Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Mediatek 8250 driver. |
| 3 | * |
| 4 | * Copyright (c) 2014 MundoReader S.L. |
| 5 | * Author: Matthias Brugger <matthias.bgg@gmail.com> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | */ |
| 17 | #include <linux/clk.h> |
| 18 | #include <linux/io.h> |
Arnd Bergmann | 88725e9 | 2016-02-17 16:02:31 +0100 | [diff] [blame] | 19 | #include <linux/module.h> |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 20 | #include <linux/of_irq.h> |
| 21 | #include <linux/of_platform.h> |
| 22 | #include <linux/platform_device.h> |
| 23 | #include <linux/pm_runtime.h> |
| 24 | #include <linux/serial_8250.h> |
| 25 | #include <linux/serial_reg.h> |
| 26 | |
| 27 | #include "8250.h" |
| 28 | |
| 29 | #define UART_MTK_HIGHS 0x09 /* Highspeed register */ |
| 30 | #define UART_MTK_SAMPLE_COUNT 0x0a /* Sample count register */ |
| 31 | #define UART_MTK_SAMPLE_POINT 0x0b /* Sample point register */ |
| 32 | #define MTK_UART_RATE_FIX 0x0d /* UART Rate Fix Register */ |
| 33 | |
| 34 | struct mtk8250_data { |
| 35 | int line; |
| 36 | struct clk *uart_clk; |
Sascha Hauer | c1c325d | 2015-04-27 08:49:57 +0200 | [diff] [blame] | 37 | struct clk *bus_clk; |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 38 | }; |
| 39 | |
| 40 | static void |
| 41 | mtk8250_set_termios(struct uart_port *port, struct ktermios *termios, |
| 42 | struct ktermios *old) |
| 43 | { |
Andy Shevchenko | 013e358 | 2016-02-18 21:22:59 +0200 | [diff] [blame] | 44 | struct uart_8250_port *up = up_to_u8250p(port); |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 45 | unsigned long flags; |
| 46 | unsigned int baud, quot; |
| 47 | |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 48 | serial8250_do_set_termios(port, termios, old); |
| 49 | |
| 50 | /* |
| 51 | * Mediatek UARTs use an extra highspeed register (UART_MTK_HIGHS) |
| 52 | * |
| 53 | * We need to recalcualte the quot register, as the claculation depends |
| 54 | * on the vaule in the highspeed register. |
| 55 | * |
| 56 | * Some baudrates are not supported by the chip, so we use the next |
| 57 | * lower rate supported and update termios c_flag. |
| 58 | * |
| 59 | * If highspeed register is set to 3, we need to specify sample count |
| 60 | * and sample point to increase accuracy. If not, we reset the |
| 61 | * registers to their default values. |
| 62 | */ |
| 63 | baud = uart_get_baud_rate(port, termios, old, |
| 64 | port->uartclk / 16 / 0xffff, |
| 65 | port->uartclk / 16); |
| 66 | |
| 67 | if (baud <= 115200) { |
| 68 | serial_port_out(port, UART_MTK_HIGHS, 0x0); |
| 69 | quot = uart_get_divisor(port, baud); |
| 70 | } else if (baud <= 576000) { |
| 71 | serial_port_out(port, UART_MTK_HIGHS, 0x2); |
| 72 | |
| 73 | /* Set to next lower baudrate supported */ |
| 74 | if ((baud == 500000) || (baud == 576000)) |
| 75 | baud = 460800; |
Eddie Huang | 2a76826 | 2014-10-22 21:12:07 +0800 | [diff] [blame] | 76 | quot = DIV_ROUND_UP(port->uartclk, 4 * baud); |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 77 | } else { |
| 78 | serial_port_out(port, UART_MTK_HIGHS, 0x3); |
| 79 | |
| 80 | /* Set to highest baudrate supported */ |
| 81 | if (baud >= 1152000) |
| 82 | baud = 921600; |
Eddie Huang | 2a76826 | 2014-10-22 21:12:07 +0800 | [diff] [blame] | 83 | quot = DIV_ROUND_UP(port->uartclk, 256 * baud); |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 84 | } |
