summaryrefslogtreecommitdiff
path: root/drivers/mfd/mc13xxx-spi.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/mfd/mc13xxx-spi.c')
-rw-r--r--drivers/mfd/mc13xxx-spi.c65
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, &regmap_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",