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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: Dylan Howey <Dylan.Howey@tennantco.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Dylan Howey 2019-05-03 19:52:10 +00:00 committed by Alexandre Belloni
parent 2372a7d32b
commit 790d033933
1 changed files with 61 additions and 81 deletions
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142
drivers/rtc/rtc-pcf2123.c
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@ -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;
if (reg & OFFSET_COARSE)
reg <<= 1; /* multiply by 2 and sign extend */
else
reg = sign_extend32(reg, OFFSET_SIGN_BIT);
val = sign_extend32((reg & OFFSET_MASK), OFFSET_SIGN_BIT);
*offset = ((long)reg) * OFFSET_STEP;
if (reg & OFFSET_COARSE)
val *= 2;
*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);
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 = pcf2123_write(dev, txbuf, sizeof(txbuf));
if (ret < 0)
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);