Add driver for Wi2Wi W2SG0004/84 GPS module connected through uart.

Use serdev API hooks to monitor and forward the UART traffic to /dev/BTn and turn on/off the module. It also detects if the module is turned on (sends data) but should be off, e.g. if it was already turned on during boot or power-on-reset.

Additionally, rfkill block/unblock can be used to control an external LNA (and power down the module if not needed).

The driver concept is based on code developed by NeilBrown neilb@suse.de but simplified and adapted to use the new serdev API introduced in 4.11.

Signed-off-by: H. Nikolaus Schaller hns@goldelico.com --- .../devicetree/bindings/misc/wi2wi,w2sg0004.txt | 20 + .../devicetree/bindings/vendor-prefixes.txt | 1 + drivers/misc/Kconfig | 16 + drivers/misc/Makefile | 1 + drivers/misc/w2sg0004.c | 646 +++++++++++++++++++++ include/linux/w2sg0004.h | 27 + 6 files changed, 711 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/wi2wi,w2sg0004.txt create mode 100644 drivers/misc/w2sg0004.c create mode 100644 include/linux/w2sg0004.h

diff --git a/Documentation/devicetree/bindings/misc/wi2wi,w2sg0004.txt b/Documentation/devicetree/bindings/misc/wi2wi,w2sg0004.txt new file mode 100644 index 000000000000..b7125c7a598c --- /dev/null +++ b/Documentation/devicetree/bindings/misc/wi2wi,w2sg0004.txt @@ -0,0 +1,20 @@ +Wi2Wi GPS module connected through UART + +Should be a subnode of the SoC UART it is connected to (serdev). + +Required properties: +- compatible: wi2wi,w2sg0004 or wi2wi,w2sg0084 +- on-off-gpio: the GPIO that controls the module's on-off toggle input + +Optional properties: +- lna-suppy: an (optional) LNA regulator that is enabled together with the GPS receiver + +Example: + +&uart2 { + gps: w2sg0004 { + compatible = "wi2wi,w2sg0004"; + lna-supply = <&vsim>; /* LNA regulator */ + on-off-gpios = <&gpio5 17 GPIO_ACTIVE_HIGH>; /* GPIO_145: trigger for turning on/off w2sg0004 */ + }; +}; diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt index c03d20140366..c56b3181b266 100644 --- a/Documentation/devicetree/bindings/vendor-prefixes.txt +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt @@ -345,6 +345,7 @@ voipac Voipac Technologies s.r.o. wd Western Digital Corp. wetek WeTek Electronics, limited. wexler Wexler +wi2wi Wi2Wi, Inc. winbond Winbond Electronics corp. winstar Winstar Display Corp. wlf Wolfson Microelectronics diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 60f876b03586..7f97ef8fb6cd 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -509,4 +509,20 @@ source "drivers/misc/mic/Kconfig" source "drivers/misc/genwqe/Kconfig" source "drivers/misc/echo/Kconfig" source "drivers/misc/cxl/Kconfig" + +config W2SG0004 + tristate "W2SG00x4 on/off control" + depends on GPIOLIB && SERIAL_DEV_BUS + help + Enable on/off control of W2SG00x4 GPS moduled connected + to some SoC UART to allow powering up/down if the /dev/ttyGPSn + is opened/closed. + It also provides a rfkill gps name to control the LNA power. + +config W2SG0004_DEBUG + bool "W2SG0004 on/off debugging" + depends on W2SG0004 + help + Enable driver debugging mode of W2SG0004 GPS. + endmenu diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index 81ef3e67acc9..0e88e06e5ee0 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -50,6 +50,7 @@ obj-$(CONFIG_SRAM_EXEC) += sram-exec.o obj-y += mic/ obj-$(CONFIG_GENWQE) += genwqe/ obj-$(CONFIG_ECHO) += echo/ +obj-$(CONFIG_W2SG0004) += w2sg0004.o obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o obj-$(CONFIG_CXL_BASE) += cxl/ obj-$(CONFIG_ASPEED_LPC_CTRL) += aspeed-lpc-ctrl.o diff --git a/drivers/misc/w2sg0004.c b/drivers/misc/w2sg0004.c new file mode 100644 index 000000000000..1b335317c8ac --- /dev/null +++ b/drivers/misc/w2sg0004.c @@ -0,0 +1,646 @@ +/* + * w2sg0004.c + * Driver for power controlling the w2sg0004/w2sg0084 GPS receiver. + * + * This receiver has an ON/OFF pin which must be toggled to + * turn the device 'on' of 'off'. A high->low->high toggle + * will switch the device on if it is off, and off if it is on. + * + * To enable receiving on/off requests we register with the + * UART power management notifications. + * + * It is not possible to directly detect the state of the device. + * However when it is on it will send characters on a UART line + * regularly. + * + * To detect that the power state is out of sync (e.g. if GPS + * was enabled before a reboot), we register for UART data received + * notifications. + * + * In addition we register as a rfkill client so that we can + * control the LNA power. + * + */ + +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_gpio.h> +#include <linux/platform_device.h> +#include <linux/rfkill.h> +#include <linux/serdev.