From patchwork Sun Nov 12 20:59:56 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "H. Nikolaus Schaller" X-Patchwork-Id: 10054913 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6ABE86028A for ; Sun, 12 Nov 2017 21:01:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5B1C8292CE for ; Sun, 12 Nov 2017 21:01:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4FD6C2933C; Sun, 12 Nov 2017 21:01:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D548A29338 for ; Sun, 12 Nov 2017 21:01:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751470AbdKLVBB (ORCPT ); Sun, 12 Nov 2017 16:01:01 -0500 Received: from mo4-p00-ob.smtp.rzone.de ([81.169.146.216]:24117 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750926AbdKLVAL (ORCPT ); Sun, 12 Nov 2017 16:00:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1510520409; s=domk; d=goldelico.com; h=References:In-Reply-To:References:In-Reply-To:Date:Subject:Cc:To: From; bh=9GH2N577tvn1JDS3+IPUmpaTzZhmh3PHTNwBYVZwtYA=; b=sSxpj4TCKiP2MdXD2nSSo8mw2Y8hhENv7nehL3pun5k5/Htxk/GvsCeci0GFhcA7r4 1gYQYjToVXq3nFIBKbV0uJMdhFa/+TSk0sRx52DSNSFXPLi4hsrdsqUU+mcOlKntaKCa jlbmTDR14OZFF3yrbzBxrM9FAvpodDqcoBzu0= X-RZG-AUTH: :JGIXVUS7cutRB/49FwqZ7WcJeFKiMgPgp8VKxflSZ1P34KBj4Qpw87WiuclqET730Q== X-RZG-CLASS-ID: mo00 Received: from localhost.localdomain (p57AE0E66.dip0.t-ipconnect.de [87.174.14.102]) by smtp.strato.de (RZmta 42.9 DYNA|AUTH) with ESMTPSA id f05bb6tACL001xH (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (curve secp521r1 with 521 ECDH bits, eq. 15360 bits RSA)) (Client did not present a certificate); Sun, 12 Nov 2017 22:00:00 +0100 (CET) From: "H. Nikolaus Schaller" To: Rob Herring , Mark Rutland , =?UTF-8?q?Beno=C3=AEt=20Cousson?= , Tony Lindgren , Russell King , "H. Nikolaus Schaller" , Thierry Reding , Jonathan Cameron , Maxime Ripard , Jarkko Sakkinen Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, letux-kernel@openphoenux.org, kernel@pyra-handheld.com Subject: [PATCH v2 3/5] misc: Add w2sg0004 (gps receiver) power control driver Date: Sun, 12 Nov 2017 21:59:56 +0100 Message-Id: <1dd7e2ccf3d0361c0bb947bacbc2c00066e528c4.1510520397.git.hns@goldelico.com> X-Mailer: git-send-email 2.12.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add driver for Wi2Wi W2SG0004/84 GPS module connected through uart. Use serdev API hooks to monitor and forward the UART traffic to /dev/GPSn 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 but simplified and adapted to use the new serdev API introduced in 4.11. Signed-off-by: H. Nikolaus Schaller --- drivers/misc/Kconfig | 10 + drivers/misc/Makefile | 1 + drivers/misc/w2sg0004.c | 565 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/w2sg0004.h | 27 +++ 4 files changed, 603 insertions(+) create mode 100644 drivers/misc/w2sg0004.c create mode 100644 include/linux/w2sg0004.h diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 8136dc7e863d..09d171d68408 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -518,4 +518,14 @@ 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. + endmenu diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index ad0e64fdba34..abcb667e0ff0 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -51,6 +51,7 @@ 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..55101aa6beeb --- /dev/null +++ b/drivers/misc/w2sg0004.c @@ -0,0 +1,565 @@ +/* + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * 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; /* uart connected to the chip */ + struct tty_driver *tty_drv; /* this is the user space tty */ + struct device *dev; /* from 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; + 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); + + 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; + if (!data->suspended) + schedule_delayed_work(&data->work, 0); + } + } else if (data->open_count > 0) { + int n; + + pr_debug("w2sg00x4: push %d chars to tty port\n", count); + + /* pass to user-space */ + n = tty_insert_flip_string(&data->port, rxdata, count); + if (n != count) + pr_err("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: + if (data->requested == data->is_on) + return; + + 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, +}; + +/* + * 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); + + 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); + + w2sg_set_power(data, ++data->open_count > 0); + + 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__); + + 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); +} + + +static const struct tty_operations w2sg_serial_ops = { + .install = w2sg_tty_install, + .open = w2sg_tty_open, + .close = w2sg_tty_close, + .write = w2sg_tty_write, +}; + +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; + } + + 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, + "enable-gpios", 0, + &flags); + + /* defer until we have all gpios */ + if (pdata->on_off_gpio == -EPROBE_DEFER) + return -EPROBE_DEFER; + + pdata->lna_regulator = devm_regulator_get_optional(dev, "lna"); + if (IS_ERR(pdata->lna_regulator)) { + /* defer until we can get the regulator */ + if (PTR_ERR(pdata->lna_regulator) == -EPROBE_DEFER) + return -EPROBE_DEFER; + + pdata->lna_regulator = NULL; + } + + 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; + + 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); + + 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); + + rf_kill = rfkill_alloc("GPS", &serdev->dev, RFKILL_TYPE_GPS, + &w2sg0004_rfkill_ops, data); + if (rf_kill == NULL) { + err = -ENOMEM; + goto err_rfkill; + } + + err = rfkill_register(rf_kill); + if (err) { + dev_err(&serdev->dev, "Cannot register rfkill device\n"); + goto err_rfkill; + } + + data->rf_kill = rf_kill; + + /* 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; + /* + * optional: + * 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); + + /* 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; + } + + tty_port_init(&data->port); + data->port.ops = &w2sg_port_ops; + +/* + * 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); + + pr_debug("w2sg probed\n"); + + /* keep off until user space requests the device */ + w2sg_set_power(data, false); + + return 0; + +err_rfkill: + rfkill_destroy(rf_kill); + serdev_device_close(data->uart); +out: + 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); + + 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); + + data->suspended = true; + + 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); + + data->suspended = false; + + 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 "); +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 + * + * 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 + +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 */