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serial: mctrl_gpio: implement interrupt handling
This allows to reduce the per-driver boiler plate considerably. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
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7d8c70d804
commit
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3 changed files with 171 additions and 3 deletions
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@ -439,11 +439,13 @@ Modem control lines via GPIO
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Some helpers are provided in order to set/get modem control lines via GPIO.
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mctrl_gpio_init(dev, idx):
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mctrl_gpio_init(port, idx):
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This will get the {cts,rts,...}-gpios from device tree if they are
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present and request them, set direction etc, and return an
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allocated structure. devm_* functions are used, so there's no need
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to call mctrl_gpio_free().
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As this sets up the irq handling make sure to not handle changes to the
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gpio input lines in your driver, too.
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mctrl_gpio_free(dev, gpios):
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This will free the requested gpios in mctrl_gpio_init().
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@ -458,3 +460,9 @@ mctrl_gpio_set(gpios, mctrl):
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mctrl_gpio_get(gpios, mctrl):
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This will update mctrl with the gpios values.
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mctrl_gpio_enable_ms(gpios):
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Enables irqs and handling of changes to the ms lines.
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mctrl_gpio_disable_ms(gpios):
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Disables irqs and handling of changes to the ms lines.
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@ -12,18 +12,23 @@
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/err.h>
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#include <linux/device.h>
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#include <linux/irq.h>
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#include <linux/gpio/consumer.h>
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#include <linux/termios.h>
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#include <linux/serial_core.h>
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#include "serial_mctrl_gpio.h"
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struct mctrl_gpios {
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struct uart_port *port;
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struct gpio_desc *gpio[UART_GPIO_MAX];
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int irq[UART_GPIO_MAX];
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unsigned int mctrl_prev;
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bool mctrl_on;
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};
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static const struct {
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@ -112,13 +117,133 @@ struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
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#define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
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static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
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{
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struct mctrl_gpios *gpios = context;
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struct uart_port *port = gpios->port;
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u32 mctrl = gpios->mctrl_prev;
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u32 mctrl_diff;
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mctrl_gpio_get(gpios, &mctrl);
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mctrl_diff = mctrl ^ gpios->mctrl_prev;
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gpios->mctrl_prev = mctrl;
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if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
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if ((mctrl_diff & mctrl) & TIOCM_RI)
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port->icount.rng++;
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if ((mctrl_diff & mctrl) & TIOCM_DSR)
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port->icount.dsr++;
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if (mctrl_diff & TIOCM_CD)
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uart_handle_dcd_change(port, mctrl & TIOCM_CD);
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if (mctrl_diff & TIOCM_CTS)
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uart_handle_cts_change(port, mctrl & TIOCM_CTS);
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wake_up_interruptible(&port->state->port.delta_msr_wait);
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}
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return IRQ_HANDLED;
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}
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struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
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{
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struct mctrl_gpios *gpios;
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enum mctrl_gpio_idx i;
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gpios = mctrl_gpio_init_noauto(port->dev, idx);
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if (IS_ERR(gpios))
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return gpios;
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gpios->port = port;
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for (i = 0; i < UART_GPIO_MAX; ++i) {
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int ret;
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if (!gpios->gpio[i] || mctrl_gpios_desc[i].dir_out)
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continue;
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ret = gpiod_to_irq(gpios->gpio[i]);
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if (ret <= 0) {
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dev_err(port->dev,
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"failed to find corresponding irq for %s (idx=%d, err=%d)\n",
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mctrl_gpios_desc[i].name, idx, ret);
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return ERR_PTR(ret);
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}
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gpios->irq[i] = ret;
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/* irqs should only be enabled in .enable_ms */
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irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
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ret = devm_request_irq(port->dev, gpios->irq[i],
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mctrl_gpio_irq_handle,
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IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
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gpios);
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if (ret) {
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/* alternatively implement polling */
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dev_err(port->dev,
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"failed to request irq for %s (idx=%d, err=%d)\n",
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mctrl_gpios_desc[i].name, idx, ret);
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return ERR_PTR(ret);
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}
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}
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return gpios;
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}
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void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
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{
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enum mctrl_gpio_idx i;
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for (i = 0; i < UART_GPIO_MAX; i++)
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for (i = 0; i < UART_GPIO_MAX; i++) {
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if (gpios->irq[i])
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devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
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if (gpios->gpio[i])
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devm_gpiod_put(dev, gpios->gpio[i]);
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}
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devm_kfree(dev, gpios);
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_free);
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void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
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{
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enum mctrl_gpio_idx i;
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/* .enable_ms may be called multiple times */
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if (gpios->mctrl_on)
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return;
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gpios->mctrl_on = true;
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/* get initial status of modem lines GPIOs */
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mctrl_gpio_get(gpios, &gpios->mctrl_prev);
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for (i = 0; i < UART_GPIO_MAX; ++i) {
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if (!gpios->irq[i])
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continue;
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enable_irq(gpios->irq[i]);
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}
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
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void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
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{
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enum mctrl_gpio_idx i;
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if (!gpios->mctrl_on)
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return;
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gpios->mctrl_on = false;
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for (i = 0; i < UART_GPIO_MAX; ++i) {
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if (!gpios->irq[i])
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continue;
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disable_irq(gpios->irq[i]);
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}
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}
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@ -22,6 +22,8 @@
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#include <linux/device.h>
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#include <linux/gpio/consumer.h>
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struct uart_port;
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enum mctrl_gpio_idx {
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UART_GPIO_CTS,
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UART_GPIO_DSR,
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@ -59,6 +61,15 @@ unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl);
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struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
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enum mctrl_gpio_idx gidx);
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/*
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* Request and set direction of modem control lines GPIOs and sets up irq
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* handling.
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* devm_* functions are used, so there's no need to call mctrl_gpio_free().
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* Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
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* allocation error.
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*/
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struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx);
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/*
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* Request and set direction of modem control lines GPIOs.
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* devm_* functions are used, so there's no need to call mctrl_gpio_free().
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@ -75,6 +86,16 @@ struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev,
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*/
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void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
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/*
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* Enable gpio interrupts to report status line changes.
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*/
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void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
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/*
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* Disable gpio interrupts to report status line changes.
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*/
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void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios);
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#else /* GPIOLIB */
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static inline
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@ -95,6 +116,12 @@ struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
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return ERR_PTR(-ENOSYS);
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}
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static inline
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struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
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{
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return ERR_PTR(-ENOSYS);
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}
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static inline
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struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
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{
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{
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}
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void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
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{
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}
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void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
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{
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}
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#endif /* GPIOLIB */
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#endif
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