| 85 | |
| 86 | /* |
| 87 | * Ok, we're now changing the port state. Do it with |
| 88 | * interrupts disabled. |
| 89 | */ |
| 90 | spin_lock_irqsave(&port->lock, flags); |
| 91 | |
| 92 | /* set DLAB we have cval saved in up->lcr from the call to the core */ |
| 93 | serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB); |
| 94 | serial_dl_write(up, quot); |
| 95 | |
| 96 | /* reset DLAB */ |
| 97 | serial_port_out(port, UART_LCR, up->lcr); |
| 98 | |
| 99 | if (baud > 460800) { |
| 100 | unsigned int tmp; |
| 101 | |
| 102 | tmp = DIV_ROUND_CLOSEST(port->uartclk, quot * baud); |
| 103 | serial_port_out(port, UART_MTK_SAMPLE_COUNT, tmp - 1); |
| 104 | serial_port_out(port, UART_MTK_SAMPLE_POINT, |
| 105 | (tmp - 2) >> 1); |
| 106 | } else { |
| 107 | serial_port_out(port, UART_MTK_SAMPLE_COUNT, 0x00); |
| 108 | serial_port_out(port, UART_MTK_SAMPLE_POINT, 0xff); |
| 109 | } |
| 110 | |
| 111 | spin_unlock_irqrestore(&port->lock, flags); |
| 112 | /* Don't rewrite B0 */ |
| 113 | if (tty_termios_baud_rate(termios)) |
| 114 | tty_termios_encode_baud_rate(termios, baud, baud); |
| 115 | } |
| 116 | |
Arnd Bergmann | 9db669f | 2016-02-08 14:36:13 +0100 | [diff] [blame] | 117 | static int __maybe_unused mtk8250_runtime_suspend(struct device *dev) |
Sascha Hauer | 68e5fc4 | 2015-04-27 08:49:56 +0200 | [diff] [blame] | 118 | { |
| 119 | struct mtk8250_data *data = dev_get_drvdata(dev); |
| 120 | |
| 121 | clk_disable_unprepare(data->uart_clk); |
Sascha Hauer | c1c325d | 2015-04-27 08:49:57 +0200 | [diff] [blame] | 122 | clk_disable_unprepare(data->bus_clk); |
Sascha Hauer | 68e5fc4 | 2015-04-27 08:49:56 +0200 | [diff] [blame] | 123 | |
| 124 | return 0; |
| 125 | } |
| 126 | |
Arnd Bergmann | 9db669f | 2016-02-08 14:36:13 +0100 | [diff] [blame] | 127 | static int __maybe_unused mtk8250_runtime_resume(struct device *dev) |
Sascha Hauer | 68e5fc4 | 2015-04-27 08:49:56 +0200 | [diff] [blame] | 128 | { |
| 129 | struct mtk8250_data *data = dev_get_drvdata(dev); |
| 130 | int err; |
| 131 | |
| 132 | err = clk_prepare_enable(data->uart_clk); |
| 133 | if (err) { |
| 134 | dev_warn(dev, "Can't enable clock\n"); |
| 135 | return err; |
| 136 | } |
| 137 | |
Sascha Hauer | c1c325d | 2015-04-27 08:49:57 +0200 | [diff] [blame] | 138 | err = clk_prepare_enable(data->bus_clk); |
| 139 | if (err) { |
| 140 | dev_warn(dev, "Can't enable bus clock\n"); |
| 141 | return err; |
| 142 | } |
| 143 | |
Sascha Hauer | 68e5fc4 | 2015-04-27 08:49:56 +0200 | [diff] [blame] | 144 | return 0; |
| 145 | } |
| 146 | |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 147 | static void |
| 148 | mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old) |
| 149 | { |
| 150 | if (!state) |
| 151 | pm_runtime_get_sync(port->dev); |
| 152 | |
| 153 | serial8250_do_pm(port, state, old); |
| 154 | |
| 155 | if (state) |
| 156 | pm_runtime_put_sync_suspend(port->dev); |
| 157 | } |
| 158 | |
| 159 | static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p, |
| 160 | struct mtk8250_data *data) |
| 161 | { |
Sascha Hauer | c1c325d | 2015-04-27 08:49:57 +0200 | [diff] [blame] | 162 | data->uart_clk = devm_clk_get(&pdev->dev, "baud"); |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 163 | if (IS_ERR(data->uart_clk)) { |
Sascha Hauer | c1c325d | 2015-04-27 08:49:57 +0200 | [diff] [blame] | 164 | /* |
