drivers/tty/serial/8250/8250_pxa.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  drivers/tty/serial/8250/8250_pxa.c -- driver for PXA on-board UARTS
   4  *  Copyright:  (C) 2013 Sergei Ianovich <ynvich@gmail.com>
   5  *
   6  *  replaces drivers/serial/pxa.c by Nicolas Pitre
   7  *  Created:    Feb 20, 2003
   8  *  Copyright:  (C) 2003 Monta Vista Software, Inc.
   9  *
  10  *  Based on drivers/serial/8250.c by Russell King.
  11  */
  12
  13 #include <linux/device.h>
  14 #include <linux/init.h>
  15 #include <linux/io.h>
  16 #include <linux/module.h>
  17 #include <linux/serial_8250.h>
  18 #include <linux/serial_core.h>
  19 #include <linux/serial_reg.h>
  20 #include <linux/of.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/slab.h>
  24 #include <linux/clk.h>
  25 #include <linux/pm_runtime.h>
  26
  27 #include "8250.h"
  28
  29 struct pxa8250_data {
  30         int                     line;
  31         struct clk              *clk;
  32 };
  33
  34 static int __maybe_unused serial_pxa_suspend(struct device *dev)
  35 {
  36         struct pxa8250_data *data = dev_get_drvdata(dev);
  37
  38         serial8250_suspend_port(data->line);
  39
  40         return 0;
  41 }
  42
  43 static int __maybe_unused serial_pxa_resume(struct device *dev)
  44 {
  45         struct pxa8250_data *data = dev_get_drvdata(dev);
  46
  47         serial8250_resume_port(data->line);
  48
  49         return 0;
  50 }
  51
  52 static const struct dev_pm_ops serial_pxa_pm_ops = {
  53         SET_SYSTEM_SLEEP_PM_OPS(serial_pxa_suspend, serial_pxa_resume)
  54 };
  55
  56 static const struct of_device_id serial_pxa_dt_ids[] = {
  57         { .compatible = "mrvl,pxa-uart", },
  58         { .compatible = "mrvl,mmp-uart", },
  59         {}
  60 };
  61 MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);
  62
  63 /* Uart divisor latch write */
  64 static void serial_pxa_dl_write(struct uart_8250_port *up, int value)
  65 {
  66         unsigned int dll;
  67
  68         serial_out(up, UART_DLL, value & 0xff);
  69         /*
  70          * work around Erratum #74 according to Marvel(R) PXA270M Processor
  71          * Specification Update (April 19, 2010)
  72          */
  73         dll = serial_in(up, UART_DLL);
  74         WARN_ON(dll != (value & 0xff));
  75
  76         serial_out(up, UART_DLM, value >> 8 & 0xff);
  77 }
  78
  79
  80 static void serial_pxa_pm(struct uart_port *port, unsigned int state,
  81               unsigned int oldstate)
  82 {
  83         struct pxa8250_data *data = port->private_data;
  84
  85         if (!state)
  86                 clk_prepare_enable(data->clk);
  87         else
  88                 clk_disable_unprepare(data->clk);
  89 }
  90
  91 static int serial_pxa_probe(struct platform_device *pdev)
  92 {
  93         struct uart_8250_port uart = {};
  94         struct pxa8250_data *data;
  95         struct resource *mmres;
  96         int irq, ret;
  97
  98         irq = platform_get_irq(pdev, 0);
  99         if (irq < 0)
 100                 return irq;
 101
 102         mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 103         if (!mmres)
 104                 return -ENODEV;
 105
 106         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 107         if (!data)
 108                 return -ENOMEM;
 109
 110         data->clk = devm_clk_get(&pdev->dev, NULL);
 111         if (IS_ERR(data->clk))
 112                 return PTR_ERR(data->clk);
 113
 114         ret = clk_prepare(data->clk);
 115         if (ret)
 116                 return ret;
 117
 118         ret = of_alias_get_id(pdev->dev.of_node, "serial");
 119         if (ret >= 0)
 120                 uart.port.line = ret;
 121
 122         uart.port.type = PORT_XSCALE;
 123         uart.port.iotype = UPIO_MEM32;
 124         uart.port.mapbase = mmres->start;
 125         uart.port.regshift = 2;
 126         uart.port.irq = irq;
 127         uart.port.fifosize = 64;
 128         uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST | UPF_FIXED_TYPE;
 129         uart.port.dev = &pdev->dev;
 130         uart.port.uartclk = clk_get_rate(data->clk);
 131         uart.port.pm = serial_pxa_pm;
 132         uart.port.private_data = data;
 133         uart.dl_write = serial_pxa_dl_write;
 134
 135         ret = serial8250_register_8250_port(&uart);
 136         if (ret < 0)
 137                 goto err_clk;
 138
 139         data->line = ret;
 140
 141         platform_set_drvdata(pdev, data);
 142
 143         return 0;
 144
 145  err_clk:
 146         clk_unprepare(data->clk);
 147         return ret;
 148 }
 149
 150 static int serial_pxa_remove(struct platform_device *pdev)
 151 {
 152         struct pxa8250_data *data = platform_get_drvdata(pdev);
 153
 154         serial8250_unregister_port(data->line);
 155
 156         clk_unprepare(data->clk);
 157
 158         return 0;
 159 }
 160
 161 static struct platform_driver serial_pxa_driver = {
 162         .probe          = serial_pxa_probe,
 163         .remove         = serial_pxa_remove,
 164
 165         .driver         = {
 166                 .name   = "pxa2xx-uart",
 167                 .pm     = &serial_pxa_pm_ops,
 168                 .of_match_table = serial_pxa_dt_ids,
 169         },
 170 };
 171
 172 module_platform_driver(serial_pxa_driver);
 173
 174 #ifdef CONFIG_SERIAL_8250_CONSOLE
 175 static int __init early_serial_pxa_setup(struct earlycon_device *device,
 176                                   const char *options)
 177 {
 178         struct uart_port *port = &device->port;
 179
 180         if (!(device->port.membase || device->port.iobase))
 181                 return -ENODEV;
 182
 183         port->regshift = 2;
 184         return early_serial8250_setup(device, NULL);
 185 }
 186 OF_EARLYCON_DECLARE(early_pxa, "mrvl,pxa-uart", early_serial_pxa_setup);
 187 #endif
 188
 189 MODULE_AUTHOR("Sergei Ianovich");
 190 MODULE_LICENSE("GPL");
 191 MODULE_ALIAS("platform:pxa2xx-uart");