SPI: Add SPI Driver for EXYNOS.

This patch adds SPI driver for EXYNOS.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Signed-off-by: Gabe Black <gabeblack@google.com>
Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Signed-off-by: Hatim Ali <hatim.rv@samsung.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: jy0922.shim@samsung.com
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

1 files changed, 367 insertions, 0 deletions

diff --git a/drivers/spi/exynos_spi.c b/drivers/spi/exynos_spi.c
new file mode 100644
index 0000000..3e6c18f
--- /dev/null
+++ b/drivers/spi/exynos_spi.c
@@ -0,0 +1,367 @@
+/*
+ * (C) Copyright 2012 SAMSUNG Electronics
+ * Padmavathi Venna <padma.v@samsung.com>
+ *
+ * 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/arch/clk.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/gpio.h>
+#include <asm/arch/pinmux.h>
+#include <asm/arch-exynos/spi.h>
+#include <asm/io.h>
+
+/* Information about each SPI controller */
+struct spi_bus {
+	enum periph_id periph_id;
+	s32 frequency;		/* Default clock frequency, -1 for none */
+	struct exynos_spi *regs;
+	int inited;		/* 1 if this bus is ready for use */
+};
+
+/* A list of spi buses that we know about */
+static struct spi_bus spi_bus[EXYNOS5_SPI_NUM_CONTROLLERS];
+
+struct exynos_spi_slave {
+	struct spi_slave slave;
+	struct exynos_spi *regs;
+	unsigned int freq;		/* Default frequency */
+	unsigned int mode;
+	enum periph_id periph_id;	/* Peripheral ID for this device */
+	unsigned int fifo_size;
+};
+
+static struct spi_bus *spi_get_bus(unsigned dev_index)
+{
+	if (dev_index < EXYNOS5_SPI_NUM_CONTROLLERS)
+		return &spi_bus[dev_index];
+	debug("%s: invalid bus %d", __func__, dev_index);
+
+	return NULL;
+}
+
+static inline struct exynos_spi_slave *to_exynos_spi(struct spi_slave *slave)
+{
+	return container_of(slave, struct exynos_spi_slave, slave);
+}
+
+/**
+ * Setup the driver private data
+ *
+ * @param bus		ID of the bus that the slave is attached to
+ * @param cs		ID of the chip select connected to the slave
+ * @param max_hz	Required spi frequency
+ * @param mode		Required spi mode (clk polarity, clk phase and
+ *			master or slave)
+ * @return new device or NULL
+ */
+struct spi_slave *spi_setup_slave(unsigned int busnum, unsigned int cs,
+			unsigned int max_hz, unsigned int mode)
+{
+	struct exynos_spi_slave *spi_slave;
+	struct spi_bus *bus;
+
+	if (!spi_cs_is_valid(busnum, cs)) {
+		debug("%s: Invalid bus/chip select %d, %d\n", __func__,
+		      busnum, cs);
+		return NULL;
+	}
+
+	spi_slave = malloc(sizeof(*spi_slave));
+	if (!spi_slave) {
+		debug("%s: Could not allocate spi_slave\n", __func__);
+		return NULL;
+	}
+
+	bus = &spi_bus[busnum];
+	spi_slave->slave.bus = busnum;
+	spi_slave->slave.cs = cs;
+	spi_slave->regs = bus->regs;
+	spi_slave->mode = mode;
+	spi_slave->periph_id = bus->periph_id;
+	if (bus->periph_id == PERIPH_ID_SPI1 ||
+	    bus->periph_id == PERIPH_ID_SPI2)
+		spi_slave->fifo_size = 64;
+	else
+		spi_slave->fifo_size = 256;
+
+	spi_slave->freq = bus->frequency;
+	if (max_hz)
+		spi_slave->freq = min(max_hz, spi_slave->freq);
+
+	return &spi_slave->slave;
+}
+
+/**
