Commit 790d0339 authored by Dylan Howey's avatar Dylan Howey Committed by Alexandre Belloni
Browse files

rtc: pcf2123: port to regmap 



Also remove pcf2123_delay_trec. This claimed to add a 30ns delay to SPI
writes, but I could not see any reference to this requirement in the
datasheet. Closest thing I could find to a requirement are timings for the
SPI chip enable line, which cannot be controlled by this driver (the ndelay
came after the call to spi_write_then_read, which means it would sleep
after CE has already gone inactive). Things seem to work fine without it.

Signed-off-by: default avatarDylan Howey <Dylan.Howey@tennantco.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 2372a7d3

drivers/rtc/rtc-pcf2123.c

+61 −81
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
#include <linux/rtc.h>

#include <linux/spi/spi.h>

#include <linux/module.h>

#include <linux/regmap.h>



/* REGISTERS */

#define PCF2123_REG_CTRL1	(0x00)	/* Control Register 1 */
@@ -98,6 +99,7 @@ 
#define OFFSET_SIGN_BIT		6	/* 2's complement sign bit */

#define OFFSET_COARSE		BIT(7)	/* Coarse mode offset */

#define OFFSET_STEP		(2170)	/* Offset step in parts per billion */

#define OFFSET_MASK		GENMASK(6, 0)	/* Offset value */



/* READ/WRITE ADDRESS BITS */

#define PCF2123_WRITE		BIT(4)
@@ -108,66 +110,33 @@ static struct spi_driver pcf2123_driver; 


struct pcf2123_plat_data {

	struct rtc_device *rtc;

	struct regmap *map;

};



/*

 * Causes a 30 nanosecond delay to ensure that the PCF2123 chip select

 * is released properly after an SPI write.  This function should be

 * called after EVERY read/write call over SPI.

 */

static inline void pcf2123_delay_trec(void)

{

	ndelay(30);

}



static int pcf2123_read(struct device *dev, u8 reg, u8 *rxbuf, size_t size)

{

	struct spi_device *spi = to_spi_device(dev);

	int ret;



	reg |= PCF2123_READ;

	ret = spi_write_then_read(spi, &reg, 1, rxbuf, size);

	pcf2123_delay_trec();



	return ret;

}



static int pcf2123_write(struct device *dev, u8 *txbuf, size_t size)

{

	struct spi_device *spi = to_spi_device(dev);

	int ret;



	txbuf[0] |= PCF2123_WRITE;

	ret = spi_write(spi, txbuf, size);

	pcf2123_delay_trec();



	return ret;

}



static int pcf2123_write_reg(struct device *dev, u8 reg, u8 val)

{

	u8 txbuf[2];



	txbuf[0] = reg;

	txbuf[1] = val;

	return pcf2123_write(dev, txbuf, sizeof(txbuf));

}

static const struct regmap_config pcf2123_regmap_config = {

	.reg_bits = 8,

	.val_bits = 8,

	.read_flag_mask = PCF2123_READ,

	.write_flag_mask = PCF2123_WRITE,

	.max_register = PCF2123_REG_CTDWN_TMR,

};



static int pcf2123_read_offset(struct device *dev, long *offset)

{

	int ret;

	s8 reg;

	struct pcf2123_plat_data *pdata = dev_get_platdata(dev);

	int ret, val;

	unsigned int reg;



	ret = pcf2123_read(dev, PCF2123_REG_OFFSET, &reg, 1);

	if (ret < 0)

	ret = regmap_read(pdata->map, PCF2123_REG_OFFSET, &reg);

	if (ret)

		return ret;



	val = sign_extend32((reg & OFFSET_MASK), OFFSET_SIGN_BIT);



	if (reg & OFFSET_COARSE)

		reg <<= 1; /* multiply by 2 and sign extend */

	else

		reg = sign_extend32(reg, OFFSET_SIGN_BIT);

		val *= 2;



	*offset = ((long)reg) * OFFSET_STEP;

	*offset = ((long)val) * OFFSET_STEP;



	return 0;

}
@@ -184,6 +153,7 @@ static int pcf2123_read_offset(struct device *dev, long *offset) 
 */

static int pcf2123_set_offset(struct device *dev, long offset)

{

	struct pcf2123_plat_data *pdata = dev_get_platdata(dev);

	s8 reg;



	if (offset > OFFSET_STEP * 127)
@@ -203,16 +173,18 @@ static int pcf2123_set_offset(struct device *dev, long offset) 
		reg |= OFFSET_COARSE;