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/w2sg0004.h> +#include <linux/workqueue.h> + +#ifdef CONFIG_W2SG0004_DEBUG // not for upstreaming +#undef pr_debug +#define pr_debug printk +#endif + +/* + * There seems to be restrictions on how quickly we can toggle the + * on/off line. data sheets says "two rtc ticks", whatever that means. + * If we do it too soon it doesn't work. + * So we have a state machine which uses the common work queue to ensure + * clean transitions. + * When a change is requested we record that request and only act on it + * once the previous change has completed. + * A change involves a 10ms low pulse, and a 990ms raised level, so only + * one change per second. + */ + +enum w2sg_state { + W2SG_IDLE, /* is not changing state */ + W2SG_PULSE, /* activate on/off impulse */ + W2SG_NOPULSE /* deactivate on/off impulse */ +}; + +struct w2sg_data { + struct rfkill *rf_kill; + struct regulator *lna_regulator; + int lna_blocked; /* rfkill block gps active */ + int lna_is_off; /* LNA is currently off */ + int is_on; /* current state (0/1) */ + unsigned long last_toggle; + unsigned long backoff; /* time to wait since last_toggle */ + int on_off_gpio; /* the on-off gpio number */ + struct serdev_device *uart; /* the uart connected to the chip */ + struct tty_driver *tty_drv; /* this is the user space tty */ + struct device *dev; /* returned by tty_port_register_device() */ + struct tty_port port; + int open_count; /* how often we were opened */ + enum w2sg_state state; + int requested; /* requested state (0/1) */ + int suspended; + spinlock_t lock; + struct delayed_work work; + int discard_count; +}; + +static struct w2sg_data *w2sg_by_minor[1]; + +static int w2sg_set_lna_power(struct w2sg_data *data) +{ + int ret = 0; + int off = data->suspended || !data->requested || data->lna_blocked; + + pr_debug("%s: %s\n", __func__, off ? "off" : "on"); + + if (off != data->lna_is_off) { + data->lna_is_off = off; + if (!IS_ERR_OR_NULL(data->lna_regulator)) { + if (off) + regulator_disable(data->lna_regulator); + else + ret = regulator_enable(data->lna_regulator); + } + } + + return ret; +} + +static void w2sg_set_power(void *pdata, int val) +{ + struct w2sg_data *data = (struct w2sg_data *) pdata; + + pr_debug("%s to state=%d (requested=%d)\n", __func__, val, data->requested); + + if (val && !data->requested) { + data->requested = true; + } else if (!val && data->requested) { + data->backoff = HZ; + data->requested = false; + } else + return; + + pr_debug("w2sg00x4 scheduled for %d\n", data->requested); + + if (!data->suspended) + schedule_delayed_work(&data->work, 0); +} + +/* called each time data is received by the UART (i.e. sent by the w2sg0004) */ + +static int w2sg_uart_receive_buf(struct serdev_device *serdev, const unsigned char *rxdata, + size_t count) +{ + struct w2sg_data *data = (struct w2sg_data *) serdev_device_get_drvdata(serdev); +// unsigned long flags; + +// pr_debug("w2sg: %d characters\n", count); + + if (!data->requested && !data->is_on) { + /* we have received characters while the w2sg should have been be turned off */ + data->discard_count += count; + if ((data->state == W2SG_IDLE) && + time_after(jiffies, + data->last_toggle + data->backoff)) { + /* Should be off by now, time to toggle again */ + pr_debug("w2sg00x4 has sent %d characters data although it should be off!\n", data->discard_count); + data->discard_count = 0; + + data->is_on = true; + data->backoff *= 2; +// spin_lock_irqsave(&data->lock, flags); + if (!data->suspended) + schedule_delayed_work(&data->work, 0); +// spin_unlock_irqrestore(&data->lock, flags); + } + } else if (data->open_count > 0) { + int n; + +// pr_debug("w2sg00x4: push %d chars to tty port\n", count); + n = tty_insert_flip_string(&data->port, rxdata, count); /* pass to user-space */ + if (n != count) + pr_debug("w2sg00x4: did loose %d characters\n", count - n); + tty_flip_buffer_push(&data->port); + return n; + } + + /* assume we have processed everything */ + return count; +} + +/* try to toggle the