From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.micronovasrl.com ([212.103.203.10]:37960 "EHLO mail.micronovasrl.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729501AbeGYSi5 (ORCPT ); Wed, 25 Jul 2018 14:38:57 -0400 Received: from mail.micronovasrl.com (mail.micronovasrl.com [127.0.0.1]) by mail.micronovasrl.com (Postfix) with ESMTP id B6643B008F3 for ; Wed, 25 Jul 2018 19:26:18 +0200 (CEST) Received: from mail.micronovasrl.com ([127.0.0.1]) by mail.micronovasrl.com (mail.micronovasrl.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id v7NK724sp3px for ; Wed, 25 Jul 2018 19:26:18 +0200 (CEST) From: Giulio Benetti To: alexandre.belloni@bootlin.com Cc: a.zummo@towertech.it, andy.shevchenko@gmail.com, robh@kernel.org, linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org, Giulio Benetti Subject: [PATCH v11 3/4] rtc: ds1307: add offset sysfs for mt41txx chips. Date: Wed, 25 Jul 2018 19:26:04 +0200 Message-Id: <20180725172605.108040-3-giulio.benetti@micronovasrl.com> In-Reply-To: <20180725172605.108040-1-giulio.benetti@micronovasrl.com> References: <20180725172605.108040-1-giulio.benetti@micronovasrl.com> Sender: linux-rtc-owner@vger.kernel.org List-ID: m41txx chips can hold a calibration value to get correct clock bias. Add offset handling (ranging between -63ppm and 126ppm) via sysfs. Signed-off-by: Giulio Benetti --- drivers/rtc/rtc-ds1307.c | 77 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index 0162a600ff1b..c6d871456f25 100644 --- a/drivers/rtc/rtc-ds1307.c +++ b/drivers/rtc/rtc-ds1307.c @@ -114,6 +114,20 @@ enum ds_type { # define RX8025_BIT_VDET 0x40 # define RX8025_BIT_XST 0x20 +#define M41TXX_REG_CONTROL 0x07 +# define M41TXX_BIT_OUT BIT(7) +# define M41TXX_BIT_FT BIT(6) +# define M41TXX_BIT_CALIB_SIGN BIT(5) +# define M41TXX_M_CALIBRATION GENMASK(4, 0) + +/* negative offset step is -2.034ppm */ +#define M41TXX_NEG_OFFSET_STEP_PPB 2034 +/* positive offset step is +4.068ppm */ +#define M41TXX_POS_OFFSET_STEP_PPB 4068 +/* Min and max values supported with 'offset' interface by M41TXX */ +#define M41TXX_MIN_OFFSET ((-31) * M41TXX_NEG_OFFSET_STEP_PPB) +#define M41TXX_MAX_OFFSET ((31) * M41TXX_POS_OFFSET_STEP_PPB) + struct ds1307 { enum ds_type type; unsigned long flags; @@ -146,6 +160,9 @@ struct chip_desc { static int ds1307_get_time(struct device *dev, struct rtc_time *t); static int ds1307_set_time(struct device *dev, struct rtc_time *t); +static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t); +static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t); +static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled); static u8 do_trickle_setup_ds1339(struct ds1307 *, u32 ohms, bool diode); static irqreturn_t rx8130_irq(int irq, void *dev_id); static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t); @@ -155,6 +172,8 @@ static irqreturn_t mcp794xx_irq(int irq, void *dev_id); static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t); static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t); static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled); +static int m41txx_rtc_read_offset(struct device *dev, long *offset); +static int m41txx_rtc_set_offset(struct device *dev, long offset); static const struct rtc_class_ops rx8130_rtc_ops = { .read_time = ds1307_get_time, @@ -172,6 +191,16 @@ static const struct rtc_class_ops mcp794xx_rtc_ops = { .alarm_irq_enable = mcp794xx_alarm_irq_enable, }; +static const struct rtc_class_ops m41txx_rtc_ops = { + .read_time = ds1307_get_time, + .set_time = ds1307_set_time, + .read_alarm = ds1337_read_alarm, + .set_alarm = ds1337_set_alarm, + .alarm_irq_enable = ds1307_alarm_irq_enable, + .read_offset = m41txx_rtc_read_offset, + .set_offset = m41txx_rtc_set_offset, +}; + static const struct chip_desc chips[last_ds_type] = { [ds_1307] = { .nvram_offset = 8, @@ -228,10 +257,17 @@ static const struct chip_desc chips[last_ds_type] = { .irq_handler = rx8130_irq, .rtc_ops = &rx8130_rtc_ops, }, + [m41t0] = { + .rtc_ops = &m41txx_rtc_ops, + }, + [m41t00] = { + .rtc_ops = &m41txx_rtc_ops, + }, [m41t11] = { /* this is battery backed SRAM */ .nvram_offset = 8, .nvram_size = 56, + .rtc_ops = &m41txx_rtc_ops, }, [mcp794xx] = { .alarm = 1, @@ -973,6 +1009,47 @@ static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled) enabled ? MCP794XX_BIT_ALM0_EN : 0); } +static int m41txx_rtc_read_offset(struct device *dev, long *offset) +{ + struct ds1307 *ds1307 = dev_get_drvdata(dev); + unsigned int ctrl_reg; + u8 val; + + regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg); + + val = ctrl_reg & M41TXX_M_CALIBRATION; + + /* check if positive */ + if (ctrl_reg & M41TXX_BIT_CALIB_SIGN) + *offset = (val * M41TXX_POS_OFFSET_STEP_PPB); + else + *offset = -(val * M41TXX_NEG_OFFSET_STEP_PPB); + + return 0; +} + +static int m41txx_rtc_set_offset(struct device *dev, long offset) +{ + struct ds1307 *ds1307 = dev_get_drvdata(dev); + unsigned int ctrl_reg; + + if ((offset < M41TXX_MIN_OFFSET) || (offset > M41TXX_MAX_OFFSET)) + return -ERANGE; + + if (offset >= 0) { + ctrl_reg = DIV_ROUND_CLOSEST(offset, + M41TXX_POS_OFFSET_STEP_PPB); + ctrl_reg |= M41TXX_BIT_CALIB_SIGN; + } else { + ctrl_reg = DIV_ROUND_CLOSEST(abs(offset), + M41TXX_NEG_OFFSET_STEP_PPB); + } + + return regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL, + M41TXX_M_CALIBRATION | M41TXX_BIT_CALIB_SIGN, + ctrl_reg); +} + /*----------------------------------------------------------------------*/ static int ds1307_nvram_read(void *priv, unsigned int offset, void *val, -- 2.17.1