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 X-Spam-Level: X-Spam-Status: No, score=-6.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEBF5C433E2 for ; Wed, 9 Sep 2020 00:44:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23EB92177B for ; Wed, 9 Sep 2020 00:44:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mb+37Pjo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726660AbgIIAoc (ORCPT ); Tue, 8 Sep 2020 20:44:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51992 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726642AbgIIAo3 (ORCPT ); Tue, 8 Sep 2020 20:44:29 -0400 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 18618C061573; Tue, 8 Sep 2020 17:44:29 -0700 (PDT) Received: by mail-pg1-x544.google.com with SMTP id 67so751060pgd.12; Tue, 08 Sep 2020 17:44:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=K8QsISLidxurmPHK5+YsjnPP/PckoOJ6G9b+uwLzbMw=; b=mb+37PjoeLRqv2WjK4oAy8ZM56SLsUERgXMJV+xnvceYAg8LDU9j3g+mPnNZafXStS fprzt259PdmatRcwBUd80MYT4qOUqdqOx7swopNaXHu5XAIScv0v+FZRPqRh9F8Db1lC JV02KtL1zQ1dv9FEOAvHVJGXwVEBvqVKeEEHNgjVfz7HiNJPag/6HC2V/e/pFbuT4n7y OLTm0Ul1Hc1XRprsmrF7VxTvuXALGq0dBrhPCazKdNqOFs7RW/NG/Oe4hFhbirV+RNXb 1lFe5OHGFhoa1NDHw+/VoV/4/Lj96dcvhcBjlciPyPhWdP91rgeoxsmfsX0UJKno29iV ZPeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=K8QsISLidxurmPHK5+YsjnPP/PckoOJ6G9b+uwLzbMw=; b=aN6ksq5MqTChZ3LvBxNoCCFdUaJBRMp1YEMiFophfLCbaCujqNGDUbGudFPlYs110D jY9tr5BNLXOekiwuUgoTGyD08GTsp8W8pr0988KYlxCIazy0aDy5cXdCXzNzcdZ7IX5Y oSr1xanvDoGDVRKWDgPIZf59yTi6ymD+5j9h/NqWmp/FTWTMlz43Eydvavlita9R3uF+ zJ4GYAdghtmGq9QByDjlgYZGlZcRdfjFmCEQ+nrHHh8QKAlRdCuAIJ9KKD4srFBAE+ud 26A38+DzIh3g2dM7mEz6iEsS7AEE/YSKT+CtAFfFFZMWaAqS5m8AfTsK1zr4VaCGsepW BZ5Q== X-Gm-Message-State: AOAM5301PWpYJwryIKK3yo3GKDYqRdGrmkyTAM5/CPyNbWnlRFmusExE lVq4SVrd5Wlq8WZO31CjFHI= X-Google-Smtp-Source: ABdhPJzXqypVIDq1EkovtOZSBjPHx3Aef9gcdPgJx8+NPlHLPtiYhOsFRQXaiEqyLmrxEuEuIaFmHQ== X-Received: by 2002:a63:ff01:: with SMTP id k1mr1045030pgi.141.1599612268290; Tue, 08 Sep 2020 17:44:28 -0700 (PDT) Received: from dtor-ws ([2620:15c:202:201:a6ae:11ff:fe11:fcc3]) by smtp.gmail.com with ESMTPSA id ga3sm342882pjb.18.2020.09.08.17.44.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Sep 2020 17:44:26 -0700 (PDT) Date: Tue, 8 Sep 2020 17:44:24 -0700 From: Dmitry Torokhov To: Furquan Shaikh Cc: Dan Carpenter , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, adurbin@google.com Subject: Re: [PATCH v2] drivers: input: Use single i2c_transfer transaction when using RM_CMD_BANK_SWITCH Message-ID: <20200909004424.GD1665100@dtor-ws> References: <20200820224551.GX1665100@dtor-ws> <20200821024006.3399663-1-furquan@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200821024006.3399663-1-furquan@google.com> Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org Hi Furquan, On Thu, Aug 20, 2020 at 07:40:06PM -0700, Furquan Shaikh wrote: > On an AMD chromebook, where the same I2C bus is shared by both Raydium > touchscreen and a trackpad device, it is observed that interleaving of > I2C messages when `raydium_i2c_read_message()` is called leads to the > Raydium touch IC reporting incorrect information. This is the sequence > that was observed to result in the above issue: > > * I2C write to Raydium device for RM_CMD_BANK_SWITCH > * I2C write to trackpad device > * I2C read from trackpad device > * I2C write to Raydium device for setting address > * I2C read from Raydium device >>>> This provides incorrect > information > > This change adds a new helper function `raydium_i2c_xfer()` that > performs I2C transactions to the Raydium device. It uses the register > address to decide if RM_CMD_BANK_SWITCH header needs to be sent to the > device (i.e. if register address is greater than 255, then bank switch > header is sent before the rest of the transaction). Additionally, it > ensures that all the I2C operations performed as part of > `raydium_i2c_xfer()` are done as a single i2c_transfer. This > guarantees that no other transactions are initiated to any other > device on the same bus in between. Additionally, > `raydium_i2c_{send|read}*` functions are refactored to use this new > helper function. > > Verified