platform/x86: Add lenovo-yoga-tab2-pro-1380-fastcharger driver (b2ed33e8) · Commits · git / linux-net

drivers/platform/x86/Kconfig

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Original line number	Diff line number	Diff line
		@@ -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

drivers/platform/x86/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -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

drivers/platform/x86/lenovo-yoga-tab2-pro-1380-fastcharger.c

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+338 −0

Original line number	Diff line number	Diff line
		// 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 <hansg@kernel.org>
		*/
		#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

		#include <linux/delay.h>
		#include <linux/err.h>
		#include <linux/errno.h>
		#include <linux/extcon.h>
		#include <linux/gpio/consumer.h>
		#include <linux/module.h>
		#include <linux/notifier.h>
		#include <linux/pinctrl/consumer.h>
		#include <linux/pinctrl/machine.h>
		#include <linux/platform_device.h>
		#include <linux/serdev.h>
		#include <linux/time.h>
		#include <linux/types.h>
		#include <linux/workqueue.h>
		#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 <hansg@kernel.org>");
		MODULE_LICENSE("GPL");