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1// SPDX-License-Identifier: GPL-2.02/*3 * Generic serial GNSS receiver driver4 *5 * Copyright (C) 2018 Johan Hovold <johan@kernel.org>6 */7 8#include <linux/errno.h>9#include <linux/gnss.h>10#include <linux/init.h>11#include <linux/kernel.h>12#include <linux/module.h>13#include <linux/of.h>14#include <linux/pm.h>15#include <linux/pm_runtime.h>16#include <linux/sched.h>17#include <linux/serdev.h>18#include <linux/slab.h>19 20#include "serial.h"21 22static int gnss_serial_open(struct gnss_device *gdev)23{24 struct gnss_serial *gserial = gnss_get_drvdata(gdev);25 struct serdev_device *serdev = gserial->serdev;26 int ret;27 28 ret = serdev_device_open(serdev);29 if (ret)30 return ret;31 32 serdev_device_set_baudrate(serdev, gserial->speed);33 serdev_device_set_flow_control(serdev, false);34 35 ret = pm_runtime_get_sync(&serdev->dev);36 if (ret < 0) {37 pm_runtime_put_noidle(&serdev->dev);38 goto err_close;39 }40 41 return 0;42 43err_close:44 serdev_device_close(serdev);45 46 return ret;47}48 49static void gnss_serial_close(struct gnss_device *gdev)50{51 struct gnss_serial *gserial = gnss_get_drvdata(gdev);52 struct serdev_device *serdev = gserial->serdev;53 54 serdev_device_close(serdev);55 56 pm_runtime_put(&serdev->dev);57}58 59static int gnss_serial_write_raw(struct gnss_device *gdev,60 const unsigned char *buf, size_t count)61{62 struct gnss_serial *gserial = gnss_get_drvdata(gdev);63 struct serdev_device *serdev = gserial->serdev;64 int ret;65 66 /* write is only buffered synchronously */67 ret = serdev_device_write(serdev, buf, count, MAX_SCHEDULE_TIMEOUT);68 if (ret < 0 || ret < count)69 return ret;70 71 /* FIXME: determine if interrupted? */72 serdev_device_wait_until_sent(serdev, 0);73 74 return count;75}76 77static const struct gnss_operations gnss_serial_gnss_ops = {78 .open = gnss_serial_open,79 .close = gnss_serial_close,80 .write_raw = gnss_serial_write_raw,81};82 83static size_t gnss_serial_receive_buf(struct serdev_device *serdev,84 const u8 *buf, size_t count)85{86 struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);87 struct gnss_device *gdev = gserial->gdev;88 89 return gnss_insert_raw(gdev, buf, count);90}91 92static const struct serdev_device_ops gnss_serial_serdev_ops = {93 .receive_buf = gnss_serial_receive_buf,94 .write_wakeup = serdev_device_write_wakeup,95};96 97static int gnss_serial_set_power(struct gnss_serial *gserial,98 enum gnss_serial_pm_state state)99{100 if (!gserial->ops || !gserial->ops->set_power)101 return 0;102 103 return gserial->ops->set_power(gserial, state);104}105 106/*107 * FIXME: need to provide subdriver defaults or separate dt parsing from108 * allocation.109 */110static int gnss_serial_parse_dt(struct serdev_device *serdev)111{112 struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);113 struct device_node *node = serdev->dev.of_node;114 u32 speed = 4800;115 116 of_property_read_u32(node, "current-speed", &speed);117 118 gserial->speed = speed;119 120 return 0;121}122 123struct gnss_serial *gnss_serial_allocate(struct serdev_device *serdev,124 size_t data_size)125{126 struct gnss_serial *gserial;127 struct gnss_device *gdev;128 int ret;129 130 gserial = kzalloc(sizeof(*gserial) + data_size, GFP_KERNEL);131 if (!gserial)132 return ERR_PTR(-ENOMEM);133 134 gdev = gnss_allocate_device(&serdev->dev);135 if (!gdev) {136 ret = -ENOMEM;137 goto err_free_gserial;138 }139 140 gdev->ops = &gnss_serial_gnss_ops;141 gnss_set_drvdata(gdev, gserial);142 143 gserial->serdev = serdev;144 gserial->gdev = gdev;145 146 serdev_device_set_drvdata(serdev, gserial);147 serdev_device_set_client_ops(serdev, &gnss_serial_serdev_ops);148 149 ret = gnss_serial_parse_dt(serdev);150 if (ret)151 goto err_put_device;152 153 return gserial;154 155err_put_device:156 gnss_put_device(gserial->gdev);157err_free_gserial:158 kfree(gserial);159 160 return ERR_PTR(ret);161}162EXPORT_SYMBOL_GPL(gnss_serial_allocate);163 164void gnss_serial_free(struct gnss_serial *gserial)165{166 gnss_put_device(gserial->gdev);167 kfree(gserial);168}169EXPORT_SYMBOL_GPL(gnss_serial_free);170 171int gnss_serial_register(struct gnss_serial *gserial)172{173 struct serdev_device *serdev = gserial->serdev;174 int ret;175 176 if (IS_ENABLED(CONFIG_PM)) {177 pm_runtime_enable(&serdev->dev);178 } else {179 ret = gnss_serial_set_power(gserial, GNSS_SERIAL_ACTIVE);180 if (ret < 0)181 return ret;182 }183 184 ret = gnss_register_device(gserial->gdev);185 if (ret)186 goto err_disable_rpm;187 188 return 0;189 190err_disable_rpm:191 if (IS_ENABLED(CONFIG_PM))192 pm_runtime_disable(&serdev->dev);193 else194 gnss_serial_set_power(gserial, GNSS_SERIAL_OFF);195 196 return ret;197}198EXPORT_SYMBOL_GPL(gnss_serial_register);199 200void gnss_serial_deregister(struct gnss_serial *gserial)201{202 struct serdev_device *serdev = gserial->serdev;203 204 gnss_deregister_device(gserial->gdev);205 206 if (IS_ENABLED(CONFIG_PM))207 pm_runtime_disable(&serdev->dev);208 else209 gnss_serial_set_power(gserial, GNSS_SERIAL_OFF);210}211EXPORT_SYMBOL_GPL(gnss_serial_deregister);212 213#ifdef CONFIG_PM214static int gnss_serial_runtime_suspend(struct device *dev)215{216 struct gnss_serial *gserial = dev_get_drvdata(dev);217 218 return gnss_serial_set_power(gserial, GNSS_SERIAL_STANDBY);219}220 221static int gnss_serial_runtime_resume(struct device *dev)222{223 struct gnss_serial *gserial = dev_get_drvdata(dev);224 225 return gnss_serial_set_power(gserial, GNSS_SERIAL_ACTIVE);226}227#endif /* CONFIG_PM */228 229static int gnss_serial_prepare(struct device *dev)230{231 if (pm_runtime_suspended(dev))232 return 1;233 234 return 0;235}236 237#ifdef CONFIG_PM_SLEEP238static int gnss_serial_suspend(struct device *dev)239{240 struct gnss_serial *gserial = dev_get_drvdata(dev);241 int ret = 0;242 243 /*244 * FIXME: serdev currently lacks support for managing the underlying245 * device's wakeup settings. A workaround would be to close the serdev246 * device here if it is open.247 */248 249 if (!pm_runtime_suspended(dev))250 ret = gnss_serial_set_power(gserial, GNSS_SERIAL_STANDBY);251 252 return ret;253}254 255static int gnss_serial_resume(struct device *dev)256{257 struct gnss_serial *gserial = dev_get_drvdata(dev);258 int ret = 0;259 260 if (!pm_runtime_suspended(dev))261 ret = gnss_serial_set_power(gserial, GNSS_SERIAL_ACTIVE);262 263 return ret;264}265#endif /* CONFIG_PM_SLEEP */266 267const struct dev_pm_ops gnss_serial_pm_ops = {268 .prepare = gnss_serial_prepare,269 SET_SYSTEM_SLEEP_PM_OPS(gnss_serial_suspend, gnss_serial_resume)270 SET_RUNTIME_PM_OPS(gnss_serial_runtime_suspend, gnss_serial_runtime_resume, NULL)271};272EXPORT_SYMBOL_GPL(gnss_serial_pm_ops);273 274MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");275MODULE_DESCRIPTION("Generic serial GNSS receiver driver");276MODULE_LICENSE("GPL v2");277