with the patch across multiple reboots (>100) that the > information reported by the Raydium touchscreen device during probe > is correct. > > Signed-off-by: Furquan Shaikh > > --- > v2: Added a new helper function raydium_i2c_xfer so that all read and > send transfers are handled using the same path. This helper function > uses register address > 255 to decide whether to send > RM_CMD_BANK_SWITCH command. Additionally, __packed keyword is moved > to be placed after the structure defintion. > > drivers/input/touchscreen/raydium_i2c_ts.c | 132 +++++++++------------ > 1 file changed, 58 insertions(+), 74 deletions(-) > > diff --git a/drivers/input/touchscreen/raydium_i2c_ts.c b/drivers/input/touchscreen/raydium_i2c_ts.c > index fe245439adee..261e4a290836 100644 > --- a/drivers/input/touchscreen/raydium_i2c_ts.c > +++ b/drivers/input/touchscreen/raydium_i2c_ts.c > @@ -51,6 +51,7 @@ > > /* Touch relative info */ > #define RM_MAX_RETRIES 3 > +#define RM_RETRY_DELAY_MS 20 > #define RM_MAX_TOUCH_NUM 10 > #define RM_BOOT_DELAY_MS 100 > > @@ -136,114 +137,98 @@ struct raydium_data { > bool wake_irq_enabled; > }; > > -static int raydium_i2c_send(struct i2c_client *client, > - u8 addr, const void *data, size_t len) > +static int raydium_i2c_xfer(struct i2c_client *client, u32 addr, void *data, > + size_t len, bool is_read) > { > - u8 *buf; > - int tries = 0; > - int ret; > - > - buf = kmalloc(len + 1, GFP_KERNEL); > - if (!buf) > - return -ENOMEM; > - > - buf[0] = addr; > - memcpy(buf + 1, data, len); > - > - do { > - ret = i2c_master_send(client, buf, len + 1); > - if (likely(ret == len + 1)) > - break; > - > - msleep(20); > - } while (++tries < RM_MAX_RETRIES); > - > - kfree(buf); > - > - if (unlikely(ret != len + 1)) { > - if (ret >= 0) > - ret = -EIO; > - dev_err(&client->dev, "%s failed: %d\n", __func__, ret); > - return ret; > - } > + struct raydium_bank_switch_header { > + u8 cmd; > + __be32 be_addr; > + } __packed header = { > + .cmd = RM_CMD_BANK_SWITCH, > + .be_addr = cpu_to_be32(addr), > + }; > > - return 0; > -} > + u8 reg_addr = addr & 0xff; > > -static int raydium_i2c_read(struct i2c_client *client, > - u8 addr, void *data, size_t len) > -{ > struct i2c_msg xfer[] = { > + { > + .addr = client->addr, > + .len = sizeof(header), > + .buf = (u8 *)&header, > + }, > { > .addr = client->addr, > .len = 1, > - .buf = &addr, > + .buf = ®_addr, > }, > { > .addr = client->addr, > - .flags = I2C_M_RD, > .len = len, > .buf = data, > + .flags = is_read ? I2C_M_RD : 0, > } > }; > + > + /* > + * If address is greater than 255, then RM_CMD_BANK_SWITCH needs to be > + * sent first. Else, skip the header i.e. xfer[0]. > + */ > + int xfer_start_idx = (addr > 0xff) ? 0 : 1; > + size_t xfer_count = ARRAY_SIZE(xfer) - xfer_start_idx; > int ret; > > - ret = i2c_transfer(client->adapter, xfer, ARRAY_SIZE(xfer)); > - if (unlikely(ret != ARRAY_SIZE(xfer))) > - return ret < 0 ? ret : -EIO; > + ret = i2c_transfer(client->adapter, &xfer[xfer_start_idx], xfer_count); > + if (likely(ret == xfer_count)) > + return 0; > > - return 0; > + return -EIO; We are losing real error here, I'll change this to return ret < 0 ? ret : -EIO; > } > > -static int raydium_i2c_read_message(struct i2c_client *client, > - u32 addr, void *data, size_t len) > +static int raydium_i2c_send(struct i2c_client *client, u32 addr, > + const void *data, size_t len) > { > - __be32 be_addr; > + int tries = 0; > + int ret; > + > + do { > + ret = raydium_i2c_xfer(client, addr, (void *)data, len, false); > + if (likely(ret == 0)) > + return 0; > + > + msleep(RM_RETRY_DELAY_MS); > + } while (++tries < RM_MAX_RETRIES); > + > + dev_err(&client->dev, "%s failed\n", __func__); > + return -EIO; Again losing real error here, I'll rename ret to error and do return error; here. > +} > + > +static int raydium_i2c_read(struct i2c_client *client, u32 addr, void *data, > + size_t len) > +{ > + int ret; > size_t xfer_len; > - int error; > > while (len) { > xfer_len = min_t(size_t, len, RM_MAX_READ_SIZE); > + ret = raydium_i2c_xfer(client, addr, data, len, true); I think this needs to be xfer_len, not len. I can fix it up locally if you agree. Thanks. -- Dmitry