From nobody Mon Apr 6 18:05:20 2026 Received: from mail-pj1-f54.google.com (mail-pj1-f54.google.com [209.85.216.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 85D683F23A1 for ; Wed, 18 Mar 2026 19:36:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.54 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773862609; cv=none; b=YYZuoMnbq77uElovZoRfDKp52w07xaHPJly192VmbfyxTdKni8tBLtJSpJE7VF/XSI0aZ54wtRUu6qIVndONyh6qRSWoTSseKfg56z3NV0Wfav+6pEhxIVUZZyN9udWnGgWmvyORFejJBJXW8AZnIPjODtte9jVBjxFcEoNsNNs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773862609; c=relaxed/simple; bh=NMHtYKysW+TqQN55GibvMc9/e7iQHP4Z0ItDqPkBPWc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tH60bYLto1UkC/6ClkXSrX/eu/cswLkQ2+lce6e/h83GHtk7JE5c8W15fdasyJiMF8FA7aw5K2UvbyrjwzoSebg1mIm4+/6FhBPPLqozwyE0ZrSxcbnEHgQR4CsLfn643MORDR9BBN2Hu+XAuoPVdlBKrF/HYYJ2KiD5UeZyE8M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=AyRt0A0d; arc=none smtp.client-ip=209.85.216.54 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) header.d=gmail.com header.i=@gmail.com header.b="AyRt0A0d" Received: by mail-pj1-f54.google.com with SMTP id 98e67ed59e1d1-35bb7afdc38so258512a91.1 for ; Wed, 18 Mar 2026 12:36:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1773862608; x=1774467408; 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; bh=2iY4og2qGh/roH7GFoTs23bu6QUHnKE8+1qN6pUKQh8=; b=AyRt0A0dW4wTVwhhekhMpj+mvf8CbSMCP/EVubljt/J7jiT88ljSuhXlCoFYWORCnG x0+Xgm6RqxZNVwi5GRA7hd1VY2//6S/vCOI1QCfXzmA6AKeMtZ4yjjjlTxGCC3bP9D+V jR6YjTbul5qZ/PIBwsH0G80mrVEhmC6uAOHbieNdcvWjOBp5n0vVLGX8orTZ85lw9xpQ TH0oiam/baBkn/oLEhtOy22sFqEZhZbGRuBJvXzMqgGDV1ID/onzdTzt/6jqAFe7N1xw zs1K44QlQqd21zDEB/uSzIkedtoxOtawBsLbPWw7y/NYt+KRNprXKN3xyb0ORS/9+6Us hDZw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1773862608; x=1774467408; 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; bh=2iY4og2qGh/roH7GFoTs23bu6QUHnKE8+1qN6pUKQh8=; b=NYZv/9xP1n0JU7/2ZR7HXAdhRX0JotmH6OEIEbvOoYSYnVtIA+AD1+hENAyBKuANaQ VezraVw2AY0tH4o5uwXMBwwyN0jGdOf+actrH4H2/lds0VzwuUbMlOycS2mjqZE/tctj y6XbTv4sHTwCpZEyJXeKvn6B/kUoaabsyqpPNHShQX14gsKLnKwN2OrfeDpk9DOIg6XL Fsmk3Chp1Q73UW5VP/zBk3eJgzMGvNYzWJ6W70+Z3ZUH5/dMYBBzPQ/kQF8UrhXJhVRo a8v8GtH2eQaSWYhOxbpAOXkx61WC18rli+TRq4Pj5hRQeIR2rqnW8xDTEzUUq6XW+VDS T7wQ== X-Forwarded-Encrypted: i=1; AJvYcCWdo+REA4gK6l7mBDQT8p6T4QroAOhJ9B6LUZ916KIVtjpubO+4WWRhhsq0Cl1bQ/fWn5GNvWU2pkwtJbQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yz+mULen5vWHehhoOle4k3XqUdcZMqL7MzbAAWJPhP03xxJGXdM 3eLNFJESNstuYIusnWF5pdOOc6jYaFJ6g4puC3NWEbaIT9j1ZJSHvaZ4 X-Gm-Gg: ATEYQzyw4POOLxMyrk9u91rrA0XwvYc61MHw6w+CdMbUkv+5PW1kWYRDcsyoybXpTEp XzQgQUi+s3cGjJnKDX0r463uHhH4BIKJ27QPNYj31aCp2hOwcsUO2QQ1vbt7avpawoLYDGp09rw y2W4GnLV/scTCsp4iPwbgWENCJv7zQmWo9xTd8tf/yGCH6jA054XwYjIGu6pbjMZzciYd90B0RR K+lvQPnNpJCHKxD0ZUh0pZ9oJNa53Z4TBSIKUdelvoXrNNNgqcNUDeqkWx0kj9wBRCm7wqdGXKj Lno77k+KT+GTcgWx+1oEUsmej5zzq5UXBBNU3atpH3vJr/uifkoCFBg+/BqkE6xwDngR0DAV3hP sf2YJ64m4rgMpbNSk6Ls1OldkUAaBAEYaaqyl77pI8VVWgHvTJ4Fz9leMJfupIxtY0ucdJGUlsP CqZFNjUEN63g3azZOGqg9vJZ7jxgwGFRYS/2mJuchl3EuzpsFMCf2fozleB+JoRzKpCDI4BybXw qrCqEXum52MScExV/HqYPYlhrbGGjPkOZp360k= X-Received: by 2002:a17:90b:2e04:b0:35b:982a:28d9 with SMTP id 98e67ed59e1d1-35bb9e3b705mr4266431a91.4.1773862607823; Wed, 18 Mar 2026 12:36:47 -0700 (PDT) Received: from visitorckw-work01.c.googlers.com.com (100.130.194.35.bc.googleusercontent.com. [35.194.130.100]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-35bb9ff59a4sm1521664a91.2.2026.03.18.12.36.