From aee1f94dab13552d77456f387ac189ef5036aa8b Mon Sep 17 00:00:00 2001 From: Praveen Talari Date: Mon, 20 Jul 2026 14:27:52 +0530 Subject: [PATCH] serial: qcom-geni: remove .pm callback, use runtime PM in startup/shutdown The driver currently relies on qcom_geni_serial_pm() through the uart_ops.pm callback to manage runtime PM references. However, the callback has a void return type, so failures from pm_runtime_resume_and_get() cannot be propagated to the caller. As a result, startup() may continue and access hardware even when the runtime PM resume operation failed, leading to register accesses while the device is not powered. Move runtime PM acquisition to qcom_geni_serial_startup() and release it to qcom_geni_serial_shutdown(). Since startup() can return an error, PM resume failures are now detected and propagated before any hardware initialization is performed. The startup/shutdown pair also provides a natural place to balance runtime PM references for normal port usage. During probe, uart_add_one_port() may configure the port before any user opens the TTY, meaning startup() has not yet been called. To keep the hardware powered during port registration, acquire a runtime PM reference with pm_runtime_resume_and_get() before uart_add_one_port() and release it with pm_runtime_put() afterwards. By moving runtime PM handling out of uart_ops.pm, resume failures are no longer silently ignored and all hardware accesses are guaranteed to occur while the device is powered. Signed-off-by: Praveen Talari Link: https://patch.msgid.link/20260720-remove_uart_change_state-v2-1-30153ce4333b@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/qcom_geni_serial.c | 37 +++++++++++++-------------- 1 file changed, 18 insertions(+), 19 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 67b14fda4ff9..9fc6819f7f61 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -1190,6 +1190,8 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) qcom_geni_serial_cancel_tx_cmd(uport); uart_port_unlock_irq(uport); + + pm_runtime_put_sync(uport->dev); } static void qcom_geni_serial_flush_buffer(struct uart_port *uport) @@ -1263,10 +1265,18 @@ static int qcom_geni_serial_startup(struct uart_port *uport) struct qcom_geni_serial_port *port = to_dev_port(uport); struct tty_port *tport = &uport->state->port; + ret = pm_runtime_resume_and_get(uport->dev); + if (ret < 0) { + dev_err(uport->dev, "Failed to resume and get %d\n", ret); + return ret; + } + if (!port->setup) { ret = qcom_geni_serial_port_setup(uport); - if (ret) + if (ret) { + pm_runtime_put_sync(uport->dev); return ret; + } } /* @@ -1752,22 +1762,6 @@ static int geni_serial_resource_init(struct uart_port *uport) return 0; } -static void qcom_geni_serial_pm(struct uart_port *uport, - unsigned int new_state, unsigned int old_state) -{ - - /* If we've never been called, treat it as off */ - if (old_state == UART_PM_STATE_UNDEFINED) - old_state = UART_PM_STATE_OFF; - - if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF) - pm_runtime_resume_and_get(uport->dev); - else if (new_state == UART_PM_STATE_OFF && - old_state == UART_PM_STATE_ON) - pm_runtime_put_sync(uport->dev); - -} - /** * qcom_geni_rs485_config - Configure RS485 settings for the UART port * @uport: Pointer to the UART port structure @@ -1806,7 +1800,6 @@ static const struct uart_ops qcom_geni_console_pops = { .poll_put_char = qcom_geni_serial_poll_put_char, .poll_init = qcom_geni_serial_poll_init, #endif - .pm = qcom_geni_serial_pm, }; static const struct uart_ops qcom_geni_uart_pops = { @@ -1823,7 +1816,6 @@ static const struct uart_ops qcom_geni_uart_pops = { .type = qcom_geni_serial_get_type, .set_mctrl = qcom_geni_serial_set_mctrl, .get_mctrl = qcom_geni_serial_get_mctrl, - .pm = qcom_geni_serial_pm, }; static int qcom_geni_serial_panic_notifier(struct notifier_block *nb, @@ -1973,7 +1965,14 @@ static int qcom_geni_serial_probe(struct platform_device *pdev) devm_pm_runtime_enable(port->se.dev); + ret = pm_runtime_resume_and_get(uport->dev); + if (ret < 0) { + dev_err(uport->dev, "Failed to resume and get %d\n", ret); + goto error; + } + ret = uart_add_one_port(drv, uport); + pm_runtime_put(uport->dev); if (ret) goto error;