power state by sending a pulse to the on-off GPIO */ + +static void toggle_work(struct work_struct *work) +{ + struct w2sg_data *data = container_of(work, struct w2sg_data, + work.work); + + switch (data->state) { + case W2SG_IDLE: +// spin_lock_irq(&data->lock); + if (data->requested == data->is_on) { + spin_unlock_irq(&data->lock); + return; + } +// spin_unlock_irq(&data->lock); + w2sg_set_lna_power(data); /* update LNA power state */ + gpio_set_value_cansleep(data->on_off_gpio, 0); + data->state = W2SG_PULSE; + + pr_debug("w2sg: power gpio ON\n"); + + schedule_delayed_work(&data->work, + msecs_to_jiffies(10)); + break; + + case W2SG_PULSE: + gpio_set_value_cansleep(data->on_off_gpio, 1); + data->last_toggle = jiffies; + data->state = W2SG_NOPULSE; + data->is_on = !data->is_on; + + pr_debug("w2sg: power gpio OFF\n"); + + schedule_delayed_work(&data->work, + msecs_to_jiffies(10)); + break; + + case W2SG_NOPULSE: + data->state = W2SG_IDLE; + pr_debug("w2sg: idle\n"); + + break; + + } +} + +static int w2sg_rfkill_set_block(void *pdata, bool blocked) +{ + struct w2sg_data *data = pdata; + + pr_debug("%s: blocked: %d\n", __func__, blocked); + + data->lna_blocked = blocked; + + return w2sg_set_lna_power(data); +} + +static struct rfkill_ops w2sg0004_rfkill_ops = { + .set_block = w2sg_rfkill_set_block, +}; + +static struct serdev_device_ops serdev_ops = { + .receive_buf = w2sg_uart_receive_buf, +#if 0 + .write_wakeup = w2sg_uart_wakeup, +#endif +}; + +/* + * we are a man-in the middle between the user-space visible tty port + * and the serdev tty where the chip is connected. + * This allows us to recognise when the device should be powered on + * or off and handle the "false" state that data arrives while no + * users-space tty client exists. + */ + +static struct w2sg_data *w2sg_get_by_minor(unsigned int minor) +{ + return w2sg_by_minor[minor]; +} + +static int w2sg_tty_install(struct tty_driver *driver, struct tty_struct *tty) +{ + struct w2sg_data *data; + int retval; + + pr_debug("%s() tty = %p\n", __func__, tty); + + data = w2sg_get_by_minor(tty->index); + pr_debug("%s() data = %p\n", __func__, data); + + if (!data) + return -ENODEV; + + retval = tty_standard_install(driver, tty); + if (retval) + goto error_init_termios; + + tty->driver_data = data; + + return 0; + +error_init_termios: + tty_port_put(&data->port); + return retval; +} + +static int w2sg_tty_open(struct tty_struct *tty, struct file *file) +{ + struct w2sg_data *data = tty->driver_data; + + pr_debug("%s() data = %p open_count = ++%d\n", __func__, data, data->open_count); +// val = (val & TIOCM_DTR) != 0; /* DTR controls power on/off */ + + w2sg_set_power(data, ++data->open_count > 0); + +// we could/should return -Esomething if already open... + + return tty_port_open(&data->port, tty, file); +} + +static void w2sg_tty_close(struct tty_struct *tty, struct file *file) +{ + struct w2sg_data *data = tty->driver_data; + + pr_debug("%s()\n", __func__); +// val = (val & TIOCM_DTR) != 0; /* DTR controls power on/off */ + w2sg_set_power(data, --data->open_count > 0); + + tty_port_close(&data->port, tty, file); +} + +static int w2sg_tty_write(struct tty_struct *tty, + const unsigned char *buffer, int count) +{ + struct w2sg_data *data = tty->driver_data; + + /* simply pass down to UART */ + return serdev_device_write_buf(data->uart, buffer, count); +} + +#if 0 +static void w2sg_tty_tiocmget(...) +{ + int val; + + pr_debug("%s(...,%x)\n", __func__, val); + val = (val & TIOCM_DTR) != 0; /* DTR controls power on/off */ + w2sg_set_power((struct w2sg_data *) pdata, val); +} +#endif + + +static const struct tty_operations w2sg_serial_ops = { + .install = w2sg_tty_install, + .open = w2sg_tty_open, + .close = w2sg_tty_close, + .write = w2sg_tty_write, +#if 0 + .write_room = w2sg_tty_write_room, + .cleanup = w2sg_tty_cleanup, + .ioctl = w2sg_tty_ioctl, + .set_termios = w2sg_tty_set_termios, + .chars_in_buffer = w2sg_tty_chars_in_buffer, + .tiocmget = w2sg_tty_tiocmget, + .tiocmset = w2sg_tty_tiocmset, + .get_icount = w2sg_tty_get_count, + .unthrottle = w2sg_tty_unthrottle +#endif +}; + +static const struct tty_port_operations w2sg_port_ops = { +}; + +static int w2sg_probe(struct serdev_device *serdev) +{ + struct w2sg_pdata *pdata = NULL; + struct w2sg_data *data; + struct rfkill *rf_kill; + int err; + int minor; + + pr_debug("%s()\n", __func__); + + minor = 0; + if (w2sg_by_minor[minor]) { + pr_err("w2sg minor is already in use!