[6/8] 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>
---
 arch/arm/include/asm/arch-exynos/spi.h |   78 ++++++
 drivers/spi/Makefile                   |    1 +
 drivers/spi/exynos_spi.c               |  400 ++++++++++++++++++++++++++++++++
 3 files changed, 479 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/arch-exynos/spi.h
 create mode 100644 drivers/spi/exynos_spi.c

Hi,

On Tue, Jul 31, 2012 at 3:42 AM, Rajeshwari Shinde
<rajeshwari.s@samsung.com> wrote:
> 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>
> ---
>  arch/arm/include/asm/arch-exynos/spi.h |   78 ++++++
>  drivers/spi/Makefile                   |    1 +
>  drivers/spi/exynos_spi.c               |  400 ++++++++++++++++++++++++++++++++
>  3 files changed, 479 insertions(+), 0 deletions(-)
>  create mode 100644 arch/arm/include/asm/arch-exynos/spi.h
>  create mode 100644 drivers/spi/exynos_spi.c
>
> diff --git a/arch/arm/include/asm/arch-exynos/spi.h b/arch/arm/include/asm/arch-exynos/spi.h
> new file mode 100644
> index 0000000..7cab1e9
> --- /dev/null
> +++ b/arch/arm/include/asm/arch-exynos/spi.h
> @@ -0,0 +1,78 @@
> +/*
> + * (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
> + */
> +
> +#ifndef __ASM_ARCH_EXYNOS_COMMON_SPI_H_
> +#define __ASM_ARCH_EXYNOS_COMMON_SPI_H_
> +
> +#ifndef __ASSEMBLY__
> +
> +/* SPI peripheral register map; padded to 64KB */
> +struct exynos_spi {
> +       unsigned int            ch_cfg;         /* 0x00 */
> +       unsigned char           reserved0[4];
> +       unsigned int            mode_cfg;       /* 0x08 */
> +       unsigned int            cs_reg;         /* 0x0c */
> +       unsigned char           reserved1[4];
> +       unsigned int            spi_sts;        /* 0x14 */
> +       unsigned int            tx_data;        /* 0x18 */
> +       unsigned int            rx_data;        /* 0x1c */
> +       unsigned int            pkt_cnt;        /* 0x20 */
> +       unsigned char           reserved2[4];
> +       unsigned char           reserved3[4];
> +       unsigned int            fb_clk;         /* 0x2c */
> +       unsigned char           padding[0xffd0];
> +};
> +
> +#define EXYNOS_SPI_MAX_FREQ    50000000
> +
> +#define SPI_TIMEOUT_MS         10
> +
> +/* SPI_CHCFG */
> +#define SPI_CH_HS_EN           (1 << 6)
> +#define SPI_CH_RST             (1 << 5)
> +#define SPI_SLAVE_MODE         (1 << 4)
> +#define SPI_CH_CPOL_L          (1 << 3)
> +#define SPI_CH_CPHA_B          (1 << 2)
> +#define SPI_RX_CH_ON           (1 << 1)
> +#define SPI_TX_CH_ON           (1 << 0)
> +
> +/* SPI_MODECFG */
> +#define SPI_MODE_CH_WIDTH_WORD (0x2 << 29)
> +#define SPI_MODE_BUS_WIDTH_WORD        (0x2 << 17)
> +
> +/* SPI_CSREG */
> +#define SPI_SLAVE_SIG_INACT    (1 << 0)
> +
> +/* SPI_STS */
> +#define SPI_ST_TX_DONE         (1 << 25)
> +#define SPI_FIFO_LVL_MASK      0x1ff
> +#define SPI_TX_LVL_OFFSET      6
> +#define SPI_RX_LVL_OFFSET      15
> +
> +/* Feedback Delay */
> +#define SPI_CLK_BYPASS         (0 << 0)
> +#define SPI_FB_DELAY_90                (1 << 0)
> +#define SPI_FB_DELAY_180       (2 << 0)
> +#define SPI_FB_DELAY_270       (3 << 0)
> +
> +/* Packet Count */
> +#define SPI_PACKET_CNT_EN      (1 << 16)
> +
> +#endif /* __ASSEMBLY__ */
> +#endif
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index c20f1f2..f15adf0 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -33,6 +33,7 @@ COBJS-$(CONFIG_ATMEL_SPI) += atmel_spi.o
>  COBJS-$(CONFIG_BFIN_SPI) += bfin_spi.o
>  COBJS-$(CONFIG_CF_SPI) += cf_spi.o
>  COBJS-$(CONFIG_DAVINCI_SPI) += davinci_spi.o
> +COBJS-$(CONFIG_EXYNOS_SPI) += exynos_spi.o
>  COBJS-$(CONFIG_KIRKWOOD_SPI) += kirkwood_spi.o
>  COBJS-$(CONFIG_MPC52XX_SPI) += mpc52xx_spi.o
>  COBJS-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
> diff --git a/drivers/spi/exynos_spi.c b/drivers/spi/exynos_spi.c
> new file mode 100644
> index 0000000..73fb447
> --- /dev/null
> +++ b/drivers/spi/exynos_spi.c
> @@ -0,0 +1,400 @@
> +/*
> + * (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>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +/* 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];
> +static unsigned int bus_count;
> +
> +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 < bus_count)
> +               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);
> +}
> +
> +/**
> + * Set the required clock frequency to SPI controller
> + *
> + * @param spi_slave    SPI controller
> + *
> + * @return zero on success, negative value on error
> + */
> +static int spi_set_clk(struct exynos_spi_slave *spi_slave)
> +{
> +       if (!(spi_slave->mode & SPI_SLAVE))
> +               return spi_set_clock_rate(spi_slave->periph_id,
> +                                               spi_slave->freq);
> +
> +       return 0;
> +}
> +
> +/**
> + * Initialize the gpio for Master and Slave Mode
> + *
> + * @param spi_slave    SPI controller
> + */
> +static void spi_pinmux_init(struct exynos_spi_slave *spi)
> +{
> +       int flags = PINMUX_FLAG_NONE;
> +
> +       if (spi->mode & SPI_SLAVE)
> +               flags |= PINMUX_FLAG_SLAVE_MODE;
> +
> +       exynos_pinmux_config(spi->periph_id, flags);
> +}
> +
> +/**
> + * 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_SPI0)
> +               spi_slave->fifo_size = 256;