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Mar 2026 12:36:47 -0700 (PDT) From: Kuan-Wei Chiu To: andrew@codeconstruct.com.au, avifishman70@gmail.com, tmaimon77@gmail.com, tali.perry1@gmail.com, srini@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org Cc: venture@google.com, yuenn@google.com, benjaminfair@google.com, jserv@ccns.ncku.edu.tw, eleanor15x@gmail.com, linux-arm-kernel@lists.infradead.org, openbmc@lists.ozlabs.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Kuan-Wei Chiu Subject: [PATCH 2/3] nvmem: npcm-otp: Add Nuvoton NPCM OTP driver Date: Wed, 18 Mar 2026 19:35:37 +0000 Message-ID: <20260318193538.246853-3-visitorckw@gmail.com> X-Mailer: git-send-email 2.53.0.851.ga537e3e6e9-goog In-Reply-To: <20260318193538.246853-1-visitorckw@gmail.com> References: <20260318193538.246853-1-visitorckw@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a new NVMEM driver for the OTP memory controllers found on Nuvoton NPCM SoCs. This OTP is read-only and manages two independent arrays: Key Storage and Fuse Array, which contain cryptographic keys, hardware strapping, and calibration data. Each array provides 1024 bytes of storage. It can be accessed by writing the target address and a read command to the control registers, and then polling a status register until the data is ready. Concurrent accesses are protected by a mutex. Signed-off-by: Kuan-Wei Chiu --- MAINTAINERS | 7 +++ drivers/nvmem/Kconfig | 10 +++ drivers/nvmem/Makefile | 2 + drivers/nvmem/npcm-otp.c | 129 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 148 insertions(+) create mode 100644 drivers/nvmem/npcm-otp.c diff --git a/MAINTAINERS b/MAINTAINERS index 61bf550fd37c..e391e2bcb5f6 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18894,6 +18894,13 @@ F: drivers/nubus/ F: include/linux/nubus.h F: include/uapi/linux/nubus.h =20 +NUVOTON NPCM OTP NVMEM DRIVER +M: Kuan-Wei Chiu +L: linux-arm-kernel@lists.infradead.org (moderated for non-subscribers) +S: Maintained +F: Documentation/devicetree/bindings/nvmem/nuvoton,npcm750-otp.yaml +F: drivers/nvmem/npcm-otp.c + NUVOTON NCT6694 MFD DRIVER M: Ming Yu S: Supported diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index 74ddbd0f79b0..5d065b7448ff 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -483,4 +483,14 @@ config NVMEM_QORIQ_EFUSE This driver can also be built as a module. If so, the module will be called nvmem_qoriq_efuse. =20 +config NVMEM_NPCM_OTP + tristate "Nuvoton NPCM7xx OTP Controller" + depends on ARCH_NPCM || COMPILE_TEST + help + This option enables support for the OTP (One-Time Programmable) + controller found on Nuvoton NPCM7xx BMCs. + + This driver can also be built as a module. If so, the module + will be called npcm-otp. + endif diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index 7252b8ec88d4..63c23b304d64 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -95,3 +95,5 @@ obj-$(CONFIG_NVMEM_ZYNQMP) +=3D nvmem_zynqmp_nvmem.o nvmem_zynqmp_nvmem-y :=3D zynqmp_nvmem.o obj-$(CONFIG_NVMEM_QORIQ_EFUSE) +=3D nvmem-qoriq-efuse.o nvmem-qoriq-efuse-y :=3D qoriq-efuse.o +obj-$(CONFIG_NVMEM_NPCM_OTP) +=3D nvmem-npcm-otp.o +nvmem-npcm-otp-y :=3D npcm-otp.o diff --git a/drivers/nvmem/npcm-otp.c b/drivers/nvmem/npcm-otp.c new file mode 100644 index 000000000000..abe4bab66c06 --- /dev/null +++ b/drivers/nvmem/npcm-otp.