\n"); + return -ENODEV; + } + +// can be simplified if we require OF + + if (serdev->dev.of_node) { + struct device *dev = &serdev->dev; + enum of_gpio_flags flags; + + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return -ENOMEM; + + pdata->on_off_gpio = of_get_named_gpio_flags(dev->of_node, + "on-off-gpios", 0, + &flags); + + if (pdata->on_off_gpio == -EPROBE_DEFER) + return -EPROBE_DEFER; /* defer until we have all gpios */ + + pdata->lna_regulator = devm_regulator_get_optional(dev, "lna"); +// shouldn't we defer probing as well??? + + pr_debug("%s() lna_regulator = %p\n", __func__, pdata->lna_regulator); + + serdev->dev.platform_data = pdata; + } + + data = devm_kzalloc(&serdev->dev, sizeof(*data), GFP_KERNEL); + if (data == NULL) + return -ENOMEM; + + w2sg_by_minor[minor] = data; + +#if 1 + pr_debug("w2sg serdev_device_set_drvdata\n"); +#endif + serdev_device_set_drvdata(serdev, data); + + data->lna_regulator = pdata->lna_regulator; + data->lna_blocked = true; + data->lna_is_off = true; + + data->on_off_gpio = pdata->on_off_gpio; + + data->is_on = false; + data->requested = false; + data->state = W2SG_IDLE; + data->last_toggle = jiffies; + data->backoff = HZ; + + data->uart = serdev; + + INIT_DELAYED_WORK(&data->work, toggle_work); +// spin_lock_init(&data->lock); + +#if 1 + pr_debug("w2sg devm_gpio_request\n"); +#endif + err = devm_gpio_request(&serdev->dev, data->on_off_gpio, "w2sg0004-on-off"); + if (err < 0) + goto out; + + gpio_direction_output(data->on_off_gpio, false); + + serdev_device_set_client_ops(data->uart, &serdev_ops); + serdev_device_open(data->uart); + + serdev_device_set_baudrate(data->uart, 9600); + serdev_device_set_flow_control(data->uart, false); + +#if 1 + pr_debug("w2sg rfkill_alloc\n"); +#endif + rf_kill = rfkill_alloc("GPS", &serdev->dev, RFKILL_TYPE_GPS, + &w2sg0004_rfkill_ops, data); + if (rf_kill == NULL) { + err = -ENOMEM; + goto err_rfkill; + } + +#if 1 + pr_debug("w2sg register rfkill\n"); +#endif + err = rfkill_register(rf_kill); + if (err) { + dev_err(&serdev->dev, "Cannot register rfkill device\n"); + goto err_rfkill; + } + + data->rf_kill = rf_kill; + +#if 1 + pr_debug("w2sg alloc_tty_driver\n"); +#endif + /* allocate the tty driver */ + data->tty_drv = alloc_tty_driver(1); + if (!data->tty_drv) + return -ENOMEM; + + /* initialize the tty driver */ + data->tty_drv->owner = THIS_MODULE; + data->tty_drv->driver_name = "w2sg0004"; + data->tty_drv->name = "ttyGPS"; + data->tty_drv->major = 0; + data->tty_drv->minor_start = 0; + data->tty_drv->type = TTY_DRIVER_TYPE_SERIAL; + data->tty_drv->subtype = SERIAL_TYPE_NORMAL; + data->tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; + data->tty_drv->init_termios = tty_std_termios; + data->tty_drv->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL; + /* + * tty_termios_encode_baud_rate(&data->tty_drv->init_termios, 115200, 115200); + * w2sg_tty_termios(&data->tty_drv->init_termios); + */ + tty_set_operations(data->tty_drv, &w2sg_serial_ops); + +#if 1 + pr_debug("w2sg tty_register_driver\n"); +#endif + /* register the tty driver */ + err = tty_register_driver(data->tty_drv); + if (err) { + pr_err("%s - tty_register_driver failed(%d)\n", + __func__, err); + put_tty_driver(data->tty_drv); + goto err_rfkill; + } + +#if 1 + pr_debug("w2sg call tty_port_init\n"); +#endif + tty_port_init(&data->port); + data->port.ops = &w2sg_port_ops; + +#if 1 + pr_debug("w2sg call tty_port_register_device\n"); +#endif +/* + * FIXME: this appears to reenter this probe() function a second time + * which only fails because the gpio is already assigned + */ + + data->dev = tty_port_register_device(&data->port, + data->tty_drv, minor, &serdev->dev); + +#if 1 + pr_debug("w2sg tty_port_register_device -> %p\n", data->dev); + pr_debug("w2sg port.tty = %p\n", data->port.tty); +#endif +// data->port.tty->driver_data = data; /* make us known in tty_struct */ + + pr_debug("w2sg probed\n"); + +#ifdef CONFIG_W2SG0004_DEBUG + pr_debug("w2sg DEBUGGING MODE enabled\n"); + /* turn on for debugging rx notifications */ + pr_debug("w2sg power gpio ON\n"); + gpio_set_value_cansleep(data->on_off_gpio, 1); + mdelay(100); + pr_debug("w2sg power gpio OFF\n"); + gpio_set_value_cansleep(data->on_off_gpio, 0); + mdelay(300); +#endif + + /* keep off until user