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authorTom Warren <twarren.nvidia@gmail.com>2011-11-05 09:48:11 +0000
committerAlbert ARIBAUD <albert.u.boot@aribaud.net>2011-12-24 10:23:30 +0100
commit9112ef8d89e3e496ba6f73276f17dd5c2b93877f (patch)
tree09d5213301638175a9bbf248c31c1bdcc0b1ab12 /drivers/spi
parent1be0d75973eff5a7655f8eb5241661767b97ffd3 (diff)
tegra2: spi: Add SPI driver for Tegra2 SOC
This driver supports SPI on Tegra2, running at 48MHz. Signed-off-by: Tom Warren <twarren@nvidia.com> Acked-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/Makefile1
-rw-r--r--drivers/spi/tegra2_spi.c265
2 files changed, 266 insertions, 0 deletions
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 6f389f093..c967d8783 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -43,6 +43,7 @@ COBJS-$(CONFIG_OMAP3_SPI) += omap3_spi.o
COBJS-$(CONFIG_SOFT_SPI) += soft_spi.o
COBJS-$(CONFIG_SH_SPI) += sh_spi.o
COBJS-$(CONFIG_FSL_ESPI) += fsl_espi.o
+COBJS-$(CONFIG_TEGRA2_SPI) += tegra2_spi.o
COBJS := $(COBJS-y)
SRCS := $(COBJS:.o=.c)
diff --git a/drivers/spi/tegra2_spi.c b/drivers/spi/tegra2_spi.c
new file mode 100644
index 000000000..fdcad093c
--- /dev/null
+++ b/drivers/spi/tegra2_spi.c
@@ -0,0 +1,265 @@
+/*
+ * Copyright (c) 2010-2011 NVIDIA Corporation
+ * With help from the mpc8xxx SPI driver
+ * With more help from omap3_spi SPI driver
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+
+#include <malloc.h>
+#include <spi.h>
+#include <asm/io.h>
+#include <asm/gpio.h>
+#include <asm/arch/clk_rst.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/pinmux.h>
+#include <asm/arch/tegra2_spi.h>
+
+struct tegra_spi_slave {
+ struct spi_slave slave;
+ struct spi_tegra *regs;
+ unsigned int freq;
+ unsigned int mode;
+};
+
+static inline struct tegra_spi_slave *to_tegra_spi(struct spi_slave *slave)
+{
+ return container_of(slave, struct tegra_spi_slave, slave);
+}
+
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+ /* Tegra2 SPI-Flash - only 1 device ('bus/cs') */
+ if (bus != 0 || cs != 0)
+ return 0;
+ else
+ return 1;
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+ unsigned int max_hz, unsigned int mode)
+{
+ struct tegra_spi_slave *spi;
+
+ if (!spi_cs_is_valid(bus, cs)) {
+ printf("SPI error: unsupported bus %d / chip select %d\n",
+ bus, cs);
+ return NULL;
+ }
+
+ if (max_hz > TEGRA2_SPI_MAX_FREQ) {
+ printf("SPI error: unsupported frequency %d Hz. Max frequency"
+ " is %d Hz\n", max_hz, TEGRA2_SPI_MAX_FREQ);
+ return NULL;
+ }
+
+ spi = malloc(sizeof(struct tegra_spi_slave));
+ if (!spi) {
+ printf("SPI error: malloc of SPI structure failed\n");
+ return NULL;
+ }
+ spi->slave.bus = bus;
+ spi->slave.cs = cs;
+ spi->freq = max_hz;
+ spi->regs = (struct spi_tegra *)TEGRA2_SPI_BASE;
+ spi->mode = mode;
+
+ return &spi->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+ struct tegra_spi_slave *spi = to_tegra_spi(slave);
+
+ free(spi);
+}
+
+void spi_init(void)
+{
+ /* do nothing */
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+ struct tegra_spi_slave *spi = to_tegra_spi(slave);
+ struct spi_tegra *regs = spi->regs;
+ u32 reg;
+
+ /* Change SPI clock to correct frequency, PLLP_OUT0 source */
+ clock_start_periph_pll(PERIPH_ID_SPI1, CLOCK_ID_PERIPH, spi->freq);
+
+ /* Clear stale status here */
+ reg = SPI_STAT_RDY | SPI_STAT_RXF_FLUSH | SPI_STAT_TXF_FLUSH | \
+ SPI_STAT_RXF_UNR | SPI_STAT_TXF_OVF;
+ writel(reg, &regs->status);
+ debug("spi_init: STATUS = %08x\n", readl(&regs->status));
+
+ /*
+ * Use sw-controlled CS, so we can clock in data after ReadID, etc.
