1 /* 2 * Helpers for controlling modem lines via GPIO 3 * 4 * Copyright (C) 2014 Paratronic S.A. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 */ 17 18 #include <linux/err.h> 19 #include <linux/device.h> 20 #include <linux/gpio/consumer.h> 21 #include <linux/termios.h> 22 23 #include "serial_mctrl_gpio.h" 24 25 struct mctrl_gpios { 26 struct gpio_desc *gpio[UART_GPIO_MAX]; 27 }; 28 29 static const struct { 30 const char *name; 31 unsigned int mctrl; 32 bool dir_out; 33 } mctrl_gpios_desc[UART_GPIO_MAX] = { 34 { "cts", TIOCM_CTS, false, }, 35 { "dsr", TIOCM_DSR, false, }, 36 { "dcd", TIOCM_CD, false, }, 37 { "rng", TIOCM_RNG, false, }, 38 { "rts", TIOCM_RTS, true, }, 39 { "dtr", TIOCM_DTR, true, }, 40 { "out1", TIOCM_OUT1, true, }, 41 { "out2", TIOCM_OUT2, true, }, 42 }; 43 44 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl) 45 { 46 enum mctrl_gpio_idx i; 47 48 if (IS_ERR_OR_NULL(gpios)) 49 return; 50 51 for (i = 0; i < UART_GPIO_MAX; i++) 52 if (!IS_ERR_OR_NULL(gpios->gpio[i]) && 53 mctrl_gpios_desc[i].dir_out) 54 gpiod_set_value(gpios->gpio[i], 55 !!(mctrl & mctrl_gpios_desc[i].mctrl)); 56 } 57 EXPORT_SYMBOL_GPL(mctrl_gpio_set); 58 59 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios, 60 enum mctrl_gpio_idx gidx) 61 { 62 if (!IS_ERR_OR_NULL(gpios) && !IS_ERR_OR_NULL(gpios->gpio[gidx])) 63 return gpios->gpio[gidx]; 64 else 65 return NULL; 66 } 67 EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod); 68 69 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl) 70 { 71 enum mctrl_gpio_idx i; 72 73 /* 74 * return it unchanged if the structure is not allocated 75 */ 76 if (IS_ERR_OR_NULL(gpios)) 77 return *mctrl; 78 79 for (i = 0; i < UART_GPIO_MAX; i++) { 80 if (!IS_ERR_OR_NULL(gpios->gpio[i]) && 81 !mctrl_gpios_desc[i].dir_out) { 82 if (gpiod_get_value(gpios->gpio[i])) 83 *mctrl |= mctrl_gpios_desc[i].mctrl; 84 else 85 *mctrl &= ~mctrl_gpios_desc[i].mctrl; 86 } 87 } 88 89 return *mctrl; 90 } 91 EXPORT_SYMBOL_GPL(mctrl_gpio_get); 92 93 struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx) 94 { 95 struct mctrl_gpios *gpios; 96 enum mctrl_gpio_idx i; 97 int err; 98 99 gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL); 100 if (!gpios) 101 return ERR_PTR(-ENOMEM); 102 103 for (i = 0; i < UART_GPIO_MAX; i++) { 104 gpios->gpio[i] = devm_gpiod_get_index(dev, 105 mctrl_gpios_desc[i].name, 106 idx); 107 108 /* 109 * The GPIOs are maybe not all filled, 110 * this is not an error. 111 */ 112 if (IS_ERR_OR_NULL(gpios->gpio[i])) 113 continue; 114 115 if (mctrl_gpios_desc[i].dir_out) 116 err = gpiod_direction_output(gpios->gpio[i], 0); 117 else 118 err = gpiod_direction_input(gpios->gpio[i]); 119 if (err) { 120 dev_dbg(dev, "Unable to set direction for %s GPIO", 121 mctrl_gpios_desc[i].name); 122 devm_gpiod_put(dev, gpios->gpio[i]); 123 gpios->gpio[i] = NULL; 124 } 125 } 126 127 return gpios; 128 } 129 EXPORT_SYMBOL_GPL(mctrl_gpio_init); 130 131 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios) 132 { 133 enum mctrl_gpio_idx i; 134 135 if (IS_ERR_OR_NULL(gpios)) 136 return; 137 138 for (i = 0; i < UART_GPIO_MAX; i++) 139 if (!IS_ERR_OR_NULL(gpios->gpio[i])) 140 devm_gpiod_put(dev, gpios->gpio[i]); 141 devm_kfree(dev, gpios); 142 } 143 EXPORT_SYMBOL_GPL(mctrl_gpio_free); 144