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[34.168.169.111]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b27478cb4fsm11187535ad.29.2026.04.01.18.59.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Apr 2026 18:59:42 -0700 (PDT) From: Jingyuan Liang Date: Thu, 02 Apr 2026 01:59:40 +0000 Subject: [PATCH v3 03/11] HID: spi-hid: add transport driver skeleton for HID over SPI bus Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260402-send-upstream-v3-3-6091c458d357@chromium.org> References: <20260402-send-upstream-v3-0-6091c458d357@chromium.org> In-Reply-To: <20260402-send-upstream-v3-0-6091c458d357@chromium.org> To: Jiri Kosina , Benjamin Tissoires , Jonathan Corbet , Mark Brown , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Dmitry Torokhov , Rob Herring , Krzysztof Kozlowski , Conor Dooley Cc: linux-input@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, linux-trace-kernel@vger.kernel.org, devicetree@vger.kernel.org, hbarnor@chromium.org, tfiga@chromium.org, Jingyuan Liang , Angela Czubak , Dmitry Antipov X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1775095180; l=8512; i=jingyliang@chromium.org; s=20260213; h=from:subject:message-id; bh=k2H3ie7YFtCK66VrpOXNpoULBztAuQv+M2HBUIlKwfo=; b=1nxLuZX4OuDDCMTgcILKZSnyc1P+vds8a7ZXwwb+4u9DhHv+kUv3LpJr7WJ4xoUsTb9xytxxY 3j07DLvTVJ6CRkW91979YiP4IX+D0CA3BV9AWdeCIn0lPeb25v69YjO X-Developer-Key: i=jingyliang@chromium.org; a=ed25519; pk=VTYSdqslTtYOjWWoIGgYoWupGWqNSidrggReKMgfPo4= From: Angela Czubak Create spi-hid folder and add Kconfig and Makefile for spi-hid driver. Add basic device structure, definitions, and probe/remove functions. Signed-off-by: Dmitry Antipov Signed-off-by: Angela Czubak Signed-off-by: Jingyuan Liang --- drivers/hid/Kconfig | 2 + drivers/hid/Makefile | 2 + drivers/hid/spi-hid/Kconfig | 15 +++ drivers/hid/spi-hid/Makefile | 9 ++ drivers/hid/spi-hid/spi-hid-core.c | 213 +++++++++++++++++++++++++++++++++++++ 5 files changed, 241 insertions(+) diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig index 920a64b66b25..c6ae23bfb75d 100644 --- a/drivers/hid/Kconfig +++ b/drivers/hid/Kconfig @@ -1434,6 +1434,8 @@ source "drivers/hid/bpf/Kconfig" source "drivers/hid/i2c-hid/Kconfig" +source "drivers/hid/spi-hid/Kconfig" + source "drivers/hid/intel-ish-hid/Kconfig" source "drivers/hid/amd-sfh-hid/Kconfig" diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile index 361a7daedeb8..6b43e789b39a 100644 --- a/drivers/hid/Makefile +++ b/drivers/hid/Makefile @@ -169,6 +169,8 @@ obj-$(CONFIG_USB_KBD) += usbhid/ obj-$(CONFIG_I2C_HID_CORE) += i2c-hid/ +obj-$(CONFIG_SPI_HID_CORE) += spi-hid/ + obj-$(CONFIG_INTEL_ISH_HID) += intel-ish-hid/ obj-$(CONFIG_AMD_SFH_HID) += amd-sfh-hid/ diff --git a/drivers/hid/spi-hid/Kconfig b/drivers/hid/spi-hid/Kconfig new file mode 100644 index 000000000000..836fdefe8345 --- /dev/null +++ b/drivers/hid/spi-hid/Kconfig @@ -0,0 +1,15 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Copyright (c) 2021 Microsoft Corporation +# + +menuconfig SPI_HID + tristate "SPI HID support" + default y + depends on SPI + +if SPI_HID + +config SPI_HID_CORE + tristate +endif diff --git a/drivers/hid/spi-hid/Makefile b/drivers/hid/spi-hid/Makefile new file mode 100644 index 000000000000..92e24cddbfc2 --- /dev/null +++ b/drivers/hid/spi-hid/Makefile @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Makefile for the SPI HID input drivers +# +# Copyright (c) 2021 Microsoft Corporation +# + +obj-$(CONFIG_SPI_HID_CORE) += spi-hid.o +spi-hid-objs = spi-hid-core.o diff --git a/drivers/hid/spi-hid/spi-hid-core.c b/drivers/hid/spi-hid/spi-hid-core.c new file mode 100644 index 000000000000..d7b4d4adad95 --- /dev/null +++ b/drivers/hid/spi-hid/spi-hid-core.c @@ -0,0 +1,213 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * HID over SPI protocol implementation + * + * Copyright (c) 2021 Microsoft Corporation + * Copyright (c) 2026 Google LLC + * + * This code is partly based on "HID over I2C protocol implementation: + * + * Copyright (c) 2012 Benjamin Tissoires + * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France + * Copyright (c) 2012 Red Hat, Inc + * + * which in turn is partly based on "USB HID support for Linux": + * + * Copyright (c) 1999 Andreas Gal + * Copyright (c) 2000-2005 Vojtech Pavlik + * Copyright (c) 2005 Michael Haboustak for Concept2, Inc + * Copyright (c) 2007-2008 Oliver Neukum + * Copyright (c) 2006-2010 Jiri Kosina + */ + +#include +#include +#include +#include +#include +#include +#include + +/* struct spi_hid_conf - Conf provided to the core */ +struct spi_hid_conf { + u32 