Thread (13 messages) 13 messages, 4 authors, 2021-01-21

Re: [PATCH v7 1/5] media: rkisp1: uapi: change hist_bins array type from __u16 to __u32

From: Dafna Hirschfeld <hidden>
Date: 2021-01-21 12:50:00
Also in: linux-rockchip


Am 20.01.21 um 22:32 schrieb Sakari Ailus:
Hi Dafna,

Thanks for the update.

On Wed, Jan 20, 2021 at 05:44:42PM +0100, Dafna Hirschfeld wrote:
quoted
Each entry in the array is a 20 bits value composed of 16
bits unsigned integer and 4 bits fractional part. So the
type should change to __u32.
In addition add a documentation of how the measurements
are done.
The commit message lines wrap at 74, under 60 is not much.
quoted
Signed-off-by: Dafna Hirschfeld <redacted>
Should there be a Fixes: line? The patch is changing UAPI...

The file has been recently introduced. Should it go to fixes or to a stable
kernel, too?
The file was in the staging directory and will be first destaged in the coming 5.11,
so I don't think this is necessary.
quoted
---
  include/uapi/linux/rkisp1-config.h | 12 ++++++++----
  1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/include/uapi/linux/rkisp1-config.h b/include/uapi/linux/rkisp1-config.h
index 6e449e784260..f75f8d698fb4 100644
--- a/include/uapi/linux/rkisp1-config.h
+++ b/include/uapi/linux/rkisp1-config.h
@@ -844,13 +844,17 @@ struct rkisp1_cif_isp_af_stat {
  /**
   * struct rkisp1_cif_isp_hist_stat - statistics histogram data
   *
- * @hist_bins: measured bin counters
+ * @hist_bins: measured bin counters. Each bin is a 20 bits unsigned fixed point type.
+ *	       Bits 0-4 are the fractional part and bits 5-19 are the integer part.
   *
- * Measurement window divided into 25 sub-windows, set
- * with ISP_HIST_XXX
+ * The window of the measurements area is divided to 5x5 sub-windows. The histogram
+ * is then computed for each sub-window independently and the final result is a weighted
+ * average of the histogram measurements on all sub-windows.
+ * The window of the measurements area and the weight of each sub-window are configurable
+ * using struct @rkisp1_cif_isp_hst_config.
Please wrap the lines before 80.
ok,

Thanks,
Dafna
quoted
   */
  struct rkisp1_cif_isp_hist_stat {
-	__u16 hist_bins[RKISP1_CIF_ISP_HIST_BIN_N_MAX];
+	__u32 hist_bins[RKISP1_CIF_ISP_HIST_BIN_N_MAX];
  };
  
  /**
-- 
2.17.1
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