[PATCH v2] cmd: gpio: Make `gpio input` return pin value again

[Alex Kiernan]

4dbc107f4683 ("cmd: gpio: Correct do_gpio() return value") correctly
changed the behaviour of the gpio command to return CMD_RET_SUCCESS or
CMD_RET_FAILURE, but any existing script which expects the return value
to be the pin value is broken by this change.

Reinstate the legacy behaviour for `gpio input` only.

Fixes: 4dbc107f4683 ("cmd: gpio: Correct do_gpio() return value")
Signed-off-by: Alex Kiernan <alex.kiernan at gmail.com>
Signed-off-by: Alex Kiernan <alex.kiernan at hivehome.com>
Reviewed-by: Simon Glass <sjg at chromium.org>
---

Changes in v2:
- add test

 cmd/gpio.c                 |  7 ++++++-
 test/py/tests/test_gpio.py | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 test/py/tests/test_gpio.py

diff --git a/cmd/gpio.c b/cmd/gpio.c
index 16c2cebb3d4b..408a942455b5 100644
--- a/cmd/gpio.c
+++ b/cmd/gpio.c
@@ -248,7 +248,12 @@ static int do_gpio(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	if (ret != -EBUSY)
 		gpio_free(gpio);
 
-	return CMD_RET_SUCCESS;
+	/*
+	 * Whilst wrong, the legacy gpio input command returns the pin
+	 * value, or CMD_RET_FAILURE (which is indistinguishable from a
+	 * valid pin value).
+	 */
+	return (sub_cmd == GPIOC_INPUT) ? value : CMD_RET_SUCCESS;
 
 err:
 	if (ret != -EBUSY)
diff --git a/test/py/tests/test_gpio.py b/test/py/tests/test_gpio.py
new file mode 100644
index 000000000000..8c64f686b0ba
--- /dev/null
+++ b/test/py/tests/test_gpio.py
@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+import pytest
+
+ at pytest.mark.boardspec('sandbox')
+ at pytest.mark.buildconfigspec('cmd_gpio')
+def test_gpio_input(u_boot_console):
+    """Test that gpio input correctly returns the value of a gpio pin."""
+
+    response = u_boot_console.run_command('gpio input 0; echo rc:$?')
+    expected_response = 'rc:0'
+    assert(expected_response in response)
+    response = u_boot_console.run_command('gpio toggle 0; gpio input 0; echo rc:$?')
+    expected_response = 'rc:1'
+    assert(expected_response in response)
+
+ at pytest.mark.boardspec('sandbox')
+ at pytest.mark.buildconfigspec('cmd_gpio')
+def test_gpio_exit_statuses(u_boot_console):
+    """Test that non-input gpio commands correctly return the command
+    success/failure status."""
+
+    expected_response = 'rc:0'
+    response = u_boot_console.run_command('gpio clear 0; echo rc:$?')
+    assert(expected_response in response)
+    response = u_boot_console.run_command('gpio set 0; echo rc:$?')
+    assert(expected_response in response)
+    response = u_boot_console.run_command('gpio toggle 0; echo rc:$?')
+    assert(expected_response in response)
+    response = u_boot_console.run_command('gpio status -a; echo rc:$?')
+    assert(expected_response in response)
+
+    expected_response = 'rc:1'
+    response = u_boot_console.run_command('gpio nonexistent-command; echo rc:$?')
+    assert(expected_response in response)
+    response = u_boot_console.run_command('gpio input 200; echo rc:$?')
+    assert(expected_response in response)
-- 
2.17.1