space requests the device */ + w2sg_set_power(data, false); + +#if 0 // more debugging - not for upstreaming + w2sg_set_power(data, true); +#endif + + return 0; + +err_rfkill: + rfkill_destroy(rf_kill); + serdev_device_close(data->uart); +out: +#if 0 + if (err == -EBUSY) + err = -EPROBE_DEFER; +#endif +#if 1 + pr_debug("w2sg error %d\n", err); +#endif + return err; +} + +static void w2sg_remove(struct serdev_device *serdev) +{ + struct w2sg_data *data = serdev_device_get_drvdata(serdev); + int minor; + + cancel_delayed_work_sync(&data->work); + + /* what is the right sequence to avoid problems? */ + serdev_device_close(data->uart); + + // get minor from searching for data == w2sg_by_minor[minor] + minor = 0; + tty_unregister_device(data->tty_drv, minor); + + tty_unregister_driver(data->tty_drv); +} + +static int w2sg_suspend(struct device *dev) +{ + struct w2sg_data *data = dev_get_drvdata(dev); + +// spin_lock_irq(&data->lock); + data->suspended = true; +// spin_unlock_irq(&data->lock); + + cancel_delayed_work_sync(&data->work); + + w2sg_set_lna_power(data); /* shuts down if needed */ + + if (data->state == W2SG_PULSE) { + msleep(10); + gpio_set_value_cansleep(data->on_off_gpio, 1); + data->last_toggle = jiffies; + data->is_on = !data->is_on; + data->state = W2SG_NOPULSE; + } + + if (data->state == W2SG_NOPULSE) { + msleep(10); + data->state = W2SG_IDLE; + } + + if (data->is_on) { + pr_info("GPS off for suspend %d %d %d\n", data->requested, + data->is_on, data->lna_is_off); + + gpio_set_value_cansleep(data->on_off_gpio, 0); + msleep(10); + gpio_set_value_cansleep(data->on_off_gpio, 1); + data->is_on = 0; + } + + return 0; +} + +static int w2sg_resume(struct device *dev) +{ + struct w2sg_data *data = dev_get_drvdata(dev); + +// spin_lock_irq(&data->lock); + data->suspended = false; +// spin_unlock_irq(&data->lock); + + pr_info("GPS resuming %d %d %d\n", data->requested, + data->is_on, data->lna_is_off); + + schedule_delayed_work(&data->work, 0); /* enables LNA if needed */ + + return 0; +} + +#if defined(CONFIG_OF) +static const struct of_device_id w2sg0004_of_match[] = { + { .compatible = "wi2wi,w2sg0004" }, + { .compatible = "wi2wi,w2sg0084" }, + {}, +}; +MODULE_DEVICE_TABLE(of, w2sg0004_of_match); +#endif + +SIMPLE_DEV_PM_OPS(w2sg_pm_ops, w2sg_suspend, w2sg_resume); + +static struct serdev_device_driver w2sg_driver = { + .probe = w2sg_probe, + .remove = w2sg_remove, + .driver = { + .name = "w2sg0004", + .owner = THIS_MODULE, + .pm = &w2sg_pm_ops, + .of_match_table = of_match_ptr(w2sg0004_of_match) + }, +}; + +module_serdev_device_driver(w2sg_driver); + +MODULE_ALIAS("w2sg0004"); + +MODULE_AUTHOR("NeilBrown neilb@suse.de"); +MODULE_DESCRIPTION("w2sg0004 GPS power management driver"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/w2sg0004.h b/include/linux/w2sg0004.h new file mode 100644 index 000000000000..ad0c4a18e01d --- /dev/null +++ b/include/linux/w2sg0004.h @@ -0,0 +1,27 @@ +/* + * UART slave to allow ON/OFF control of w2sg0004 GPS receiver. + * + * Copyright (C) 2011 Neil Brown neil@brown.name + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + + + +#ifndef __LINUX_W2SG0004_H +#define __LINUX_W2SG0004_H + +#include <linux/regulator/consumer.h> + +struct w2sg_pdata { + struct regulator *lna_regulator; /* enable LNA power */ + int on_off_gpio; /* on-off input of the GPS module */ +}; +#endif /* __LINUX_W2SG0004_H */

Add driver for Wi2Wi W2CBW003 WiFi and Bluetooth module where the Bluetooth interface is connected through uart.

Uses the new serdev API to glue with tty and turn on/off the module if the tty port (/dev/ttyBTn) is opened.

Note that this is only for the Bluetooth side. The WLAN (libertas) sdio driver should be abe to enable the same vdd regulator. So that the device is powered on if either WiFi or Bluetooth is activated (or both) and powered down if neither is in use.

Signed-off-by: H. Nikolaus Schaller hns@goldelico.com --- drivers/misc/Kconfig | 7 + drivers/misc/Makefile | 1 + drivers/misc/w2cbw003-bluetooth.c | 390 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 398 insertions(+) create mode 100644 drivers/misc/w2cbw003-bluetooth.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 7f97ef8fb6cd..90ce23bef77b 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -525,4 +525,11 @@ config W2SG0004_DEBUG help Enable driver debugging mode of W2SG0004 GPS.