I believe the FIFO size for the ISP ports (SPI3 and SPI4) is also 256.

> +       else
> +               spi_slave->fifo_size = 64;
> +
> +       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
> + */
> +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 = spi_set_clk(spi_slave);
> +       if (ret < 0) {
> +               debug("%s: Failed to setup spi clock\n", __func__);
> +               return ret;
> +       }
> +       spi_pinmux_init(spi_slave);
> +
> +       spi_flush_fifo(slave);
> +
> +       reg = readl(&regs->ch_cfg);
> +       reg &= ~(SPI_CH_CPHA_B | SPI_CH_CPOL_L | SPI_SLAVE_MODE);
> +
> +       if (spi_slave->mode & SPI_CPHA)
> +               reg |= SPI_CH_CPHA_B;
> +
> +       if (spi_slave->mode & SPI_CPOL)
> +               reg |= SPI_CH_CPOL_L;
> +
> +       if (spi_slave->mode & SPI_SLAVE)
> +               reg |= SPI_SLAVE_MODE;
> +
> +       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_slave->mode & SPI_SLAVE))
> +               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_slave->mode & SPI_SLAVE))
> +               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;
> +               if (i == 1)
> +                       bus->frequency = 2500000;
> +               else
> +                       bus->frequency = 500000;

This seems strange. Can we just use the faster speed?

> +               bus->inited = 1;
> +               bus_count++;
> +       }
> +}
> --
> 1.7.4.4
>

Regards,
Simon