[PATCH] [RFC] gpiolib: introduce gpio_name() helper

[Arnd Bergmann <arnd@kernel.org>]

From: Arnd Bergmann <arnd@arndb.de>

Most remaining users of desc_to_gpio() only call it for printing debug
information.

Replace this with a new gpiod_name() helper that returns the
gpio_desc->name string after checking the gpio_desc pointer.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---

Not sure if this the way we want to take this, or if the gpio name is
an appropriate replacement in debug printk.

Since most of the callers of desc_to_gpio() and gpio_to_desc() are
otherwise in drivers that already depend on CONFIG_GPIOLIB_LEGACY and
include linux/gpio/legacy.h, only a handful of instances remain that
are otherwise in files that otherwise only use the descriptor interfaces:

arch/arm/mach-pxa/pxa27x.c:	reset_gpio = desc_to_gpio(gpiod);
arch/arm/plat-orion/gpio.c:	unsigned gpio = desc_to_gpio(desc);
drivers/gpio/gpio-nomadik.c:		mode = nmk_prcm_gpiocr_get_mode(pctldev, desc_to_gpio(desc));
drivers/gpio/gpiolib-acpi-core.c:			desc = gpio_to_desc(agpio->pin_table[pin_index]);
drivers/gpio/gpiolib-cdev.c:	hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
drivers/gpio/gpiolib-sysfs.c:	desc = gpio_to_desc(gpio);
drivers/gpio/gpiolib-sysfs.c:						   desc_to_gpio(desc));
drivers/gpio/gpiolib.c:	trace_gpio_direction(desc_to_gpio(desc), 1, ret);
drivers/input/misc/soc_button_array.c:	*gpio_ret = desc_to_gpio(desc);
drivers/pinctrl/core.c:			gdev = gpiod_to_gpio_device(gpio_to_desc(gpio_num));
drivers/platform/x86/x86-android-tablets/core.c: * 2. Calling desc_to_gpio() to get an old style GPIO number for gpio-keys
drivers/soc/fsl/qe/gpio.c:	gpio_num = desc_to_gpio(gpiod);
---
 drivers/bluetooth/hci_intel.c             |  4 ++--
 drivers/extcon/extcon-rtk-type-c.c        |  4 ++--
 drivers/gpio/gpio-aggregator.c            |  4 ++--
 drivers/gpio/gpiolib.c                    | 13 +++++++++++++
 drivers/gpu/drm/bridge/analogix/anx7625.c |  6 +++---
 drivers/i2c/busses/i2c-gpio.c             |  4 ++--
 drivers/iio/accel/mma9551.c               |  4 ++--
 drivers/iio/humidity/dht11.c              |  2 +-
 drivers/input/touchscreen/edt-ft5x06.c    |  6 +++---
 drivers/input/touchscreen/hycon-hy46xx.c  |  5 ++---
 drivers/mmc/host/atmel-mci.c              |  8 ++++----
 drivers/power/supply/bq24257_charger.c    |  2 +-
 drivers/usb/gadget/udc/at91_udc.c         |  4 ++--
 include/linux/gpio/consumer.h             |  8 ++++++++
 14 files changed, 47 insertions(+), 27 deletions(-)

diff --git a/drivers/bluetooth/hci_intel.c b/drivers/bluetooth/hci_intel.c
index c31105b91e47..2e6ebc152bcb 100644
--- a/drivers/bluetooth/hci_intel.c
+++ b/drivers/bluetooth/hci_intel.c
@@ -1176,8 +1176,8 @@ static int intel_probe(struct platform_device *pdev)
 	list_add_tail(&idev->list, &intel_device_list);
 	mutex_unlock(&intel_device_list_lock);
 
-	dev_info(&pdev->dev, "registered, gpio(%d)/irq(%d).\n",
-		 desc_to_gpio(idev->reset), idev->irq);
+	dev_info(&pdev->dev, "registered, gpio(%s)/irq(%d).\n",
+		 gpiod_name(idev->reset), idev->irq);
 
 	return 0;
 }
diff --git a/drivers/extcon/extcon-rtk-type-c.c b/drivers/extcon/extcon-rtk-type-c.c
index 82b60b927e41..fb57e9d7ddb6 100644
--- a/drivers/extcon/extcon-rtk-type-c.c
+++ b/drivers/extcon/extcon-rtk-type-c.c
@@ -1356,8 +1356,8 @@ static int extcon_rtk_type_c_probe(struct platform_device *pdev)
 				(int)PTR_ERR(gpio));
 		} else {
 			type_c->rd_ctrl_gpio_desc = gpio;
-			dev_dbg(dev, "%s get rd-ctrl-gpios (id=%d) OK\n",
-				__func__, desc_to_gpio(gpio));
+			dev_dbg(dev, "%s get rd-ctrl-gpios (id=%s) OK\n",
+				__func__, gpiod_name(gpio));
 		}
 	}
 
diff --git a/drivers/gpio/gpio-aggregator.c b/drivers/gpio/gpio-aggregator.c
index bc6699a821ee..27df680fbdbb 100644
--- a/drivers/gpio/gpio-aggregator.c
+++ b/drivers/gpio/gpio-aggregator.c
@@ -758,8 +758,8 @@ int gpiochip_fwd_desc_add(struct gpiochip_fwd *fwd, struct gpio_desc *desc,
 
 	fwd->descs[offset] = desc;
 