| 165 | * For compatibility with older device trees try unnamed |
| 166 | * clk when no baud clk can be found. |
| 167 | */ |
| 168 | data->uart_clk = devm_clk_get(&pdev->dev, NULL); |
| 169 | if (IS_ERR(data->uart_clk)) { |
| 170 | dev_warn(&pdev->dev, "Can't get uart clock\n"); |
| 171 | return PTR_ERR(data->uart_clk); |
| 172 | } |
| 173 | |
| 174 | return 0; |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 175 | } |
| 176 | |
Sascha Hauer | c1c325d | 2015-04-27 08:49:57 +0200 | [diff] [blame] | 177 | data->bus_clk = devm_clk_get(&pdev->dev, "bus"); |
| 178 | if (IS_ERR(data->bus_clk)) |
| 179 | return PTR_ERR(data->bus_clk); |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 180 | |
| 181 | return 0; |
| 182 | } |
| 183 | |
| 184 | static int mtk8250_probe(struct platform_device *pdev) |
| 185 | { |
| 186 | struct uart_8250_port uart = {}; |
| 187 | struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 188 | struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); |
| 189 | struct mtk8250_data *data; |
| 190 | int err; |
| 191 | |
| 192 | if (!regs || !irq) { |
| 193 | dev_err(&pdev->dev, "no registers/irq defined\n"); |
| 194 | return -EINVAL; |
| 195 | } |
| 196 | |
| 197 | uart.port.membase = devm_ioremap(&pdev->dev, regs->start, |
| 198 | resource_size(regs)); |
| 199 | if (!uart.port.membase) |
| 200 | return -ENOMEM; |
| 201 | |
| 202 | data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); |
| 203 | if (!data) |
| 204 | return -ENOMEM; |
| 205 | |
| 206 | if (pdev->dev.of_node) { |
| 207 | err = mtk8250_probe_of(pdev, &uart.port, data); |
| 208 | if (err) |
| 209 | return err; |
| 210 | } else |
| 211 | return -ENODEV; |
| 212 | |
| 213 | spin_lock_init(&uart.port.lock); |
| 214 | uart.port.mapbase = regs->start; |
| 215 | uart.port.irq = irq->start; |
| 216 | uart.port.pm = mtk8250_do_pm; |
| 217 | uart.port.type = PORT_16550; |
| 218 | uart.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT; |
| 219 | uart.port.dev = &pdev->dev; |
| 220 | uart.port.iotype = UPIO_MEM32; |
| 221 | uart.port.regshift = 2; |
| 222 | uart.port.private_data = data; |
| 223 | uart.port.set_termios = mtk8250_set_termios; |
Sascha Hauer | c1c325d | 2015-04-27 08:49:57 +0200 | [diff] [blame] | 224 | uart.port.uartclk = clk_get_rate(data->uart_clk); |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 225 | |
| 226 | /* Disable Rate Fix function */ |
| 227 | writel(0x0, uart.port.membase + |
| 228 | (MTK_UART_RATE_FIX << uart.port.regshift)); |
| 229 | |
Sascha Hauer | 68e5fc4 | 2015-04-27 08:49:56 +0200 | [diff] [blame] | 230 | platform_set_drvdata(pdev, data); |
| 231 | |
| 232 | pm_runtime_enable(&pdev->dev); |
| 233 | if (!pm_runtime_enabled(&pdev->dev)) { |
| 234 | err = mtk8250_runtime_resume(&pdev->dev); |
| 235 | if (err) |
| 236 | return err; |
| 237 | } |
| 238 | |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 239 | data->line = serial8250_register_8250_port(&uart); |
| 240 | if (data->line < 0) |
| 241 | return data->line; |
| 242 | |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 243 | return 0; |
| 244 | } |
| 245 | |
Arnd Bergmann | 88725e9 | 2016-02-17 16:02:31 +0100 | [diff] [blame] | 246 | static int mtk8250_remove(struct platform_device *pdev) |
| 247 | { |
| 248 | struct mtk8250_data *data = platform_get_drvdata(pdev); |
| 249 | |
| 250 | pm_runtime_get_sync(&pdev->dev); |
| 251 | |