+ */
+ reg = (spi->mode & 1) << SPI_CMD_ACTIVE_SDA_SHIFT;
+ if (spi->mode & 2)
+ reg |= 1 << SPI_CMD_ACTIVE_SCLK_SHIFT;
+ clrsetbits_le32(&regs->command, SPI_CMD_ACTIVE_SCLK_MASK |
+ SPI_CMD_ACTIVE_SDA_MASK, SPI_CMD_CS_SOFT | reg);
+ debug("spi_init: COMMAND = %08x\n", readl(&regs->command));
+
+ /*
+ * SPI pins on Tegra2 are muxed - change pinmux later due to UART
+ * issue.
+ */
+ pinmux_set_func(PINGRP_GMD, PMUX_FUNC_SFLASH);
+ pinmux_tristate_disable(PINGRP_LSPI);
+ return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+ /*
+ * We can't release UART_DISABLE and set pinmux to UART4 here since
+ * some code (e,g, spi_flash_probe) uses printf() while the SPI
+ * bus is held. That is arguably bad, but it has the advantage of
+ * already being in the source tree.
+ */
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+ struct tegra_spi_slave *spi = to_tegra_spi(slave);
+
+ /* CS is negated on Tegra, so drive a 1 to get a 0 */
+ setbits_le32(&spi->regs->command, SPI_CMD_CS_VAL);
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+ struct tegra_spi_slave *spi = to_tegra_spi(slave);
+
+ /* CS is negated on Tegra, so drive a 0 to get a 1 */
+ clrbits_le32(&spi->regs->command, SPI_CMD_CS_VAL);
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+ const void *data_out, void *data_in, unsigned long flags)
+{
+ struct tegra_spi_slave *spi = to_tegra_spi(slave);
+ struct spi_tegra *regs = spi->regs;
+ u32 reg, tmpdout, tmpdin = 0;
+ const u8 *dout = data_out;
+ u8 *din = data_in;
+ int num_bytes;
+ int ret;
+
+ debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
+ slave->bus, slave->cs, *(u8 *)dout, *(u8 *)din, bitlen);
+ if (bitlen % 8)
+ return -1;
+ num_bytes = bitlen / 8;
+
+ ret = 0;
+
+ reg = readl(&regs->status);
+ writel(reg, &regs->status); /* Clear all SPI events via R/W */
+ debug("spi_xfer entry: STATUS = %08x\n", reg);
+
+ reg = readl(&regs->command);
+ reg |= SPI_CMD_TXEN | SPI_CMD_RXEN;
+ writel(reg, &regs->command);
+ debug("spi_xfer: COMMAND = %08x\n", readl(&regs->command));
+
+ if (flags & SPI_XFER_BEGIN)
+ spi_cs_activate(slave);
+
+ /* handle data in 32-bit chunks */
+ while (num_bytes > 0) {
+ int bytes;
+ int is_read = 0;
+ int tm, i;
+
+ tmpdout = 0;
+ bytes = (num_bytes > 4) ? 4 : num_bytes;
+
+ if (dout != NULL) {
+ for (i = 0; i < bytes; ++i)
+ tmpdout = (tmpdout << 8) | dout[i];
+ }
+
+ num_bytes -= bytes;
+ if (dout)
+ dout += bytes;
+
+ clrsetbits_le32(&regs->command, SPI_CMD_BIT_LENGTH_MASK,
+ bytes * 8 - 1);
+ writel(tmpdout, &regs->tx_fifo);
+ setbits_le32(&regs->command, SPI_CMD_GO);
+
+ /*
+ * Wait for SPI transmit FIFO to empty, or to time out.
+ * The RX FIFO status will be read and cleared last
+ */
+ for (tm = 0, is_read = 0; tm < SPI_TIMEOUT; ++tm) {
+ u32 status;
+
+ status = readl(&regs->status);
+
+ /* We can exit when we've had both RX and TX activity */
+ if (is_read && (status & SPI_STAT_TXF_EMPTY))
+ break;
+
+ if ((status & (SPI_STAT_BSY | SPI_STAT_RDY)) !=
+ SPI_STAT_RDY)
+ tm++;
+
+ else if (!(status & SPI_STAT_RXF_EMPTY)) {
+ tmpdin = readl(&regs->rx_fifo);
+ is_read = 1;
+
+ /* swap bytes read in */
+ if (din != NULL) {
+ for (i = bytes - 1; i >= 0; --i) {
+ din[i] = tmpdin & 0xff;
+ tmpdin >>= 8;
+ }
+ din += bytes;
+ }
+ }
+ }
+
+ if (tm >= SPI_TIMEOUT)
+ ret = tm;
+
+ /* clear ACK RDY, etc. bits */
+ writel(readl(&regs->status), &regs->status);
+ }
+
+ if (flags & SPI_XFER_END)
+ spi_cs_deactivate(slave);
+
+ debug("spi_xfer: transfer ended. Value=%08x, status = %08x\n",
+ tmpdin, readl(&regs->status));
+
+ if (ret) {
+ printf("spi_xfer: timeout during SPI transfer, tm %d\n", ret);
+ return -1;
+ }
+
+ return 0;
+}