-	dev_dbg(chip->parent, "%u => gpio %d irq %d\n", offset,
-		desc_to_gpio(desc), gpiod_to_irq(desc));
+	dev_dbg(chip->parent, "%u => gpio %s irq %d\n", offset,
+		gpiod_name(desc), gpiod_to_irq(desc));
 
 	return 0;
 }
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 1f498d6c8c68..00de24db74a5 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -4122,6 +4122,19 @@ int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name)
 }
 EXPORT_SYMBOL_GPL(gpiod_set_consumer_name);
 
+/**
+ * gpiod_name() - get a name to print for a gpio descriptor
+ * @desc: gpio or NULL pointer to query
+ *
+ * Returns:
+ * The desc->name field or a dummy string for unknown GPIOs.
+ */
+const char *gpiod_name(const struct gpio_desc *desc)
+{
+	return desc ? desc->name : "(no gpio)";
+}
+EXPORT_SYMBOL_GPL(gpiod_name);
+
 /**
  * gpiod_is_shared() - check if this GPIO can be shared by multiple consumers
  * @desc: GPIO to inspect
diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index fffcd6154c71..5dce097d4045 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1448,9 +1448,9 @@ static void anx7625_init_gpio(struct anx7625_data *platform)
 
 	if (platform->pdata.gpio_p_on && platform->pdata.gpio_reset) {
 		platform->pdata.low_power_mode = 1;
-		DRM_DEV_DEBUG_DRIVER(dev, "low power mode, pon %d, reset %d.\n",
-				     desc_to_gpio(platform->pdata.gpio_p_on),
-				     desc_to_gpio(platform->pdata.gpio_reset));
+		DRM_DEV_DEBUG_DRIVER(dev, "low power mode, pon %s, reset %s.\n",
+				     gpiod_name(platform->pdata.gpio_p_on),
+				     gpiod_name(platform->pdata.gpio_reset));
 	} else {
 		platform->pdata.low_power_mode = 0;
 		DRM_DEV_DEBUG_DRIVER(dev, "not low power mode.\n");
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index f4355b17bfbf..4c320a833d9e 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -440,8 +440,8 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	 * get accessors to get the actual name of the GPIO line,
 	 * from the descriptor, then provide that instead.
 	 */
-	dev_info(dev, "using lines %u (SDA) and %u (SCL%s)\n",
-		 desc_to_gpio(priv->sda), desc_to_gpio(priv->scl),
+	dev_info(dev, "using lines %s (SDA) and %s (SCL%s)\n",
+		 gpiod_name(priv->sda), gpiod_name(priv->scl),
 		 pdata->scl_is_output_only
 		 ? ", no clock stretching" : "");
 
diff --git a/drivers/iio/accel/mma9551.c b/drivers/iio/accel/mma9551.c
index 020370b0ec07..b9d1fc3caf83 100644
--- a/drivers/iio/accel/mma9551.c
+++ b/drivers/iio/accel/mma9551.c
@@ -426,8 +426,8 @@ static int mma9551_gpio_probe(struct iio_dev *indio_dev)
 			return ret;
 		}
 
-		dev_dbg(dev, "gpio resource, no:%d irq:%d\n",
-			desc_to_gpio(gpio), data->irqs[i]);
+		dev_dbg(dev, "gpio resource, no:%s irq:%d\n",
+			gpiod_name(gpio), data->irqs[i]);
 	}
 
 	return 0;
diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c
index 980cb946bbf7..ca6b8c53e462 100644
--- a/drivers/iio/humidity/dht11.c
+++ b/drivers/iio/humidity/dht11.c
@@ -305,7 +305,7 @@ static int dht11_probe(struct platform_device *pdev)
 
 	dht11->irq = gpiod_to_irq(dht11->gpiod);
 	if (dht11->irq < 0) {
-		dev_err(dev, "GPIO %d has no interrupt\n", desc_to_gpio(dht11->gpiod));
+		dev_err(dev, "GPIO %s has no interrupt\n", gpiod_name(dht11->gpiod));
 		return -EINVAL;
 	}
 
diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
index d3b1177185a3..2d31c77614b0 100644
--- a/drivers/input/touchscreen/edt-ft5x06.c
+++ b/drivers/input/touchscreen/edt-ft5x06.c
@@ -1326,10 +1326,10 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client)
 	edt_ft5x06_ts_prepare_debugfs(tsdata);
 
