From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.128.42 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793399856; b=NrUuN1ZI7w7vxX96vPpzU1ap/wyrnry/WZCyeXIoWp+TrP18/w0hohmn/gsCnBgJT1MP 7WVJ+0kRn+kmZegPHCTmnriMWgll3IvdScUyzPA9LPIzfK2IoqRJ2xwwG2V0JaieiLZzn pxPsIREckl0EeOfWmC8/MQImlse5tiuDxfEImwBRVC7pOHnRuw9bjQSQ9ONRDkiPnO2bn ArB1sZwIlqz6YelmibjZ0EtvLDRTpe37XxxUME3OIfZIWsC4zDxYPRXXKMi9hNsyUvI4A WvlKV/YQ0Rvr7PkYRtE/1HJfuj6KdBikYiUWk5NLAoaapG+UX66w2yDd6qxxD3UtdPg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793399856; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:To:Cc:Subject:Date:Message-ID:X-Mailer:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding; bh=g7GpuRiIRj4DVraCupDVTmqjMX8L6GHmgvZBL/BLQ9A=; b=VRZ4Fmras43u3tJ31vuIBby9PzWuqe5GOcoJqs8ivbgfZqAFGb8Zs2/90/ukmSiWylge 5Q9/zx1ifc6p+vwgIFTgM+UdVoX+lv2H6Wcg68tW1zRyInJampoe3FuIqxBKUAwDK5w36 IWrfwphDWRE7WaKzogIs+9iaEKP12xhkZmW+9at7wke/3cz0XEjQAYiSHWs8LWDhTxcSv Qi3WFjkVRYOVeMP5orKG3mNxpFKNoIhqk0d8jVs8kNxcgYq3zxpThZEraMhRIlDHHw18T fQ/vrRnnM9KsTlSciSYyvwlzmFbYBxT3EXlv8mdanEandp2P+iU5gntT3JpLgM2sPPg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=OYKeXa1g; arc=none smtp.remote-ip=209.85.128.42 Received: from mail-wm1-f42.google.com (mail-wm1-f42.google.com [209.85.128.42]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 748BD60A5BE5 for ; Fri, 30 Oct 2026 22:37:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 748BD60A5BE5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=OYKeXa1g Received: by mail-wm1-f42.google.com with SMTP id 5b1f17b1804b1-4a218c463d1so7465885e9.0 for ; Fri, 30 Oct 2026 15:37:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20260707; t=1793399845; x=1794004645; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=g7GpuRiIRj4DVraCupDVTmqjMX8L6GHmgvZBL/BLQ9A=; b=OYKeXa1gGPpQxA3whFTS6ivltypONZOdWmQKnRj627TD9pLLQ8F0nTgl9FoIql/39s GBiio2Aiwf1kPRgC+blk4DbO4HhB04qKQXm33vDOk5t7m/XuZgoccgHhYg42XWS1jjTa vKANcpKh4OEcT6dV6E85g5LEf8xK4ZgeX1b6XaHR15Q0pM5+BPhFbEPbUDM9Vrf6B8Y1 pDrUJer0qbtMGS/psn2AaUGrMnNjI9+Xc1xVPkHcPRP/DaUPtWOkWJajWzV+gykvJzm2 0pV8RfpvclPuz8d1lgxU/Dp9Tx1H2La6L27qsNjfjJzTp1v3v7kM8mIgdjctfbQasge7 LW9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793399845; x=1794004645; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=g7GpuRiIRj4DVraCupDVTmqjMX8L6GHmgvZBL/BLQ9A=; b=cg+qPVluDPryE/3aR4cjomT7fsP2/Gb5DFONJsm0q7r/FaSMtKNPbYu015GWx8V7hs 3T7lYi14wKoctl/wCBQygmPPIq9NYdOWjkIgMqST7xepWOXQ2Q3O4Kv6aydk3wSl7PkE mOMClb75HPVEYymM6HG3nKYV7/u9yLNjRo7xYCk3KtQrb0V4xSMIGZs4tryBdNxdIUB9 WynHm/Nz+KAAnckedMAEcgUUVqtAi2jnkBVFcCzOEDH59UUjesXjiqdEE2TYXdTdCK5t