[U-Boot] [PATCH 1/2] SPI: Add i.MX ECSPI driver

[Stefano Babic]

On 12/01/2012 16:27, Dirk Behme wrote:
> From: Eric Nelson <eric.nelson at boundarydevices.com>
> 
> Signed-off-by: Eric Nelson <eric.nelson at boundarydevices.com>
> CC: Jason Liu <jason.hui at linaro.org>
> CC: Stefano Babic <sbabic at denx.de>
> ---
>  drivers/spi/Makefile    |    1 +
>  drivers/spi/imx_ecspi.c |  334 +++++++++++++++++++++++++++++++++++++++++++++++
>  include/imx_spi.h       |   97 ++++++++++++++
>  3 files changed, 432 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/spi/imx_ecspi.c
>  create mode 100644 include/imx_spi.h
> 

Hi Dirk,

before digging too deep inside the driver: I do not see any apoparent
reason why we must add a separate driver instead of adapting what we
currently have. And most part are quite identical to
drivers/spi/mxc_spi.c. We should change mxc_spi.c for the imx6 relevant
parts, instead of adding a new copy.

> new file mode 100644
> index 0000000..1468208
> --- /dev/null
> +++ b/drivers/spi/imx_ecspi.c
> @@ -0,0 +1,334 @@
> +/*
> + * (C) Copyright 2008-2010 Freescale Semiconductor, Inc.
> + *
> + * 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 <config.h>
> +#include <common.h>
> +#include <spi.h>
> +#include <asm/errno.h>
> +#include <linux/types.h>
> +#include <asm/io.h>
> +#include <malloc.h>
> +#include <asm/arch/clock.h>
> +#include <imx_spi.h>
> +
> +static inline struct imx_spi_dev_t *to_imx_spi_slave(struct spi_slave *slave)
> +{
> +	return container_of(slave, struct imx_spi_dev_t, slave);
> +}
> +
> +static s32 spi_reset(struct spi_slave *slave)
> +{
> +	u32 clk_src = mxc_get_clock(MXC_CSPI_CLK);
> +	u32 pre_div = 0, post_div = 0, reg_ctrl, reg_config;
> +	struct imx_spi_dev_t *dev = to_imx_spi_slave(slave);
> +	struct spi_reg_t *reg = &(dev->reg);
> +
> +	if (dev->freq == 0) {
> +		printf("Error: desired clock is 0\n");
> +		return 1;
> +	}
> +
> +	reg_ctrl = readl(dev->base + SPI_CON_REG);
> +	reg_config = readl(dev->base + SPI_CFG_REG);
> +	/* Reset spi */

The functiion reassembles spi_cfg_mxc in mxc_spi.c, usinf fixed offset
instead of structures.

> +/*
> + * SPI xchg
> + */
> +
> +int spi_xchg_single(struct spi_slave *slave, unsigned int bitlen,
> +	const u8 *dout, u8 *din, unsigned long flags)
> +{
> +	int nbytes = (bitlen + 7) / 8;
> +	struct imx_spi_dev_t *dev = to_imx_spi_slave(slave);
> +	struct spi_reg_t *spi_reg = &(dev->reg);
> +	u32 loop_cnt ;
> +	if (!slave)
> +		return -1;
> +
> +	if (spi_reg->ctrl_reg == 0) {
> +		printf("Error: spi(base=0x%x) has not been initialized yet\n",
> +				dev->base);
> +		return -1;
> +	}
> +	spi_reg->ctrl_reg = (spi_reg->ctrl_reg & ~0xFFF00000) | \
> +			((bitlen - 1) << 20);
> +
> +	writel(spi_reg->ctrl_reg, dev->base + SPI_CON_REG);
> +	writel(spi_reg->cfg_reg, dev->base + SPI_CFG_REG);
> +
> +	/* move data to the tx fifo */
> +	debug("dout=0x%p, bitlen=%x\n", dout, bitlen);
> +
> +	/*
> +	 * The SPI controller works only with words,
> +	 * check if less than a word is sent.
> +	 * Access to the FIFO is only 32 bit
> +	 */
> +	if (bitlen % 32) {
> +		u32 data = 0;

I see no specific i.MX6 code here, and the function is not very
different as spi_xchg_single(). Really I do not think we can add a copy
of the already provided driver, sorry.

Best regards,
Stefano Babic

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