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[35.230.117.218]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ea151e1b7esm4473105ad.75.2026.10.19.12.01.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Oct 2026 12:01:42 -0700 (PDT) From: Jingyuan Liang Date: Mon, 19 Oct 2026 19:01:23 +0000 Subject: [PATCH v6 11/11] HID: spi-hid: add panel follower support X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261019-send-upstream-v6-11-cb9ba4b3d6fa@chromium.org> References: <20261019-send-upstream-v6-0-cb9ba4b3d6fa@chromium.org> In-Reply-To: <20261019-send-upstream-v6-0-cb9ba4b3d6fa@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, fqwqf@fqwqf.xyz, daleyo@gmail.com, Jingyuan Liang X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1792436487; l=11787; i=jingyliang@chromium.org; s=20260213; h=from:subject:message-id; bh=58Z5ay6cDlPDvzDgbQSMgMYgeRWx5N4kbp52bg9SFvU=; b=vtse1LNlmFkZ8YhPhTjehDIf2rFltt7WFZ1zjOUr0uz2IK85yhSTsNvjAL8GKUxAVeLxD10rn iCi51tQF17nDero898EYpCdb5JD+LUTOfy4/WnsPpCXQo7mq4ZJJaRg X-Developer-Key: i=jingyliang@chromium.org; a=ed25519; pk=VTYSdqslTtYOjWWoIGgYoWupGWqNSidrggReKMgfPo4= Add support to spi-hid to be a panel follower. Tested-by: Dale Whinham Signed-off-by: Jingyuan Liang --- drivers/hid/spi-hid/Kconfig | 4 + drivers/hid/spi-hid/spi-hid-core.c | 213 ++++++++++++++++++++++++++++--------- drivers/hid/spi-hid/spi-hid-core.h | 7 ++ 3 files changed, 174 insertions(+), 50 deletions(-) diff --git a/drivers/hid/spi-hid/Kconfig b/drivers/hid/spi-hid/Kconfig index 63f202975ac3..656dbda1c5d8 100644 --- a/drivers/hid/spi-hid/Kconfig +++ b/drivers/hid/spi-hid/Kconfig @@ -13,6 +13,7 @@ if SPI_HID config SPI_HID_ACPI tristate "HID over SPI transport layer ACPI driver" depends on ACPI + depends on DRM || !DRM select RESET_CONTROLLER select SPI_HID_CORE help @@ -29,6 +30,7 @@ config SPI_HID_ACPI config SPI_HID_OF tristate "HID over SPI transport layer Open Firmware driver" depends on OF + depends on DRM || !DRM select SPI_HID_CORE help Say Y here if you use a keyboard, a touchpad, a touchscreen, or any @@ -43,4 +45,6 @@ config SPI_HID_OF config SPI_HID_CORE tristate + # We need to call into panel code so if DRM=m, this can't be 'y' + depends on DRM || !DRM endif diff --git a/drivers/hid/spi-hid/spi-hid-core.c b/drivers/hid/spi-hid/spi-hid-core.c index c2232d5959b8..8b2e21be5107 100644 --- a/drivers/hid/spi-hid/spi-hid-core.c +++ b/drivers/hid/spi-hid/spi-hid-core.c @@ -281,7 +281,9 @@ static int spi_hid_suspend(struct spi_hid *shid) if (error) { dev_err(dev, "%s failed to suspend hid driver: %d\n", __func__, error); - return error; + /* A follower powers off with the panel anyway. */ + if (!shid->is_panel_follower) + return error; } } } @@ -311,6 +313,9 @@ static int spi_hid_suspend(struct spi_hid *shid) dev_err(dev, "%s: could not power down\n", __func__); shid->regulator_error_count++; shid->regulator_last_error = error; + } + /* A follower powers off with the panel anyway. */ + if (error && !shid->is_panel_follower) { /* * Undo partial suspend before returning error. * Complete the reset; RESET_PENDING stays set @@ -346,26 +351,28 @@ static int spi_hid_resume(struct spi_hid *shid) return 0; } - if (!device_may_wakeup(dev)) { - if (shid->power_state == HIDSPI_OFF) { - shid->ops->assert_reset(shid->ops); + /* + * Check power_state, not device_may_wakeup(): power/wakeup can change + * while the device is off. + */ + if (shid->power_state == HIDSPI_OFF) { + shid->ops->assert_reset(shid->ops); - shid->ops->sleep_minimal_reset_delay(shid->ops); + shid->ops->sleep_minimal_reset_delay(shid->ops); - error = shid->ops->power_up(shid->ops); - if (error) { - dev_err(dev, "%s: could not power up\n", __func__); - shid->regulator_error_count++; - shid->regulator_last_error = error; - /* Suspend runs next even if resume fails. */ - enable_irq(shid->spi->irq); - return