From fe6b92f8b700db5310164339e71110953a59e110 Mon Sep 17 00:00:00 2001
From: "Luke T. Shumaker" <lukeshu@lukeshu.com>
Date: Sun, 2 Mar 2025 13:38:44 -0700
Subject: libhw: w5500: Re-add SPI validation

This reverts commit 063f263f84d517c6497e7ca37f503956bad7075a.
---
 libhw/w5500.c | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'libhw/w5500.c')

diff --git a/libhw/w5500.c b/libhw/w5500.c
index b4ad86b..fafc846 100644
--- a/libhw/w5500.c
+++ b/libhw/w5500.c
@@ -312,6 +312,15 @@ void _w5500_init(struct w5500 *chip,
 		};
 	}
 
+	/* Validate that SPI works correctly.  */
+	for (uint16_t a = 0; a < 0x100; a++) {
+		w5500ll_write_sock_reg(chip->spidev, 0, mode, a);
+		uint8_t b = w5500ll_read_sock_reg(chip->spidev, 0, mode);
+		if (b != a)
+			errorf("SPI to W5500 does not appear to be functional: wrote:%d != read:%d", a, b);
+	}
+	w5500ll_write_sock_reg(chip->spidev, 0, mode, 0);
+
 	/* Initialize the hardware.  */
 	gpioirq_set_and_enable_exclusive_handler(pin_intr, GPIO_IRQ_EDGE_FALL, w5500_intrhandler, chip);
 	gpio_set_dir(chip->pin_reset, GPIO_OUT);
-- 
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