From b2ed33e8d486ab2f1920131dd76fab38c8ef3550 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Mon, 22 Apr 2024 15:16:49 +0200 Subject: [PATCH] platform/x86: Add lenovo-yoga-tab2-pro-1380-fastcharger driver MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Add a new driver for the custom fast charging protocol found on Lenovo Yoga Tablet 2 1380F / 1380L models. Signed-off-by: Hans de Goede Reviewed-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20240422131649.46002-1-hdegoede@redhat.com --- drivers/platform/x86/Kconfig | 11 + drivers/platform/x86/Makefile | 1 + .../lenovo-yoga-tab2-pro-1380-fastcharger.c | 338 ++++++++++++++++++ 3 files changed, 350 insertions(+) create mode 100644 drivers/platform/x86/lenovo-yoga-tab2-pro-1380-fastcharger.c diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig index b744f18bbfa7..e5601d8fba68 100644 --- a/drivers/platform/x86/Kconfig +++ b/drivers/platform/x86/Kconfig @@ -133,6 +133,17 @@ config YOGABOOK To compile this driver as a module, choose M here: the module will be called lenovo-yogabook. +config YT2_1380 + tristate "Lenovo Yoga Tablet 2 1380 fast charge driver" + depends on SERIAL_DEV_BUS + depends on ACPI + help + Say Y here to enable support for the custom fast charging protocol + found on the Lenovo Yoga Tablet 2 1380F / 1380L models. + + To compile this driver as a module, choose M here: the module will + be called lenovo-yogabook. + config ACERHDF tristate "Acer Aspire One temperature and fan driver" depends on ACPI && THERMAL diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile index 26b8af55738b..cf3032e4e27f 100644 --- a/drivers/platform/x86/Makefile +++ b/drivers/platform/x86/Makefile @@ -66,6 +66,7 @@ obj-$(CONFIG_SENSORS_HDAPS) += hdaps.o obj-$(CONFIG_THINKPAD_ACPI) += thinkpad_acpi.o obj-$(CONFIG_THINKPAD_LMI) += think-lmi.o obj-$(CONFIG_YOGABOOK) += lenovo-yogabook.o +obj-$(CONFIG_YT2_1380) += lenovo-yoga-tab2-pro-1380-fastcharger.o obj-$(CONFIG_LENOVO_WMI_CAMERA) += lenovo-wmi-camera.o # Intel diff --git a/drivers/platform/x86/lenovo-yoga-tab2-pro-1380-fastcharger.c b/drivers/platform/x86/lenovo-yoga-tab2-pro-1380-fastcharger.c new file mode 100644 index 000000000000..d525bdc8ca9b --- /dev/null +++ b/drivers/platform/x86/lenovo-yoga-tab2-pro-1380-fastcharger.c @@ -0,0 +1,338 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Support for the custom fast charging protocol found on the Lenovo Yoga + * Tablet 2 1380F / 1380L models. + * + * Copyright (C) 2024 Hans de Goede + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "serdev_helpers.h" + +#define YT2_1380_FC_PDEV_NAME "lenovo-yoga-tab2-pro-1380-fastcharger" +#define YT2_1380_FC_SERDEV_CTRL "serial0" +#define YT2_1380_FC_SERDEV_NAME "serial0-0" +#define YT2_1380_FC_EXTCON_NAME "i2c-lc824206xa" + +#define YT2_1380_FC_MAX_TRIES 5 +#define YT2_1380_FC_PIN_SW_DELAY_US (10 * USEC_PER_MSEC) +#define YT2_1380_FC_UART_DRAIN_DELAY_US (50 * USEC_PER_MSEC) +#define YT2_1380_FC_VOLT_SW_DELAY_US (1000 * USEC_PER_MSEC) + +struct yt2_1380_fc { + struct device *dev; + struct pinctrl *pinctrl; + struct pinctrl_state *gpio_state; + struct pinctrl_state *uart_state; + struct gpio_desc *uart3_txd; + struct gpio_desc *uart3_rxd; + struct extcon_dev *extcon; + struct notifier_block nb; + struct work_struct work; + bool fast_charging; +}; + +static int yt2_1380_fc_set_gpio_mode(struct yt2_1380_fc *fc, bool enable) +{ + struct pinctrl_state *state = enable ? fc->gpio_state : fc->uart_state; + int ret; + + ret = pinctrl_select_state(fc->pinctrl, state); + if (ret) { + dev_err(fc->dev, "Error %d setting pinctrl state\n", ret); + return ret; + } + + fsleep(YT2_1380_FC_PIN_SW_DELAY_US); + return 0; +} + +static bool yt2_1380_fc_dedicated_charger_connected(struct yt2_1380_fc *fc) +{ + return extcon_get_state(fc->extcon, EXTCON_CHG_USB_DCP) > 0; +} + +static bool yt2_1380_fc_fast_charger_connected(struct yt2_1380_fc *fc) +{ + return extcon_get_state(fc->extcon, EXTCON_CHG_USB_FAST) > 