svn commit: r335594 - head/sys/arm/broadcom/bcm2835
Ian Lepore
ian at FreeBSD.org
Sat Jun 23 23:44:37 UTC 2018
Author: ian
Date: Sat Jun 23 23:44:36 2018
New Revision: 335594
URL: https://svnweb.freebsd.org/changeset/base/335594
Log:
Retrieve the bus clock speed and mode (polarity/phase) from the child device
and set up the hardware accordingly on each transfer. This replaces the old
configuration done via sysctl, and allows both fdt configuration data and
userland control via the spigen device to work.
Submitted by: Bob Frazier
Differential Revision: https://reviews.freebsd.org/D15031
Modified:
head/sys/arm/broadcom/bcm2835/bcm2835_spi.c
Modified: head/sys/arm/broadcom/bcm2835/bcm2835_spi.c
==============================================================================
--- head/sys/arm/broadcom/bcm2835/bcm2835_spi.c Sat Jun 23 23:08:25 2018 (r335593)
+++ head/sys/arm/broadcom/bcm2835/bcm2835_spi.c Sat Jun 23 23:44:36 2018 (r335594)
@@ -132,17 +132,6 @@ bcm_spi_clock_proc(SYSCTL_HANDLER_ARGS)
if (error != 0 || req->newptr == NULL)
return (error);
- clk = SPI_CORE_CLK / clk;
- if (clk <= 1)
- clk = 2;
- else if (clk % 2)
- clk--;
- if (clk > 0xffff)
- clk = 0;
- BCM_SPI_LOCK(sc);
- BCM_SPI_WRITE(sc, SPI_CLK, clk);
- BCM_SPI_UNLOCK(sc);
-
return (0);
}
@@ -163,12 +152,6 @@ bcm_spi_cs_bit_proc(SYSCTL_HANDLER_ARGS, uint32_t bit)
if (error != 0 || req->newptr == NULL)
return (error);
- if (reg)
- reg = bit;
- BCM_SPI_LOCK(sc);
- bcm_spi_modifyreg(sc, SPI_CS, bit, reg);
- BCM_SPI_UNLOCK(sc);
-
return (0);
}
@@ -200,6 +183,13 @@ bcm_spi_cspol1_proc(SYSCTL_HANDLER_ARGS)
return (bcm_spi_cs_bit_proc(oidp, arg1, arg2, req, SPI_CS_CSPOL1));
}
+static int
+bcm_spi_cspol2_proc(SYSCTL_HANDLER_ARGS)
+{
+
+ return (bcm_spi_cs_bit_proc(oidp, arg1, arg2, req, SPI_CS_CSPOL2));
+}
+
static void
bcm_spi_sysctl_init(struct bcm_spi_softc *sc)
{
@@ -214,20 +204,23 @@ bcm_spi_sysctl_init(struct bcm_spi_softc *sc)
tree_node = device_get_sysctl_tree(sc->sc_dev);
tree = SYSCTL_CHILDREN(tree_node);
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "clock",
- CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc),
+ CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_clock_proc, "IU", "SPI BUS clock frequency");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cpol",
- CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc),
+ CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_cpol_proc, "IU", "SPI BUS clock polarity");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cpha",
- CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc),
+ CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_cpha_proc, "IU", "SPI BUS clock phase");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cspol0",
- CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc),
+ CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_cspol0_proc, "IU", "SPI BUS chip select 0 polarity");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cspol1",
- CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc),
+ CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_cspol1_proc, "IU", "SPI BUS chip select 1 polarity");
+ SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cspol2",
+ CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
+ bcm_spi_cspol2_proc, "IU", "SPI BUS chip select 2 polarity");
}
static int
@@ -303,9 +296,6 @@ bcm_spi_attach(device_t dev)
*/
BCM_SPI_WRITE(sc, SPI_CS, SPI_CS_CLEAR_RXFIFO | SPI_CS_CLEAR_TXFIFO);
- /* Set the SPI clock to 500Khz. */
- BCM_SPI_WRITE(sc, SPI_CLK, SPI_CORE_CLK / 500000);
-
#ifdef BCM_SPI_DEBUG
bcm_spi_printr(dev);
#endif
