Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751511AbdFGQon (ORCPT ); Wed, 7 Jun 2017 12:44:43 -0400 Received: from mail-wr0-f170.google.com ([209.85.128.170]:33573 "EHLO mail-wr0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751382AbdFGQol (ORCPT ); Wed, 7 Jun 2017 12:44:41 -0400 Subject: Re: [PATCH v3 2/3] nvmem: add snvs_lpgpr driver To: Oleksij Rempel , devicetree@vger.kernel.org, kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mark Rutland , Maxime Ripard , Rob Herring , Shawn Guo References: <20170607064158.16422-1-o.rempel@pengutronix.de> <20170607064158.16422-3-o.rempel@pengutronix.de> From: Srinivas Kandagatla Message-ID: Date: Wed, 7 Jun 2017 17:44:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20170607064158.16422-3-o.rempel@pengutronix.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6156 Lines: 223 On 07/06/17 07:41, Oleksij Rempel wrote: > This is a driver for Low Power General Purpose Register (LPGPR) > available on i.MX6 SoCs in Secure Non-Volatile Storage (SNVS) > of this chip. > > It is a 32-bit read/write register located in the low power domain. > Since LPGPR is located in the battery-backed power domain, LPGPR can > be used by any application for retaining data during an SoC power-down > mode. > > Signed-off-by: Oleksij Rempel > --- > drivers/nvmem/Kconfig | 13 +++++ > drivers/nvmem/Makefile | 2 + > drivers/nvmem/snvs_lpgpr.c | 143 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 158 insertions(+) > create mode 100644 drivers/nvmem/snvs_lpgpr.c Minor comments... > > diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig > index 101ced4c84be..00537b91cc22 100644 > --- a/drivers/nvmem/Kconfig > +++ b/drivers/nvmem/Kconfig > @@ -144,4 +144,17 @@ config MESON_EFUSE > This driver can also be built as a module. If so, the module > will be called nvmem_meson_efuse. > > +config NVMEM_SNVS_LPGPR > + tristate "Support for Low Power General Purpose Register" <-- > + depends on HAS_IOMEM > + depends on OF > + select REGMAP_MMIO --> Not sure why we need this selects here, if you are accessing regmap via syscon. Consider adding COMPILE_TEST so that driver gets good test coverage. > + select MFD_SYSCON > + help > + This is a driver for Low Power General Purpose Register (LPGPR) available on > + i.MX6 SoCs in Secure Non-Volatile Storage (SNVS) of this chip. > + > + This driver can also be built as a module. If so, the module > + will be called nvmem-snvs-lpgpr. > + > endif > diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile > index 173140658693..4c589184acee 100644 > --- a/drivers/nvmem/Makefile > +++ b/drivers/nvmem/Makefile > @@ -30,3 +30,5 @@ obj-$(CONFIG_NVMEM_VF610_OCOTP) += nvmem-vf610-ocotp.o > nvmem-vf610-ocotp-y := vf610-ocotp.o > obj-$(CONFIG_MESON_EFUSE) += nvmem_meson_efuse.o > nvmem_meson_efuse-y := meson-efuse.o > +obj-$(CONFIG_NVMEM_SNVS_LPGPR) += nvmem_snvs_lpgpr.o > +nvmem_snvs_lpgpr-y := snvs_lpgpr.o > diff --git a/drivers/nvmem/snvs_lpgpr.c b/drivers/nvmem/snvs_lpgpr.c > new file mode 100644 > index 000000000000..c90a8e8a161f > --- /dev/null > +++ b/drivers/nvmem/snvs_lpgpr.c > @@ -0,0 +1,143 @@ > +/* > + * Copyright (c) 2015 Pengutronix, Steffen Trumtrar > + * Copyright (c) 2017 Pengutronix, Oleksij Rempel > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 > + * as published by the Free Software Foundation. > + */ > + > +#include ?? > +#include > +#include ?? > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct snvs_lpgpr_priv { > + struct device_d *dev; > + struct regmap *regmap; > + int offset; > + struct nvmem_config cfg; > +}; > + > +struct snvs_lpgpr_cfg { > + int offset; > +}; > + > +static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = { > + .offset = 0x68, > +}; > + > +static int snvs_lpgpr_write(void *context, unsigned int offset, void *_val, > + size_t bytes) > +{ > + struct snvs_lpgpr_priv *priv = context; > + const u32 *val = _val; > + int i = 0, words = bytes / 4; > + > + while (words--) > + regmap_write(priv->regmap, priv->offset + offset + (i++ * 4), > + *val++); > + > + return 0; > +} > + > +static int snvs_lpgpr_read(void *context, unsigned int offset, void *_val, > + size_t bytes) > +{ > + struct snvs_lpgpr_priv *priv = context; > + u32 *val = _val; > + int i = 0, words = bytes / 4; > + > + while (words--) > + regmap_read(priv->regmap, priv->offset + offset + (i++ * 4), > + val++); > + > + return 0; > +} > + > +static int snvs_lpgpr_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct device_node *node = dev->of_node; > + struct device_node *syscon_node; > + struct snvs_lpgpr_priv *priv; > + struct nvmem_config *cfg; > + struct nvmem_device *nvmem; > + const struct snvs_lpgpr_cfg *dcfg; > + int err; > + > + if (!node) > + return -ENOENT; > + > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + dcfg = of_device_get_match_data(dev); > + if (!dcfg) > + return -EINVAL; > + > + syscon_node = of_get_parent(node); > + if (!syscon_node) > + return -ENODEV; > + > + priv->regmap = syscon_node_to_regmap(syscon_node); > + of_node_put(syscon_node); > + if (IS_ERR(priv->regmap)) > + return PTR_ERR(priv->regmap); > + > + priv->offset = dcfg->offset; > + > + cfg = &priv->cfg; > + cfg->priv = priv; > + cfg->name = dev_name(dev); > + cfg->dev = dev; > + cfg->stride = 4, > + cfg->word_size = 4, > + cfg->size = 4, > + cfg->owner = THIS_MODULE, > + cfg->reg_read = snvs_lpgpr_read, > + cfg->reg_write = snvs_lpgpr_write, > + > + nvmem = nvmem_register(cfg); > + if (IS_ERR(nvmem)) > + return PTR_ERR(nvmem); > + > + platform_set_drvdata(pdev, nvmem); > + > + return 0; > +} > + > +static int snvs_lpgpr_remove(struct platform_device *pdev) > +{ > + struct nvmem_device *nvmem = platform_get_drvdata(pdev); > + > + return nvmem_unregister(nvmem); > +} > + > +static const struct of_device_id snvs_lpgpr_dt_ids[] = { > + { .compatible = "fsl,imx6q-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx6q }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids); > + > +static struct platform_driver snvs_lpgpr_driver = { > + .probe = snvs_lpgpr_probe, > + .remove = snvs_lpgpr_remove, > + .driver = { > + .name = "snvs_lpgpr", > + .of_match_table = snvs_lpgpr_dt_ids, > + }, > +}; > +module_platform_driver(snvs_lpgpr_driver); > + > +MODULE_AUTHOR("Oleksij Rempel "); > +MODULE_DESCRIPTION("Low Power General Purpose Register in i.MX6 Secure Non-Volatile Storage"); > +MODULE_LICENSE("GPL"); GPLv2?? >