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 AFF9FC7EE2C for ; Wed, 24 May 2023 07:52:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240093AbjEXHw0 (ORCPT ); Wed, 24 May 2023 03:52:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232910AbjEXHwY (ORCPT ); Wed, 24 May 2023 03:52:24 -0400 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E4A6E91; Wed, 24 May 2023 00:52:21 -0700 (PDT) Received: from loongson.cn (unknown [10.20.42.35]) by gateway (Coremail) with SMTP id _____8DxqvI0wm1kx1gAAA--.1050S3; Wed, 24 May 2023 15:52:20 +0800 (CST) Received: from [10.20.42.35] (unknown [10.20.42.35]) by localhost.localdomain (Coremail) with SMTP id AQAAf8AxQbQywm1ku2pzAA--.61392S3; Wed, 24 May 2023 15:52:19 +0800 (CST) Subject: Re: [PATCH v11 2/2] spi: loongson: add bus driver for the loongson spi controller To: andy.shevchenko@gmail.com Cc: Mark Brown , Rob Herring , Krzysztof Kozlowski , linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Jianmin Lv , wanghongliang@loongson.cn, Liu Peibao , loongson-kernel@lists.loongnix.cn, zhuyinbo@loongson.cn References: <20230522071030.5193-1-zhuyinbo@loongson.cn> <20230522071030.5193-3-zhuyinbo@loongson.cn> From: zhuyinbo Message-ID: <35b0500c-d7fe-6479-eeff-d45bbf9a9426@loongson.cn> Date: Wed, 24 May 2023 15:52:18 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=gbk; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID: AQAAf8AxQbQywm1ku2pzAA--.61392S3 X-CM-SenderInfo: 52kx5xhqerqz5rrqw2lrqou0/ X-Coremail-Antispam: 1Uk129KBjvJXoW3AFyfGFy3ArW8CryrtF15CFg_yoW3JFW5pF 48Aa15KFWSyr4Iyw18XFs5GF4Yqry3J3W7JFWav3y8Kr98Zw1xXa45KF1fCr4SvFZ5ZF1x ZFWUur4kCFs8C3DanT9S1TB71UUUUUDqnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU bxkFc2x0x2IEx4CE42xK8VAvwI8IcIk0rVWrJVCq3wAFIxvE14AKwVWUXVWUAwA2ocxC64 kIII0Yj41l84x0c7CEw4AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28E F7xvwVC0I7IYx2IY6xkF7I0E14v26r4j6F4UM28EF7xvwVC2z280aVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gr1j6F4UJwAS0I0E0xvYzxvE52x082IY62kv0487 Mc804VCY07AIYIkI8VC2zVCFFI0UMc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUXVWUAwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcVAKI48JMxk0xIA0c2IEe2xFo4CEbIxvr21l42xK82IYc2Ij64vIr41l42xK82IY6x 8ErcxFaVAv8VWrMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4l x2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrw CI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwCI 42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z2 80aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU8c_-PUUUUU== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ÔÚ 2023/5/23 ÏÂÎç8:54, andy.shevchenko@gmail.com дµÀ: > Mon, May 22, 2023 at 03:10:30PM +0800, Yinbo Zhu kirjoitti: >> This bus driver supports the Loongson SPI hardware controller in the >> Loongson platforms and supports to use DTS and PCI framework to >> register SPI device resources. > > It's polite to add reviewers of the previous versions to the Cc list. okay, I got it. > > ... > >> +static void loongson_spi_set_clk(struct loongson_spi *loongson_spi, unsigned int hz) >> +{ >> + unsigned char val; >> + unsigned int div, div_tmp; > >> + const char rdiv[12] = {0, 1, 4, 2, 3, 5, 6, 7, 8, 9, 10, 11}; > > static? okay, I will define "static const char rdiv". > >> + >> + div = clamp_val(DIV_ROUND_UP_ULL(loongson_spi->clk_rate, hz), 2, 4096); >> + div_tmp = rdiv[fls(div - 1)]; >> + loongson_spi->spcr = (div_tmp & GENMASK(1, 0)) >> 0; >> + loongson_spi->sper = (div_tmp & GENMASK(3, 2)) >> 2; >> + val = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPCR_REG); >> + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPCR_REG, (val & ~3) | >> + loongson_spi->spcr); >> + val = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPER_REG); >> + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPER_REG, (val & ~3) | >> + loongson_spi->sper); >> + loongson_spi->hz = hz; >> +} > > ... > >> +static int loongson_spi_update_state(struct loongson_spi *loongson_spi, >> + struct spi_device *spi, struct spi_transfer *t) >> +{ >> + unsigned int hz; >> + >> + if (t) >> + hz = t->speed_hz; > > And if t is NULL? hz will be uninitialized. Don't you get a compiler warning? > (Always test your code with `make W=1 ...