serdev_count--; + goto out_unlock; + } + + serdev_device_set_baudrate(data->serdev, data->speed); + serdev_device_set_flow_control(data->serdev, false); + } + +out_unlock: + mutex_unlock(&data->serdev_mutex); + + return ret; +} + +static void sirf_serdev_close(struct sirf_data *data) +{ + mutex_lock(&data->serdev_mutex); + if (--data->serdev_count == 0) + serdev_device_close(data->serdev); + mutex_unlock(&data->serdev_mutex); +} + +static int sirf_open(struct gnss_device *gdev) +{ + struct sirf_data *data = gnss_get_drvdata(gdev); + struct serdev_device *serdev = data->serdev; + int ret; + + mutex_lock(&data->gdev_mutex); + data->open = true; + mutex_unlock(&data->gdev_mutex); + + ret = sirf_serdev_open(data); + if (ret) { + mutex_lock(&data->gdev_mutex); + data->open = false; + mutex_unlock(&data->gdev_mutex); + return ret; + } + + ret = pm_runtime_get_sync(&serdev->dev); + if (ret < 0) { + dev_err(&gdev->dev, "failed to runtime resume: %d\n", ret); + pm_runtime_put_noidle(&serdev->dev); + goto err_close; + } + + return 0; + +err_close: + sirf_serdev_close(data); + + mutex_lock(&data->gdev_mutex); + data->open = false; + mutex_unlock(&data->gdev_mutex); + + return ret; +} + +static void sirf_close(struct gnss_device *gdev) +{ + struct sirf_data *data = gnss_get_drvdata(gdev); + struct serdev_device *serdev = data->serdev; + + sirf_serdev_close(data); + + pm_runtime_put(&serdev->dev); + + mutex_lock(&data->gdev_mutex); + data->open = false; + mutex_unlock(&data->gdev_mutex); +} + +static int sirf_write_raw(struct gnss_device *gdev, const unsigned char *buf, + size_t count) +{ + struct sirf_data *data = gnss_get_drvdata(gdev); + struct serdev_device *serdev = data->serdev; + int ret; + + /* write is only buffered synchronously */ + ret = serdev_device_write(serdev, buf, count, MAX_SCHEDULE_TIMEOUT); + if (ret < 0 || ret < count) + return ret; + + /* FIXME: determine if interrupted? */ + serdev_device_wait_until_sent(serdev, 0); + + return count; +} + +static const struct gnss_operations sirf_gnss_ops = { + .open = sirf_open, + .close = sirf_close, + .write_raw = sirf_write_raw, +}; + +static int sirf_receive_buf(struct serdev_device *serdev, + const unsigned char *buf, size_t count) +{ + struct sirf_data *data = serdev_device_get_drvdata(serdev); + struct gnss_device *gdev = data->gdev; + int ret = 0; + + if (!data->wakeup && !data->active) { + data->active = true; + wake_up_interruptible(&data->power_wait); + } + + mutex_lock(&data->gdev_mutex); + if (data->open) + ret = gnss_insert_raw(gdev, buf, count); + mutex_unlock(&data->gdev_mutex); + + return ret; +} + +static const struct serdev_device_ops sirf_serdev_ops = { + .receive_buf = sirf_receive_buf, + .write_wakeup = serdev_device_write_wakeup, +}; + +static irqreturn_t sirf_wakeup_handler(int irq, void *dev_id) +{ + struct sirf_data *data = dev_id; + struct device *dev = &data->serdev->dev; + int ret; + + ret = gpiod_get_value_cansleep(data->wakeup); + dev_dbg(dev, "%s - wakeup = %d\n", __func__, ret); + if (ret < 0) + goto out; + + data->active = ret; + wake_up_interruptible(&data->power_wait); +out: + return IRQ_HANDLED; +} + +static int sirf_wait_for_power_state_nowakeup(struct sirf_data *data, + bool active, + unsigned long timeout) +{ + int ret; + + /* Wait for state change (including any shutdown messages). */ + msleep(timeout); + + /* Wait for data reception or timeout. */ + data->active = false; + ret = wait_event_interruptible_timeout(data->power_wait, + data->active, msecs_to_jiffies(SIRF_REPORT_CYCLE)); + if (ret < 0) + return ret; + + if (ret > 0 && !active) + return -ETIMEDOUT; + + if (ret == 0 && active) + return -ETIMEDOUT; + + return 0; +} + +static int sirf_wait_for_power_state(struct sirf_data *data, bool active, + unsigned long timeout) +{ + int ret; + + if (!data->wakeup) + return sirf_wait_for_power_state_nowakeup(data, active, timeout); + + ret = wait_event_interruptible_timeout(data->power_wait, + data->active == active, msecs_to_jiffies(timeout)); + if (ret < 0) + return ret; + + if (ret == 0) { + dev_warn(&data->serdev->dev, "timeout waiting for active state = %d\n", + active); + return -ETIMEDOUT; + } + + return 0; +} + +static void sirf_pulse_on_off(struct sirf_data *data) +{ + gpiod_set_value_cansleep(data->on_off, 1); + msleep(SIRF_ON_OFF_PULSE_TIME); + gpiod_set_value_cansleep(data->on_off, 0); +} + +static int sirf_set_active(struct sirf_data *data, bool active) +{ + unsigned long timeout; + int retries = 3; + int ret; + + if (active) + timeout = SIRF_ACTIVATE_TIMEOUT; + else + timeout = SIRF_HIBERNATE_TIMEOUT; + + if (!data->wakeup) { + ret = sirf_serdev_open(data); + if (ret) + return ret; + } + + do { + sirf_pulse_on_off(data); + ret = sirf_wait_for_power_state(data, active, timeout); + } while (ret == -ETIMEDOUT && retries--); + + if (!data->wakeup) + sirf_serdev_close(data); + + if (ret) + return ret; + + return 0; +} + +static int sirf_runtime_suspend(struct device *dev) +{ + struct sirf_data *data = dev_get_drvdata(dev); + int ret2; + int ret; + + if (data->on_off) + ret = sirf_set_active(data, false); + else + ret = regulator_disable(data->vcc); + + if (ret) + return ret; + + ret = regulator_disable(data->lna); + if (ret) + goto err_reenable; + + return 0; + +err_reenable: + if (data->on_off) + ret2 = sirf_set_active(data, true); + else + ret2 = regulator_enable(data->vcc); + + if (ret2) + dev_err(dev, + "failed to reenable power on failed suspend: %d\n", + ret2); + + return ret; +} + +static int sirf_runtime_resume(struct device *dev) +{ + struct sirf_data *data = dev_get_drvdata(dev); + int ret; + + ret = regulator_enable(data->lna); + if (ret) + return ret; + + if (data->on_off) + ret = sirf_set_active(data, true); + else + ret = regulator_enable(data->vcc); + + if (ret) + goto err_disable_lna; + + return 0; + +err_disable_lna: + regulator_disable(data->lna); + + return ret; +} + +static int __maybe_unused sirf_suspend(struct device *dev) +{ + struct sirf_data *data = dev_get_drvdata(dev); + int ret = 0; + + if (!pm_runtime_suspended(dev)) + ret = sirf_runtime_suspend(dev); + + if (data->wakeup) + disable_irq(data->irq); + + return ret; +} + +static int __maybe_unused sirf_resume(struct device *dev) +{ + struct sirf_data *data = dev_get_drvdata(dev); + int ret = 0; + + if (data->wakeup) + enable_irq(data->irq); + + if (!pm_runtime_suspended(dev)) + ret = sirf_runtime_resume(dev); + + return ret; +} + +static const struct dev_pm_ops sirf_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(sirf_suspend, sirf_resume) + SET_RUNTIME_PM_OPS(sirf_runtime_suspend, sirf_runtime_resume, NULL) +}; + +static int sirf_parse_dt(struct serdev_device *serdev) +{ + struct sirf_data *data = serdev_device_get_drvdata(serdev); + struct device_node *node = serdev->dev.of_node; + u32 speed = 9600; + + of_property_read_u32(node, "current-speed", &speed); + + data->speed = speed; + + return 0; +} + +static int sirf_probe(struct serdev_device *serdev) +{ + struct device *dev = &serdev->dev; + struct gnss_device *gdev; + struct sirf_data *data; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + gdev = gnss_allocate_device(dev); + if (!gdev) + return -ENOMEM; + + gdev->type = GNSS_TYPE_SIRF; + gdev->ops = &sirf_gnss_ops; + gnss_set_drvdata(gdev, data); + + data->serdev = serdev; + data->gdev = gdev; + + mutex_init(&data->gdev_mutex); + mutex_init(&data->serdev_mutex); + init_waitqueue_head(&data->power_wait); + + serdev_device_set_drvdata(serdev, data); + serdev_device_set_client_ops(serdev, &sirf_serdev_ops); + + ret = sirf_parse_dt(serdev); + if (ret) + goto err_put_device; + + data->vcc = devm_regulator_get(dev, "vcc"); + if (IS_ERR(data->vcc)) { + ret = PTR_ERR(data->vcc); + goto err_put_device; + } + + data->lna = devm_regulator_get(dev, "lna"); + if (IS_ERR(data->lna)) { + ret = PTR_ERR(data->lna); + goto err_put_device; + } + + data->on_off = devm_gpiod_get_optional(dev, "sirf,onoff", + GPIOD_OUT_LOW); + if (IS_ERR(data->on_off)) { + ret = PTR_ERR(data->on_off); + goto err_put_device; + } + + if (data->on_off) { + data->wakeup = devm_gpiod_get_optional(dev, "sirf,wakeup", + GPIOD_IN); + if (IS_ERR(data->wakeup)) { + ret = PTR_ERR(data->wakeup); + goto err_put_device; + } + + ret = regulator_enable(data->vcc); + if (ret) + goto err_put_device; + + /* Wait for chip to boot into hibernate mode. */ + msleep(SIRF_BOOT_DELAY); + } + + if (data->wakeup) { + ret = gpiod_get_value_cansleep(data->wakeup); + if (ret < 0) + goto err_disable_vcc; + data->active = ret; + + ret = gpiod_to_irq(data->wakeup); + if (ret < 0) + goto err_disable_vcc; + data->irq = ret; + + ret = request_threaded_irq(data->irq, NULL, sirf_wakeup_handler, + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT, + "wakeup", data); + if (ret) + goto err_disable_vcc; + } + + if (data->on_off) { + if (!data->wakeup) { + data->active = false; + + ret = sirf_serdev_open(data); + if (ret) + goto err_disable_vcc; + + msleep(SIRF_REPORT_CYCLE); + sirf_serdev_close(data); + } + + /* Force hibernate mode if already active. */ + if (data->active) { + ret = sirf_set_active(data, false); + if (ret) { + dev_err(dev, "failed to set hibernate mode: %d\n", + ret); + goto err_free_irq; + } + } + } + + if (IS_ENABLED(CONFIG_PM)) { + pm_runtime_set_suspended(dev); /* clear runtime_error flag */ + pm_runtime_enable(dev); + } else { + ret = sirf_runtime_resume(dev); + if (ret < 0) + goto err_free_irq; + } + + ret = gnss_register_device(gdev); + if (ret) + goto err_disable_rpm; + + return 0; + +err_disable_rpm: + if (IS_ENABLED(CONFIG_PM)) + pm_runtime_disable(dev); + else + sirf_runtime_suspend(dev); +err_free_irq: + if (data->wakeup) + free_irq(data->irq, data); +err_disable_vcc: + if (data->on_off) + regulator_disable(data->vcc); +err_put_device: + gnss_put_device(data->gdev); + + return ret; +} + +static void sirf_remove(struct serdev_device *serdev) +{ + struct sirf_data *data = serdev_device_get_drvdata(serdev); + + gnss_deregister_device(data->gdev); + + if (IS_ENABLED(CONFIG_PM)) + pm_runtime_disable(&serdev->dev); + else + sirf_runtime_suspend(&serdev->dev); + + if (data->wakeup) + free_irq(data->irq, data); + + if (data->on_off) + regulator_disable(data->vcc); + + gnss_put_device(data->gdev); +} + +#ifdef CONFIG_OF +static const struct of_device_id sirf_of_match[] = { + { .compatible = "fastrax,uc430" }, + { .compatible = "linx,r4" }, + { .compatible = "wi2wi,w2sg0004" }, + { .compatible = "wi2wi,w2sg0008i" }, + { .compatible = "wi2wi,w2sg0084i" }, + {}, +}; +MODULE_DEVICE_TABLE(of, sirf_of_match); +#endif + +static struct serdev_device_driver sirf_driver = { + .driver = { + .name = "gnss-sirf", + .of_match_table = of_match_ptr(sirf_of_match), + .pm = &sirf_pm_ops, + }, + .probe = sirf_probe, + .remove = sirf_remove, +}; +module_serdev_device_driver(sirf_driver); + +MODULE_AUTHOR("Johan Hovold <johan@kernel.org>"); +MODULE_DESCRIPTION("SiRFstar GNSS receiver driver"); +MODULE_LICENSE("GPL v2"); |