[PATCH i-g-t v4 1/3] lib/igt_kms: Move backlight read and write to lib

[Santhosh Reddy Guddati]

move backlight_read and backlight_write functions from
kms_pm_backlight to library to reuse in other tests.

move and rename struct context to intel_backlight_context_t.
v2: Rename backlight_read to igt_backlight_read and backlight_write to
backlight_write (Suraj).
Add a new member to intel_backlight_context_t to cache vendor specific
backlight path.

Signed-off-by: Santhosh Reddy Guddati <santhosh.reddy.guddati at intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal at intel.com>
---
 lib/igt_kms.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/igt_kms.h | 12 ++++++++++
 2 files changed, 78 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index bb35d4b82..5d8096a17 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -7119,3 +7119,69 @@ void igt_reset_link_params(int drm_fd, igt_output_t *output)
 	temp = drmModeGetConnector(drm_fd, output->config.connector->connector_id);
 	drmModeFreeConnector(temp);
 }
+
+/**
+ * igt_backlight_read:
+ * @result:	Pointer to store the result
+ * @fname:	Name of the file to read
+ * @context:	Pointer to the context structure
+ */
+int igt_backlight_read(int *result, const char *fname, igt_backlight_context_t *context)
+{
+	int fd;
+	char full[PATH_MAX];
+	char dst[64];
+	int r, e;
+
+	igt_assert(snprintf(full, PATH_MAX, "%s/%s/%s",
+			    context->backlight_dir_path,
+			    context->path,
+			    fname) < PATH_MAX);
+
+	fd = open(full, O_RDONLY);
+	if (fd == -1)
+		return -errno;
+
+	r = read(fd, dst, sizeof(dst));
+	e = errno;
+	close(fd);
+
+	if (r < 0)
+		return -e;
+
+	errno = 0;
+	*result = strtol(dst, NULL, 10);
+	return errno;
+}
+
+/**
+ * igt_backlight_write:
+ * @value:		Value to write
+ * @fname:		Name of the file to write
+ * @context:	Pointer to the context structure
+ */
+int igt_backlight_write(int value, const char *fname, igt_backlight_context_t *context)
+{
+	int fd;
+	char full[PATH_MAX];
+	char src[64];
+	int len;
+
+	igt_assert(snprintf(full, PATH_MAX, "%s/%s/%s",
+			    context->backlight_dir_path,
+			    context->path,
+			    fname) < PATH_MAX);
+
+	fd = open(full, O_WRONLY);
+	if (fd == -1)
+		return -errno;
+
+	len = snprintf(src, sizeof(src), "%i", value);
+	len = write(fd, src, len);
+	close(fd);
+
+	if (len < 0)
+		return len;
+
+	return 0;
+}
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index 2b26d2bbf..bd154d1c1 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -33,6 +33,7 @@
 #include <stdint.h>
 #include <stddef.h>
 #include <assert.h>
+#include <limits.h>
 
 #include <xf86drmMode.h>
 
@@ -513,6 +514,15 @@ typedef struct {
 	uint16_t tile_h_size, tile_v_size;
 } igt_tile_info_t;
 
+/* Backlight context*/
+typedef struct {
+	int max;
+	int old;
+	igt_output_t *output;
+	char path[PATH_MAX];
+	char backlight_dir_path[PATH_MAX];
+} igt_backlight_context_t;
+
 void igt_display_reset_outputs(igt_display_t *display);
 void igt_display_require(igt_display_t *display, int drm_fd);
 void igt_display_fini(igt_display_t *display);
@@ -1253,5 +1263,7 @@ bool igt_has_force_link_training_failure_debugfs(int drmfd, igt_output_t *output
 int igt_get_dp_pending_lt_failures(int drm_fd, igt_output_t *output);
 int igt_get_dp_pending_retrain(int drm_fd, igt_output_t *output);
 void igt_reset_link_params(int drm_fd, igt_output_t *output);
+int igt_backlight_read(int *result, const char *fname, igt_backlight_context_t *context);
+int igt_backlight_write(int value, const char *fname, igt_backlight_context_t *context);
 
 #endif /* __IGT_KMS_H__ */
-- 
2.34.1