[PATCH v2] serial: 8250_fsl: Add ACPI support

* [PATCH v2] serial: 8250_fsl: Add ACPI support
@ 2020-08-25 13:31 kuldip dwivedi
  2020-08-28  8:13 ` Greg Kroah-Hartman
  0 siblings, 1 reply; 3+ messages in thread
From: kuldip dwivedi @ 2020-08-25 13:31 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Jiri Slaby, Dmitry Safonov, linux-serial
  Cc: Vabhav Sharma, Pankaj Bansal, Varun Sethi, kuldip dwivedi

This adds support for ACPI enumerated FSL 16550 UARTs.
For supporting ACPI, I added a wrapper so that this driver
can be used if firmware has exposed the HID "NXP0018" in
DSDT table.

This will be built as object file if config "SERIAL_8250_FSL"
is enabled which depends on config "SERIAL_8250_CONSOLE".

Signed-off-by: kuldip dwivedi <kuldip.dwivedi@puresoftware.com>
---

Notes:
    1. revert the license change from v1
    2. revert the file header format change from v1
    3. remove extra headers from v1
    4. this is tested on layerscape platform LS1046A
       with the firmware having ACPI support.
    
       This will be built as object file if config " SERIAL_8250_FSL"
       is enabled which depends on config " SERIAL_8250_CONSOLE ".
       this driver will be probed if firmware has exposed HID " NXP0018" in DSDT table

 drivers/tty/serial/8250/8250_fsl.c | 98 ++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c
index 0d0c80905c58..62e5e2d33f69 100644
--- a/drivers/tty/serial/8250/8250_fsl.c
+++ b/drivers/tty/serial/8250/8250_fsl.c
@@ -1,11 +1,16 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/acpi.h>
 #include <linux/serial_reg.h>
 #include <linux/serial_8250.h>
 
 #include "8250.h"
 
+#define DRIVER_NAME		"fsl-ns16550-uart"
+
 /*
  * Freescale 16550 UART "driver", Copyright (C) 2011 Paul Gortmaker.
+ * Copyright 2020 NXP
+ * Copyright 2020 Puresoftware Ltd.
  *
  * This isn't a full driver; it just provides an alternate IRQ
  * handler to deal with an errata.  Everything else is just
@@ -20,6 +25,10 @@
  * IRQ event to the next one.
  */
 
+struct fsl8250_data {
+	int	line;
+};
+
 int fsl8250_handle_irq(struct uart_port *port)
 {
 	unsigned char lsr, orig_lsr;
@@ -79,3 +88,92 @@ int fsl8250_handle_irq(struct uart_port *port)
 	return 1;
 }
 EXPORT_SYMBOL_GPL(fsl8250_handle_irq);
+
+static int fsl8250_acpi_probe(struct platform_device *pdev)
+{
+	struct fsl8250_data *data;
+	struct uart_8250_port port8250;
+	struct device *dev = &pdev->dev;
+	struct resource *regs;
+
+	int ret, irq;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs) {
+		dev_err(dev, "no registers defined\n");
+		return -EINVAL;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		if (irq != -EPROBE_DEFER)
+			dev_err(dev, "cannot get irq\n");
+		return irq;
+	}
+
+	memset(&port8250, 0, sizeof(port8250));
+
+	ret = device_property_read_u32(dev, "clock-frequency",
+					&port8250.port.uartclk);
+	if (ret)
+		return ret;
+
+	spin_lock_init(&port8250.port.lock);
+
+	port8250.port.mapbase           = regs->start;
+	port8250.port.irq               = irq;
+	port8250.port.handle_irq        = fsl8250_handle_irq;
+	port8250.port.type              = PORT_16550A;
+	port8250.port.flags             = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF
+						| UPF_FIXED_PORT | UPF_IOREMAP
+						| UPF_FIXED_TYPE;
+	port8250.port.dev               = dev;
+	port8250.port.mapsize           = resource_size(regs);
+	port8250.port.iotype            = UPIO_MEM;
+	port8250.port.irqflags          = IRQF_SHARED;
+
+	port8250.port.membase = devm_ioremap(dev,  port8250.port.mapbase,
+							port8250.port.mapsize);
+	if (!port8250.port.membase)
+		return -ENOMEM;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->line = serial8250_register_8250_port(&port8250);
+	if (data->line < 0)
+		ret = data->line;
+
+	platform_set_drvdata(pdev, data);
+	return 0;
+}
+
+static int fsl8250_acpi_remove(struct platform_device *pdev)
+{
+	struct fsl8250_data *data = platform_get_drvdata(pdev);
+
+	serial8250_unregister_port(data->line);
+	return 0;
+}
+
+static const struct acpi_device_id fsl_8250_acpi_id[] = {
+	{ "NXP0018", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, fsl_8250_acpi_id);
+
+static struct platform_driver fsl8250_platform_driver = {
+	.driver = {
+		.name			= "fsl-16550-uart",
+		.acpi_match_table	= ACPI_PTR(fsl_8250_acpi_id),
+	},
+	.probe			= fsl8250_acpi_probe,
+	.remove			= fsl8250_acpi_remove,
+};
+
+module_platform_driver(fsl8250_platform_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("FSL 8250 serial port driver");
+MODULE_ALIAS("platform:" DRIVER_NAME);
-- 
2.17.1


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