error; - } - shid->power_state = HIDSPI_ON; - reinit_completion(&shid->reset_done); - shid->ops->deassert_reset(shid->ops); - was_reset = true; + error = shid->ops->power_up(shid->ops); + if (error) { + dev_err(dev, "%s: could not power up\n", __func__); + shid->regulator_error_count++; + shid->regulator_last_error = error; + /* Suspend runs next even if resume fails. */ + enable_irq(shid->spi->irq); + return error; } + shid->power_state = HIDSPI_ON; + reinit_completion(&shid->reset_done); + shid->ops->deassert_reset(shid->ops); + was_reset = true; } enable_irq(shid->spi->irq); @@ -1504,6 +1511,110 @@ const struct attribute_group *spi_hid_groups[] = { }; EXPORT_SYMBOL_GPL(spi_hid_groups); +/* + * At the end of probe we initialize the device: + * 0) assert reset, bias the interrupt line + * 1) sleep minimal reset delay + * 2) power up the device + * 3) deassert reset (high) + * After this we expect an IRQ with a reset response. + */ +static int spi_hid_dev_init(struct spi_hid *shid) +{ + struct spi_device *spi = shid->spi; + struct device *dev = &spi->dev; + int error; + + guard(mutex)(&shid->power_lock); + + shid->ops->assert_reset(shid->ops); + + shid->ops->sleep_minimal_reset_delay(shid->ops); + + error = shid->ops->power_up(shid->ops); + if (error) { + dev_err(dev, "%s: could not power up\n", __func__); + shid->regulator_error_count++; + shid->regulator_last_error = error; + return error; + } + + shid->power_state = HIDSPI_ON; + error = shid->ops->deassert_reset(shid->ops); + if (error) { + dev_err(dev, "%s: failed to deassert reset: %d\n", __func__, error); + shid->ops->power_down(shid->ops); + shid->power_state = HIDSPI_OFF; + return error; + } + + enable_irq(spi->irq); + + return 0; +} + +static void spi_hid_panel_follower_work(struct work_struct *work) +{ + struct spi_hid *shid = container_of(work, struct spi_hid, + panel_follower_work); + int error; + + /* Also does the first power up: probe leaves the device off. */ + error = spi_hid_resume(shid); + if (error) + dev_warn(&shid->spi->dev, "Power on failed: %d\n", error); + /* Even a failed resume enables the IRQ; let suspend undo it. */ + WRITE_ONCE(shid->panel_follower_work_finished, true); +} + +static int spi_hid_panel_follower_resume(struct drm_panel_follower *follower) +{ + struct spi_hid *shid = container_of(follower, struct spi_hid, panel_follower); + + /* Powering on can be slow; don't block the panel's power up. */ + WRITE_ONCE(shid->panel_follower_work_finished, false); + schedule_work(&shid->panel_follower_work); + + return 0; +} + +static int spi_hid_panel_follower_suspend(struct drm_panel_follower *follower) +{ + struct spi_hid *shid = container_of(follower, struct spi_hid, panel_follower); + + cancel_work_sync(&shid->panel_follower_work); + + if (!READ_ONCE(shid->panel_follower_work_finished)) + return 0; + + return spi_hid_suspend(shid); +} + +static const struct drm_panel_follower_funcs + spi_hid_panel_follower_prepare_funcs = { + .panel_prepared = spi_hid_panel_follower_resume, + .panel_unpreparing = spi_hid_panel_follower_suspend, +}; + +static int spi_hid_register_panel_follower(struct spi_hid *shid) +{ + struct device *dev = &shid->spi->dev; + + shid->panel_follower.funcs = &spi_hid_panel_follower_prepare_funcs; + + /* + * If we're not in control of our own power up/power down then we can't + * do the logic to manage wakeups. Give a warning if a user thought + * that was possible then force the capability off. + */ + if (device_can_wakeup(dev)) { + dev_warn(dev, "Can't wakeup if following panel\n"); + device_set_wakeup_capable(dev, false); + } + + return drm_panel_add_follower(dev, &shid->panel_follower); +} + int spi_hid_core_probe(struct spi_device *spi, struct spihid_ops *ops, struct spi_hid_conf *conf) { @@ -1519,10 +1630,11 @@ int spi_hid_core_probe(struct spi_device *spi, struct spihid_ops *ops, return -ENOMEM; shid->spi = spi; - shid->power_state = HIDSPI_ON; + shid->power_state = HIDSPI_OFF; shid->ops = ops; shid->conf = conf; set_bit(SPI_HID_RESET_PENDING, &shid->flags); + shid->is_panel_follower = drm_is_panel_follower(&spi->dev); spi_set_drvdata(spi, shid); @@ -1537,6 +1649,7 @@ int spi_hid_core_probe(struct spi_device *spi, struct spihid_ops *ops, init_completion(&shid->reset_done); INIT_WORK(&shid->reset_work, spi_hid_reset_work); + INIT_WORK(&shid->panel_follower_work, spi_hid_panel_follower_work); /* * we need to allocate the buffer without knowing the maximum @@ -1547,20 +1660,6 @@ int spi_hid_core_probe(struct spi_device *spi, struct spihid_ops *ops, if (error) return error; - /* - * 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 | IRQF_NO_AUTOEN, dev_name(&spi->dev), shid); if (error) { @@ -1580,21 +1679,17 @@ int spi_hid_core_probe(struct spi_device *spi, struct spihid_ops *ops, } } - error = shid->ops->power_up(shid->ops); - if (error) { - dev_err(dev, "%s: could not power up\n", __func__); - return error; - } - - error = shid->ops->deassert_reset(shid->ops); - if (error) { - dev_err(dev, "%s: failed to deassert reset: %d\n", __func__, error); - shid->ops->power_down(shid->ops); - return error; + if (shid->is_panel_follower) { + error = spi_hid_register_panel_follower(shid); + if (error) + return dev_err_probe(dev, error, + "Failed to register panel follower\n"); + } else { + error = spi_hid_dev_init(shid); + if (error) + return error; } - enable_irq(spi->irq); - dev_dbg(dev, "%s: d3 -> %s\n", __func__, spi_hid_power_mode_string(shid->power_state)); @@ -1608,15 +1703,27 @@ void spi_hid_core_remove(struct spi_device *spi) struct device *dev = &spi->dev; int error; + if (shid->is_panel_follower) { + drm_panel_remove_follower(&shid->panel_follower); + /* Already cancelled by panel_unpreparing; be explicit. */ + cancel_work_sync(&shid->panel_follower_work); + } + + /* + * Follower suspend above can be skipped. Disabling again is + * fine: nothing re-enables the IRQ before devres frees it. + */ disable_irq(spi->irq); disable_work_sync(&shid->reset_work); spi_hid_stop_hid(shid); - shid->ops->assert_reset(shid->ops); - error = shid->ops->power_down(shid->ops); - if (error) - dev_err(dev, "failed to disable regulator\n"); + if (shid->power_state != HIDSPI_OFF) { + shid->ops->assert_reset(shid->ops); + error = shid->ops->power_down(shid->ops); + if (error) + dev_err(dev, "failed to disable regulator\n"); + } } EXPORT_SYMBOL_GPL(spi_hid_core_remove); @@ -1624,6 +1731,9 @@ static int spi_hid_core_pm_suspend(struct device *dev) { struct spi_hid *shid = dev_get_drvdata(dev); + if (shid->is_panel_follower) + return 0; + return spi_hid_suspend(shid); } @@ -1631,6 +1741,9 @@ static int spi_hid_core_pm_resume(struct device *dev) { struct spi_hid *shid = dev_get_drvdata(dev); + if (shid->is_panel_follower) + return 0; + return spi_hid_resume(shid); } diff --git a/drivers/hid/spi-hid/spi-hid-core.h b/drivers/hid/spi-hid/spi-hid-core.h index 0b3248aedfce..631897dd9e8a 100644 --- a/drivers/hid/spi-hid/spi-hid-core.h +++ b/drivers/hid/spi-hid/spi-hid-core.h @@ -10,6 +10,8 @@ #include #include +#include + /* Protocol message size constants */ #define SPI_HID_READ_APPROVAL_LEN 5 #define SPI_HID_OUTPUT_HEADER_LEN 8 @@ -56,6 +58,10 @@ struct spi_hid { struct spi_hid_input_buf *input; /* Input buffer. */ struct spi_hid_input_buf *response; /* Response buffer. */ + struct drm_panel_follower panel_follower; + bool is_panel_follower; + bool panel_follower_work_finished; + u16 response_length; u16 bufsize; /* Response type awaited by a sync request, 0 if none. Protected by io_lock. */ @@ -70,6 +76,7 @@ struct spi_hid { unsigned long flags; /* device flags. */ struct work_struct reset_work; + struct work_struct panel_follower_work; /* * Serializes request/response transactions: held from sending a -- 2.56.0.212.g129ede20d9-goog