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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Helpers for controlling modem lines via GPIO4 *5 * Copyright (C) 2014 Paratronic S.A.6 */7 8#include <linux/err.h>9#include <linux/device.h>10#include <linux/irq.h>11#include <linux/gpio/consumer.h>12#include <linux/termios.h>13#include <linux/serial_core.h>14#include <linux/module.h>15#include <linux/property.h>16 17#include "serial_mctrl_gpio.h"18 19struct mctrl_gpios {20 struct uart_port *port;21 struct gpio_desc *gpio[UART_GPIO_MAX];22 int irq[UART_GPIO_MAX];23 unsigned int mctrl_prev;24 bool mctrl_on;25};26 27static const struct {28 const char *name;29 unsigned int mctrl;30 enum gpiod_flags flags;31} mctrl_gpios_desc[UART_GPIO_MAX] = {32 { "cts", TIOCM_CTS, GPIOD_IN, },33 { "dsr", TIOCM_DSR, GPIOD_IN, },34 { "dcd", TIOCM_CD, GPIOD_IN, },35 { "rng", TIOCM_RNG, GPIOD_IN, },36 { "rts", TIOCM_RTS, GPIOD_OUT_LOW, },37 { "dtr", TIOCM_DTR, GPIOD_OUT_LOW, },38};39 40static bool mctrl_gpio_flags_is_dir_out(unsigned int idx)41{42 return mctrl_gpios_desc[idx].flags & GPIOD_FLAGS_BIT_DIR_OUT;43}44 45/**46 * mctrl_gpio_set - set gpios according to mctrl state47 * @gpios: gpios to set48 * @mctrl: state to set49 *50 * Set the gpios according to the mctrl state.51 */52void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)53{54 enum mctrl_gpio_idx i;55 struct gpio_desc *desc_array[UART_GPIO_MAX];56 DECLARE_BITMAP(values, UART_GPIO_MAX);57 unsigned int count = 0;58 59 if (gpios == NULL)60 return;61 62 for (i = 0; i < UART_GPIO_MAX; i++)63 if (gpios->gpio[i] && mctrl_gpio_flags_is_dir_out(i)) {64 desc_array[count] = gpios->gpio[i];65 __assign_bit(count, values,66 mctrl & mctrl_gpios_desc[i].mctrl);67 count++;68 }69 gpiod_set_array_value(count, desc_array, NULL, values);70}71EXPORT_SYMBOL_GPL(mctrl_gpio_set);72 73/**74 * mctrl_gpio_to_gpiod - obtain gpio_desc of modem line index75 * @gpios: gpios to look into76 * @gidx: index of the modem line77 * Returns: the gpio_desc structure associated to the modem line index78 */79struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,80 enum mctrl_gpio_idx gidx)81{82 if (gpios == NULL)83 return NULL;84 85 return gpios->gpio[gidx];86}87EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);88 89/**90 * mctrl_gpio_get - update mctrl with the gpios values.91 * @gpios: gpios to get the info from92 * @mctrl: mctrl to set93 * Returns: modified mctrl (the same value as in @mctrl)94 *95 * Update mctrl with the gpios values.96 */97unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)98{99 enum mctrl_gpio_idx i;100 101 if (gpios == NULL)102 return *mctrl;103 104 for (i = 0; i < UART_GPIO_MAX; i++) {105 if (gpios->gpio[i] && !mctrl_gpio_flags_is_dir_out(i)) {106 if (gpiod_get_value(gpios->gpio[i]))107 *mctrl |= mctrl_gpios_desc[i].mctrl;108 else109 *mctrl &= ~mctrl_gpios_desc[i].mctrl;110 }111 }112 113 return *mctrl;114}115EXPORT_SYMBOL_GPL(mctrl_gpio_get);116 117unsigned int118mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)119{120 enum mctrl_gpio_idx i;121 122 if (gpios == NULL)123 return *mctrl;124 125 for (i = 0; i < UART_GPIO_MAX; i++) {126 if (gpios->gpio[i] && mctrl_gpio_flags_is_dir_out(i)) {127 if (gpiod_get_value(gpios->gpio[i]))128 *mctrl |= mctrl_gpios_desc[i].mctrl;129 else130 *mctrl &= ~mctrl_gpios_desc[i].mctrl;131 }132 }133 134 return *mctrl;135}136EXPORT_SYMBOL_GPL(mctrl_gpio_get_outputs);137 138struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)139{140 struct mctrl_gpios *gpios;141 enum mctrl_gpio_idx i;142 143 gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);144 if (!gpios)145 return ERR_PTR(-ENOMEM);146 147 for (i = 0; i < UART_GPIO_MAX; i++) {148 char *gpio_str;149 bool present;150 151 /* Check if GPIO property exists and continue if not */152 gpio_str = kasprintf(GFP_KERNEL, "%s-gpios",153 mctrl_gpios_desc[i].name);154 if (!gpio_str)155 continue;156 157 present = device_property_present(dev, gpio_str);158 kfree(gpio_str);159 if (!present)160 continue;161 162 gpios->gpio[i] =163 devm_gpiod_get_index_optional(dev,164 mctrl_gpios_desc[i].name,165 idx,166 mctrl_gpios_desc[i].flags);167 168 if (IS_ERR(gpios->gpio[i]))169 return ERR_CAST(gpios->gpio[i]);170 }171 172 return gpios;173}174EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);175 176#define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)177static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)178{179 struct mctrl_gpios *gpios = context;180 struct uart_port *port = gpios->port;181 u32 mctrl = gpios->mctrl_prev;182 u32 mctrl_diff;183 unsigned long flags;184 185 mctrl_gpio_get(gpios, &mctrl);186 187 uart_port_lock_irqsave(port, &flags);188 189 mctrl_diff = mctrl ^ gpios->mctrl_prev;190 gpios->mctrl_prev = mctrl;191 192 if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {193 if ((mctrl_diff & mctrl) & TIOCM_RI)194 port->icount.rng++;195 196 if ((mctrl_diff & mctrl) & TIOCM_DSR)197 port->icount.dsr++;198 199 if (mctrl_diff & TIOCM_CD)200 uart_handle_dcd_change(port, mctrl & TIOCM_CD);201 202 if (mctrl_diff & TIOCM_CTS)203 uart_handle_cts_change(port, mctrl & TIOCM_CTS);204 205 wake_up_interruptible(&port->state->port.delta_msr_wait);206 }207 208 uart_port_unlock_irqrestore(port, flags);209 210 return IRQ_HANDLED;211}212 213/**214 * mctrl_gpio_init - initialize uart gpios215 * @port: port to initialize gpios for216 * @idx: index of the gpio in the @port's device217 *218 * This will get the {cts,rts,...