@@ -412,7 +402,7 @@ static int
bcm_spi_transfer(device_t dev, device_t child, struct spi_command *cmd)
{
struct bcm_spi_softc *sc;
- uint32_t cs;
+ uint32_t cs, mode, clock;
int err;
sc = device_get_softc(dev);
@@ -422,21 +412,34 @@ bcm_spi_transfer(device_t dev, device_t child, struct
KASSERT(cmd->tx_data_sz == cmd->rx_data_sz,
("TX/RX data sizes should be equal"));
- /* Get the proper chip select for this child. */
+ /* Get the bus speed, mode, and chip select for this child. */
+
spibus_get_cs(child, &cs);
+ if ((cs & (~SPIBUS_CS_HIGH)) > 2) {
+ device_printf(dev,
+ "Invalid chip select %u requested by %s\n", cs,
+ device_get_nameunit(child));
+ return (EINVAL);
+ }
- cs &= ~SPIBUS_CS_HIGH;
+ spibus_get_clock(child, &clock);
+ if (clock == 0) {
+ device_printf(dev,
+ "Invalid clock %uHz requested by %s\n", clock,
+ device_get_nameunit(child));
+ return (EINVAL);
+ }
- if (cs > 2) {
+ spibus_get_mode(child, &mode);
+ if (mode > 3) {
device_printf(dev,
- "Invalid chip select %d requested by %s\n", cs,
+ "Invalid mode %u requested by %s\n", mode,
device_get_nameunit(child));
return (EINVAL);
}
- BCM_SPI_LOCK(sc);
-
/* If the controller is in use wait until it is available. */
+ BCM_SPI_LOCK(sc);
while (sc->sc_flags & BCM_SPI_BUSY)
mtx_sleep(dev, &sc->sc_mtx, 0, "bcm_spi", 0);
@@ -454,13 +457,63 @@ bcm_spi_transfer(device_t dev, device_t child, struct
sc->sc_written = 0;
sc->sc_len = cmd->tx_cmd_sz + cmd->tx_data_sz;
+#ifdef BCM2835_SPI_USE_CS_HIGH /* TODO: for when behavior is correct */
/*
+ * Assign CS polarity first, while the CS indicates 'inactive'.
+ * This will need to set the correct polarity bit based on the 'cs', and
+ * the polarity bit will remain in this state, even after the transaction
+ * is complete.
+ */
+ if((cs & ~SPIBUS_CS_HIGH) == 0) {
+ bcm_spi_modifyreg(sc, SPI_CS,
+ SPI_CS_CSPOL0,
+ ((cs & (SPIBUS_CS_HIGH)) ? SPI_CS_CSPOL0 : 0));
+ }
+ else if((cs & ~SPIBUS_CS_HIGH) == 1) {
+ bcm_spi_modifyreg(sc, SPI_CS,
+ SPI_CS_CSPOL1,
+ ((cs & (SPIBUS_CS_HIGH)) ? SPI_CS_CSPOL1 : 0));
+ }
+ else if((cs & ~SPIBUS_CS_HIGH) == 2) {
+ bcm_spi_modifyreg(sc, SPI_CS,
+ SPI_CS_CSPOL2,
+ ((cs & (SPIBUS_CS_HIGH)) ? SPI_CS_CSPOL2 : 0));
+ }
+#endif
+
+ /*
+ * Set the mode in 'SPI_CS' (clock phase and polarity bits).
+ * This must happen before CS output pin is active.
+ * Otherwise, you might glitch and drop the first bit.
+ */
+ bcm_spi_modifyreg(sc, SPI_CS,
+ SPI_CS_CPOL | SPI_CS_CPHA,
+ ((mode & SPIBUS_MODE_CPHA) ? SPI_CS_CPHA : 0) |
+ ((mode & SPIBUS_MODE_CPOL) ? SPI_CS_CPOL : 0));
+
+ /*
+ * Set the clock divider in 'SPI_CLK - see 'bcm_spi_clock_proc()'.
+ */
+
+ /* calculate 'clock' as a divider value from freq */
+ clock = SPI_CORE_CLK / clock;
+ if (clock <= 1)
+ clock = 2;
+ else if (clock % 2)
+ clock--;
+ if (clock > 0xffff)
+ clock = 0;
+
+ BCM_SPI_WRITE(sc, SPI_CLK, clock);
+
+ /*
* Set the CS for this transaction, enable interrupts and announce
* we're ready to tx. This will kick off the first interrupt.
*/
bcm_spi_modifyreg(sc, SPI_CS,
SPI_CS_MASK | SPI_CS_TA | SPI_CS_INTR | SPI_CS_INTD,
- cs | SPI_CS_TA | SPI_CS_INTR | SPI_CS_INTD);
+ (cs & (~SPIBUS_CS_HIGH)) | /* cs is the lower 2 bits of the reg */
+ SPI_CS_TA | SPI_CS_INTR | SPI_CS_INTD);
/* Wait for the transaction to complete. */
err = mtx_sleep(dev, &sc->sc_mtx, 0, "bcm_spi", hz * 2);
@@ -478,7 +531,7 @@ bcm_spi_transfer(device_t dev, device_t child, struct
* return errors.
*/
if (err == EWOULDBLOCK) {
- device_printf(sc->sc_dev, "SPI error\n");
+ device_printf(sc->sc_dev, "SPI error (timeout)\n");
err = EIO;
}
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