Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1034041AbcJRQI2 (ORCPT ); Tue, 18 Oct 2016 12:08:28 -0400 Received: from up.free-electrons.com ([163.172.77.33]:36631 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1031000AbcJRQIM (ORCPT ); Tue, 18 Oct 2016 12:08:12 -0400 Date: Tue, 18 Oct 2016 18:08:09 +0200 From: Alexandre Belloni To: VENKAT PRASHANTH B U Cc: linux-kernel@vger.kernel.org, a.zummo@towertech.it Subject: Re: [PATCH] rtc: add support for rtc NXP pca21125 Message-ID: <20161018160809.euibeokn5pciccy5@piout.net> References: <1476802044-6016-1-git-send-email-venkat.prashanth2498@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1476802044-6016-1-git-send-email-venkat.prashanth2498@gmail.com> User-Agent: NeoMutt/20160916 (1.7.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7341 Lines: 258 Hi, Don't forget to Cc the rtc-linux mailing list. Also, please please run checkpatch on your patches On 18/10/2016 at 07:47:24 -0700, VENKAT PRASHANTH B U wrote : > This is the patch to add support for > NXP rtc pca21125 > > Signed-off-by: Venkat Prashanth B U > --- > --- > drivers/rtc/Kconfig | 12 ++++ > drivers/rtc/Makefile | 1 + > drivers/rtc/rtc-pca21125.c | 164 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 177 insertions(+) > > diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig > index e215f50..df10e0e 100644 > --- a/drivers/rtc/Kconfig > +++ b/drivers/rtc/Kconfig > @@ -686,6 +686,18 @@ config RTC_DRV_MAX6916 > This driver can also be built as a module. If so, the module > will be called rtc-max6916. > > +config RTC_DRV_PCA21125 > + tristate "NXP PCA21125" > + help > + If you say yes here you will get support for the > + NXP PCA21125 SPI RTC chip. > + > + This driver only supports the RTC feature, and not other chip > + features such as alarms. > + > + This driver can also be built as a module. If so, the module > + will be called rtc-pca21125. > + > config RTC_DRV_R9701 > tristate "Epson RTC-9701JE" > help > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile > index 7cf7ad5..2c6af37 100644 > --- a/drivers/rtc/Makefile > +++ b/drivers/rtc/Makefile > @@ -105,6 +105,7 @@ obj-$(CONFIG_RTC_DRV_NUC900) += rtc-nuc900.o > obj-$(CONFIG_RTC_DRV_OMAP) += rtc-omap.o > obj-$(CONFIG_RTC_DRV_OPAL) += rtc-opal.o > obj-$(CONFIG_RTC_DRV_PALMAS) += rtc-palmas.o > +obj-$(CONFIG_RTC_DRV_PCA21125) += rtc-pca21125.o > obj-$(CONFIG_RTC_DRV_PCAP) += rtc-pcap.o > obj-$(CONFIG_RTC_DRV_PCF2123) += rtc-pcf2123.o > obj-$(CONFIG_RTC_DRV_PCF2127) += rtc-pcf2127.o > diff --git a/drivers/rtc/rtc-pca21125.c b/drivers/rtc/rtc-pca21125.c > index e69de29..8d42e4e 100644 > --- a/drivers/rtc/rtc-pca21125.c > +++ b/drivers/rtc/rtc-pca21125.c The whole file is badly indented > @@ -0,0 +1,164 @@ > + /* rtc-pca21125.c > + * > + * Driver for NXP PCA21125 CMOS, SPI Compatible > + * Real Time Clock > + * > + * Author : Venkat Prashanth B U > + * > + * 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 > + > + /* Registers in pca21125 rtc */ > + > + #define PCA21125_SECONDS_REG 0x02 > + #define PCA21125_MINUTES_REG 0x03 > + #define PCA21125_HOURS_REG 0x04 > + #define PCA21125_DATE_REG 0x05 > + #define PCA21125_DAY_REG 0x06 > + #define PCA21125_MONTH_REG 0x07 > + #define PCA21125_YEAR_REG 0x08 Those are defined but not used > + #define PCA21125_CONTROL_REG 0x01 > + #define PCA21125_STATUS_REG 0x00 > + #define PCA21125_CLOCK_BURST 0x0D > + > + static int pca21125_read_reg(struct device *dev, unsigned char address, > + unsigned char *data) > + { > + struct spi_device *spi = to_spi_device(dev); > + > + *data = address | 0x80; > + > + return spi_write_then_read(spi, data, 1, data, 1); > + } > + > + static int pca21125_write_reg(struct device *dev, unsigned char