[RFC PATCH v2 05/12] mtd: spi-nor: perform controller tuning during probe

[Santhosh Kumar K]

SPI controllers may need tuning for reliable high-speed operation.
Without it, controllers use conservative timing that limits performance.

Call spi_mem_execute_tuning() during probe to optimize timing for
the device's read operation. Failures are non-fatal as controllers
fall back to default timing.

Signed-off-by: Santhosh Kumar K <s-k6 at ti.com>
---
 drivers/mtd/spi-nor/core.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 63f3051d7a6b..d69cb8eaad83 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -3704,6 +3704,7 @@ static int spi_nor_probe(struct spi_mem *spimem)
 	struct device *dev = &spi->dev;
 	struct flash_platform_data *data = dev_get_platdata(dev);
 	struct spi_nor *nor;
+	struct spi_mem_op read_op;
 	/*
 	 * Enable all caps by default. The core will mask them after
 	 * checking what's really supported using spi_mem_supports_op().
@@ -3773,6 +3774,16 @@ static int spi_nor_probe(struct spi_mem *spimem)
 	if (ret)
 		return ret;
 
+	read_op = spi_nor_spimem_get_read_op(nor);
+	ret = spi_mem_execute_tuning(spimem, &read_op, NULL);
+	if (ret && ret != -EOPNOTSUPP) {
+		dev_warn(dev, "Failed to execute PHY tuning: %d\n", ret);
+		/*
+		 * Tuning failure is non-fatal; the controller falls back to
+		 * default timing, reducing speed but ensuring operation.
+		 */
+	}
+
 	return mtd_device_register(&nor->mtd, data ? data->parts : NULL,
 				   data ? data->nr_parts : 0);
 }
-- 
2.34.1