diff options
Diffstat (limited to 'drivers/mfd')
| -rw-r--r-- | drivers/mfd/mc13xxx-spi.c | 65 |
1 files changed, 64 insertions, 1 deletions
diff --git a/drivers/mfd/mc13xxx-spi.c b/drivers/mfd/mc13xxx-spi.c index 5d1969f67d82..03df422feb76 100644 --- a/drivers/mfd/mc13xxx-spi.c +++ b/drivers/mfd/mc13xxx-spi.c @@ -54,6 +54,67 @@ static struct regmap_config mc13xxx_regmap_spi_config = { .max_register = MC13XXX_NUMREGS, .cache_type = REGCACHE_NONE, + .use_single_rw = 1, +}; + +static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size, + void *val, size_t val_size) +{ + unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0}; + unsigned char r[4]; + unsigned char *p = val; + struct device *dev = context; + struct spi_device *spi = to_spi_device(dev); + struct spi_transfer t = { + .tx_buf = w, + .rx_buf = r, + .len = 4, + }; + + struct spi_message m; + int ret; + + if (val_size != 3 || reg_size != 1) + return -ENOTSUPP; + + spi_message_init(&m); + spi_message_add_tail(&t, &m); + ret = spi_sync(spi, &m); + + memcpy(p, &r[1], 3); + + return ret; +} + +static int mc13xxx_spi_write(void *context, const void *data, size_t count) +{ + struct device *dev = context; + struct spi_device *spi = to_spi_device(dev); + + if (count != 4) + return -ENOTSUPP; + + return spi_write(spi, data, count); +} + +/* + * We cannot use regmap-spi generic bus implementation here. + * The MC13783 chip will get corrupted if CS signal is deasserted + * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller + * has the following errata (DSPhl22960): + * "The CSPI negates SS when the FIFO becomes empty with + * SSCTL= 0. Software cannot guarantee that the FIFO will not + * drain because of higher priority interrupts and the + * non-realtime characteristics of the operating system. As a + * result, the SS will negate before all of the data has been + * transferred to/from the peripheral." + * We workaround this by accessing the SPI controller with a + * single transfert. + */ + +static struct regmap_bus regmap_mc13xxx_bus = { + .write = mc13xxx_spi_write, + .read = mc13xxx_spi_read, }; static int mc13xxx_spi_probe(struct spi_device *spi) @@ -78,7 +139,9 @@ static int mc13xxx_spi_probe(struct spi_device *spi) mc13xxx->dev = &spi->dev; mutex_init(&mc13xxx->lock); - mc13xxx->regmap = regmap_init_spi(spi, &mc13xxx_regmap_spi_config); + mc13xxx->regmap = regmap_init(&spi->dev, ®map_mc13xxx_bus, &spi->dev, + &mc13xxx_regmap_spi_config); + if (IS_ERR(mc13xxx->regmap)) { ret = PTR_ERR(mc13xxx->regmap); dev_err(mc13xxx->dev, "Failed to initialize register map: %d\n", |