+ * Free spi controller
+ *
+ * @param slave	Pointer to spi_slave to which controller has to
+ *		communicate with
+ */
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
+
+	free(spi_slave);
+}
+
+/**
+ * Flush spi tx, rx fifos and reset the SPI controller
+ *
+ * @param slave	Pointer to spi_slave to which controller has to
+ *		communicate with
+ */
+static void spi_flush_fifo(struct spi_slave *slave)
+{
+	struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
+	struct exynos_spi *regs = spi_slave->regs;
+
+	clrsetbits_le32(&regs->ch_cfg, SPI_CH_HS_EN, SPI_CH_RST);
+	clrbits_le32(&regs->ch_cfg, SPI_CH_RST);
+	setbits_le32(&regs->ch_cfg, SPI_TX_CH_ON | SPI_RX_CH_ON);
+}
+
+/**
+ * Initialize the spi base registers, set the required clock frequency and
+ * initialize the gpios
+ *
+ * @param slave	Pointer to spi_slave to which controller has to
+ *		communicate with
+ * @return zero on success else a negative value
+ */
+int spi_claim_bus(struct spi_slave *slave)
+{
+	struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
+	struct exynos_spi *regs = spi_slave->regs;
+	u32 reg = 0;
+	int ret;
+
+	ret = set_spi_clk(spi_slave->periph_id,
+					spi_slave->freq);
+	if (ret < 0) {
+		debug("%s: Failed to setup spi clock\n", __func__);
+		return ret;
+	}
+
+	exynos_pinmux_config(spi_slave->periph_id, PINMUX_FLAG_NONE);
+
+	spi_flush_fifo(slave);
+
+	reg = readl(&regs->ch_cfg);
+	reg &= ~(SPI_CH_CPHA_B | SPI_CH_CPOL_L);
+
+	if (spi_slave->mode & SPI_CPHA)
+		reg |= SPI_CH_CPHA_B;
+
+	if (spi_slave->mode & SPI_CPOL)
+		reg |= SPI_CH_CPOL_L;
+
+	writel(reg, &regs->ch_cfg);
+	writel(SPI_FB_DELAY_180, &regs->fb_clk);
+
+	return 0;
+}
+
+/**
+ * Reset the spi H/W and flush the tx and rx fifos
+ *
+ * @param slave	Pointer to spi_slave to which controller has to
+ *		communicate with
+ */
+void spi_release_bus(struct spi_slave *slave)
+{
+	spi_flush_fifo(slave);
+}
+
+static void spi_get_fifo_levels(struct exynos_spi *regs,
+	int *rx_lvl, int *tx_lvl)
+{
+	uint32_t spi_sts = readl(&regs->spi_sts);
+
+	*rx_lvl = (spi_sts >> SPI_RX_LVL_OFFSET) & SPI_FIFO_LVL_MASK;
+	*tx_lvl = (spi_sts >> SPI_TX_LVL_OFFSET) & SPI_FIFO_LVL_MASK;
+}
+
+/**
+ * If there's something to transfer, do a software reset and set a
+ * transaction size.
+ *
+ * @param regs	SPI peripheral registers
+ * @param count	Number of bytes to transfer
+ */
+static void spi_request_bytes(struct exynos_spi *regs, int count)
+{
+	assert(count && count < (1 << 16));
+	setbits_le32(&regs->ch_cfg, SPI_CH_RST);
+	clrbits_le32(&regs->ch_cfg, SPI_CH_RST);
+	writel(count | SPI_PACKET_CNT_EN, &regs->pkt_cnt);
+}
+
+static void spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo,
+			void **dinp, void const **doutp)
+{
+	struct exynos_spi *regs = spi_slave->regs;
+	uchar *rxp = *dinp;
+	const uchar *txp = *doutp;
+	int rx_lvl, tx_lvl;
+	uint out_bytes, in_bytes;
+
+	out_bytes = in_bytes = todo;
+
+	/*
+	 * If there's something to send, do a software reset and set a
+	 * transaction size.
+	 */
+	spi_request_bytes(regs, todo);
+
+	/*
+	 * Bytes are transmitted/received in pairs. Wait to receive all the
+	 * data because then transmission will be done as well.
