mmc: core: expose the capability of gpio card detect

Add new helper API mmc_can_gpio_cd for slot-gpio to make
host drivers know whether it supports gpio card detect.

Signed-off-by: Shawn Lin <[e-mail]>
Signed-off-by: Jaehoon Chung <[e-mail]>
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/core/slot-gpio.c

···
 }
 EXPORT_SYMBOL(mmc_gpiod_request_cd);
 
+bool mmc_can_gpio_cd(struct mmc_host *host)
+{
+	struct mmc_gpio *ctx = host->slot.handler_priv;
+
+	return ctx->cd_gpio ? true : false;
+}
+EXPORT_SYMBOL(mmc_can_gpio_cd);
+
 /**
  * mmc_gpiod_request_ro - request a gpio descriptor for write protection
  * @host: mmc host

include/linux/mmc/slot-gpio.h

···
 void mmc_gpio_set_cd_isr(struct mmc_host *host,
 			 irqreturn_t (*isr)(int irq, void *dev_id));
 void mmc_gpiod_request_cd_irq(struct mmc_host *host);
+bool mmc_can_gpio_cd(struct mmc_host *host);
 
 #endif