+config W2CBW003 + tristate "W2CBW003 power on/off control" + depends on GPIOLIB + help + Enable on/off power control of W2CBW003 if the /dev/tty$n for + Bluetooth is opened. + endmenu diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index 0e88e06e5ee0..f6d3f096c5e0 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -51,6 +51,7 @@ obj-y += mic/ obj-$(CONFIG_GENWQE) += genwqe/ obj-$(CONFIG_ECHO) += echo/ obj-$(CONFIG_W2SG0004) += w2sg0004.o +obj-$(CONFIG_W2CBW003) += w2cbw003-bluetooth.o obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o obj-$(CONFIG_CXL_BASE) += cxl/ obj-$(CONFIG_ASPEED_LPC_CTRL) += aspeed-lpc-ctrl.o diff --git a/drivers/misc/w2cbw003-bluetooth.c b/drivers/misc/w2cbw003-bluetooth.c new file mode 100644 index 000000000000..3bcfd51bbf09 --- /dev/null +++ b/drivers/misc/w2cbw003-bluetooth.c @@ -0,0 +1,390 @@ +/* + * w2scbw003.c + * Driver for power controlling the w2cbw003 WiFi/Bluetooth chip. + * + * powers on the chip if the tty port associated/connected + * to the bluetooth subsystem is opened (e.g. hciattach /dev/ttyBT0) + */ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/err.h> +#include <linux/of.h> +#include <linux/regulator/consumer.h> +#include <linux/serdev.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> + +#undef pr_debug +#define pr_debug printk + +struct w2cbw_data { + struct regulator *vdd_regulator; + struct serdev_device *uart; /* the uart connected to the chip */ + struct tty_driver *tty_drv; /* this is the user space tty */ + struct device *dev; /* returned by tty_port_register_device() */ + struct tty_port port; + int open_count; /* how often we were opened */ +}; + +static struct w2cbw_data *w2cbw_by_minor[1]; + +static void w2cbw_set_power(void *pdata, int val) +{ + struct w2cbw_data *data = (struct w2cbw_data *) pdata; + + pr_debug("%s(...,%x)\n", __func__, val); + + if (val != 0) + WARN_ON(regulator_enable(data->vdd_regulator)); + else + regulator_disable(data->vdd_regulator); +} + +/* called each time data is received by the UART (i.e. sent by the w2cbw003) */ + +static int w2cbw_uart_receive_buf(struct serdev_device *serdev, const unsigned char *rxdata, + size_t count) +{ + struct w2cbw_data *data = (struct w2cbw_data *) serdev_device_get_drvdata(serdev); + +// pr_debug("%s() characters\n", __func__, count); + + if (data->open_count > 0) { + int n; + + pr_debug("w2cbw003: uart->tty %d chars\n", count); + n = tty_insert_flip_string(&data->port, rxdata, count); /* pass to user-space */ + if (n != count) + pr_debug("w2cbw003: did loose %d characters\n", count - n); + tty_flip_buffer_push(&data->port); + return n; + } + + /* nobody is listenig - ignore incoming data */ + return count; +} + +static struct serdev_device_ops serdev_ops = { + .receive_buf = w2cbw_uart_receive_buf, +#if 0 + .write_wakeup = w2cbw_uart_wakeup, +#endif +}; + +static struct w2cbw_data *w2cbw_get_by_minor(unsigned int minor) +{ + return w2cbw_by_minor[minor]; +} + +static int w2cbw_tty_install(struct tty_driver *driver, struct tty_struct *tty) +{ + struct w2cbw_data *data; + int retval; + + pr_debug("%s() tty = %p\n", __func__, tty); + + data = w2cbw_get_by_minor(tty->index); + pr_debug("%s() data = %p\n", __func__, data); + + if (!data) + return -ENODEV; + + retval = tty_standard_install(driver, tty); + if (retval) + goto error_init_termios; + + tty->driver_data = data; + + return 0; + +error_init_termios: + tty_port_put(&data->port); + return retval; +} + +static int w2cbw_tty_open(struct tty_struct *tty, struct file *file) +{ + struct w2cbw_data *data = tty->driver_data; + + pr_debug("%s() data = %p open_count = ++%d\n", __func__, data, data->open_count); +// val = (val & TIOCM_DTR) != 0; /* DTR controls power on/off */ + + w2cbw_set_power(data, ++data->open_count > 0); + +// we could/should return -Esomething if already open... + + return tty_port_open(&data->port, tty, file); +} + +static void w2cbw_tty_close(struct tty_struct *tty, struct file *file) +{ + struct w2cbw_data *data = tty->driver_data; + + pr_debug("%s()\n", __func__); +// val = (val & TIOCM_DTR) != 0; /* DTR controls power on/off */ + w2cbw_set_power(data, --data->open_count > 0); + + tty_port_close(&data->port, tty, file); +} + +static int w2cbw_tty_write(struct tty_struct *tty, + const unsigned char *buffer, int count) +{ + struct w2cbw_data *data = tty->driver_data; + + pr_debug("w2cbw003: tty->uart %d chars\n", count); + + return serdev_device_write_buf(data->uart, buffer, count); /* simply pass down to UART */ +} + +static void w2cbw_tty_set_termios(struct tty_struct *tty, + struct ktermios *old) +{ /* copy from tty settings */ + struct w2cbw_data *data = tty->driver_data; + +pr_debug("%s() flow = %d\n", __func__, tty_port_cts_enabled(tty->port)); +pr_debug("%s() baud rate = %d\n", __func__, tty_termios_baud_rate(&tty->termios)); + + serdev_device_set_flow_control(data->uart, tty_port_cts_enabled(tty->port)); + serdev_device_set_baudrate(data->uart, tty_termios_baud_rate(&tty->termios)); +/* this may trigger +[ 295.607781] +[ 295.609349] ============================================= +[ 295.615024] [ INFO: possible recursive locking detected ] +[ 295.620707] 4.11.0-rc8-letux+ #1026 Tainted: G W +[ 295.626745] --------------------------------------------- +[ 295.632421] hciattach/2633 is trying to acquire lock: +[ 295.637737] (&tty->termios_rwsem){++++.+}, at: [<c04bb400>] tty_set_termios+0x40/0x1b0 +[ 295.646190] +[ 295.646190] but task is already holding lock: +[ 295.652329] (&tty->termios_rwsem){++++.+}, at: [<c04bb400>] tty_set_termios+0x40/0x1b0 +[ 295.660780] +[ 295.660780] other info that might help us debug this: +[ 295.667646] Possible unsafe locking scenario: +[ 295.667646] +[ 295.673873] CPU0 +[ 295.676444] ---- +[ 295.679017] lock(&tty->termios_rwsem); +[ 295.683151] lock(&tty->termios_rwsem); +[ 295.687288] +[ 295.687288] *** DEADLOCK *** +[ 295.687288] +[ 295.693517] May be due to missing lock nesting notation +[ 295.693517] +[ 295.700666] 2 locks held by hciattach/2633: +[ 295.705063] #0: (&tty->ldisc_sem){++++++}, at: [<c04bc790>] tty_ldisc_ref_wait+0x18/0x34 +[ 295.713789] #1: (&tty->termios_rwsem){++++.+}, at: [<c04bb400>] tty_set_termios+0x40/0x1b0 +[ 295.722691] +[ 295.722691] stack backtrace: +[ 295.727285] CPU: 1 PID: 2633 Comm: hciattach Tainted: G W 4.11.0-rc8-letux+ #1026 +[ 295.736342] Hardware name: Generic OMAP5 (Flattened Device Tree) +[ 295.742679] [<c010f378>] (unwind_backtrace) from [<c010b8fc>] (show_stack+0x10/0x14) +[ 295.750841] [<c010b8fc>] (show_stack) from [<c043e4a0>] (dump_stack+0x98/0xd0) +[ 295.758450] [<c043e4a0>] (dump_stack) from [<c0186ff0>] (validate_chain+0x760/0x1010) +[ 295.766694] [<c0186ff0>] (validate_chain) from [<c0188e58>] (__lock_acquire+0x690/0x760) +[ 295.775214] [<c0188e58>] (__lock_acquire) from [<c0189428>] (lock_acquire+0x1d0/0x29c) +[ 295.783558] [<c0189428>] (lock_acquire) from [<c0754a88>] (down_write+0x28/0x78) +[ 295.791354] [<c0754a88>] (down_write) from [<c04bb400>] (tty_set_termios+0x40/0x1b0) +[ 295.799508] [<c04bb400>] (tty_set_termios) from [<c04d50dc>] (ttyport_set_flow_control+0x58/0x60) +[ 295.808856] [<c04d50dc>] (ttyport_set_flow_control) from [<bf0a4080>] (w2cbw_tty_set_termios+0x58/0x80 [w2cbw003_bluetooth]) +[ 295.820675] [<bf0a4080>] (w2cbw_tty_set_termios [w2cbw003_bluetooth]) from [<c04bb514>] (tty_set_termios+0x154/0x1b0) +[ 295.831859] [<c04bb514>] (tty_set_termios) from [<c04bbd18>] (set_termios.part.1+0x3b4/0x42c) +[ 295.840841] [<c04bbd18>] (set_termios.part.1) from [<c04bbff4>] (tty_mode_ioctl+0x1e8/0x598) +[ 295.849721] [<c04bbff4>] (tty_mode_ioctl) from [<c04b7080>] (tty_ioctl+0xe84/0xedc) +[ 295.857784] [<c04b7080>] (tty_ioctl) from [<c0282e80>] (vfs_ioctl+0x20/0x34) +[ 295.865215] [<c0282e80>] (vfs_ioctl) from [<c0283844>] (do_vfs_ioctl+0x82c/0x93c) +[ 295.873098] [<c0283844>] (do_vfs_ioctl) from [<c02839a0>] (SyS_ioctl+0x4c/0x74) +[ 295.880801] [<c02839a0>] (SyS_ioctl) from [<c0107040>] (ret_fast_syscall+0x0/0x1c) +*/ +} + +static const struct tty_operations w2cbw_serial_ops = { + .install = w2cbw_tty_install, + .open = w2cbw_tty_open, + .close = w2cbw_tty_close, + .write = w2cbw_tty_write, + .set_termios = w2cbw_tty_set_termios, +#if 0 + /* sometimes: [ 300.314968] ttyBT ttyBT0: missing write_room method */ + .write_room = w2cbw_tty_write_room, + .cleanup = w2cbw_tty_cleanup, + .ioctl = w2cbw_tty_ioctl, + .chars_in_buffer = w2cbw_tty_chars_in_buffer, + .tiocmget = w2cbw_tty_tiocmget, + .tiocmset = w2cbw_tty_tiocmset, + .get_icount = w2cbw_tty_get_count, + .unthrottle = w2cbw_tty_unthrottle +#endif +}; + +static const struct tty_port_operations w2cbw_port_ops = { +}; + +static int w2cbw_probe(struct serdev_device *serdev) +{ + struct device *dev = &serdev->dev; + struct w2cbw_data *data; + int err; + int minor; + + pr_debug("%s()\n", __func__); + + minor = 0; + if (w2cbw_by_minor[minor]) { + pr_err("w2cbw minor is already in use!