	}



	return pcf2123_write_reg(dev, PCF2123_REG_OFFSET, reg);

	return regmap_write(pdata->map, PCF2123_REG_OFFSET, (unsigned int)reg);

}



static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	struct pcf2123_plat_data *pdata = dev_get_platdata(dev);

	u8 rxbuf[7];

	int ret;



	ret = pcf2123_read(dev, PCF2123_REG_SC, rxbuf, sizeof(rxbuf));

	if (ret < 0)

	ret = regmap_bulk_read(pdata->map, PCF2123_REG_SC, rxbuf,

				sizeof(rxbuf));

	if (ret)

		return ret;



	if (rxbuf[0] & OSC_HAS_STOPPED) {
@@ -241,7 +213,8 @@ static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm) 


static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	u8 txbuf[8];

	struct pcf2123_plat_data *pdata = dev_get_platdata(dev);

	u8 txbuf[7];

	int ret;



	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
@@ -251,27 +224,27 @@ static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm) 
			tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);



	/* Stop the counter first */

	ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_STOP);

	if (ret < 0)

	ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_STOP);

	if (ret)

		return ret;



	/* Set the new time */

	txbuf[0] = PCF2123_REG_SC;

	txbuf[1] = bin2bcd(tm->tm_sec & 0x7F);

	txbuf[2] = bin2bcd(tm->tm_min & 0x7F);

	txbuf[3] = bin2bcd(tm->tm_hour & 0x3F);

	txbuf[4] = bin2bcd(tm->tm_mday & 0x3F);

	txbuf[5] = tm->tm_wday & 0x07;

	txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */

	txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100);



	ret = pcf2123_write(dev, txbuf, sizeof(txbuf));

	if (ret < 0)

	txbuf[0] = bin2bcd(tm->tm_sec & 0x7F);

	txbuf[1] = bin2bcd(tm->tm_min & 0x7F);

	txbuf[2] = bin2bcd(tm->tm_hour & 0x3F);

	txbuf[3] = bin2bcd(tm->tm_mday & 0x3F);

	txbuf[4] = tm->tm_wday & 0x07;

	txbuf[5] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */

	txbuf[6] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100);



	ret = regmap_bulk_write(pdata->map, PCF2123_REG_SC, txbuf,

				sizeof(txbuf));

	if (ret)

		return ret;



	/* Start the counter */

	ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_CLEAR);

	if (ret < 0)

	ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_CLEAR);

	if (ret)

		return ret;



	return 0;
@@ -279,33 +252,33 @@ static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm) 


static int pcf2123_reset(struct device *dev)

{

	struct pcf2123_plat_data *pdata = dev_get_platdata(dev);

	int ret;

	u8  rxbuf[2];

	unsigned int val = 0;



	ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_SW_RESET);

	if (ret < 0)

	ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_SW_RESET);

	if (ret)

		return ret;



	/* Stop the counter */

	dev_dbg(dev, "stopping RTC\n");

	ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_STOP);

	if (ret < 0)

	ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_STOP);

	if (ret)

		return ret;



	/* See if the counter was actually stopped */

	dev_dbg(dev, "checking for presence of RTC\n");

	ret = pcf2123_read(dev, PCF2123_REG_CTRL1, rxbuf, sizeof(rxbuf));

	if (ret < 0)

	ret = regmap_read(pdata->map, PCF2123_REG_CTRL1, &val);

	if (ret)

		return ret;



	dev_dbg(dev, "received data from RTC (0x%02X 0x%02X)\n",

		rxbuf[0], rxbuf[1]);

	if (!(rxbuf[0] & CTRL1_STOP))

	dev_dbg(dev, "received data from RTC (0x%08X)\n", val);

	if (!(val & CTRL1_STOP))

		return -ENODEV;



	/* Start the counter */

	ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_CLEAR);

	if (ret < 0)

	ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_CLEAR);

	if (ret)

		return ret;



	return 0;
@@ -332,6 +305,13 @@ static int pcf2123_probe(struct spi_device *spi) 
		return -ENOMEM;

	spi->dev.platform_data = pdata;



	pdata->map = devm_regmap_init_spi(spi, &pcf2123_regmap_config);



	if (IS_ERR(pdata->map)) {

		dev_err(&spi->dev, "regmap init failed.\n");

		goto kfree_exit;

	}



	ret = pcf2123_rtc_read_time(&spi->dev, &tm);

	if (ret < 0) {

		ret = pcf2123_reset(&spi->dev);

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