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,