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