drqca9Gy7DMHcvhoHPq4phtMHzQrHyFSnM4gUxdjZhcmhBrvN5I7d182JkMI6FBySqBy iqow== X-Forwarded-Encrypted: i=1; AKwUvBxpld8CzKuj4hGaqINEtsqud0cWehWDLuSpx5Xo+atOx4AzHTXfdbzwlw6GM5DmorPwbY6J6cutj0hkzrE=@vger.kernel.org X-Gm-Message-State: AFq9FYK0Pko5Cz7Je3zIJdQ+z2yukWDufk12XCmt2mcaG1BJCAS1jIqr bfcNTH4pJeaBEmRJYGM14L7nyiokC4tP+jCi4pPApztWSavsb+Fgx5zu X-Gm-Gg: AYBFou0IGK4ggwc61fz/SHCFl2vlhd9P+ZTgiuLpcDo9uQrUqeoYPfY7jvCIODR/e/x lqIw8Vl+3ow0HNQajlZrGu9ZrOMS4MQAzOPzHTl7dldgL2LT2kfBEaH4cKACpgxmiGpqN53/tNb NWpJI3pTjvW9Mc1X+b1XsezAhrbD2NJUN7Pzt3y9TzA9mj7rdFzEEhmZuhQd5vUFGSSgITDjJzR tgzpq93NeTaz55sY9MiKiKLuOwXpJ7VkGEYogAR/yrcYxjKOVoTWbDtobgkpd5osAgRLRIukuzK vtvp+6Yid0vDKgp5boGSU4wUkXYwbGrnByv/k0Ue+nzYkOdy3wk5Tewwsy5Y8yQieAeVQQTL/II GOZKcwT7Djln8r4WTLYKlcHFHwwNCOin5aewOMjojNTkmHAt/6U6fWI9YH6Zm2pBZBJUgVOWrQZ ixuutYAjCDq705Ru1VE3AqfFKkQtP8d8LwyNvIbntKOxQB/IiZKEQISQj/ixu5tIAiajW/dwN7y HJQbanWZx2WSvsUVnr7PCvu5wY4ML9dS5EPh9bbcYi48/gNCLpbZ0jD1ckpDV+ul3B4ZIfFXlXf FaKBTRRtcjkOl+3x3ZG/bfmIhI/d X-Received: by 2002:a05:600c:6099:b0:4a1:992f:d0e7 with SMTP id 5b1f17b1804b1-4ac180f2ac5mr76556665e9.16.1793399844709; Fri, 30 Oct 2026 15:37:24 -0700 (PDT) Received: from m2.. ([37.142.145.227]) by smtp.googlemail.com with ESMTPSA id ffacd0b85a97d-48e71b959c1sm5457300f8f.45.2026.10.30.15.37.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Oct 2026 15:37:24 -0700 (PDT) From: Michael Zaidman To: Jiri Kosina , Benjamin Tissoires Cc: Linus Walleij , Bartosz Golaszewski , Greg Kroah-Hartman , Jiri Slaby , Raman Varabets , Germain Hebert , Christina Quast , Rio Liu , Bruno Giacomazzi , linux-input@vger.kernel.org, linux-serial@vger.kernel.org, linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Michael Zaidman Subject: [PATCH v2 13/15] HID: ft260: i2c: reject an I2C clock outside the supported range Date: Sat, 31 Oct 2026 00:36:35 +0200 Message-ID: <20261030223637.86907-14-michael.zaidman@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261030223637.86907-1-michael.zaidman@gmail.com> References: <20261030223637.86907-1-michael.zaidman@gmail.com> X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The clock sysfs attribute passes any 16-bit value to the chip. The chip accepts it, reports it back in the I2C status report that clock_show reads, and runs the bus at the 100 kHz default. A read of 2048 bytes takes the same 0.298 s after writing 50, 3500 or 65535 as it does after writing 100, while 60 and 3400 give 0.387 s and 0.058 s. Userspace has no way to see that the value was not applied. Refuse a value outside the 60-3400 kHz range named in the datasheet section 4.4.16. ft260_uart_change_speed() checks the baud