dm: Expand and complete Kconfig in drivers/

Expand the help messages for each driver. Add missing Kconfig for I2C,
SPI flash and thermal.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

doc/driver-model/spi-howto.txt

@@ -40,8 +40,8 @@ with only minor changes:
 
 Add these to your board config:
 
-#define CONFIG_DM_SPI
-#define CONFIG_DM_SPI_FLASH
+CONFIG_DM_SPI
+CONFIG_DM_SPI_FLASH
 
 
 2. Add the skeleton

drivers/Kconfig

@@ -50,4 +50,6 @@ source "drivers/dma/Kconfig"
 
 source "drivers/crypto/Kconfig"
 
+source "drivers/thermal/Kconfig"
+
 endmenu

drivers/core/Kconfig

@@ -2,5 +2,7 @@ config DM
 	bool "Enable Driver Model"
 	depends on !SPL_BUILD
 	help
-	  This config option enables Driver Model.
-	  To use legacy drivers, say N.
+	  This config option enables Driver Model. This brings in the core
+	  support, including scanning of platform data on start-up. If
+	  CONFIG_OF_CONTROL is enabled, the device tree will be scanned also
+	  when available.

drivers/gpio/Kconfig

@@ -2,5 +2,8 @@ config DM_GPIO
 	bool "Enable Driver Model for GPIO drivers"
 	depends on DM
 	help
-	  If you want to use driver model for GPIO drivers, say Y.
-	  To use legacy GPIO drivers, say N.
+	  Enable driver model for GPIO access. The standard GPIO
+	  interface (gpio_get_value(), etc.) is then implemented by
+	  the GPIO uclass. Drivers provide methods to query the
+	  particular GPIOs that they provide. The uclass interface
+	  is defined in include/asm-generic/gpio.h.

drivers/i2c/Kconfig

@@ -2,8 +2,16 @@ config DM_I2C
 	bool "Enable Driver Model for I2C drivers"
 	depends on DM
 	help
-	  If you want to use driver model for I2C drivers, say Y.
-	  To use legacy I2C drivers, say N.
+	  Enable driver model for I2C. This SPI flash interface
+	  (spi_flash_probe(), spi_flash_write(), etc.) is then
+	  implemented by the SPI flash uclass. There is one standard
+	  SPI flash driver which knows how to probe most chips
+	  supported by U-Boot. The uclass interface is defined in
+	  include/spi_flash.h, but is currently fully compatible
+	  with the old interface to avoid confusion and duplication
+	  during the transition parent. SPI and SPI flash must be
+	  enabled together (it is not possible to use driver model
+	  for one and not the other).
 
 config SYS_I2C_UNIPHIER
 	bool "UniPhier I2C driver"

drivers/misc/Kconfig

@@ -0,0 +1,9 @@
+config DM_CROS_EC
+	bool "Enable Driver Model for Chrome OS EC"
+	depends on DM
+	help
+	  Enable driver model for the Chrome OS EC interface. This
+	  allows the cros_ec SPI driver to operate with CONFIG_DM_SPI
+	  but otherwise makes few changes. Since cros_ec also supports
+	  I2C and LPC (which don't support driver model yet), a full
+	  conversion is not yet possible.

drivers/mtd/Kconfig

@@ -1 +1,3 @@
 source "drivers/mtd/nand/Kconfig"
+
+source "drivers/mtd/spi/Kconfig"

drivers/mtd/spi/Kconfig

@@ -0,0 +1,14 @@
+config DM_SPI_FLASH
+	bool "Enable Driver Model for SPI flash"
+	depends on DM && SPI
+	help
+	  Enable driver model for SPI flash. This SPI flash interface
+	  (spi_flash_probe(), spi_flash_write(), etc.) is then
+	  implemented by the SPI flash uclass. There is one standard
+	  SPI flash driver which knows how to probe most chips
+	  supported by U-Boot. The uclass interface is defined in
+	  include/spi_flash.h, but is currently fully compatible
+	  with the old interface to avoid confusion and duplication
+	  during the transition parent. SPI and SPI flash must be
+	  enabled together (it is not possible to use driver model
+	  for one and not the other).

drivers/serial/Kconfig

@@ -2,8 +2,10 @@ config DM_SERIAL
 	bool "Enable Driver Model for serial drivers"
 	depends on DM
 	help
-	  If you want to use driver model for serial drivers, say Y.
-	  To use legacy serial drivers, say N.
+	  Enable driver model for serial. This replaces
+	  drivers/serial/serial.c with the serial uclass, which
+	  implements serial_putc() etc. The uclass interface is
+	  defined in include/serial.h.
 
 config UNIPHIER_SERIAL
 	bool "UniPhier on-chip UART support"

drivers/spi/Kconfig

@@ -2,5 +2,11 @@ config DM_SPI
 	bool "Enable Driver Model for SPI drivers"
 	depends on DM
 	help
-	  If you want to use driver model for SPI drivers, say Y.
-	  To use legacy SPI drivers, say N.
+	  Enable driver model for SPI. The SPI slave interface
+	  (spi_setup_slave(), spi_xfer(), etc.) is then implemented by
+	  the SPI uclass. Drivers provide methods to access the SPI
+	  buses that they control. The uclass interface is defined in
+	  include/spi.h. The existing spi_slave structure is attached
+	  as 'parent data' to every slave on each bus. Slaves
+	  typically use driver-private data instead of extending the
+	  spi_slave structure.

drivers/thermal/Kconfig

@@ -0,0 +1,7 @@
+config DM_THERMAL
+	bool "Driver support for thermal devices"
+	help
+	  Enable support for temporary-sensing devices. Some SoCs have on-chip
+	  temperature sensors to permit warnings, speed throttling or even
+	  automatic power-off when the temperature gets too high or low. Other
+	  devices may be discrete but connected on a suitable bus.