}-gpios from device tree if they are present219 * and request them, set direction etc, and return an allocated structure.220 * `devm_*` functions are used, so there's no need to call mctrl_gpio_free().221 * As this sets up the irq handling, make sure to not handle changes to the222 * gpio input lines in your driver, too.223 */224struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)225{226 struct mctrl_gpios *gpios;227 enum mctrl_gpio_idx i;228 229 gpios = mctrl_gpio_init_noauto(port->dev, idx);230 if (IS_ERR(gpios))231 return gpios;232 233 gpios->port = port;234 235 for (i = 0; i < UART_GPIO_MAX; ++i) {236 int ret;237 238 if (!gpios->gpio[i] || mctrl_gpio_flags_is_dir_out(i))239 continue;240 241 ret = gpiod_to_irq(gpios->gpio[i]);242 if (ret < 0) {243 dev_err(port->dev,244 "failed to find corresponding irq for %s (idx=%d, err=%d)\n",245 mctrl_gpios_desc[i].name, idx, ret);246 return ERR_PTR(ret);247 }248 gpios->irq[i] = ret;249 250 /* irqs should only be enabled in .enable_ms */251 irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);252 253 ret = devm_request_irq(port->dev, gpios->irq[i],254 mctrl_gpio_irq_handle,255 IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),256 gpios);257 if (ret) {258 /* alternatively implement polling */259 dev_err(port->dev,260 "failed to request irq for %s (idx=%d, err=%d)\n",261 mctrl_gpios_desc[i].name, idx, ret);262 return ERR_PTR(ret);263 }264 }265 266 return gpios;267}268EXPORT_SYMBOL_GPL(mctrl_gpio_init);269 270/**271 * mctrl_gpio_free - explicitly free uart gpios272 * @dev: uart port's device273 * @gpios: gpios structure to be freed274 *275 * This will free the requested gpios in mctrl_gpio_init(). As `devm_*`276 * functions are used, there's generally no need to call this function.277 */278void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)279{280 enum mctrl_gpio_idx i;281 282 if (gpios == NULL)283 return;284 285 for (i = 0; i < UART_GPIO_MAX; i++) {286 if (gpios->irq[i])287 devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);288 289 if (gpios->gpio[i])290 devm_gpiod_put(dev, gpios->gpio[i]);291 }292 devm_kfree(dev, gpios);293}294EXPORT_SYMBOL_GPL(mctrl_gpio_free);295 296/**297 * mctrl_gpio_enable_ms - enable irqs and handling of changes to the ms lines298 * @gpios: gpios to enable299 */300void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)301{302 enum mctrl_gpio_idx i;303 304 if (gpios == NULL)305 return;306 307 /* .enable_ms may be called multiple times */308 if (gpios->mctrl_on)309 return;310 311 gpios->mctrl_on = true;312 313 /* get initial status of modem lines GPIOs */314 mctrl_gpio_get(gpios, &gpios->mctrl_prev);315 316 for (i = 0; i < UART_GPIO_MAX; ++i) {317 if (!gpios->irq[i])318 continue;319 320 enable_irq(gpios->irq[i]);321 }322}323EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);324 325/**326 * mctrl_gpio_disable_ms - disable irqs and handling of changes to the ms lines327 * @gpios: gpios to disable328 */329void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)330{331 enum mctrl_gpio_idx i;332 333 if (gpios == NULL)334 return;335 336 if (!gpios->mctrl_on)337 return;338 339 gpios->mctrl_on = false;340 341 for (i = 0; i < UART_GPIO_MAX; ++i) {342 if (!gpios->irq[i])343 continue;344 345 disable_irq(gpios->irq[i]);346 }347}348EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);349 350void mctrl_gpio_enable_irq_wake(struct mctrl_gpios *gpios)351{352 enum mctrl_gpio_idx i;353 354 if (!gpios)355 return;356 357 if (!gpios->mctrl_on)358 return;359 360 for (i = 0; i < UART_GPIO_MAX; ++i) {361 if (!gpios->irq[i])362 continue;363 364 enable_irq_wake(gpios->irq[i]);365 }366}367EXPORT_SYMBOL_GPL(mctrl_gpio_enable_irq_wake);368 369void mctrl_gpio_disable_irq_wake(struct mctrl_gpios *gpios)370{371 enum mctrl_gpio_idx i;372 373 if (!gpios)374 return;375 376 if (!gpios->mctrl_on)377 return;378 379 for (i = 0; i < UART_GPIO_MAX; ++i) {380 if (!gpios->irq[i])381 continue;382 383 disable_irq_wake(gpios->irq[i]);384 }385}386EXPORT_SYMBOL_GPL(mctrl_gpio_disable_irq_wake);387 388MODULE_DESCRIPTION("Helpers for controlling modem lines via GPIO");389MODULE_LICENSE("GPL");390