// SPDX-License-Identifier: GPL-2.0+
/*
 *  drivers/tty/serial/8250/8250_pxa.c -- driver for PXA on-board UARTS
 *  Copyright:  (C) 2013 Sergei Ianovich <ynvich@gmail.com>
 *
 *  replaces drivers/serial/pxa.c by Nicolas Pitre
 *  Created:    Feb 20, 2003
 *  Copyright:  (C) 2003 Monta Vista Software, Inc.
 *
 *  Based on drivers/serial/8250.c by Russell King.
 */

#include <linux/device.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/serial_8250.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/clk.h>

#include "8250.h"

struct pxa8250_data {
        int                     line;
        struct clk              *clk;
};

static int __maybe_unused serial_pxa_suspend(struct device *dev)
{
        struct pxa8250_data *data = dev_get_drvdata(dev);

        serial8250_suspend_port(data->line);

        return 0;
}

static int __maybe_unused serial_pxa_resume(struct device *dev)
{
        struct pxa8250_data *data = dev_get_drvdata(dev);

        serial8250_resume_port(data->line);

        return 0;
}

static const struct dev_pm_ops serial_pxa_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(serial_pxa_suspend, serial_pxa_resume)
};

static const struct of_device_id serial_pxa_dt_ids[] = {
        { .compatible = "mrvl,pxa-uart", },
        { .compatible = "mrvl,mmp-uart", },
        {}
};
MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);

/* Uart divisor latch write */
static void serial_pxa_dl_write(struct uart_8250_port *up, u32 value)
{
        unsigned int dll;

        serial_out(up, UART_DLL, value & 0xff);
        /*
         * work around Erratum #74 according to Marvel(R) PXA270M Processor
         * Specification Update (April 19, 2010)
         */
        dll = serial_in(up, UART_DLL);
        WARN_ON(dll != (value & 0xff));

        serial_out(up, UART_DLM, value >> 8 & 0xff);
}


static void serial_pxa_pm(struct uart_port *port, unsigned int state,
              unsigned int oldstate)
{
        struct pxa8250_data *data = port->private_data;

        if (!state)
                clk_prepare_enable(data->clk);
        else
                clk_disable_unprepare(data->clk);
}

static int serial_pxa_probe(struct platform_device *pdev)
{
        struct uart_8250_port uart = {};
        struct pxa8250_data *data;
        struct resource *mmres;
        int ret;

        mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!mmres)
                return -ENODEV;

        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(data->clk))
                return PTR_ERR(data->clk);

        ret = clk_prepare(data->clk);
        if (ret)
                return ret;

        uart.port.type = PORT_XSCALE;
        uart.port.mapbase = mmres->start;
        uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST | UPF_FIXED_TYPE;
        uart.port.dev = &pdev->dev;
        uart.port.uartclk = clk_get_rate(data->clk);
        uart.port.pm = serial_pxa_pm;
        uart.port.private_data = data;

        ret = uart_read_port_properties(&uart.port);
        if (ret)
                return ret;

        uart.port.iotype = UPIO_MEM32;
        uart.port.regshift = 2;
        uart.port.fifosize = 64;
        uart.tx_loadsz = 32;
        uart.dl_write = serial_pxa_dl_write;

        ret = serial8250_register_8250_port(&uart);
        if (ret < 0)
                goto err_clk;

        data->line = ret;

        platform_set_drvdata(pdev, data);

        return 0;

 err_clk:
        clk_unprepare(data->clk);
        return ret;
}

static void serial_pxa_remove(struct platform_device *pdev)
{
        struct pxa8250_data *data = platform_get_drvdata(pdev);

        serial8250_unregister_port(data->line);

        clk_unprepare(data->clk);
}

static struct platform_driver serial_pxa_driver = {
        .probe          = serial_pxa_probe,
        .remove         = serial_pxa_remove,

        .driver         = {
                .name   = "pxa2xx-uart",
                .pm     = &serial_pxa_pm_ops,
                .of_match_table = serial_pxa_dt_ids,
        },
};

module_platform_driver(serial_pxa_driver);

MODULE_AUTHOR("Sergei Ianovich");
MODULE_DESCRIPTION("driver for PXA on-board UARTS");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pxa2xx-uart");