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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 | // SPDX-License-Identifier: GPL-2.0 /* * Renesas Emma Mobile 8250 driver * * Copyright (C) 2012 Magnus Damm */ #include <linux/device.h> #include <linux/io.h> #include <linux/module.h> #include <linux/mod_devicetable.h> #include <linux/serial_8250.h> #include <linux/serial_reg.h> #include <linux/platform_device.h> #include <linux/clk.h> #include <linux/slab.h> #include "8250.h" #define UART_DLL_EM 9 #define UART_DLM_EM 10 struct serial8250_em_priv { struct clk *sclk; int line; }; static void serial8250_em_serial_out(struct uart_port *p, int offset, int value) { switch (offset) { case UART_TX: /* TX @ 0x00 */ writeb(value, p->membase); break; case UART_FCR: /* FCR @ 0x0c (+1) */ case UART_LCR: /* LCR @ 0x10 (+1) */ case UART_MCR: /* MCR @ 0x14 (+1) */ case UART_SCR: /* SCR @ 0x20 (+1) */ writel(value, p->membase + ((offset + 1) << 2)); break; case UART_IER: /* IER @ 0x04 */ value &= 0x0f; /* only 4 valid bits - not Xscale */ fallthrough; case UART_DLL_EM: /* DLL @ 0x24 (+9) */ case UART_DLM_EM: /* DLM @ 0x28 (+9) */ writel(value, p->membase + (offset << 2)); } } static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset) { switch (offset) { case UART_RX: /* RX @ 0x00 */ return readb(p->membase); case UART_MCR: /* MCR @ 0x14 (+1) */ case UART_LSR: /* LSR @ 0x18 (+1) */ case UART_MSR: /* MSR @ 0x1c (+1) */ case UART_SCR: /* SCR @ 0x20 (+1) */ return readl(p->membase + ((offset + 1) << 2)); case UART_IER: /* IER @ 0x04 */ case UART_IIR: /* IIR @ 0x08 */ case UART_DLL_EM: /* DLL @ 0x24 (+9) */ case UART_DLM_EM: /* DLM @ 0x28 (+9) */ return readl(p->membase + (offset << 2)); } return 0; } static int serial8250_em_serial_dl_read(struct uart_8250_port *up) { return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8; } static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value) { serial_out(up, UART_DLL_EM, value & 0xff); serial_out(up, UART_DLM_EM, value >> 8 & 0xff); } static int serial8250_em_probe(struct platform_device *pdev) { struct serial8250_em_priv *priv; struct uart_8250_port up; struct resource *regs; int irq, ret; irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!regs) { dev_err(&pdev->dev, "missing registers\n"); return -EINVAL; } priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->sclk = devm_clk_get(&pdev->dev, "sclk"); if (IS_ERR(priv->sclk)) { dev_err(&pdev->dev, "unable to get clock\n"); return PTR_ERR(priv->sclk); } memset(&up, 0, sizeof(up)); up.port.mapbase = regs->start; up.port.irq = irq; up.port.type = PORT_16750; up.port.flags = UPF_FIXED_PORT | UPF_IOREMAP | UPF_FIXED_TYPE; up.port.dev = &pdev->dev; up.port.private_data = priv; clk_prepare_enable(priv->sclk); up.port.uartclk = clk_get_rate(priv->sclk); up.port.iotype = UPIO_MEM32; up.port.serial_in = serial8250_em_serial_in; up.port.serial_out = serial8250_em_serial_out; up.dl_read = serial8250_em_serial_dl_read; up.dl_write = serial8250_em_serial_dl_write; ret = serial8250_register_8250_port(&up); if (ret < 0) { dev_err(&pdev->dev, "unable to register 8250 port\n"); clk_disable_unprepare(priv->sclk); return ret; } priv->line = ret; platform_set_drvdata(pdev, priv); return 0; } static int serial8250_em_remove(struct platform_device *pdev) { struct serial8250_em_priv *priv = platform_get_drvdata(pdev); serial8250_unregister_port(priv->line); clk_disable_unprepare(priv->sclk); return 0; } static const struct of_device_id serial8250_em_dt_ids[] = { { .compatible = "renesas,em-uart", }, {}, }; MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids); static struct platform_driver serial8250_em_platform_driver = { .driver = { .name = "serial8250-em", .of_match_table = serial8250_em_dt_ids, }, .probe = serial8250_em_probe, .remove = serial8250_em_remove, }; module_platform_driver(serial8250_em_platform_driver); MODULE_AUTHOR("Magnus Damm"); MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver"); MODULE_LICENSE("GPL v2"); |