\n"); + return -ENODEV; + } + + if (!serdev->dev.of_node) { + dev_err(&serdev->dev, "No device tree data\n"); + return -EINVAL; + } + + data = devm_kzalloc(&serdev->dev, sizeof(*data), GFP_KERNEL); + if (data == NULL) + return -ENOMEM; + + data->vdd_regulator = devm_regulator_get_optional(dev, "vdd"); + + if (IS_ERR(data->vdd_regulator)) { + if (PTR_ERR(data->vdd_regulator) == -EPROBE_DEFER) + return -EPROBE_DEFER; /* we can't probe yet */ + data->uart = NULL; /* no regulator yet */ + } + + pr_debug("%s() vdd_regulator = %p\n", __func__, data->vdd_regulator); + + w2cbw_by_minor[minor] = data; + + serdev_device_set_drvdata(serdev, data); + + pr_debug("w2cbw003 probed\n"); + + data->uart = serdev; + + serdev_device_set_client_ops(data->uart, &serdev_ops); + serdev_device_open(data->uart); + + serdev_device_set_baudrate(data->uart, 9600); + serdev_device_set_flow_control(data->uart, false); +#if 1 + pr_debug("w2cbw alloc_tty_driver\n"); +#endif + /* allocate the tty driver */ + data->tty_drv = alloc_tty_driver(1); + if (!data->tty_drv) + return -ENOMEM; + + /* initialize the tty driver */ + data->tty_drv->owner = THIS_MODULE; + data->tty_drv->driver_name = "w2cbw003"; + data->tty_drv->name = "ttyBT"; + data->tty_drv->major = 0; + data->tty_drv->minor_start = 0; + data->tty_drv->type = TTY_DRIVER_TYPE_SERIAL; + data->tty_drv->subtype = SERIAL_TYPE_NORMAL; + data->tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; + data->tty_drv->init_termios = tty_std_termios; + data->tty_drv->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL; + /* + * tty_termios_encode_baud_rate(&data->tty_drv->init_termios, 115200, 115200); + * w2cbw_tty_termios(&data->tty_drv->init_termios); + */ + tty_set_operations(data->tty_drv, &w2cbw_serial_ops); + +#if 1 + pr_debug("w2cbw tty_register_driver\n"); +#endif + /* register the tty driver */ + err = tty_register_driver(data->tty_drv); + if (err) { + pr_err("%s - tty_register_driver failed(%d)\n", + __func__, err); + put_tty_driver(data->tty_drv); + goto err; + } + +#if 1 + pr_debug("w2cbw call tty_port_init\n"); +#endif + tty_port_init(&data->port); + data->port.ops = &w2cbw_port_ops; + +#if 1 + pr_debug("w2cbw call tty_port_register_device\n"); +#endif +/* + * FIXME: this appears to reenter this probe() function a second time + * which only fails because the minor number is already assigned + */ + + data->dev = tty_port_register_device(&data->port, + data->tty_drv, minor, &serdev->dev); + +#if 1 + pr_debug("w2cbw tty_port_register_device -> %p\n", data->dev); + pr_debug("w2cbw port.tty = %p\n", data->port.tty); +#endif +// data->port.tty->driver_data = data; /* make us known in tty_struct */ + + /* keep off until user space requests the device */ + if (regulator_is_enabled(data->vdd_regulator)) + w2cbw_set_power(data, false); + + pr_debug("w2cbw probed\n"); + + return 0; + +err: + serdev_device_close(data->uart); +#if 0 + if (err == -EBUSY) + err = -EPROBE_DEFER; +#endif +#if 1 + pr_debug("w2cbw error %d\n", err); +#endif + return err; +} + +static void w2cbw_remove(struct serdev_device *serdev) +{ + struct w2cbw_data *data = serdev_device_get_drvdata(serdev); + int minor; + + /* what is the right sequence to avoid problems? */ + serdev_device_close(data->uart); + + // should get minor from searching for data == w2cbw_by_minor[minor] + minor = 0; + tty_unregister_device(data->tty_drv, minor); + + tty_unregister_driver(data->tty_drv); +} + +// suspend/resume? handle by regulator + +static const struct of_device_id w2cbw_of_match[] = { + { .compatible = "wi2wi,w2cbw003-bluetooth" }, + {}, +}; +MODULE_DEVICE_TABLE(of, w2cbw_of_match); + +static struct serdev_device_driver w2cbw_driver = { + .probe = w2cbw_probe, + .remove = w2cbw_remove, + .driver = { + .name = "w2cbw003", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(w2cbw_of_match) + }, +}; + +module_serdev_device_driver(w2cbw_driver); + +MODULE_ALIAS("w2cbw003-bluetooth"); + +MODULE_AUTHOR("H. Nikolaus Schaller hns@goldelico.com"); +MODULE_DESCRIPTION("w2cbw003 power management driver"); +MODULE_LICENSE("GPL v2");