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(unknown [212.185.67.148]) by mail.systec-electronic.com (Postfix) with ESMTPSA id B068094016AB; Thu, 9 Jan 2025 10:38:36 +0100 (CET) From: Andre Werner To: gregkh@linuxfoundation.org, jirislaby@kernel.org, hvilleneuve@dimonoff.com, andy@kernel.org, devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, lech.perczak@camlingroup.com, krzk+dt@kernel.org, conor+dt@kernel.org, robh@kernel.org, Andre Werner Subject: [PATCH v4 2/2] serial: sc16is7xx: Add polling mode if no IRQ pin is available Date: Thu, 9 Jan 2025 10:38:34 +0100 Message-ID: <20250109093834.1013025-2-andre.werner@systec-electronic.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250109093834.1013025-1-andre.werner@systec-electronic.com> References: <20250109093834.1013025-1-andre.werner@systec-electronic.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Fall back to polling mode if no interrupt is configured because there is no possibility to connect the interrupt pin. If "interrupts" property is missing in devicetree the driver uses a delayed worker to pull the state of interrupt status registers. Signed-off-by: Andre Werner --- V2: - Change warning for polling mode to debug log entry - Correct typo: Resuse -> Reuse - Format define with missing tabs for SC16IS7XX_POLL_PERIOD - Format struct declaration sc16is7xx_one_config with missing tabs for po= lling and shutdown - Adapt dtbinding with new polling feature V3: - Use suffix with units and drop a comment SC16IS7XX_POLL_PERIOD_MS. Sorr= y for that miss. - Make Kernel lowercase. V4: - Reword commit messages for better understanding. - Remove 'shutdown' property for canceling delayed worker. - Rename worker function: sc16is7xx_transmission_poll -> sc16is7xx_poll_p= roc - Unify argument for worker functions: kthread_work *work -> kthread_work= *ws --- drivers/tty/serial/sc16is7xx.c | 38 ++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7x= x.c index a3093e09309f..6645cab2ae5f 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -314,6 +314,7 @@ #define SC16IS7XX_FIFO_SIZE (64) #define SC16IS7XX_GPIOS_PER_BANK 4 =20 +#define SC16IS7XX_POLL_PERIOD_MS 10 #define SC16IS7XX_RECONF_MD BIT(0) #define SC16IS7XX_RECONF_IER BIT(1) #define SC16IS7XX_RECONF_RS485 BIT(2) @@ -348,6 +349,8 @@ struct sc16is7xx_port { u8 mctrl_mask; struct kthread_worker kworker; struct task_struct *kworker_task; + struct kthread_delayed_work poll_work; + bool polling; struct sc16is7xx_one p[]; }; =20 @@ -861,6 +864,18 @@ static irqreturn_t sc16is7xx_irq(int irq, void *dev_= id) return IRQ_HANDLED; } =20 +static void sc16is7xx_poll_proc(struct kthread_work *ws) +{ + struct sc16is7xx_port *s =3D container_of(ws, struct sc16is7xx_port, po= ll_work.work); + + /* Reuse standard IRQ handler. Interrupt ID is unused in this context. = */ + sc16is7xx_irq(0, s); + + /* Setup delay based on SC16IS7XX_POLL_PERIOD_MS */ + kthread_queue_delayed_work(&s->kworker, &s->poll_work, + msecs_to_jiffies(SC16IS7XX_POLL_PERIOD_MS)); +} + static void sc16is7xx_tx_proc(struct kthread_work *ws) { struct uart_port *port =3D &(to_sc16is7xx_one(ws, tx_work)->port); @@ -1149,6 +1164,7 @@ static int sc16is7xx_config_rs485(struct uart_port = *port, struct ktermios *termi static int sc16is7xx_startup(struct uart_port *port) { struct sc16is7xx_one *one =3D to_sc16is7xx_one(port, port); + struct sc16is7xx_port *s =3D dev_get_drvdata(port->dev); unsigned int val; unsigned long flags; =20 @@ -1211,6 +1227,10 @@ static int sc16is7xx_startup(struct uart_port *por= t) sc16is7xx_enable_ms(port); uart_port_unlock_irqrestore(port, flags); =20 + if (s->polling) + kthread_queue_delayed_work(&s->kworker, &s->poll_work, + msecs_to_jiffies(SC16IS7XX_POLL_PERIOD_MS)); + return 0; } =20 @@ -1232,6 +1252,9 @@ static void sc16is7xx_shutdown(struct uart_port *po= rt) =20 sc16is7xx_power(port, 0); =20 + if (s->polling) + kthread_cancel_delayed_work_sync(&s->poll_work); + kthread_flush_worker(&s->kworker); } =20 @@ -1537,6 +1560,12 @@ int sc16is7xx_probe(struct device *dev, const stru= ct sc16is7xx_devtype *devtype, =20 /* Always ask for fixed clock rate from a property. */ device_property_read_u32(dev, "clock-frequency", &uartclk); + s->polling =3D !device_property_present(dev, "interrupts"); + if (s->polling) { + dev_dbg(dev, + "No interrupt pin definition, falling back to polling mode\n"); + irq =3D 0; + } =20 s->clk =3D devm_clk_get_optional(dev, NULL); if (IS_ERR(s->clk)) @@ -1665,6 +1694,12 @@ int sc16is7xx_probe(struct device *dev, const stru= ct sc16is7xx_devtype *devtype, goto out_ports; #endif =20 + if (s->polling) { + /* Initialize kernel thread for polling */ + kthread_init_delayed_work(&s->poll_work, sc16is7xx_poll_proc); + return 0; + } + /* * Setup interrupt. We first try to acquire the IRQ line as level IRQ. * If that succeeds, we can allow sharing the interrupt as well. @@ -1724,6 +1759,9 @@ void sc16is7xx_remove(struct device *dev) sc16is7xx_power(&s->p[i].port, 0); } =20 + if (s->polling) + kthread_cancel_delayed_work_sync(&s->poll_work); + kthread_flush_worker(&s->kworker); kthread_stop(s->kworker_task); =20 --=20 2.47.1