From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36061C54FB9 for ; Thu, 16 Nov 2023 12:18:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345193AbjKPMS2 (ORCPT ); Thu, 16 Nov 2023 07:18:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345138AbjKPMS1 (ORCPT ); Thu, 16 Nov 2023 07:18:27 -0500 Received: from out-184.mta1.migadu.com (out-184.mta1.migadu.com [IPv6:2001:41d0:203:375::b8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE72B9B for ; Thu, 16 Nov 2023 04:18:23 -0800 (PST) Message-ID: <7602cd83-0e05-4e11-9bd1-10eb1d48a507@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1700137102; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mojXKgKsD6OOdOdTVyAHt9qNfNzmLYV5MNq0diPZ0zo=; b=ui0PNUIWnN3h0wZZlTNPpzsTYt72RGpccxzSG5u2mJgqPIRlWezUkSceAZfLDNwbl7aiyd f3Z0dAwKeBEj8HzSlDEuC5fobUcRY/59txepIFCGunD1O2JARyC5JKOYlhwgCNb57bFBjR LLkrWlUnt+Qx0bphCRc3GD+DZfsPIik= Date: Thu, 16 Nov 2023 20:18:12 +0800 MIME-Version: 1.0 Subject: Re: [PATCH 5/8] drm/bridge: it66121: Add a helper function to read chip id Content-Language: en-US To: Dmitry Baryshkov Cc: Phong LE , Neil Armstrong , Maxime Ripard , Sui Jingfeng , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Laurent Pinchart , Thomas Zimmermann References: <20231114150130.497915-1-sui.jingfeng@linux.dev> <20231114150130.497915-6-sui.jingfeng@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sui Jingfeng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 2023/11/15 00:06, Dmitry Baryshkov wrote: > On Tue, 14 Nov 2023 at 17:09, Sui Jingfeng wrote: >> From: Sui Jingfeng >> >> Read the required chip id data back by calling regmap_bulk_read() once, >> reduce the number of local variables needed in it66121_probe() function. >> And store its values into struct it66121_ctx, as it will be used latter. >> >> Signed-off-by: Sui Jingfeng >> --- >> drivers/gpu/drm/bridge/ite-it66121.c | 47 ++++++++++++++++++++-------- >> 1 file changed, 34 insertions(+), 13 deletions(-) >> >> diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c >> index 7e473beefc79..f36d05331f25 100644 >> --- a/drivers/gpu/drm/bridge/ite-it66121.c >> +++ b/drivers/gpu/drm/bridge/ite-it66121.c >> @@ -313,6 +313,9 @@ struct it66121_ctx { >> bool auto_cts; >> } audio; >> const struct it66121_chip_info *info; >> + u16 vender_id; >> + u16 device_id; >> + u8 revision; > There is no need to store them, they are not used by the driver anywhere. > >> }; >> >> static inline struct it66121_ctx *bridge_to_it66121(struct drm_bridge *bridge) >> @@ -399,6 +402,30 @@ static void it66121_hw_reset(struct it66121_ctx *ctx) >> gpiod_set_value(ctx->gpio_reset, 0); >> } >> >> +static int it66121_read_chip_id(struct it66121_ctx *ctx, bool verbose) >> +{ >> + u8 id[4]; >> + int ret; >> + >> + ret = regmap_bulk_read(ctx->regmap, IT66121_VENDOR_ID0_REG, id, 4); >> + if (ret < 0) { >> + dev_err(ctx->dev, "Failed to read chip ID: %d\n", ret); >> + return ret; >> + } >> + >> + ctx->vender_id = (u16)id[1] << 8 | id[0]; >> + ctx->device_id = ((u16)(id[3] & IT66121_DEVICE_ID1_MASK) << 8 | id[2]); >> + /* Revision is shared with DEVICE_ID1 */ >> + ctx->revision = FIELD_GET(IT66121_REVISION_MASK, id[3]); >> + >> + if (verbose) { >> + dev_info(ctx->dev, "Found ITE66121: 0x%x%x, revision: %u\n", >> + ctx->vender_id, ctx->device_id, ctx->revision); >> + } >> + >> + return 0; >> +} >> + >> static inline int it66121_preamble_ddc(struct it66121_ctx *ctx) >> { >> return regmap_write(ctx->regmap, IT66121_MASTER_SEL_REG, IT66121_MASTER_SEL_HOST); >> @@ -1561,7 +1588,6 @@ static const char * const it66121_supplies[] = { >> >> static int it66121_probe(struct i2c_client *client) >> { >> - u32 revision_id, vendor_ids[2] = { 0 }, device_ids[2] = { 0 }; >> int ret; >> struct it66121_ctx *ctx; >> struct device *dev = &client->dev; >> @@ -1603,19 +1629,13 @@ static int it66121_probe(struct i2c_client *client) >> if (IS_ERR(ctx->regmap)) >> return PTR_ERR(ctx->regmap); >> >> - regmap_read(ctx->regmap, IT66121_VENDOR_ID0_REG, &vendor_ids[0]); >> - regmap_read(ctx->regmap, IT66121_VENDOR_ID1_REG, &vendor_ids[1]); >> - regmap_read(ctx->regmap, IT66121_DEVICE_ID0_REG, &device_ids[0]); >> - regmap_read(ctx->regmap, IT66121_DEVICE_ID1_REG, &device_ids[1]); >> - >> - /* Revision is shared with DEVICE_ID1 */ >> - revision_id = FIELD_GET(IT66121_REVISION_MASK, device_ids[1]); >> - device_ids[1] &= IT66121_DEVICE_ID1_MASK; >> + ret = it66121_read_chip_id(ctx, false); >> + if (ret) >> + return ret; >> >> - if ((vendor_ids[1] << 8 | vendor_ids[0]) != ctx->info->vid || >> - (device_ids[1] << 8 | device_ids[0]) != ctx->info->pid) { >> + if (ctx->vender_id != ctx->info->vid || >> + ctx->device_id != ctx->info->pid) Q: There is no need to store them, they are not used by the driver anywhere. A: Here it is used, it is also used by the 0007-patch to get the entity(instance)-specific data. Since it6610 was introduced, this is used for chip identifying. It can also be used with in debugfs context, to show who I am. >> return -ENODEV; >> - } >> >> ctx->bridge.funcs = &it66121_bridge_funcs; >> ctx->bridge.of_node = dev->of_node; >> @@ -1633,7 +1653,8 @@ static int it66121_probe(struct i2c_client *client) >> >> drm_bridge_add(&ctx->bridge); >> >> - dev_info(dev, "IT66121 revision %d probed\n", revision_id); >> + dev_info(dev, "IT66121 probed, chip id: 0x%x:0x%x, revision: %u\n", >> + ctx->vender_id, ctx->device_id, ctx->revision); >> >> return 0; >> } >> -- >> 2.34.1 >> >