| 252 | serial8250_unregister_port(data->line); |
| 253 | |
| 254 | pm_runtime_disable(&pdev->dev); |
| 255 | pm_runtime_put_noidle(&pdev->dev); |
| 256 | |
| 257 | if (!pm_runtime_status_suspended(&pdev->dev)) |
| 258 | mtk8250_runtime_suspend(&pdev->dev); |
| 259 | |
| 260 | return 0; |
| 261 | } |
| 262 | |
Arnd Bergmann | 9db669f | 2016-02-08 14:36:13 +0100 | [diff] [blame] | 263 | static int __maybe_unused mtk8250_suspend(struct device *dev) |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 264 | { |
| 265 | struct mtk8250_data *data = dev_get_drvdata(dev); |
| 266 | |
| 267 | serial8250_suspend_port(data->line); |
| 268 | |
| 269 | return 0; |
| 270 | } |
| 271 | |
Arnd Bergmann | 9db669f | 2016-02-08 14:36:13 +0100 | [diff] [blame] | 272 | static int __maybe_unused mtk8250_resume(struct device *dev) |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 273 | { |
| 274 | struct mtk8250_data *data = dev_get_drvdata(dev); |
| 275 | |
| 276 | serial8250_resume_port(data->line); |
| 277 | |
| 278 | return 0; |
| 279 | } |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 280 | |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 281 | static const struct dev_pm_ops mtk8250_pm_ops = { |
| 282 | SET_SYSTEM_SLEEP_PM_OPS(mtk8250_suspend, mtk8250_resume) |
| 283 | SET_RUNTIME_PM_OPS(mtk8250_runtime_suspend, mtk8250_runtime_resume, |
| 284 | NULL) |
| 285 | }; |
| 286 | |
| 287 | static const struct of_device_id mtk8250_of_match[] = { |
| 288 | { .compatible = "mediatek,mt6577-uart" }, |
| 289 | { /* Sentinel */ } |
| 290 | }; |
Arnd Bergmann | 88725e9 | 2016-02-17 16:02:31 +0100 | [diff] [blame] | 291 | MODULE_DEVICE_TABLE(of, mtk8250_of_match); |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 292 | |
| 293 | static struct platform_driver mtk8250_platform_driver = { |
| 294 | .driver = { |
Arnd Bergmann | 88725e9 | 2016-02-17 16:02:31 +0100 | [diff] [blame] | 295 | .name = "mt6577-uart", |
| 296 | .pm = &mtk8250_pm_ops, |
| 297 | .of_match_table = mtk8250_of_match, |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 298 | }, |
| 299 | .probe = mtk8250_probe, |
Arnd Bergmann | 88725e9 | 2016-02-17 16:02:31 +0100 | [diff] [blame] | 300 | .remove = mtk8250_remove, |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 301 | }; |
Arnd Bergmann | 88725e9 | 2016-02-17 16:02:31 +0100 | [diff] [blame] | 302 | module_platform_driver(mtk8250_platform_driver); |
Matthias Brugger | b4756f4 | 2014-09-09 17:31:42 +0200 | [diff] [blame] | 303 | |
Arnd Bergmann | 3f5921a | 2016-02-17 16:02:35 +0100 | [diff] [blame] | 304 | #if defined(CONFIG_SERIAL_8250_CONSOLE) && !defined(MODULE) |
Eddie Huang | 2c40b57 | 2015-04-28 21:40:33 +0800 | [diff] [blame] | 305 | static int __init early_mtk8250_setup(struct earlycon_device *device, |
| 306 | const char *options) |
| 307 | { |
| 308 | if (!device->port.membase) |
| 309 | return -ENODEV; |
| 310 | |
| 311 | device->port.iotype = UPIO_MEM32; |
| 312 | |
| 313 | return early_serial8250_setup(device, NULL); |
| 314 | } |
| 315 | |
| 316 | OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup); |
Arnd Bergmann | 7798ede | 2015-05-19 22:11:09 +0200 | [diff] [blame] | 317 | #endif |
Arnd Bergmann | 88725e9 | 2016-02-17 16:02:31 +0100 | [diff] [blame] | 318 | |
| 319 | MODULE_AUTHOR("Matthias Brugger"); |
| 320 | MODULE_LICENSE("GPL"); |
| 321 | MODULE_DESCRIPTION("Mediatek 8250 serial port driver"); |