address, > + unsigned char data) > + { > + struct spi_device *spi = to_spi_device(dev); > + unsigned char buf[2]; > + > + buf[0] = address & 0x7F; > + buf[1] = data; > + > + return spi_write_then_read(spi, buf, 2, NULL, 0); > + } > + > + static int pca21125_read_time(struct device *dev, struct rtc_time *dt) > + { > + struct spi_device *spi = to_spi_device(dev); > + int err; > + unsigned char buf[8]; > + > + buf[0] = PCA21125_CLOCK_BURST | 0x80; > + > + err = spi_write_then_read(spi, buf, 1, buf, 8); > + > + if (err) > + return err; > + I'm not sure to understand how this can actually work, time/date starts at 0x2 > + dt->tm_sec = bcd2bin(buf[0]); > + dt->tm_min = bcd2bin(buf[1]); > + dt->tm_hour = bcd2bin(buf[2] & 0x3F); > + dt->tm_mday = bcd2bin(buf[3]); > + dt->tm_mon = bcd2bin(buf[4]) - 1; > + dt->tm_wday = bcd2bin(buf[5]) - 1; > + dt->tm_year = bcd2bin(buf[6]) + 100; > + > + return rtc_valid_tm(dt); > + } > + > + static int pca21125_set_time(struct device *dev, struct rtc_time *dt) > + { > + struct spi_device *spi = to_spi_device(dev); > + unsigned char buf[9]; > + > + if (dt->tm_year < 100 || dt->tm_year > 199) { > + dev_err(&spi->dev, "Year must be between 2000 and 2099. It's %d.\n", > + dt->tm_year + 1900); > + return -EINVAL; > + } > + > + buf[0] = bin2bcd(dt->tm_sec); > + buf[1] = bin2bcd(dt->tm_min); > + buf[2] = (bin2bcd(dt->tm_hour) & 0X3F); > + buf[3] = bin2bcd(dt->tm_mday); > + buf[4] = bin2bcd(dt->tm_mon + 1); > + buf[5] = bin2bcd(dt->tm_wday + 1); > + buf[6] = bin2bcd(dt->tm_year % 100); > + buf[7] = bin2bcd(0x00); > + Isn't it necessary to write the address on the bus first? How does that work? > + /* write the rtc settings */ > + return spi_write_then_read(spi, buf, 9, NULL, 0); > + } > + > + static const struct rtc_class_ops pca21125_rtc_ops = { > + .read_time = pca21125_read_time, > + .set_time = pca21125_set_time, > + }; > + > + static int pca21125_probe(struct spi_device *spi) > + { > + struct rtc_device *rtc; > + unsigned char data; > + int res; > + > + /* spi setup with pca21125 in mode 3 and bits per word as 8 */ > + spi->mode = SPI_MODE_3; > + spi->bits_per_word = 8; > + spi_setup(spi); > + > + /* RTC Settings */ > + res = pca21125_read_reg(&spi->dev, PCA21125_SECONDS_REG, &data); > + if (res) > + return res; > + Is that read useful? > + /* Disable the write protect of rtc */ > + pca21125_read_reg(&spi->dev, PCA21125_CONTROL_REG, &data); > + data = data & ~(1 << 7); This is a magic value, please use a define > + pca21125_write_reg(&spi->dev, PCA21125_CONTROL_REG, data); > + > + /*Enable oscillator,disable oscillator stop flag, glitch filter*/ > + pca21125_read_reg(&spi->dev, PCA21125_STATUS_REG, &data); > + data = data & 0x1B; ditto > + pca21125_write_reg(&spi->dev, PCA21125_STATUS_REG, data); > + > + /* display the settings */ > + pca21125_read_reg(&spi->dev, PCA21125_CONTROL_REG, &data); > + dev_info(&spi->dev, "PCA21125 RTC CTRL Reg = 0x%02x\n", data); > + I don't think anybody actually cares about that information > + pca21125_read_reg(&spi->dev, PCA21125_STATUS_REG, &data); > + dev_info(&spi->dev, "PCA21125 RTC Status Reg = 0x%02x\n", data); > + ditto > + rtc = devm_rtc_device_register(&spi->dev, "pca21125", > + &pca21125_rtc_ops, THIS_MODULE); > + if (IS_ERR(rtc)) > + return PTR_ERR(rtc); > + > + spi_set_drvdata(spi, rtc); > + > + return 0; > + } > + > + static struct spi_driver pca21125_driver = { > + .driver = { > + .name = "pca21125", > + }, > + .probe = pca21125_probe, > + }; > + module_spi_driver(pca21125_driver); > + > + MODULE_DESCRIPTION("PCA21125 SPI RTC DRIVER"); > + MODULE_AUTHOR("Venkat Prashanth B U "); > + MODULE_LICENSE("GPL v2"); > + > -- > 1.9.2 > -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com