rate against FT260_UART_CFG_BAUD_MIN and FT260_UART_CFG_BAUD_MAX, but termios has no error return, so it falls back to 9600. A sysfs store can return an error, so the clock store refuses the value. FT260_WORD_ATTR_STORE() takes the parse function as a parameter now, so a word attribute with no range of its own keeps passing kstrtou16. Signed-off-by: Michael Zaidman --- drivers/hid/hid-ft260.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c index 50f68790c04d..f7d01d9e07f7 100644 --- a/drivers/hid/hid-ft260.c +++ b/drivers/hid/hid-ft260.c @@ -68,6 +68,11 @@ MODULE_PARM_DESC(debug, "Toggle FT260 debugging messages"); #define FT260_WR_I2C_DATA_MAX 60 #define FT260_WR_UART_DATA_MAX 62 + +/* I2C bus clock range in kHz, see the FT260 datasheet section 4.4.16 */ +#define FT260_I2C_CLOCK_MIN 60 +#define FT260_I2C_CLOCK_MAX 3400 + #define FT260_GPIOCHIP "ft260_gpio" #define FT260_GPIO_0_5_COUNT 6 #define FT260_GPIO_A_H_COUNT 8 @@ -1529,6 +1534,25 @@ static void ft260_attr_dummy_func(struct hid_device *hdev, u8 req, u16 value) { } +/* + * The chip takes any 16-bit value and reports it back in the I2C status + * report, but runs the bus at the 100 kHz default when the value is + * outside the documented range. The report gives no way to tell the two + * cases apart, so refuse the value here. + */ +static int ft260_i2c_clock_parse(const char *buf, unsigned int base, u16 *clock) +{ + int ret = kstrtou16(buf, base, clock); + + if (ret) + return ret; + + if (*clock < FT260_I2C_CLOCK_MIN || *clock > FT260_I2C_CLOCK_MAX) + return -EINVAL; + + return 0; +} + #define FT260_ATTR_SHOW(name, reptype, id, type, func) \ static ssize_t name##_show(struct device *kdev, \ struct device_attribute *attr, char *buf) \ @@ -1586,9 +1610,9 @@ static void ft260_attr_dummy_func(struct hid_device *hdev, u8 req, u16 value) FT260_ATTR_STORE(name, reptype, FT260_SYSTEM_SETTINGS, req, \ u8, kstrtou8, func, FT260_STORE_NATIVE) -#define FT260_WORD_ATTR_STORE(name, reptype, req, func) \ +#define FT260_WORD_ATTR_STORE(name, reptype, req, strtou, func) \ FT260_ATTR_STORE(name, reptype, FT260_SYSTEM_SETTINGS, req, \ - u16, kstrtou16, func, cpu_to_le16) + u16, strtou, func, cpu_to_le16) FT260_SSTAT_ATTR_SHOW(chip_mode); static DEVICE_ATTR_RO(chip_mode); @@ -1641,7 +1665,8 @@ static DEVICE_ATTR_RW(clock_ctl); FT260_I2CST_ATTR_SHOW(clock); FT260_WORD_ATTR_STORE(clock, ft260_set_i2c_speed_report, - FT260_SET_I2C_CLOCK_SPEED, ft260_attr_dummy_func); + FT260_SET_I2C_CLOCK_SPEED, ft260_i2c_clock_parse, + ft260_attr_dummy_func); static DEVICE_ATTR_RW(clock); static ssize_t i2c_reset_store(struct device *kdev, -- 2.43.0