Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757408AbbLBXlD (ORCPT ); Wed, 2 Dec 2015 18:41:03 -0500 Received: from down.free-electrons.com ([37.187.137.238]:53223 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755306AbbLBXlA (ORCPT ); Wed, 2 Dec 2015 18:41:00 -0500 Date: Thu, 3 Dec 2015 00:40:58 +0100 From: Alexandre Belloni To: Akshay Bhat Cc: a.zummo@towertech.it, rtc-linux@googlegroups.com, linux-kernel@vger.kernel.org, justin.waters@timesys.com Subject: Re: [PATCH] rtc: Add Epson RX8010SJ RTC driver Message-ID: <20151202234058.GG22136@piout.net> References: <1447281118-25275-1-git-send-email-akshay.bhat@timesys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1447281118-25275-1-git-send-email-akshay.bhat@timesys.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8619 Lines: 296 On 11/11/2015 at 17:31:58 -0500, Akshay Bhat wrote : > diff --git a/drivers/rtc/rtc-rx8010.c b/drivers/rtc/rtc-rx8010.c > new file mode 100644 > index 0000000..9b8bd76 > --- /dev/null > +++ b/drivers/rtc/rtc-rx8010.c > @@ -0,0 +1,570 @@ > +/* > + * Driver for the Epson RTC module RX-8010 SJ > + * > + * Copyright(C) Timesys Corporation 2015 > + * Copyright(C) General Electric Company 2015 > + * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved. > + * > + * Derived from RX-8025 driver: > + * Copyright (C) 2009 Wolfgang Grandegger > + * > + * Copyright (C) 2005 by Digi International Inc. > + * All rights reserved. > + * > + * Modified by fengjh at rising.com.cn > + * > + * 2006.11 > + * > + * Code cleanup by Sergei Poselenov, > + * Converted to new style by Wolfgang Grandegger > + * Alarm and periodic interrupt added by Dmitry Rakhchev > + * Please remove all those unnecessary copyrights, the original rx-8025 has been heavily rewritten anyway. > +static int rx8010_read_reg(struct i2c_client *client, int number, u8 *value) > +{ > + int ret = i2c_smbus_read_byte_data(client, number); > + > + if (ret < 0) > + return ret; > + > + *value = ret; > + return 0; > +} I don't see the benefit of that function, calling i2c_smbus_read_byte_data directly is more efficient. > + > +static int rx8010_read_regs(struct i2c_client *client, int number, u8 length, > + u8 *values) > +{ > + int ret = i2c_smbus_read_i2c_block_data(client, number, length, values); > + > + if (ret != length) > + return ret < 0 ? ret : -EIO; > + > + return 0; > +} Apart from the error handling, I'd say the same for that function. > + > +static irqreturn_t rx8010_irq_1_handler(int irq, void *dev_id) > +{ > + struct i2c_client *client = dev_id; > + struct rx8010_data *rx8010 = i2c_get_clientdata(client); > + u8 flagreg; > + > + spin_lock(&rx8010->flags_lock); > + > + if (rx8010_read_reg(client, RX8010_FLAG, &flagreg)) { > + spin_unlock(&rx8010->flags_lock); > + return IRQ_NONE; > + } > + > + if (flagreg & RX8010_FLAG_VLF) > + dev_warn(&client->dev, "Frequency stop detected\n"); > + > + if (flagreg & RX8010_FLAG_TF) { > + flagreg &= ~RX8010_FLAG_TF; > + rtc_update_irq(rx8010->rtc, 1, RTC_PF | RTC_IRQF); > + } > + > + if (flagreg & RX8010_FLAG_AF) { > + flagreg &= ~RX8010_FLAG_AF; > + rtc_update_irq(rx8010->rtc, 1, RTC_AF | RTC_IRQF); > + } > + > + if (flagreg & RX8010_FLAG_UF) { > + flagreg &= ~RX8010_FLAG_UF; > + rtc_update_irq(rx8010->rtc, 1, RTC_UF | RTC_IRQF); > + } > + > + i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg); > + > + spin_unlock(&rx8010->flags_lock); > + return IRQ_HANDLED; > +} > + > +static int rx8010_get_time(struct device *dev, struct rtc_time *dt) > +{ > + struct rx8010_data *rx8010 = dev_get_drvdata(dev); > + u8 date[7]; > + u8 flagreg; > + int err; > + > + err = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg); > + if (err) > + return err; > + > + if (flagreg & RX8010_FLAG_VLF) { > + dev_warn(dev, "Frequency stop detected\n"); > + return -EINVAL; > + } > + > + err = rx8010_read_regs(rx8010->client, RX8010_SEC, 7, date); > + if (err) > + return err; > + > + dt->tm_sec = bcd2bin(date[RX8010_SEC-RX8010_SEC] & 0x7f); > + dt->tm_min = bcd2bin(date[RX8010_MIN-RX8010_SEC] & 0x7f); > + dt->tm_hour = bcd2bin(date[RX8010_HOUR-RX8010_SEC] & 0x3f); > + dt->tm_mday = bcd2bin(date[RX8010_MDAY-RX8010_SEC] & 0x3f); > + dt->tm_mon = bcd2bin(date[RX8010_MONTH-RX8010_SEC] & 0x1f) - 1; > + dt->tm_year = bcd2bin(date[RX8010_YEAR-RX8010_SEC]); > + dt->tm_wday = bcd2bin(date[RX8010_WDAY-RX8010_SEC] & 0x7f); > + This is not the correct value for tm_wday, you should use ffs(), not that anybody