Merge tag 'gpio-v3.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio into next

Pull GPIO updates from Linus Walleij:
 "This is the bulk of GPIO changes for the v3.16 series.

  There is a lot of action in the GPIO subsystem doing refactorings and
  cleanups, almost as many deletions as insertions and minor feature
  growth and no new drivers this time.  Which is actually pretty nice.
  Some GPIO-related stuff will come in through the pin control tree as
  well.

  Details:

   - We are finalizing and fixing up the gpiochip irqchip helpers
     bringing a helpful irqchip implementation into the gpiolib core and
     avoiding duplicate code and, more importantly, duplicate bug fixes:

     * Support for using the helpers with threaded interrupt handlers as
       used on sleeping GPIO-irqchips

     * Do not set up hardware triggers for edges or levels if the
       default IRQ type is IRQ_TYPE_NONE - some drivers would exploit
       the fact that you could get default initialization of the IRQ
       type from the core at probe() but if no default type is set up
       from the helper, we should not call the driver to configure
       anything.  Wait until a consumer requests the interrupt instead.

     * Make the irqchip helpers put the GPIO irqs into their own lock
       class.  The GPIO irqchips can often emit (harmless, but annoying)
       lockdep warnings about recursions when they are in fact just
       cascaded IRQs.  By putting them into their own lock class we help
       the lockdep core to keep track of things.

     * Switch the tc3589x GPIO expanders to use the irqchip helpers

     * Switch the OMAP GPIO driver to use the irqchip helpers

     * Add some documentation for the irqchip helpers

     * select IRQ_DOMAIN when using the helpers since some platforms may
       not be using this by default and it's a strict dependency.

   - Continued GPIO descriptor refactoring:

     * Remove the one instance of gpio_to_desc() from the device tree
       code, making the OF GPIO code use GPIO descriptors only.

     * Introduce gpiod_get_optional() and gpiod_get_optional_index()
       akin to the similar regulator functions for cases where the use
       of GPIO is optional and not strictly required.

     * Make of_get_named_gpiod_flags() private - we do not want to
       unnecessarily expose APIs to drivers that make the gpiolib harder
       than necessary to maintain and refactor.  Privatize this
       function.

   - Support "-gpio" suffix for the OF GPIO retrieveal path.  We used to
     look for "foo-gpios" or just "gpios" in device tree nodes, but it
     turns out that some drivers with a single GPIO line will just state
     "foo-gpio" (singularis).  Sigh.  Support this with a fallback
     looking for it, as this simplifies driver code and handles it in
     core code.

   - Switch the ACPI GPIO core to fetch GPIOs with the *_cansleep
     function variants as the GPIO operation region handler can sleep,
     and shall be able to handle gpiochips that sleep.

   - Tons of cleanups and janitorial work from Jingoo Han, Axel Lin,
     Javier Martinez Canillas and Abdoulaye Berthe.  Notably Jingoo cut
     off a ton of pointless OOM messages.

   - Incremental development and fixes for various drivers, nothing
     really special here"

* tag 'gpio-v3.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (85 commits)
  gpio: select IRQ_DOMAIN for gpiolib irqchip helpers
  gpio: pca953x: use gpiolib irqchip helpers
  gpio: pcf857x: Add IRQF_SHARED when request irq
  gpio: pcf857x: Avoid calling irq_domain_cleanup twice
  gpio: mcp23s08: switch chip count to int
  gpio: dwapb: use a second irq chip
  gpio: ep93xx: Use devm_ioremap_resource()
  gpio: mcp23s08: fixed count variable for devicetree probing
  gpio: Add run-time dependencies to R-Car driver
  gpio: pch: add slab include
  Documentation / ACPI: Fix location of GPIO documentation
  gpio / ACPI: use *_cansleep version of gpiod_get/set APIs
  gpio: generic: add request function pointer
  gpio-pch: Fix Kconfig dependencies
  gpio: make of_get_named_gpiod_flags() private
  gpio: gpioep93xx: use devm functions
  gpio: janzttl: use devm function
  gpio: timberdale: use devm functions
  gpio: bt8xx: use devm function for memory allocation
  gpio: include linux/bug.h in interface header
  ...

1 files changed, 12 insertions, 5 deletions

diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c
index 3d53fd6880d1..fe7c0e211f9a 100644
--- a/drivers/gpio/gpio-mcp23s08.c
+++ b/drivers/gpio/gpio-mcp23s08.c
@@ -714,7 +714,7 @@ fail:
 
 #ifdef CONFIG_OF
 #ifdef CONFIG_SPI_MASTER
-static struct of_device_id mcp23s08_spi_of_match[] = {
+static const struct of_device_id mcp23s08_spi_of_match[] = {
 	{
 		.compatible = "microchip,mcp23s08",
 		.data = (void *) MCP_TYPE_S08,
@@ -738,7 +738,7 @@ MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
 #endif
 
 #if IS_ENABLED(CONFIG_I2C)
-static struct of_device_id mcp23s08_i2c_of_match[] = {
+static const struct of_device_id mcp23s08_i2c_of_match[] = {
 	{
 		.compatible = "microchip,mcp23008",
 		.data = (void *) MCP_TYPE_008,
@@ -867,7 +867,7 @@ static int mcp23s08_probe(struct spi_device *spi)
 {
 	struct mcp23s08_platform_data	*pdata;
 	unsigned			addr;
-	unsigned			chips = 0;
+	int				chips = 0;
 	struct mcp23s08_driver_data	*data;
 	int				status, type;
 	unsigned			base = -1,
@@ -894,11 +894,14 @@ static int mcp23s08_probe(struct spi_device *spi)
 			dev_err(&spi->dev, "invalid spi-present-mask\n");
 			return -ENODEV;
 		}
+
 		for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
-			if ((spi_present_mask & (1 << addr)))
-				chips++;
 			pullups[addr] = 0;
+			if (spi_present_mask & (1 << addr))
+				chips++;
 		}
+		if (!chips)
+			return -ENODEV;
 	} else {
 		type = spi_get_device_id(spi)->driver_data;
 		pdata = dev_get_platdata(&spi->dev);
@@ -937,6 +940,10 @@ static int mcp23s08_probe(struct spi_device *spi)
 		if (!(spi_present_mask & (1 << addr)))
 			continue;
 		chips--;
+		if (chips < 0) {
+			dev_err(&spi->dev, "FATAL: invalid negative chip id\n");
+			goto fail;
+		}
 		data->mcp[addr] = &data->chip[chips];
 		status = mcp23s08_probe_one(data->mcp[addr], &spi->dev, spi,
 					    0x40 | (addr << 1), type, base,