drivers/flash: A support for SPI gpio-cs logic into w25qxxdv driver

Up to SPI API user code to handle providing the right SPI GPIO-CS
parameters now.

Signed-off-by: Tomasz Bursztyka <[email protected]>

Author: Tomasz Bursztyka

drivers/flash/Kconfig

@@ -79,6 +79,30 @@ config	SPI_FLASH_W25QXXDV_SPI_SLAVE
 	  This option sets the SPI slave number the SPI controller has to switch
 	  to when dealing with WinBond SPI flash chip.
 
+config SPI_FLASH_W25QXXDV_GPIO_SPI_CS
+	bool "Manage SPI CS through a GPIO pin"
+	default n
+	depends on SPI_FLASH_W25QXXDV
+	help
+	This option is useful if one needs to manage SPI CS through a GPIO
+	pin to by-pass the SPI controller's CS logic.
+
+config SPI_FLASH_W25QXXDV_GPIO_SPI_CS_DRV_NAME
+	string "GPIO driver's name to use to drive SPI CS through"
+	default ""
+	depends on SPI_FLASH_W25QXXDV_GPIO_SPI_CS
+	help
+	This option is mandatory to set which GPIO controller to use in order
+	to actually emulate the SPI CS.
+
+config SPI_FLASH_W25QXXDV_GPIO_SPI_CS_PIN
+	int "GPIO PIN to use to drive SPI CS through"
+	default 0
+	depends on SPI_FLASH_W25QXXDV_GPIO_SPI_CS
+	help
+	This option is mandatory to set which GPIO pin to use in order
+	to actually emulate the SPI CS.
+
 config SPI_FLASH_W25QXXDV_FLASH_SIZE
 	int "Flash size in bytes"
 	depends on SPI_FLASH_W25QXXDV

drivers/flash/spi_flash_w25qxxdv.c

@@ -325,6 +325,19 @@ static int spi_flash_wb_configure(struct device *dev)
 	data->spi_cfg.operation = SPI_WORD_SET(8);
 	data->spi_cfg.slave = CONFIG_SPI_FLASH_W25QXXDV_SPI_SLAVE;
 
+#if defined(CONFIG_SPI_FLASH_W25QXXDV_GPIO_SPI_CS)
+	data->cs_ctrl.gpio_dev = device_get_binding(
+		CONFIG_SPI_FLASH_W25QXXDV_GPIO_SPI_CS_DRV_NAME);
+	if (!data->cs_ctrl.gpio_dev) {
+		return -ENODEV;
+	}
+
+	data->cs_ctrl.gpio_pin = CONFIG_SPI_FLASH_W25QXXDV_GPIO_SPI_CS_PIN;
+	data->cs_ctrl.delay = 0;
+
+	data->spi_cfg.cs = &data->cs_ctrl;
+#endif /* CONFIG_SPI_FLASH_W25QXXDV_GPIO_SPI_CS */
+
 	return spi_flash_wb_id(dev);
 }
 
@@ -336,7 +349,7 @@ static int spi_flash_init(struct device *dev)
 	k_sem_init(&data->sem, 1, UINT_MAX);
 
 	ret = spi_flash_wb_configure(dev);
-	if (ret) {
+	if (!ret) {
 		dev->driver_api = &spi_flash_api;
 	}
 

drivers/flash/spi_flash_w25qxxdv.h

@@ -16,6 +16,9 @@
 
 struct spi_flash_data {
 	struct device *spi;
+#if defined(CONFIG_SPI_FLASH_W25QXXDV_GPIO_SPI_CS)
+	struct spi_cs_control cs_ctrl;
+#endif /* CONFIG_SPI_FLASH_W25QXXDV_GPIO_SPI_CS */
 	struct spi_config spi_cfg;
 	struct k_sem sem;
 };