actually cares. Also, checkpatch --strict complains about missing spaces around those '-' and a few alignments are not correct, can fix those? > + if (dt->tm_year < 70) > + dt->tm_year += 100; > + I'd say that we don't care about handling dates before 2000 and that the range should be 2000-2100 as this is actually the range where the leap year calculation is correct. Also your are not respecting that in rx8010_set_time() so setting a date in 2072 will end up reading 1972. > + return rtc_valid_tm(dt); > +} > + > +static int rx8010_set_time(struct device *dev, struct rtc_time *dt) > +{ > + struct rx8010_data *rx8010 = dev_get_drvdata(dev); > + u8 date[7]; > + u8 ctrl, flagreg; > + int ret; > + unsigned long irqflags; > + > + /* BUG: The HW assumes every year that is a multiple of 4 to be a leap > + * year. Next time this is wrong is 2100, which will not be a leap > + * year. > + */ > + Then, return -EINVAL if the year is out of the 100-200 range. > + /* set STOP bit before changing clock/calendar */ > + ret = rx8010_read_reg(rx8010->client, RX8010_CTRL, &ctrl); > + if (ret) > + return ret; > + rx8010->ctrlreg = ctrl | RX8010_CTRL_STOP; > + ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL, > + rx8010->ctrlreg); > + if (ret < 0) > + return ret; > + > + date[RX8010_SEC-RX8010_SEC] = bin2bcd(dt->tm_sec); > + date[RX8010_MIN-RX8010_SEC] = bin2bcd(dt->tm_min); > + date[RX8010_HOUR-RX8010_SEC] = bin2bcd(dt->tm_hour); > + date[RX8010_MDAY-RX8010_SEC] = bin2bcd(dt->tm_mday); > + date[RX8010_MONTH-RX8010_SEC] = bin2bcd(dt->tm_mon + 1); > + date[RX8010_YEAR-RX8010_SEC] = bin2bcd(dt->tm_year % 100); > + date[RX8010_WDAY-RX8010_SEC] = bin2bcd(dt->tm_wday); this is not the expected value for RX8010_WDAY, it must be 1 << dt->tm_wday, see the datasheet. > + > + ret = i2c_smbus_write_i2c_block_data(rx8010->client, > + RX8010_SEC, 7, date); > + if (ret < 0) > + return ret; > + > + /* clear STOP bit after changing clock/calendar */ > + ret = rx8010_read_reg(rx8010->client, RX8010_CTRL, &ctrl); > + if (ret) > + return ret; > + rx8010->ctrlreg = ctrl & ~RX8010_CTRL_STOP; > + ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL, > + rx8010->ctrlreg); > + if (ret < 0) > + return ret; > + > + spin_lock_irqsave(&rx8010->flags_lock, irqflags); > + > + ret = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg); > + if (ret) { > + spin_unlock_irqrestore(&rx8010->flags_lock, irqflags); > + return ret; > + } > + > + if (flagreg & RX8010_FLAG_VLF) > + ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG, > + flagreg & ~RX8010_FLAG_VLF); > + > + spin_unlock_irqrestore(&rx8010->flags_lock, irqflags); > + > + return 0; > +} > + > +static int rx8010_init_client(struct i2c_client *client) > +{ > + struct rx8010_data *rx8010 = i2c_get_clientdata(client); > + u8 ctrl[3]; > + int need_clear = 0, need_reset = 0, err = 0; > + > + /* Initialize reserved registers as specified in datasheet */ > + err = i2c_smbus_write_byte_data(client, RX8010_RESV17, 0xD8); > + if (err < 0) > + return err; > + > + err = i2c_smbus_write_byte_data(client, RX8010_RESV30, 0x00); > + if (err < 0) > + return err; > + > + err = i2c_smbus_write_byte_data(client, RX8010_RESV31, 0x08); > + if (err < 0) > + return err; > + > + err = i2c_smbus_write_byte_data(client, RX8010_IRQ, 0x00); > + if (err < 0) > + return err; > + > + err = rx8010_read_regs(rx8010->client, RX8010_EXT, 3, ctrl); > + if (err) > + return err; > + > + if ((ctrl[1] & RX8010_FLAG_VLF)) { > + dev_warn(&client->dev, "Frequency stop was detected\n"); > + need_reset = 1; > + } > + > + if (ctrl[1] & RX8010_FLAG_AF) { > + dev_warn(&client->dev, "Alarm was detected\n"); > + need_clear = 1; > + } > + > + if (ctrl[1] & RX8010_FLAG_TF) > + need_clear = 1; > + > + if (ctrl[1] & RX8010_FLAG_UF) > + need_clear = 1; > + > + if (need_reset) { > + ctrl[0] = ctrl[1] = ctrl[2] = 0; > + err = i2c_smbus_write_i2c_block_data(client, RX8010_EXT, > + 3, ctrl); > + if (err < 0) > + return err; Please don't do that, reseting RX8010_FLAG_VLF will make userspace believe that the bogus date is valid. > + } else if (need_clear) { > + err = i2c_smbus_write_byte_data(client, RX8010_FLAG, 0x00); > + if (err < 0) > + return err; > + } > + > + rx8010->ctrlreg = (ctrl[2] & ~RX8010_CTRL_TEST); > + BTW, I'm not sure about the necessity to cache ctrl. It actually only saves one i2c read in the alarm functions. > + return err; > +} > + -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/