`) I alwasy use `make W=1` and I don't find any warnig, but that what you said was right and I will initial hz. > >> + if (hz && loongson_spi->hz != hz) >> + loongson_spi_set_clk(loongson_spi, hz); >> + >> + if ((spi->mode ^ loongson_spi->mode) & SPI_MODE_X_MASK) >> + loongson_spi_set_mode(loongson_spi, spi); >> + >> + return 0; >> +} > > ... > >> + readb_poll_timeout(loongson_spi->base + LOONGSON_SPI_SPSR_REG, loongson_spi->spsr, >> + (loongson_spi->spsr & 0x1) != 1, 1, MSEC_PER_SEC); > > Wouldn't be better to use ' == 0' in the conditional? Or if you think your > approach is better (to show the exact expectation) the definition of the bit 0 > might help > > #define LOONGSON_... BIT(0) okay, I got it. > > > readb_poll_timeout(loongson_spi->base + LOONGSON_SPI_SPSR_REG, loongson_spi->spsr, > (loongson_spi->spsr & LOONGSON_...) != LOONGSON_..., > 1, MSEC_PER_SEC); > > ... > >> + do { >> + if (loongson_spi_write_read_8bit(spi, &tx, &rx, count) < 0) > >> + goto out; > > break; > >> + count--; >> + } while (count); > > } while (--count); > > ? okay, I got it. > >> +out: >> + return xfer->len - count; > > Shouldn't you return an error code if the write failed? okay, I got it. I will add a error code for return when write failed. > > ... > >> + master = devm_spi_alloc_master(dev, sizeof(struct loongson_spi)); > >> + if (master == NULL) > > if (!master) > >> + return -ENOMEM; > > Why do you use deprecated naming? Can you use spi_controller* instead of > spi_master* in all cases? It seems was a personal code style issue and I don't find the differences between spi_controller and spi_master, Using spi_controller* is also acceptable to me and I will use spi_controller* instead of spi_master* in all cases. > > ... > >> + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; > > = SPI_MODE_X_MASK | SPI_CS_HIGH; > > ... > >> + clk = devm_clk_get_optional(dev, NULL); >> + if (!IS_ERR(clk)) >> + spi->clk_rate = clk_get_rate(clk); > >> + else > > Redundant. Just check for the error first as it's very usual pattern in the > Linux kernel. Like below ? clk = devm_clk_get_optional(dev, NULL); - if (!IS_ERR(clk)) - spi->clk_rate = clk_get_rate(clk); - else + if (IS_ERR(clk)) return dev_err_probe(dev, PTR_ERR(clk), "unable to get clock\n"); + spi->clk_rate = clk_get_rate(clk); loongson_spi_reginit(spi); > >> + return dev_err_probe(dev, PTR_ERR(clk), "unable to get clock\n"); > > ... > >> +static void loongson_spi_pci_unregister(struct pci_dev *pdev) >> +{ > >> + pcim_iounmap_regions(pdev, BIT(0)); > > Not needed due to 'm' in the API name, which means "managed". > >> + pci_disable_device(pdev); > > This is simply wrong. We don't do explicit clean up for managed resources. > >> +} > > That said, drop the ->remove() completely. okay, I will drop the ->remove() completely. > > ... > >> +static struct pci_device_id loongson_spi_devices[] = { >> + { PCI_DEVICE(PCI_VENDOR_ID_LOONGSON, 0x7a0b) }, >> + { PCI_DEVICE(PCI_VENDOR_ID_LOONGSON, 0x7a1b) }, >> + { }, > > No comma for the terminator entry. It's by definition "terminating" something. okay, I got it. > >> +}; > > ... > >> +#include > > There is no user of this header. Please, replace with what actually is being > used (presumably mod_devicetable.h and maybe others). > okay, I got it. >> +#include >> + >> +#include "spi-loongson.h" >> + >> +static int loongson_spi_platform_probe(struct platform_device *pdev) >> +{ >> + int ret; >> + void __iomem *reg_base; >> + struct device *dev = &pdev->dev; >> + >> + reg_base = devm_platform_ioremap_resource(pdev, 0); >> + if (IS_ERR(reg_base)) >> + return PTR_ERR(reg_base); >> + >> + ret = loongson_spi_init_master(dev, reg_base); >> + if (ret) >> + return dev_err_probe(dev, ret, "failed to initialize master\n"); >> + >> + return ret; > > return 0; It seems was more appropriate that initialize ret then return ret. Do you think so ? > >> +} > > ... > >> +#ifndef __LINUX_SPI_LOONGSON_H >> +#define __LINUX_SPI_LOONGSON_H >> + >> +#include > >> +#include > > This header is not used. okay, I got it. > >> +#include > >> +#include > > This neither. That other .c file seems to need it and I will move it to other .c code file. > >> +#include > > > For them use forward declarations > > struct device; > struct spi_controller; > > The rest of the inclusions is correct. okay, I got it. > > ... > >> +#define LOONGSON_SPI_SPCR_REG 0x00 >> +#define LOONGSON_SPI_SPSR_REG 0x01 >> +#define LOONGSON_SPI_FIFO_REG 0x02 >> +#define LOONGSON_SPI_SPER_REG 0x03 >> +#define LOONGSON_SPI_PARA_REG 0x04 >> +#define LOONGSON_SPI_SFCS_REG 0x05 >> +#define LOONGSON_SPI_TIMI_REG 0x06 > > Where is this used outside of the main driver? These definitions are only used in core.c > >> +/* Bits definition for Loongson SPI register */ >> +#define LOONGSON_SPI_PARA_MEM_EN BIT(0) >> +#define LOONGSON_SPI_SPCR_CPHA BIT(2) >> +#define LOONGSON_SPI_SPCR_CPOL BIT(3) >> +#define LOONGSON_SPI_SPCR_SPE BIT(6) >> +#define LOONGSON_SPI_SPSR_WCOL BIT(6) >> +#define LOONGSON_SPI_SPSR_SPIF BIT(7) >> + >> +struct loongson_spi { >> + struct spi_master *master; >> + void __iomem *base; >> + int cs_active; >> + unsigned int hz; >> + unsigned char spcr; >> + unsigned char sper; >> + unsigned char spsr; >> + unsigned char para; >> + unsigned char sfcs; >> + unsigned char timi; >> + unsigned int mode; >> + u64 clk_rate; >> +}; >> + >> +int loongson_spi_init_master(struct device *dev, void __iomem *reg); >> +extern const struct dev_pm_ops loongson_spi_dev_pm_ops; >> +#endif /* __LINUX_SPI_LOONGSON_H */ >