Am 2022-09-01 09:29, schrieb Sai Krishna Potthuri:
Add support for spi-nor flash reset via GPIO controller by reading the
reset-gpio property. If there is a valid GPIO specifier then reset will
be performed by asserting and deasserting the GPIO using gpiod APIs
otherwise it will not perform any operation.
Signed-off-by: Sai Krishna Potthuri <sai.krishna.potthuri@xxxxxxx>
Reviewed-by: Michael Walle <michael@xxxxxxxx>
Just one comment, see below
---
drivers/mtd/spi-nor/core.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index f2c64006f8d7..a78ab9bae2be 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -2933,6 +2933,27 @@ static void spi_nor_set_mtd_info(struct spi_nor
*nor)
mtd->_put_device = spi_nor_put_device;
}
+static int spi_nor_hw_reset(struct spi_nor *nor)
+{
+ struct gpio_desc *reset;
+
+ reset = devm_gpiod_get_optional(nor->dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR_OR_NULL(reset))
+ return PTR_ERR_OR_ZERO(reset);
+
+ /*
+ * Experimental delay values by looking at different flash device
+ * vendors datasheets.
+ */
+ usleep_range(1, 5);
I think this is superfluous, because parts of the kernel
will boot which should take longer than 1us. But I'm
fine with leaving it here.
-michael
+ gpiod_set_value_cansleep(reset, 1);
+ usleep_range(100, 150);
+ gpiod_set_value_cansleep(reset, 0);
+ usleep_range(1000, 1200);
+
+ return 0;
+}
+
int spi_nor_scan(struct spi_nor *nor, const char *name,
const struct spi_nor_hwcaps *hwcaps)
{
@@ -2965,6 +2986,10 @@ int spi_nor_scan(struct spi_nor *nor, const char
*name,
if (!nor->bouncebuf)
return -ENOMEM;
+ ret = spi_nor_hw_reset(nor);
+ if (ret)
+ return ret;
+
info = spi_nor_get_flash_info(nor, name);
if (IS_ERR(info))
return PTR_ERR(info);
