gpio updates for v5.7 part 4

- improve comments in the uapi header
 - fix documentation issues
 - add a warning to gpio-pl061 when the IRQ line is not configured
 - allow building gpio-mxc and gpio-mxs with COMPILE_TEST enabled
 - don't print an error message when an optional IRQ is missing in gpio-mvebu
 - fix a potential segfault in gpio-hammer
 - fix a couple typos and coding style issues in gpio tools
 - provide a new flag in gpio-mmio and use it in mt7621 to fix an issue with
   the controller ignoring value setting when a GPIO is in input mode
 - slightly refactor gpio_name_to_desc()
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Merge tag 'gpio-updates-for-v5.7-part4' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux into devel

gpio updates for v5.7 part 4

- improve comments in the uapi header
- fix documentation issues
- add a warning to gpio-pl061 when the IRQ line is not configured
- allow building gpio-mxc and gpio-mxs with COMPILE_TEST enabled
- don't print an error message when an optional IRQ is missing in gpio-mvebu
- fix a potential segfault in gpio-hammer
- fix a couple typos and coding style issues in gpio tools
- provide a new flag in gpio-mmio and use it in mt7621 to fix an issue with
  the controller ignoring value setting when a GPIO is in input mode
- slightly refactor gpio_name_to_desc()

Documentation/driver-api/gpio/driver.rst

@@ -416,7 +416,7 @@ The preferred way to set up the helpers is to fill in the
 struct gpio_irq_chip inside struct gpio_chip before adding the gpio_chip.
 If you do this, the additional irq_chip will be set up by gpiolib at the
 same time as setting up the rest of the GPIO functionality. The following
-is a typical example of a cascaded interrupt handler using gpio_irq_chip::
+is a typical example of a cascaded interrupt handler using gpio_irq_chip:
 
 .. code-block:: c
 
@@ -453,7 +453,7 @@ is a typical example of a cascaded interrupt handler using gpio_irq_chip::
   return devm_gpiochip_add_data(dev, &g->gc, g);
 
 The helper support using hierarchical interrupt controllers as well.
-In this case the typical set-up will look like this::
+In this case the typical set-up will look like this:
 
 .. code-block:: c
 

drivers/gpio/Kconfig

@@ -394,13 +394,13 @@ config GPIO_MVEBU
 
 config GPIO_MXC
 	def_bool y
-	depends on ARCH_MXC
+	depends on ARCH_MXC || COMPILE_TEST
 	select GPIO_GENERIC
 	select GENERIC_IRQ_CHIP
 
 config GPIO_MXS
 	def_bool y
-	depends on ARCH_MXS
+	depends on ARCH_MXS || COMPILE_TEST
 	select GPIO_GENERIC
 	select GENERIC_IRQ_CHIP
 

drivers/gpio/gpio-mmio.c

@@ -389,12 +389,10 @@ static int bgpio_get_dir(struct gpio_chip *gc, unsigned int gpio)
 	return GPIO_LINE_DIRECTION_IN;
 }
 
-static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+static void bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 {
 	unsigned long flags;
 
-	gc->set(gc, gpio, val);
-
 	spin_lock_irqsave(&gc->bgpio_lock, flags);
 
 	gc->bgpio_dir |= bgpio_line2mask(gc, gpio);
@@ -405,7 +403,21 @@ static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 		gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);
 
 	spin_unlock_irqrestore(&gc->bgpio_lock, flags);
+}
 
+static int bgpio_dir_out_dir_first(struct gpio_chip *gc, unsigned int gpio,
+				   int val)
+{
+	bgpio_dir_out(gc, gpio, val);
+	gc->set(gc, gpio, val);
+	return 0;
+}
+
+static int bgpio_dir_out_val_first(struct gpio_chip *gc, unsigned int gpio,
+				   int val)
+{
+	gc->set(gc, gpio, val);
+	bgpio_dir_out(gc, gpio, val);
 	return 0;
 }
 
@@ -538,7 +550,10 @@ static int bgpio_setup_direction(struct gpio_chip *gc,
 	if (dirout || dirin) {
 		gc->reg_dir_out = dirout;
 		gc->reg_dir_in = dirin;
-		gc->direction_output = bgpio_dir_out;
+		if (flags & BGPIOF_NO_SET_ON_INPUT)
+			gc->direction_output = bgpio_dir_out_dir_first;
+		else
+			gc->direction_output = bgpio_dir_out_val_first;
 		gc->direction_input = bgpio_dir_in;
 		gc->get_direction = bgpio_get_dir;
 	} else {

drivers/gpio/gpio-mt7621.c

@@ -227,8 +227,8 @@ mediatek_gpio_bank_probe(struct device *dev,
 	ctrl = mtk->base + GPIO_REG_DCLR + (rg->bank * GPIO_BANK_STRIDE);
 	diro = mtk->base + GPIO_REG_CTRL + (rg->bank * GPIO_BANK_STRIDE);
 
