[{"id":18234,"web_url":"https://patchwork.libcamera.org/comment/18234/","msgid":"","date":"2021-07-19T23:52:23","subject":"Re: [libcamera-devel] [PATCH] imx258: Read analog gain register\n\tvalues","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Umang,\n\nThank you for the patch.\n\nAs this is meant for testing but not integration, adding a [DNI] or\nsimilar prefix in the subject line would be nice.\n\nOn Mon, Jul 19, 2021 at 03:44:37PM +0530, Umang Jain wrote:\n> Also copy and tweak imx258_read_reg() to allow signed int values.\n> (These constants are signed ints).\n> \n> ---\n> drivers/media/i2c/imx258.c | 78 ++++++++++++++++++++++++++++++++++++++\n> 1 file changed, 78 insertions(+)\n> \n> diff --git a/drivers/media/i2c/imx258.c b/drivers/media/i2c/imx258.c\n> index f86ae18bc104..d029706f4d51 100644\n> --- a/drivers/media/i2c/imx258.c\n> +++ b/drivers/media/i2c/imx258.c\n> @@ -21,6 +21,13 @@\n> #define IMX258_REG_CHIP_ID\t\t0x0016\n> #define IMX258_CHIP_ID\t\t\t0x0258\n> \n> +/* Gain constant registers */\n> +#define IMX258_REG_GAIN_CAP\t\t0x0080\n> +#define IMX258_REG_C0\t\t\t0x008E\n\nLowercase for hex constants please.\n\n> +#define IMX258_REG_M0\t\t\t0x008C\n> +#define IMX258_REG_C1\t\t\t0x0092\n> +#define IMX258_REG_M1\t\t\t0x0090\n\nIt would be useful to also read the limits.\n\n> +\n> /* V_TIMING internal */\n> #define IMX258_VTS_30FPS\t\t0x0c98\n> #define IMX258_VTS_30FPS_2K\t\t0x0638\n> @@ -650,6 +657,38 @@ static int imx258_read_reg(struct imx258 *imx258, u16 reg, u32 len, u32 *val)\n> \treturn 0;\n> }\n> \n> +static int imx258_read_reg_signed(struct imx258 *imx258, u16 reg, u32 len, int16_t *val)\n\nThe 16-bit signed type in the kernel is s16.\n\n> +{\n> +\tstruct i2c_client *client = v4l2_get_subdevdata(&imx258->sd);\n> +\tstruct i2c_msg msgs[2];\n> +\tu8 addr_buf[2] = { reg >> 8, reg & 0xff };\n> +\tu8 data_buf[4] = { 0, };\n> +\tint ret;\n> +\n> +\tif (len > 4)\n> +\t\treturn -EINVAL;\n> +\n> +\t/* Write register address */\n> +\tmsgs[0].addr = client->addr;\n> +\tmsgs[0].flags = 0;\n> +\tmsgs[0].len = ARRAY_SIZE(addr_buf);\n> +\tmsgs[0].buf = addr_buf;\n> +\n> +\t/* Read data from register */\n> +\tmsgs[1].addr = client->addr;\n> +\tmsgs[1].flags = I2C_M_RD;\n> +\tmsgs[1].len = len;\n> +\tmsgs[1].buf = &data_buf[4 - len];\n> +\n> +\tret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));\n> +\tif (ret != ARRAY_SIZE(msgs))\n> +\t\treturn -EIO;\n> +\n> +\t*val = get_unaligned_be32(data_buf);\n> +\n> +\treturn 0;\n> +}\n\nInstead of duplicating all the code, you could implement this as a\nwrapper around imx258_read_reg().\n\n> +\n> /* Write registers up to 2 at a time */\n> static int imx258_write_reg(struct imx258 *imx258, u16 reg, u32 len, u32 val)\n> {\n> @@ -1055,6 +1094,7 @@ static int imx258_identify_module(struct imx258 *imx258)\n> \tstruct i2c_client *client = v4l2_get_subdevdata(&imx258->sd);\n> \tint ret;\n> \tu32 val;\n> +\tint16_t value;\n> \n> \tret = imx258_read_reg(imx258, IMX258_REG_CHIP_ID,\n> \t\t\t IMX258_REG_VALUE_16BIT, &val);\n> @@ -1070,6 +1110,44 @@ static int imx258_identify_module(struct imx258 *imx258)\n> \t\treturn -EIO;\n> \t}\n> \n> +\t// Hijack this to also read analog gain registers and print values\n> +\tdev_info(&client->dev, \"Reading analog gain registers...