+	 */
+	while (in_bytes) {
+		int temp;
+
+		/* Keep the fifos full/empty. */
+		spi_get_fifo_levels(regs, &rx_lvl, &tx_lvl);
+		if (tx_lvl < spi_slave->fifo_size && out_bytes) {
+			temp = txp ? *txp++ : 0xff;
+			writel(temp, &regs->tx_data);
+			out_bytes--;
+		}
+		if (rx_lvl > 0 && in_bytes) {
+			temp = readl(&regs->rx_data);
+			if (rxp)
+				*rxp++ = temp;
+			in_bytes--;
+		}
+	}
+	*dinp = rxp;
+	*doutp = txp;
+}
+
+/**
+ * Transfer and receive data
+ *
+ * @param slave		Pointer to spi_slave to which controller has to
+ *			communicate with
+ * @param bitlen	No of bits to tranfer or receive
+ * @param dout		Pointer to transfer buffer
+ * @param din		Pointer to receive buffer
+ * @param flags		Flags for transfer begin and end
+ * @return zero on success else a negative value
+ */
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
+	     void *din, unsigned long flags)
+{
+	struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
+	int upto, todo;
+	int bytelen;
+
+	/* spi core configured to do 8 bit transfers */
+	if (bitlen % 8) {
+		debug("Non byte aligned SPI transfer.\n");
+		return -1;
+	}
+
+	/* Start the transaction, if necessary. */
+	if ((flags & SPI_XFER_BEGIN))
+		spi_cs_activate(slave);
+
+	/* Exynos SPI limits each transfer to 65535 bytes */
+	bytelen =  bitlen / 8;
+	for (upto = 0; upto < bytelen; upto += todo) {
+		todo = min(bytelen - upto, (1 << 16) - 1);
+		spi_rx_tx(spi_slave, todo, &din, &dout);
+	}
+
+	/* Stop the transaction, if necessary. */
+	if ((flags & SPI_XFER_END))
+		spi_cs_deactivate(slave);
+
+	return 0;
+}
+
+/**
+ * Validates the bus and chip select numbers
+ *
+ * @param bus	ID of the bus that the slave is attached to
+ * @param cs	ID of the chip select connected to the slave
+ * @return one on success else zero
+ */
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	return spi_get_bus(bus) && cs == 0;
+}
+
+/**
+ * Activate the CS by driving it LOW
+ *
+ * @param slave	Pointer to spi_slave to which controller has to
+ *		communicate with
+ */
+void spi_cs_activate(struct spi_slave *slave)
+{
+	struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
+
+	clrbits_le32(&spi_slave->regs->cs_reg, SPI_SLAVE_SIG_INACT);
+	debug("Activate CS, bus %d\n", spi_slave->slave.bus);
+}
+
+/**
+ * Deactivate the CS by driving it HIGH
+ *
+ * @param slave	Pointer to spi_slave to which controller has to
+ *		communicate with
+ */
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+	struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
+
+	setbits_le32(&spi_slave->regs->cs_reg, SPI_SLAVE_SIG_INACT);
+	debug("Deactivate CS, bus %d\n", spi_slave->slave.bus);
+}
+
+static inline struct exynos_spi *get_spi_base(int dev_index)
+{
+	if (dev_index < 3)
+		return (struct exynos_spi *)samsung_get_base_spi() + dev_index;
+	else
+		return (struct exynos_spi *)samsung_get_base_spi_isp() +
+					(dev_index - 3);
+}
+
+/* Sadly there is no error return from this function */
+void spi_init(void)
+{
+	int i;
+	struct spi_bus *bus;
+
+	for (i = 0; i < EXYNOS5_SPI_NUM_CONTROLLERS; i++) {
+		bus = &spi_bus[i];
+		bus->regs = get_spi_base(i);
+		bus->periph_id = PERIPH_ID_SPI0 + i;
+
+		/* Although Exynos5 supports upto 50Mhz speed,
+		 * we are setting it to 10Mhz for safe side
+		 */
+		bus->frequency = 10000000;
+		bus->inited = 1;
+	}
+}