-	ret = bgpio_init(&rg->chip, dev, 4,
-			 dat, set, ctrl, diro, NULL, 0);
+	ret = bgpio_init(&rg->chip, dev, 4, dat, set, ctrl, diro, NULL,
+			 BGPIOF_NO_SET_ON_INPUT);
 	if (ret) {
 		dev_err(dev, "bgpio_init() failed\n");
 		return ret;

drivers/gpio/gpio-mvebu.c

@@ -1247,7 +1247,7 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
 	 * pins.
 	 */
 	for (i = 0; i < 4; i++) {
-		int irq = platform_get_irq(pdev, i);
+		int irq = platform_get_irq_optional(pdev, i);
 
 		if (irq < 0)
 			continue;

drivers/gpio/gpio-pl061.c

@@ -326,10 +326,8 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 
 	writeb(0, pl061->base + GPIOIE); /* disable irqs */
 	irq = adev->irq[0];
-	if (irq < 0) {
-		dev_err(&adev->dev, "invalid IRQ\n");
-		return -ENODEV;
-	}
+	if (!irq)
+		dev_warn(&adev->dev, "IRQ support disabled\n");
 	pl061->parent_irq = irq;
 
 	girq = &pl061->gc.irq;

drivers/gpio/gpiolib.c

@@ -301,6 +301,9 @@ static struct gpio_desc *gpio_name_to_desc(const char * const name)
 	struct gpio_device *gdev;
 	unsigned long flags;
 
+	if (!name)
+		return NULL;
+
 	spin_lock_irqsave(&gpio_lock, flags);
 
 	list_for_each_entry(gdev, &gpio_devices, list) {
@@ -309,7 +312,7 @@ static struct gpio_desc *gpio_name_to_desc(const char * const name)
 		for (i = 0; i != gdev->ngpio; ++i) {
 			struct gpio_desc *desc = &gdev->descs[i];
 
-			if (!desc->name || !name)
+			if (!desc->name)
 				continue;
 
 			if (!strcmp(desc->name, name)) {

include/linux/gpio/driver.h

@@ -572,6 +572,7 @@ int bgpio_init(struct gpio_chip *gc, struct device *dev,
 #define BGPIOF_BIG_ENDIAN_BYTE_ORDER	BIT(3)
 #define BGPIOF_READ_OUTPUT_REG_SET	BIT(4) /* reg_set stores output value */
 #define BGPIOF_NO_OUTPUT		BIT(5) /* only input */
+#define BGPIOF_NO_SET_ON_INPUT		BIT(6)
 
 int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
 		     irq_hw_number_t hwirq);

include/uapi/linux/gpio.h

@@ -18,7 +18,7 @@
  * struct gpiochip_info - Information about a certain GPIO chip
  * @name: the Linux kernel name of this GPIO chip
  * @label: a functional name for this GPIO chip, such as a product
- * number, may be NULL
+ * number, may be empty
  * @lines: number of GPIO lines on this chip
  */
 struct gpiochip_info {
@@ -44,10 +44,10 @@ struct gpiochip_info {
  * @flags: various flags for this line
  * @name: the name of this GPIO line, such as the output pin of the line on the
  * chip, a rail or a pin header name on a board, as specified by the gpio
- * chip, may be NULL
+ * chip, may be empty
  * @consumer: a functional name for the consumer of this GPIO line as set by
- * whatever is using it, will be NULL if there is no current user but may
- * also be NULL if the consumer doesn't set this up
+ * whatever is using it, will be empty if there is no current user but may
+ * also be empty if the consumer doesn't set this up
  */
 struct gpioline_info {
 	__u32 line_offset;

tools/gpio/gpio-hammer.c

@@ -77,7 +77,7 @@ int hammer_device(const char *device_name, unsigned int *lines, int nlines,
 
 		fprintf(stdout, "[%c] ", swirr[j]);
 		j++;
-		if (j == sizeof(swirr)-1)
+		if (j == sizeof(swirr) - 1)
 			j = 0;
 
 		fprintf(stdout, "[");
@@ -135,7 +135,14 @@ int main(int argc, char **argv)
 			device_name = optarg;
 			break;
 		case 'o':
-			lines[i] = strtoul(optarg, NULL, 10);
+			/*
+			 * Avoid overflow. Do not immediately error, we want to
+			 * be able to accurately report on the amount of times
+			 * '-o' was given to give an accurate error message
+			 */
+			if (i < GPIOHANDLES_MAX)
+				lines[i] = strtoul(optarg, NULL, 10);
+
 			i++;
 			break;
 		case '?':
@@ -143,6 +150,14 @@ int main(int argc, char **argv)
 			return -1;
 		}
 	}
+
+	if (i >= GPIOHANDLES_MAX) {
+		fprintf(stderr,
+			"Only %d occurrences of '-o' are allowed, %d were found\n",
+			GPIOHANDLES_MAX, i + 1);
+		return -1;
+	}
+
 	nlines = i;
 
 	if (!device_name || !nlines) {

tools/gpio/gpio-utils.c

@@ -17,7 +17,7 @@
 #include <linux/gpio.h>
 #include "gpio-utils.h"
 
-#define COMSUMER "gpio-utils"
+#define CONSUMER "gpio-utils"
 
 /**
  * doc: Operation of gpio
@@ -209,7 +209,7 @@ int gpiotools_gets(const char *device_name, unsigned int *lines,
 
 	ret = gpiotools_request_linehandle(device_name, lines, nlines,
 					   GPIOHANDLE_REQUEST_INPUT, data,
-					   COMSUMER);
+					   CONSUMER);
 	if (ret < 0)
 		return ret;
 
@@ -259,7 +259,7 @@ int gpiotools_sets(const char *device_name, unsigned int *lines,
 
 	ret = gpiotools_request_linehandle(device_name, lines, nlines,
 					   GPIOHANDLE_REQUEST_OUTPUT, data,
-					   COMSUMER);
+					   CONSUMER);
 	if (ret < 0)
 		return ret;