From patchwork Thu May 19 23:00:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 574381 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBF85C4332F for ; Thu, 19 May 2022 23:01:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245618AbiESXBD (ORCPT ); Thu, 19 May 2022 19:01:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243295AbiESXA6 (ORCPT ); Thu, 19 May 2022 19:00:58 -0400 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A08C811170 for ; Thu, 19 May 2022 16:00:56 -0700 (PDT) Received: by mail-pj1-x1034.google.com with SMTP id o13-20020a17090a9f8d00b001df3fc52ea7so9970237pjp.3 for ; Thu, 19 May 2022 16:00:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=AVmXcvX5RI0eUQU+0pWHTtIEk1TgLh8qYyVgwB1l/Yc=; b=aeASWatYdgTkxr8Y7aeWjlioyeD1lkR3R12ZCkEl+hiIR9iPjgJc7ji64JOHhA4HF6 g2bHtRU2s2hXUvykYPXiVuAlTCIT8Rh5E2E/xkgQaJEY+wrajnYoLx3NcSOmGvR0s6h9 BKTiq3j1qWxH0O1kMFLHjg4Mzhp7BN10Q0X4s= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=AVmXcvX5RI0eUQU+0pWHTtIEk1TgLh8qYyVgwB1l/Yc=; b=jln2CaF2Di3T5M30kICTkRzRnSeMWR/hbaQopYbcI4HNkYzE/a86pq0LxG5Mw4jUJm cG2R2nmHsIAUICzccCw++LhTuqr/hqWbujQHbSbfxc1Qa0fR39GJtkUEon47e7DTOndQ 3MRafkKur8e6C74mm4FXlGJtRJQgnHaUzM6+oFpYx9TVQBmJ+r7sKKgcHvW1Hg3B4NU1 e6pAVN1Bcs3EZoMUHr/4Ssp90JWHdJfTl8BWt4G9zN2rz9KK1hVzSx1Gx1OrfWExLiUq uno7IZrPL2/SgrCtBS005pcRdPewV8aH6QmMmgFPRPBbRuYxdW0KVs1oV9b9tbhxiD7a 1aBw== X-Gm-Message-State: AOAM532aOpk0eRCTjhPMQEmgmpnKWsSyzZ1fvoBr3WiXXqI3yMrew6Qw yu6XeDF0FptJHwPqpAw9KBSd2ph7NQlKI8NN0Sc= X-Google-Smtp-Source: ABdhPJxEXU5RdehzZShhtByJsSe7J+5AZQfabkXzbPtvHpx41zBvrdYzh50n2lawqtkILJKCRo8OZQ== X-Received: by 2002:a17:90a:4fe1:b0:1de:fc11:331e with SMTP id q88-20020a17090a4fe100b001defc11331emr7477326pjh.145.1653001256167; Thu, 19 May 2022 16:00:56 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:201:e45f:1f3c:299b:4d86]) by smtp.gmail.com with ESMTPSA id m10-20020a056a00080a00b0050dc762819csm202411pfk.118.2022.05.19.16.00.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 May 2022 16:00:55 -0700 (PDT) From: Douglas Anderson To: Jiri Kosina , Benjamin Tissoires , Dmitry Torokhov , Rob Herring , Krzysztof Kozlowski Cc: swboyd@chromium.org, linux-input@vger.kernel.org, mka@chromium.org, devicetree@vger.kernel.org, Douglas Anderson , linux-kernel@vger.kernel.org Subject: [PATCH 2/2] HID: i2c-hid: elan: Add support for Elan eKTH6915 i2c-hid touchscreens Date: Thu, 19 May 2022 16:00:03 -0700 Message-Id: <20220519155925.2.I2d3f735a485157eeaa24d60be8a327f98101789d@changeid> X-Mailer: git-send-email 2.36.1.124.g0e6072fb45-goog In-Reply-To: <20220519155925.1.Iedc61f9ef220a89af6a031200a7850a27a440134@changeid> References: <20220519155925.1.Iedc61f9ef220a89af6a031200a7850a27a440134@changeid> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org Like many i2c-hid touchscreen controllers, the Elan eKTH6915 has a reset GPIO hooked up to it. According to the datasheet, the way we're supposed to turn the touchscreen on is: 1. Turn on the 3.3V supply. 2. Turn on the IO supply. It's OK if this is hardwired to the 3.3V supply, but if it's not then it must be turned on _after_ the 3.3V supply. 3. Wait >= 1 ms. 4. Deassert the reset GPIO (reset GPIO is active low, so there would be a leakage path if this was deasserted _before_ the IO supply). 5. Wait 300 ms. Much of the above can be handled by the generic i2c-hid-of driver, but the "reset" GPIO is not supported by that driver. Thus we'll do the same as we did for Goodix and add a new tiny driver that uses the i2c-hid core. NOTE: support for this new touchscreen could theorically fit into the Goodix driver. I've made it a separate driver because the Elan driver supports _two_ regulators and it's unclear exactly how that would fit in with commit 18eeef46d359 ("HID: i2c-hid: goodix: Tie the reset line to true state of the regulator"). Signed-off-by: Douglas Anderson Reviewed-by: Dmitry Torokhov --- drivers/hid/i2c-hid/Kconfig | 15 +++ drivers/hid/i2c-hid/Makefile | 1 + drivers/hid/i2c-hid/i2c-hid-of-elan.c | 127 ++++++++++++++++++++++++++ 3 files changed, 143 insertions(+) create mode 100644 drivers/hid/i2c-hid/i2c-hid-of-elan.c diff --git a/drivers/hid/i2c-hid/Kconfig b/drivers/hid/i2c-hid/Kconfig index a16c6a69680b..5273ee2bb134 100644 --- a/drivers/hid/i2c-hid/Kconfig +++ b/drivers/hid/i2c-hid/Kconfig @@ -32,6 +32,21 @@ config I2C_HID_OF will be called i2c-hid-of. It will also build/depend on the module i2c-hid. +config I2C_HID_OF_ELAN + tristate "Driver for Elan hid-i2c based devices on OF systems" + default n + depends on I2C && INPUT && OF + help + Say Y here if you want support for Elan i2c devices that use + the i2c-hid protocol on Open Firmware (Device Tree)-based + systems. + + If unsure, say N. + + This support is also available as a module. If so, the module + will be called i2c-hid-of-elan. It will also build/depend on + the module i2c-hid. + config I2C_HID_OF_GOODIX tristate "Driver for Goodix hid-i2c based devices on OF systems" default n diff --git a/drivers/hid/i2c-hid/Makefile b/drivers/hid/i2c-hid/Makefile index 302545a771f3..55bd5e0f35af 100644 --- a/drivers/hid/i2c-hid/Makefile +++ b/drivers/hid/i2c-hid/Makefile @@ -10,4 +10,5 @@ i2c-hid-$(CONFIG_DMI) += i2c-hid-dmi-quirks.o obj-$(CONFIG_I2C_HID_ACPI) += i2c-hid-acpi.o obj-$(CONFIG_I2C_HID_OF) += i2c-hid-of.o +obj-$(CONFIG_I2C_HID_OF_ELAN) += i2c-hid-of-elan.o obj-$(CONFIG_I2C_HID_OF_GOODIX) += i2c-hid-of-goodix.o diff --git a/drivers/hid/i2c-hid/i2c-hid-of-elan.c b/drivers/hid/i2c-hid/i2c-hid-of-elan.c new file mode 100644 index 000000000000..e2b3456e97b5 --- /dev/null +++ b/drivers/hid/i2c-hid/i2c-hid-of-elan.c @@ -0,0 +1,127 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Driver for Elan touchscreens that use the i2c-hid protocol. + * + * Copyright 2020 Google LLC + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "i2c-hid.h" + +struct elan_i2c_hid_timing_data { + unsigned int post_gpio_reset_delay_ms; + unsigned int post_power_delay_ms; +}; + +struct i2c_hid_of_elan { + struct i2chid_ops ops; + + struct regulator *vcc33; + struct regulator *vccio; + struct gpio_desc *reset_gpio; + const struct elan_i2c_hid_timing_data *timings; +}; + +static int elan_i2c_hid_power_up(struct i2chid_ops *ops) +{ + struct i2c_hid_of_elan *ihid_elan = + container_of(ops, struct i2c_hid_of_elan, ops); + int ret; + + ret = regulator_enable(ihid_elan->vcc33); + if (ret) + return ret; + + ret = regulator_enable(ihid_elan->vccio); + if (ret) { + regulator_disable(ihid_elan->vcc33); + return ret; + } + + if (ihid_elan->timings->post_power_delay_ms) + msleep(ihid_elan->timings->post_power_delay_ms); + + gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0); + if (ihid_elan->timings->post_gpio_reset_delay_ms) + msleep(ihid_elan->timings->post_gpio_reset_delay_ms); + + return 0; +} + +static void elan_i2c_hid_power_down(struct i2chid_ops *ops) +{ + struct i2c_hid_of_elan *ihid_elan = + container_of(ops, struct i2c_hid_of_elan, ops); + + gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1); + regulator_disable(ihid_elan->vccio); + regulator_disable(ihid_elan->vcc33); +} + +static int i2c_hid_of_elan_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct i2c_hid_of_elan *ihid_elan; + + ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL); + if (!ihid_elan) + return -ENOMEM; + + ihid_elan->ops.power_up = elan_i2c_hid_power_up; + ihid_elan->ops.power_down = elan_i2c_hid_power_down; + + /* Start out with reset asserted */ + ihid_elan->reset_gpio = + devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(ihid_elan->reset_gpio)) + return PTR_ERR(ihid_elan->reset_gpio); + + ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio"); + if (IS_ERR(ihid_elan->vccio)) + return PTR_ERR(ihid_elan->vccio); + + ihid_elan->vcc33 = devm_regulator_get(&client->dev, "vcc33"); + if (IS_ERR(ihid_elan->vcc33)) + return PTR_ERR(ihid_elan->vcc33); + + ihid_elan->timings = device_get_match_data(&client->dev); + + return i2c_hid_core_probe(client, &ihid_elan->ops, 0x0001, 0); +} + +static const struct elan_i2c_hid_timing_data elan_ekth6915_timing_data = { + .post_power_delay_ms = 1, + .post_gpio_reset_delay_ms = 300, +}; + +static const struct of_device_id elan_i2c_hid_of_match[] = { + { .compatible = "elan,ekth6915", .data = &elan_ekth6915_timing_data }, + { } +}; +MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match); + +static struct i2c_driver elan_i2c_hid_ts_driver = { + .driver = { + .name = "i2c_hid_of_elan", + .pm = &i2c_hid_core_pm, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + .of_match_table = of_match_ptr(elan_i2c_hid_of_match), + }, + .probe = i2c_hid_of_elan_probe, + .remove = i2c_hid_core_remove, + .shutdown = i2c_hid_core_shutdown, +}; +module_i2c_driver(elan_i2c_hid_ts_driver); + +MODULE_AUTHOR("Douglas Anderson "); +MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver"); +MODULE_LICENSE("GPL");