1 files changed, 146 insertions, 0 deletions

diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial/8250/8250_bcm2835aux.c
new file mode 100644
index 000000000000..e10f1244409b
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_bcm2835aux.c
@@ -0,0 +1,146 @@
+/*
+ * Serial port driver for BCM2835AUX UART
+ *
+ * Copyright (C) 2016 Martin Sperl <kernel@martin.sperl.org>
+ *
+ * Based on 8250_lpc18xx.c:
+ * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#include "8250.h"
+
+struct bcm2835aux_data {
+        struct uart_8250_port uart;
+        struct clk *clk;
+        int line;
+};
+
+static int bcm2835aux_serial_probe(struct platform_device *pdev)
+{
+        struct bcm2835aux_data *data;
+        struct resource *res;
+        int ret;
+
+        /* allocate the custom structure */
+        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+
+        /* initialize data */
+        spin_lock_init(&data->uart.port.lock);
+        data->uart.capabilities = UART_CAP_FIFO;
+        data->uart.port.dev = &pdev->dev;
+        data->uart.port.regshift = 2;
+        data->uart.port.type = PORT_16550;
+        data->uart.port.iotype = UPIO_MEM;
+        data->uart.port.fifosize = 8;
+        data->uart.port.flags = UPF_SHARE_IRQ |
+                                UPF_FIXED_PORT |
+                                UPF_FIXED_TYPE |
+                                UPF_SKIP_TEST;
+
+        /* get the clock - this also enables the HW */
+        data->clk = devm_clk_get(&pdev->dev, NULL);
+        ret = PTR_ERR_OR_ZERO(data->clk);
+        if (ret) {
+                dev_err(&pdev->dev, "could not get clk: %d\n", ret);
+                return ret;
+        }
+
+        /* get the interrupt */
+        ret = platform_get_irq(pdev, 0);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "irq not found - %i", ret);
+                return ret;
+        }
+        data->uart.port.irq = ret;
+
+        /* map the main registers */
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res) {
+                dev_err(&pdev->dev, "memory resource not found");
+                return -EINVAL;
+        }
+        data->uart.port.membase = devm_ioremap_resource(&pdev->dev, res);
+        ret = PTR_ERR_OR_ZERO(data->uart.port.membase);
+        if (ret)
+                return ret;
+
+        /* Check for a fixed line number */
+        ret = of_alias_get_id(pdev->dev.of_node, "serial");
+        if (ret >= 0)
+                data->uart.port.line = ret;
+
+        /* enable the clock as a last step */
+        ret = clk_prepare_enable(data->clk);
+        if (ret) {
+                dev_err(&pdev->dev, "unable to enable uart clock - %d\n",
+                        ret);
+                return ret;
+        }
+
+        /* the HW-clock divider for bcm2835aux is 8,
+         * but 8250 expects a divider of 16,
+         * so we have to multiply the actual clock by 2
+         * to get identical baudrates.
+         */
+        data->uart.port.uartclk = clk_get_rate(data->clk) * 2;
+
+        /* register the port */
+        ret = serial8250_register_8250_port(&data->uart);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "unable to register 8250 port - %d\n",
+                        ret);
+                goto dis_clk;
+        }
+        data->line = ret;
+
+        platform_set_drvdata(pdev, data);
+
+        return 0;
+
+dis_clk:
+        clk_disable_unprepare(data->clk);
+        return ret;
+}
+
+static int bcm2835aux_serial_remove(struct platform_device *pdev)
+{
+        struct bcm2835aux_data *data = platform_get_drvdata(pdev);
+
+        serial8250_unregister_port(data->uart.port.line);
+        clk_disable_unprepare(data->clk);
+
+        return 0;
+}
+
+static const struct of_device_id bcm2835aux_serial_match[] = {
+        { .compatible = "brcm,bcm2835-aux-uart" },
+        { },
+};
+MODULE_DEVICE_TABLE(of, bcm2835aux_serial_match);
+
+static struct platform_driver bcm2835aux_serial_driver = {
+        .driver = {
+                .name = "bcm2835-aux-uart",
+                .of_match_table = bcm2835aux_serial_match,
+        },
+        .probe  = bcm2835aux_serial_probe,
+        .remove = bcm2835aux_serial_remove,
+};
+module_platform_driver(bcm2835aux_serial_driver);
+
+MODULE_DESCRIPTION("BCM2835 auxiliar UART driver");
+MODULE_AUTHOR("Martin Sperl <kernel@martin.sperl.org>");
+MODULE_LICENSE("GPL v2");