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Nuvoton NPCM7xx OTP (One-Time Programmable) NVMEM driver + * + * Copyright (C) 2026 Kuan-Wei Chiu + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Register offsets and bitmasks */ +#define NPCM_OTP_FST 0x00 +#define NPCM_OTP_FADDR 0x04 +#define NPCM_OTP_FDATA 0x08 +#define NPCM_OTP_FCTL 0x14 + +#define FST_RDY BIT(0) +#define FST_RDST BIT(1) +#define FCTL_READ_CMD 0x02 + +/* OTP total capacity is 8192 bits (1024 Bytes) */ +#define NPCM_OTP_SIZE 1024 + +struct npcm_otp { + void __iomem *base; + struct mutex lock; /* protects concurrent OTP accesses */ +}; + +static int npcm_otp_read_byte(struct npcm_otp *otp, unsigned int offset, u= 8 *val) +{ + u32 fst; + int ret; + + writel(offset, otp->base + NPCM_OTP_FADDR); + writel(FCTL_READ_CMD, otp->base + NPCM_OTP_FCTL); + + ret =3D readl_poll_timeout(otp->base + NPCM_OTP_FST, fst, + (fst & FST_RDY), 10, 10000); + if (ret) + return ret; + + *val =3D (u8)(readl(otp->base + NPCM_OTP_FDATA) & 0xFF); + + /* Clear the status bit to prepare for the next read */ + writel(FST_RDST, otp->base + NPCM_OTP_FST); + + return 0; +} + +static int npcm_otp_read(void *context, unsigned int offset, + void *val, size_t bytes) +{ + struct npcm_otp *otp =3D context; + u8 *buf =3D val; + int ret =3D 0; + size_t i; + + mutex_lock(&otp->lock); + + for (i =3D 0; i < bytes; i++) { + ret =3D npcm_otp_read_byte(otp, offset + i, &buf[i]); + if (ret) + break; + } + + mutex_unlock(&otp->lock); + + return ret; +} + +static int npcm_otp_probe(struct platform_device *pdev) +{ + struct device *dev =3D &pdev->dev; + struct npcm_otp *otp; + struct nvmem_config config =3D { 0 }; + struct nvmem_device *nvmem; + + otp =3D devm_kzalloc(dev, sizeof(*otp), GFP_KERNEL); + if (!otp) + return -ENOMEM; + + otp->base =3D devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(otp->base)) + return PTR_ERR(otp->base); + + mutex_init(&otp->lock); + + config.dev =3D dev; + config.name =3D dev_name(dev); + config.read_only =3D true; + config.word_size =3D 1; + config.stride =3D 1; + config.reg_read =3D npcm_otp_read; + config.priv =3D otp; + config.size =3D NPCM_OTP_SIZE; + + nvmem =3D devm_nvmem_register(dev, &config); + if (IS_ERR(nvmem)) + return dev_err_probe(dev, PTR_ERR(nvmem), "Failed to register nvmem\n"); + + return 0; +} + +static const struct of_device_id npcm_otp_dt_ids[] =3D { + { .compatible =3D "nuvoton,npcm750-key-storage" }, + { .compatible =3D "nuvoton,npcm750-fuse-array" }, + { } +}; +MODULE_DEVICE_TABLE(of, npcm_otp_dt_ids); + +static struct platform_driver npcm_otp_driver =3D { + .probe =3D npcm_otp_probe, + .driver =3D { + .name =3D "npcm-otp", + .of_match_table =3D npcm_otp_dt_ids, + }, +}; +module_platform_driver(npcm_otp_driver); + +MODULE_AUTHOR("Kuan-Wei Chiu "); +MODULE_DESCRIPTION("Nuvoton NPCM7xx OTP NVMEM driver"); +MODULE_LICENSE("GPL"); --=20 2.53.0.851.ga537e3e6e9-goog