0; +} + +static void yt2_1380_fc_worker(struct work_struct *work) +{ + struct yt2_1380_fc *fc = container_of(work, struct yt2_1380_fc, work); + int i, ret; + + /* Do nothing if already fast charging */ + if (yt2_1380_fc_fast_charger_connected(fc)) + return; + + for (i = 0; i < YT2_1380_FC_MAX_TRIES; i++) { + /* Set pins to UART mode (for charger disconnect and retries) */ + ret = yt2_1380_fc_set_gpio_mode(fc, false); + if (ret) + return; + + /* Only try 12V charging if a dedicated charger is detected */ + if (!yt2_1380_fc_dedicated_charger_connected(fc)) + return; + + /* Send the command to switch to 12V charging */ + ret = serdev_device_write_buf(to_serdev_device(fc->dev), "SC", strlen("SC")); + if (ret != strlen("SC")) { + dev_err(fc->dev, "Error %d writing to uart\n", ret); + return; + } + + fsleep(YT2_1380_FC_UART_DRAIN_DELAY_US); + + /* Re-check a charger is still connected */ + if (!yt2_1380_fc_dedicated_charger_connected(fc)) + return; + + /* + * Now switch the lines to GPIO (output, high). The charger + * expects the lines being driven high after the command. + * Presumably this is used to detect the tablet getting + * unplugged (to switch back to 5V output on unplug). + */ + ret = yt2_1380_fc_set_gpio_mode(fc, true); + if (ret) + return; + + fsleep(YT2_1380_FC_VOLT_SW_DELAY_US); + + if (yt2_1380_fc_fast_charger_connected(fc)) + return; /* Success */ + } + + dev_dbg(fc->dev, "Failed to switch to 12V charging (not the original charger?)\n"); + /* Failed to enable 12V fast charging, reset pins to default UART mode */ + yt2_1380_fc_set_gpio_mode(fc, false); +} + +static int yt2_1380_fc_extcon_evt(struct notifier_block *nb, + unsigned long event, void *param) +{ + struct yt2_1380_fc *fc = container_of(nb, struct yt2_1380_fc, nb); + + schedule_work(&fc->work); + return NOTIFY_OK; +} + +static size_t yt2_1380_fc_receive(struct serdev_device *serdev, const u8 *data, size_t len) +{ + /* + * Since the USB data lines are shorted for DCP detection, echos of + * the "SC" command send in yt2_1380_fc_worker() will be received. + */ + dev_dbg(&serdev->dev, "recv: %*ph\n", (int)len, data); + return len; +} + +static const struct serdev_device_ops yt2_1380_fc_serdev_ops = { + .receive_buf = yt2_1380_fc_receive, + .write_wakeup = serdev_device_write_wakeup, +}; + +static int yt2_1380_fc_serdev_probe(struct serdev_device *serdev) +{ + struct device *dev = &serdev->dev; + struct yt2_1380_fc *fc; + int ret; + + fc = devm_kzalloc(dev, sizeof(*fc), GFP_KERNEL); + if (!fc) + return -ENOMEM; + + fc->dev = dev; + fc->nb.notifier_call = yt2_1380_fc_extcon_evt; + INIT_WORK(&fc->work, yt2_1380_fc_worker); + + /* + * Do this first since it may return -EPROBE_DEFER. + * There is no extcon_put(), so there is no need to free this. + */ + fc->extcon = extcon_get_extcon_dev(YT2_1380_FC_EXTCON_NAME); + if (IS_ERR(fc->extcon)) + return dev_err_probe(dev, PTR_ERR(fc->extcon), "getting extcon\n"); + + fc->pinctrl = devm_pinctrl_get(dev); + if (IS_ERR(fc->pinctrl)) + return dev_err_probe(dev, PTR_ERR(fc->pinctrl), "getting pinctrl\n"); + + /* + * To switch the UART3 pins connected to the USB data lines between + * UART and GPIO modes. + */ + fc->gpio_state = pinctrl_lookup_state(fc->pinctrl, "uart3_gpio"); + fc->uart_state = pinctrl_lookup_state(fc->pinctrl, "uart3_uart"); + if (IS_ERR(fc->gpio_state) || IS_ERR(fc->uart_state)) + return dev_err_probe(dev, -EINVAL, "getting pinctrl states\n"); + + ret = yt2_1380_fc_set_gpio_mode(fc, true); + if (ret) + return ret; + + fc->uart3_txd = devm_gpiod_get(dev, "uart3_txd", GPIOD_OUT_HIGH); + if (IS_ERR(fc->uart3_txd)) + return dev_err_probe(dev, PTR_ERR(fc->uart3_txd), "getting uart3_txd gpio\n"); + + fc->uart3_rxd = devm_gpiod_get(dev, "uart3_rxd", GPIOD_OUT_HIGH); + if (IS_ERR(fc->uart3_rxd)) + return dev_err_probe(dev, PTR_ERR(fc->uart3_rxd), "getting uart3_rxd gpio\n"); + + ret = yt2_1380_fc_set_gpio_mode(fc, false); + if (ret) + return ret; + + ret = devm_serdev_device_open(dev, serdev); + if (ret) + return dev_err_probe(dev, ret, "opening UART device\n"); + + serdev_device_set_baudrate(serdev, 600); + serdev_device_set_flow_control(serdev, false); + serdev_device_set_drvdata(serdev, fc); + serdev_device_set_client_ops(serdev, &yt2_1380_fc_serdev_ops); + + ret = devm_extcon_register_notifier_all(dev, fc->extcon, &fc->nb); + if (ret) + return dev_err_probe(dev, ret, "registering extcon notifier\n"); + + /* In case the extcon already has detected a DCP charger */ + schedule_work(&fc->work); + + return 0; +} + +struct serdev_device_driver yt2_1380_fc_serdev_driver = { + .probe = yt2_1380_fc_serdev_probe, + .driver = { + .name = KBUILD_MODNAME, + }, +}; + +static const struct pinctrl_map yt2_1380_fc_pinctrl_map[] = { + PIN_MAP_MUX_GROUP(YT2_1380_FC_SERDEV_NAME, "uart3_uart", + "INT33FC:00", "uart3_grp", "uart"), + PIN_MAP_MUX_GROUP(YT2_1380_FC_SERDEV_NAME, "uart3_gpio", + "INT33FC:00", "uart3_grp_gpio", "gpio"), +}; + +static int yt2_1380_fc_pdev_probe(struct platform_device *pdev) +{ + struct serdev_device *serdev; + struct device *ctrl_dev; + int ret; + + /* Register pinctrl mappings for setting the UART3 pins mode */ + ret = pinctrl_register_mappings(yt2_1380_fc_pinctrl_map, + ARRAY_SIZE(yt2_1380_fc_pinctrl_map)); + if (ret) + return ret; + + /* And create the serdev to talk to the charger over the UART3 pins */ + ctrl_dev = get_serdev_controller("PNP0501", "1", 0, YT2_1380_FC_SERDEV_CTRL); + if (IS_ERR(ctrl_dev)) { + ret = PTR_ERR(ctrl_dev); + goto out_pinctrl_unregister_mappings; + } + + serdev = serdev_device_alloc(to_serdev_controller(ctrl_dev)); + put_device(ctrl_dev); + if (!serdev) { + ret = -ENOMEM; + goto out_pinctrl_unregister_mappings; + } + + ret = serdev_device_add(serdev); + if (ret) { + dev_err_probe(&pdev->dev, ret, "adding serdev\n"); + serdev_device_put(serdev); + goto out_pinctrl_unregister_mappings; + } + + /* + * serdev device <-> driver matching relies on OF or ACPI matches and + * neither is available here, manually bind the driver. + */ + ret = device_driver_attach(&yt2_1380_fc_serdev_driver.driver, &serdev->dev); + if (ret) { + /* device_driver_attach() maps EPROBE_DEFER to EAGAIN, map it back */ + ret = (ret == -EAGAIN) ? -EPROBE_DEFER : ret; + dev_err_probe(&pdev->dev, ret, "attaching serdev driver\n"); + goto out_serdev_device_remove; + } + + /* So that yt2_1380_fc_pdev_remove() can remove the serdev */ + platform_set_drvdata(pdev, serdev); + return 0; + +out_serdev_device_remove: + serdev_device_remove(serdev); +out_pinctrl_unregister_mappings: + pinctrl_unregister_mappings(yt2_1380_fc_pinctrl_map); + return ret; +} + +static void yt2_1380_fc_pdev_remove(struct platform_device *pdev) +{ + struct serdev_device *serdev = platform_get_drvdata(pdev); + + serdev_device_remove(serdev); + pinctrl_unregister_mappings(yt2_1380_fc_pinctrl_map); +} + +static struct platform_driver yt2_1380_fc_pdev_driver = { + .probe = yt2_1380_fc_pdev_probe, + .remove_new = yt2_1380_fc_pdev_remove, + .driver = { + .name = YT2_1380_FC_PDEV_NAME, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, +}; + +static int __init yt2_1380_fc_module_init(void) +{ + int ret; + + /* + * serdev driver MUST be registered first because pdev driver calls + * device_driver_attach() on the serdev, serdev-driver pair. + */ + ret = serdev_device_driver_register(&yt2_1380_fc_serdev_driver); + if (ret) + return ret; + + ret = platform_driver_register(&yt2_1380_fc_pdev_driver); + if (ret) + serdev_device_driver_unregister(&yt2_1380_fc_serdev_driver); + + return ret; +} +module_init(yt2_1380_fc_module_init); + +static void __exit yt2_1380_fc_module_exit(void) +{ + platform_driver_unregister(&yt2_1380_fc_pdev_driver); + serdev_device_driver_unregister(&yt2_1380_fc_serdev_driver); +} +module_exit(yt2_1380_fc_module_exit); + +MODULE_ALIAS("platform:" YT2_1380_FC_PDEV_NAME); +MODULE_DESCRIPTION("Lenovo Yoga Tablet 2 1380 fast charge driver"); +MODULE_AUTHOR("Hans de Goede "); +MODULE_LICENSE("GPL"); -- 2.25.1