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 DBCE5C47071 for ; Thu, 16 Nov 2023 18:29:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345450AbjKPS3n (ORCPT ); Thu, 16 Nov 2023 13:29:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50506 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229488AbjKPS3l (ORCPT ); Thu, 16 Nov 2023 13:29:41 -0500 X-Greylist: delayed 25869 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 16 Nov 2023 10:29:35 PST Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 853D6195 for ; Thu, 16 Nov 2023 10:29:35 -0800 (PST) Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1700159373; 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=Edk6FLzHTRuYYpwZ3fxzpEOntgKfq8bYriPXqiotyZI=; b=BbdP5LbJs917g+nVPVtTSfLgSHIgGpMCVOrjedB+PT0GgKJiSDIx0DGhDbT/Ah1BqC9wpM ZD4bC24s5vEy0uF0/fkgAkyHsJWdqIQJPalBJWY4DSRUIxxg4M0MluE/FHjBS/c3OJm26G 6aAeBVSpaWnB12L7dQlA+6hK6pE7n0E= Date: Fri, 17 Nov 2023 02:29:25 +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> <7602cd83-0e05-4e11-9bd1-10eb1d48a507@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 2023/11/16 21:00, Dmitry Baryshkov wrote: > On Thu, 16 Nov 2023 at 14:18, Sui Jingfeng wrote: >> 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. > And the patch 7 will be changed once you have proper i2c client struct > registered. > We will create a "wrong"i2c client intentionally by calling i2c_new_client_device, the "wrong" here means that 'board_info.type' is not equal to "it66121" or "it6610". I probably know what you means, but please note that we are not object you at here. The reason why we prefer theit66121_get_match_data() over the i2c_get_match_data() is that our it66121_get_match_data() works with *the least dependency*. Ourversion don't rely on the DT to provide compatible strings. Because the it66121 itself already provided constant hard-coded vender id and device id on-chip register. This is a bit similar with the PCIe devices. This chip id speak everything about chip identify. By re-arranging the variants into array, searching and matching against became straight-forward. We can also utilize the vender id and device id information to dynamic bind the instance specific functions *at the setup(probe) time*. Which helps to untangle the it66121 and it6610 cases with function object. Currently they are tangled. This is not a problem simply because the model supported is too small(less). >> >> Since it6610 was introduced, this is used for chip identifying. >> It can also be used with in debugfs context, to show who I am. > I'd say, there is little point in whoami debugfs files. Debugfs is for > the useful information. > >> >>>> 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 >>>> > >