 	dev_dbg(&client->dev,
-		"EDT FT5x06 initialized: IRQ %d, WAKE pin %d, Reset pin %d.\n",
+		"EDT FT5x06 initialized: IRQ %d, WAKE pin %s, Reset pin %s.\n",
 		client->irq,
-		tsdata->wake_gpio ? desc_to_gpio(tsdata->wake_gpio) : -1,
-		tsdata->reset_gpio ? desc_to_gpio(tsdata->reset_gpio) : -1);
+		gpiod_name(tsdata->wake_gpio),
+		gpiod_name(tsdata->reset_gpio));
 
 	return 0;
 }
diff --git a/drivers/input/touchscreen/hycon-hy46xx.c b/drivers/input/touchscreen/hycon-hy46xx.c
index 1513f20cbf51..797667c5dd99 100644
--- a/drivers/input/touchscreen/hycon-hy46xx.c
+++ b/drivers/input/touchscreen/hycon-hy46xx.c
@@ -528,9 +528,8 @@ static int hycon_hy46xx_probe(struct i2c_client *client)
 		return error;
 
 	dev_dbg(&client->dev,
-		"HYCON HY46XX initialized: IRQ %d, Reset pin %d.\n",
-		client->irq,
-		tsdata->reset_gpio ? desc_to_gpio(tsdata->reset_gpio) : -1);
+		"HYCON HY46XX initialized: IRQ %d, Reset pin %s.\n",
+		client->irq, gpiod_name(tsdata->reset_gpio));
 
 	return 0;
 }
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 3b4928f5b9b2..b21820564315 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -2255,11 +2255,11 @@ static int atmci_init_slot(struct atmel_mci *host,
 	slot->sdio_irq = sdio_irq;
 
 	dev_dbg(&mmc->class_dev,
-	        "slot[%u]: bus_width=%u, detect_pin=%d, "
-		"detect_is_active_high=%s, wp_pin=%d\n",
-		id, slot_data->bus_width, desc_to_gpio(slot_data->detect_pin),
+	        "slot[%u]: bus_width=%u, detect_pin=%s, "
+		"detect_is_active_high=%s, wp_pin=%s\n",
+		id, slot_data->bus_width, gpiod_name(slot_data->detect_pin),
 		str_true_false(!gpiod_is_active_low(slot_data->detect_pin)),
-		desc_to_gpio(slot_data->wp_pin));
+		gpiod_name(slot_data->wp_pin));
 
 	mmc->ops = &atmci_ops;
 	mmc->f_min = DIV_ROUND_UP(host->bus_hz, 512);
diff --git a/drivers/power/supply/bq24257_charger.c b/drivers/power/supply/bq24257_charger.c
index 72f1bfea8d54..b756bab74eec 100644
--- a/drivers/power/supply/bq24257_charger.c
+++ b/drivers/power/supply/bq24257_charger.c
@@ -868,7 +868,7 @@ static void bq24257_pg_gpio_probe(struct bq24257_device *bq)
 	}
 
 	if (bq->pg)
-		dev_dbg(bq->dev, "probed PG pin = %d\n", desc_to_gpio(bq->pg));
+		dev_dbg(bq->dev, "probed PG pin = %s\n", gpiod_name(bq->pg));
 }
 
 static int bq24257_fw_probe(struct bq24257_device *bq)
diff --git a/drivers/usb/gadget/udc/at91_udc.c b/drivers/usb/gadget/udc/at91_udc.c
index 5aa360ba4f03..099313604387 100644
--- a/drivers/usb/gadget/udc/at91_udc.c
+++ b/drivers/usb/gadget/udc/at91_udc.c
@@ -1896,8 +1896,8 @@ static int at91udc_probe(struct platform_device *pdev)
 					gpiod_to_irq(udc->board.vbus_pin),
 					at91_vbus_irq, 0, driver_name, udc);
 			if (retval) {
-				DBG("request vbus irq %d failed\n",
-				    desc_to_gpio(udc->board.vbus_pin));
+				DBG("request vbus irq %s failed\n",
+				    gpiod_name(udc->board.vbus_pin));
 				goto err_unprepare_iclk;
 			}
 		}
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index fceeefd5f893..9c91fae62f8c 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -172,6 +172,8 @@ int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name);
 
 bool gpiod_is_shared(const struct gpio_desc *desc);
 
+const char *gpiod_name(const struct gpio_desc *desc);
+
 /* Convert between the old gpio_ and new gpiod_ interfaces */
 struct gpio_desc *gpio_to_desc(unsigned gpio);
 int desc_to_gpio(const struct gpio_desc *desc);
@@ -538,6 +540,12 @@ static inline bool gpiod_is_shared(const struct gpio_desc *desc)
 	return false;
 }
 
+static inline const char *gpiod_name(const struct gpio_desc *desc)
+{
+	WARN_ON(desc);
+	return "(no gpio)";
+}
+
 static inline struct gpio_desc *gpio_to_desc(unsigned gpio)
 {
 	return NULL;
-- 
2.39.5