input_report_header_address; + u32 input_report_body_address; + u32 output_report_address; + u8 read_opcode; + u8 write_opcode; +}; + +/** + * struct spihid_ops - Ops provided to the core + * @power_up: do sequencing to power up the device + * @power_down: do sequencing to power down the device + * @assert_reset: do sequencing to assert the reset line + * @deassert_reset: do sequencing to deassert the reset line + * @sleep_minimal_reset_delay: minimal sleep delay during reset + */ +struct spihid_ops { + int (*power_up)(struct spihid_ops *ops); + int (*power_down)(struct spihid_ops *ops); + int (*assert_reset)(struct spihid_ops *ops); + int (*deassert_reset)(struct spihid_ops *ops); + void (*sleep_minimal_reset_delay)(struct spihid_ops *ops); +}; + +/* Driver context */ +struct spi_hid { + struct spi_device *spi; /* spi device. */ + struct hid_device *hid; /* pointer to corresponding HID dev. */ + + struct spihid_ops *ops; + struct spi_hid_conf *conf; + + enum hidspi_power_state power_state; + + u32 regulator_error_count; + int regulator_last_error; + u32 bus_error_count; + int bus_last_error; + u32 dir_count; /* device initiated reset count. */ +}; + +static const char *spi_hid_power_mode_string(enum hidspi_power_state power_state) +{ + switch (power_state) { + case HIDSPI_ON: + return "d0"; + case HIDSPI_SLEEP: + return "d2"; + case HIDSPI_OFF: + return "d3"; + default: + return "unknown"; + } +} + +static irqreturn_t spi_hid_dev_irq(int irq, void *_shid) +{ + return IRQ_HANDLED; +} + +static ssize_t bus_error_count_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct spi_hid *shid = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%d (%d)\n", + shid->bus_error_count, shid->bus_last_error); +} +static DEVICE_ATTR_RO(bus_error_count); + +static ssize_t regulator_error_count_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct spi_hid *shid = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%d (%d)\n", + shid->regulator_error_count, + shid->regulator_last_error); +} +static DEVICE_ATTR_RO(regulator_error_count); + +static ssize_t device_initiated_reset_count_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct spi_hid *shid = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%d\n", shid->dir_count); +} +static DEVICE_ATTR_RO(device_initiated_reset_count); + +static struct attribute *spi_hid_attrs[] = { + &dev_attr_bus_error_count.attr, + &dev_attr_regulator_error_count.attr, + &dev_attr_device_initiated_reset_count.attr, + NULL /* Terminator */ +}; + +static const struct attribute_group spi_hid_group = { + .attrs = spi_hid_attrs, +}; + +const struct attribute_group *spi_hid_groups[] = { + &spi_hid_group, + NULL +}; +EXPORT_SYMBOL_GPL(spi_hid_groups); + +int spi_hid_core_probe(struct spi_device *spi, struct spihid_ops *ops, + struct spi_hid_conf *conf) +{ + struct device *dev = &spi->dev; + struct spi_hid *shid; + int error; + + if (spi->irq <= 0) + return dev_err_probe(dev, spi->irq ?: -EINVAL, "Missing IRQ\n"); + + shid = devm_kzalloc(dev, sizeof(*shid), GFP_KERNEL); + if (!shid) + return -ENOMEM; + + shid->spi = spi; + shid->power_state = HIDSPI_ON; + shid->ops = ops; + shid->conf = conf; + + spi_set_drvdata(spi, shid); + + /* + * At the end of probe we initialize the device: + * 0) assert reset, bias the interrupt line + * 1) sleep minimal reset delay + * 2) request IRQ + * 3) power up the device + * 4) deassert reset (high) + * After this we expect an IRQ with a reset response. + */ + + shid->ops->assert_reset(shid->ops); + + shid->ops->sleep_minimal_reset_delay(shid->ops); + + error = devm_request_threaded_irq(dev, spi->irq, NULL, spi_hid_dev_irq, + IRQF_ONESHOT, dev_name(&spi->dev), shid); + if (error) { + dev_err(dev, "%s: unable to request threaded IRQ.", __func__); + return error; + } + + error = shid->ops->power_up(shid->ops); + if (error) { + dev_err(dev, "%s: could not power up.", __func__); + return error; + } + + shid->ops->deassert_reset(shid->ops); + + dev_dbg(dev, "%s: d3 -> %s.", __func__, + spi_hid_power_mode_string(shid->power_state)); + + return 0; +} +EXPORT_SYMBOL_GPL(spi_hid_core_probe); + +void spi_hid_core_remove(struct spi_device *spi) +{ + struct spi_hid *shid = spi_get_drvdata(spi); + struct device *dev = &spi->dev; + int error; + + shid->ops->assert_reset(shid->ops); + error = shid->ops->power_down(shid->ops); + if (error) + dev_err(dev, "failed to disable regulator."); +} +EXPORT_SYMBOL_GPL(spi_hid_core_remove); + +MODULE_DESCRIPTION("HID over SPI transport driver"); +MODULE_AUTHOR("Dmitry Antipov "); +MODULE_LICENSE("GPL"); -- 2.53.0.1185.g05d4b7b318-goog