\\n\");\n> +\n> +\tret = imx258_read_reg(imx258, IMX258_REG_GAIN_CAP, IMX258_REG_VALUE_16BIT, &val);\n> +\tif (ret) {\n> +\t\tdev_err(&client->dev, \"failed to read GAIN_CAP %x\\n\",\n> +\t\t\tIMX258_REG_GAIN_CAP);\n> +\t}\n> +\tdev_info(&client->dev, \"Value of analog Gain capability: %d\\n\", val);\n\nAnother option would be to write\n\n\tdev_info(&client->dev, \"Value of analog Gain capability: %d\\n\", (s16)val);\n\nand drop the imx258_read_reg_signed() function completely.\n\n> +\n> +\tret = imx258_read_reg_signed(imx258, IMX258_REG_C0, IMX258_REG_VALUE_16BIT, &value);\n> +\tif (ret) {\n> +\t\tdev_err(&client->dev, \"failed to read C0 %x\\n\",\n> +\t\t\tIMX258_REG_C0);\n> +\t}\n> +\tdev_info(&client->dev, \"Value of C0: %d\\n\", value);\n> +\n> +\tret = imx258_read_reg_signed(imx258, IMX258_REG_M0, IMX258_REG_VALUE_16BIT, &value);\n> +\tif (ret) {\n> +\t\tdev_err(&client->dev, \"failed to read M0 %x\\n\",\n> +\t\t\tIMX258_REG_M0);\n> +\t}\n> +\tdev_info(&client->dev, \"Value of M0: %d\\n\", value);\n> +\n> +\tret = imx258_read_reg_signed(imx258, IMX258_REG_C1, IMX258_REG_VALUE_16BIT, &value);\n> +\tif (ret) {\n> +\t\tdev_err(&client->dev, \"failed to read C1 %x\\n\",\n> +\t\t\tIMX258_REG_C1);\n> +\t}\n> +\tdev_info(&client->dev, \"Value of C1: %d\\n\", value);\n> +\n> +\tret = imx258_read_reg_signed(imx258, IMX258_REG_M1, IMX258_REG_VALUE_16BIT, &value);\n> +\tif (ret) {\n> +\t\tdev_err(&client->dev, \"failed to read M1 %x\\n\",\n> +\t\t\tIMX258_REG_M1);\n> +\t}\n> +\tdev_info(&client->dev, \"Value of M1: %d\\n\", value);\n> +\n> \treturn 0;\n> }\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 70BB3C322B\n\tfor ;\n\tMon, 19 Jul 2021 23:52:33 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id CDD2160277;\n\tTue, 20 Jul 2021 01:52:32 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 7215360277\n\tfor ;\n\tTue, 20 Jul 2021 01:52:29 +0200 (CEST)","from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi\n\t[62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id E355E443;\n\tTue, 20 Jul 2021 01:52:28 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"HMIyDfFX\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1626738749;\n\tbh=pMw2vFeEj1NXSLRNpOgKaewV5y5KTjk0eJ1lbVXq9W4=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=HMIyDfFXu18oFmpp9pkZ1QyDR+EcYPiV73/M3N+/LRBJ+9KSLCAouIduit6lgmf5o\n\tOoyr0fh+iW48KtQLCo0GUpr4mZGe2MRZLRhYbsflGxq7KLYrL7My7qiVBd4jtyE2oT\n\tAn0hguEyw7RQzCtx3apBhH3xWmuwvrEehUKg9+jg=","Date":"Tue, 20 Jul 2021 02:52:23 +0300","From":"Laurent Pinchart ","To":"Umang Jain ","Message-ID":"","References":"<20210719101437.326523-1-umang.jain@ideasonboard.com>\n\t<20210719101437.326523-3-umang.jain@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<20210719101437.326523-3-umang.jain@ideasonboard.com>","Subject":"Re: [libcamera-devel] [PATCH] imx258: Read analog gain register\n\tvalues","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera-devel@lists.libcamera.org","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]