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 struct gpio_desc *desc_array[UART_GPIO_MAX]; 48 int value_array[UART_GPIO_MAX]; 49 unsigned int count = 0; 50 51 if (IS_ERR_OR_NULL(gpios)) 52 return; 53 54 for (i = 0; i < UART_GPIO_MAX; i++) 55 if (!IS_ERR_OR_NULL(gpios->gpio[i]) && 56 mctrl_gpios_desc[i].dir_out) { 57 desc_array[count] = gpios->gpio[i]; 58 value_array[count] = !!(mctrl & mctrl_gpios_desc[i].mctrl); 59 count++; 60 } 61 gpiod_set_array(count, desc_array, value_array); 62 } 63 EXPORT_SYMBOL_GPL(mctrl_gpio_set); 64 65 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios, 66 enum mctrl_gpio_idx gidx) 67 { 68 if (!IS_ERR_OR_NULL(gpios) && !IS_ERR_OR_NULL(gpios->gpio[gidx])) 69 return gpios->gpio[gidx]; 70 else 71 return NULL; 72 } 73 EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod); 74 75 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl) 76 { 77 enum mctrl_gpio_idx i; 78 79 /* 80 * return it unchanged if the structure is not allocated 81 */ 82 if (IS_ERR_OR_NULL(gpios)) 83 return *mctrl; 84 85 for (i = 0; i < UART_GPIO_MAX; i++) { 86 if (!IS_ERR_OR_NULL(gpios->gpio[i]) && 87 !mctrl_gpios_desc[i].dir_out) { 88 if (gpiod_get_value(gpios->gpio[i])) 89 *mctrl |= mctrl_gpios_desc[i].mctrl; 90 else 91 *mctrl &= ~mctrl_gpios_desc[i].mctrl; 92 } 93 } 94 95 return *mctrl; 96 } 97 EXPORT_SYMBOL_GPL(mctrl_gpio_get); 98 99 struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx) 100 { 101 struct mctrl_gpios *gpios; 102 enum mctrl_gpio_idx i; 103 int err; 104 105 gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL); 106 if (!gpios) 107 return ERR_PTR(-ENOMEM); 108 109 for (i = 0; i < UART_GPIO_MAX; i++) { 110 gpios->gpio[i] = devm_gpiod_get_index(dev, 111 mctrl_gpios_desc[i].name, 112 idx); 113 114 /* 115 * The GPIOs are maybe not all filled, 116 * this is not an error. 117 */ 118 if (IS_ERR_OR_NULL(gpios->gpio[i])) 119 continue; 120 121 if (mctrl_gpios_desc[i].dir_out) 122 err = gpiod_direction_output(gpios->gpio[i], 0); 123 else 124 err = gpiod_direction_input(gpios->gpio[i]); 125 if (err) { 126 dev_dbg(dev, "Unable to set direction for %s GPIO", 127 mctrl_gpios_desc[i].name); 128 devm_gpiod_put(dev, gpios->gpio[i]); 129 gpios->gpio[i] = NULL; 130 } 131 } 132 133 return gpios; 134 } 135 EXPORT_SYMBOL_GPL(mctrl_gpio_init); 136 137 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios) 138 { 139 enum mctrl_gpio_idx i; 140 141 if (IS_ERR_OR_NULL(gpios)) 142 return; 143 144 for (i = 0; i < UART_GPIO_MAX; i++) 145 if (!IS_ERR_OR_NULL(gpios->gpio[i])) 146 devm_gpiod_put(dev, gpios->gpio[i]); 147 devm_kfree(dev, gpios); 148 } 149 EXPORT_SYMBOL_GPL(mctrl_gpio_free); 150