linux-kernel - [PATCH 3/3] ARM: davinci: hawk: use gpio descriptor for card detect

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Date:   Mon, 21 Nov 2016 17:15:41 +0100
From:   Axel Haslam <ahaslam@...libre.com>
To:     nsekhar@...com, khilman@...nel.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Axel Haslam <ahaslam@...libre.com>
Subject: [PATCH 3/3] ARM: davinci: hawk: use gpio descriptor for card detect

Currently the mmc driver is polling the gpio to know if the
card was removed.

By using a gpio descriptor instead of the platform callbacks, the
driver will be able to register the gpio with the mmc core with API's
designed for this purpose.

This has the advantage that an irq will be registered,
and polling is no longer needed. Also, platform callbacks can be removed.

Signed-off-by: Axel Haslam <ahaslam@...libre.com>
---
 arch/arm/mach-davinci/board-omapl138-hawk.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/arch/arm/mach-davinci/board-omapl138-hawk.c b/arch/arm/mach-davinci/board-omapl138-hawk.c
index ddc312d..8e4f2102 100644
--- a/arch/arm/mach-davinci/board-omapl138-hawk.c
+++ b/arch/arm/mach-davinci/board-omapl138-hawk.c
@@ -15,6 +15,7 @@
 #include <linux/gpio.h>
 #include <linux/platform_data/gpio-davinci.h>
 #include <linux/regulator/machine.h>
+#include <linux/gpio/machine.h>
 
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
@@ -25,7 +26,6 @@
 #include <mach/mux.h>
 
 #define HAWKBOARD_PHY_ID		"davinci_mdio-0:07"
-#define DA850_HAWK_MMCSD_CD_PIN		GPIO_TO_PIN(4, 0)
 
 #define DA850_USB1_VBUS_PIN		GPIO_TO_PIN(2, 4)
 #define DA850_USB1_OC_PIN		GPIO_TO_PIN(6, 13)
@@ -122,13 +122,16 @@ static const short hawk_mmcsd0_pins[] = {
 	-1
 };
 
-static int da850_hawk_mmc_get_cd(int index)
-{
-	return !gpio_get_value(DA850_HAWK_MMCSD_CD_PIN);
-}
+static struct gpiod_lookup_table mmc_gpios_table = {
+	.dev_id = "da830-mmc.0",
+	.table = {
+		/* gpio4_0: chip 2 contains gpio range 64-95 */
+		GPIO_LOOKUP("davinci_gpio.2", 0, "cd",
+				GPIO_ACTIVE_LOW),
+	},
+};
 
 static struct davinci_mmc_config da850_mmc_config = {
-	.get_cd		= da850_hawk_mmc_get_cd,
 	.wires		= 4,
 	.max_freq	= 50000000,
 	.caps		= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED,
@@ -144,13 +147,7 @@ static __init void omapl138_hawk_mmc_init(void)
 		return;
 	}
 
-	ret = gpio_request_one(DA850_HAWK_MMCSD_CD_PIN,
-			GPIOF_DIR_IN, "MMC CD");
-	if (ret < 0) {
-		pr_warn("%s: can not open GPIO %d\n",
-			__func__, DA850_HAWK_MMCSD_CD_PIN);
-		return;
-	}
+	gpiod_add_lookup_table(&mmc_gpios_table);
 
 	ret = da8xx_register_mmcsd0(&da850_mmc_config);
 	if (ret) {
@@ -161,7 +158,7 @@ static __init void omapl138_hawk_mmc_init(void)
 	return;
 
 mmc_setup_mmcsd_fail:
-	gpio_free(DA850_HAWK_MMCSD_CD_PIN);
+	gpiod_remove_lookup_table(&mmc_gpios_table);
 }
 
 static irqreturn_t omapl138_hawk_usb_ocic_irq(int irq, void *dev_id);
-- 
2.9.3