Patchwork [U-Boot,18/31] iMX28: Add SPI driver

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Submitter Marek Vasut
Date Sept. 8, 2011, 8:42 p.m.
Message ID <1315514579-19215-19-git-send-email-marek.vasut@gmail.com>
Download mbox | patch
Permalink /patch/113970/
State Changes Requested
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Comments

Marek Vasut - Sept. 8, 2011, 8:42 p.m.
Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
---
 drivers/spi/Makefile  |    1 +
 drivers/spi/mxs_spi.c |  174 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 175 insertions(+), 0 deletions(-)
 create mode 100644 drivers/spi/mxs_spi.c
Stefano Babic - Sept. 9, 2011, 8:51 a.m.
On 09/08/2011 10:42 PM, Marek Vasut wrote:
> Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
> Cc: Stefano Babic <sbabic@denx.de>
> Cc: Wolfgang Denk <wd@denx.de>
> Cc: Detlev Zundel <dzu@denx.de>
> ---
>  drivers/spi/Makefile  |    1 +
>  drivers/spi/mxs_spi.c |  174 +++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 175 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/spi/mxs_spi.c


> diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c
> new file mode 100644
> index 0000000..b9c2f06
> --- /dev/null
> +++ b/drivers/spi/mxs_spi.c

Ok - now I am sure and I agree with your choice. Please then use mxs
consequently in all files.

> @@ -0,0 +1,174 @@
> +/*
> + * Freescale i.MX28 SPI driver
> + *
> + * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
> + * on behalf of DENX Software Engineering GmbH
> + *
> + * 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/errno.h>
> +#include <asm/io.h>
> +#include <asm/arch/clock.h>
> +#include <asm/arch/regs-common.h>
> +#include <asm/arch/regs-base.h>
> +#include <asm/arch/regs-clkctrl.h>
> +#include <asm/arch/regs-ssp.h>
> +#include <asm/arch/iomux-mx28.h>
> +#include <asm/arch/gpio.h>
> +#include <asm/arch/mx28.h>

General comment: drop this stuff and include only imx-regs.h

> +
> +#define	MXS_SPI_MAX_TIMEOUT	1000000
> +
> +static inline struct mx28_ssp_regs *to_mxs_regs(struct spi_slave *slave)
> +{
> +	return (struct mx28_ssp_regs *)(MXS_SSP0_BASE + (slave->bus * 0x2000));
> +}
> +
> +void spi_init(void)
> +{
> +}
> +
> +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
> +				  unsigned int max_hz, unsigned int mode)
> +{

Only the CS supplied in the SOC are supported, it is not possible to use
a GPIO. Please add a comment to explain that.

Best regards,
Stefano Babic
Marek Vasut - Sept. 9, 2011, 11:50 a.m.
On Friday, September 09, 2011 10:51:17 AM Stefano Babic wrote:
> On 09/08/2011 10:42 PM, Marek Vasut wrote:
> > Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
> > Cc: Stefano Babic <sbabic@denx.de>
> > Cc: Wolfgang Denk <wd@denx.de>
> > Cc: Detlev Zundel <dzu@denx.de>
> > ---
> > 
> >  drivers/spi/Makefile  |    1 +
> >  drivers/spi/mxs_spi.c |  174
> >  +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 175
> >  insertions(+), 0 deletions(-)
> >  create mode 100644 drivers/spi/mxs_spi.c
> > 
> > diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c
> > new file mode 100644
> > index 0000000..b9c2f06
> > --- /dev/null
> > +++ b/drivers/spi/mxs_spi.c
> 
> Ok - now I am sure and I agree with your choice. Please then use mxs
> consequently in all files.
> 
> > @@ -0,0 +1,174 @@
> > +/*
> > + * Freescale i.MX28 SPI driver
> > + *
> > + * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
> > + * on behalf of DENX Software Engineering GmbH
> > + *
> > + * 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/errno.h>
> > +#include <asm/io.h>
> > +#include <asm/arch/clock.h>
> > +#include <asm/arch/regs-common.h>
> > +#include <asm/arch/regs-base.h>
> > +#include <asm/arch/regs-clkctrl.h>
> > +#include <asm/arch/regs-ssp.h>
> > +#include <asm/arch/iomux-mx28.h>
> > +#include <asm/arch/gpio.h>
> > +#include <asm/arch/mx28.h>
> 
> General comment: drop this stuff and include only imx-regs.h
> 
> > +
> > +#define	MXS_SPI_MAX_TIMEOUT	1000000
> > +
> > +static inline struct mx28_ssp_regs *to_mxs_regs(struct spi_slave *slave)
> > +{
> > +	return (struct mx28_ssp_regs *)(MXS_SSP0_BASE + (slave->bus * 0x2000));
> > +}
> > +
> > +void spi_init(void)
> > +{
> > +}
> > +
> > +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
> > +				  unsigned int max_hz, unsigned int mode)
> > +{
> 
> Only the CS supplied in the SOC are supported, it is not possible to use
> a GPIO. Please add a comment to explain that.

I don't think I understand here.

> 
> Best regards,
> Stefano Babic
Stefano Babic - Sept. 9, 2011, 12:34 p.m.
On 09/09/2011 01:50 PM, Marek Vasut wrote:

>>
>> Only the CS supplied in the SOC are supported, it is not possible to use
>> a GPIO. Please add a comment to explain that.

If you see other SPI drivers (mxc_spi.c, or blackfin, and other, too)
the CS is or can be implemented with a gpio. Some architecture have a
board specific spi_cs_activate.

In your driver, only the CS of the SPI controller are supported. My only
remark is if we can add a comment to explain this.

Best regards,
Stefano Babic
Marek Vasut - Sept. 9, 2011, 12:50 p.m.
On Friday, September 09, 2011 02:34:05 PM Stefano Babic wrote:
> On 09/09/2011 01:50 PM, Marek Vasut wrote:
> >> Only the CS supplied in the SOC are supported, it is not possible to use
> >> a GPIO. Please add a comment to explain that.
> 
> If you see other SPI drivers (mxc_spi.c, or blackfin, and other, too)
> the CS is or can be implemented with a gpio. Some architecture have a
> board specific spi_cs_activate.
> 
> In your driver, only the CS of the SPI controller are supported. My only
> remark is if we can add a comment to explain this.
> 

Done,cheers

> Best regards,
> Stefano Babic

Patch

diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 96c9642..9a0c475 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -36,6 +36,7 @@  COBJS-$(CONFIG_KIRKWOOD_SPI) += kirkwood_spi.o
 COBJS-$(CONFIG_MPC52XX_SPI) += mpc52xx_spi.o
 COBJS-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
 COBJS-$(CONFIG_MXC_SPI) += mxc_spi.o
+COBJS-$(CONFIG_MXS_SPI) += mxs_spi.o
 COBJS-$(CONFIG_OC_TINY_SPI) += oc_tiny_spi.o
 COBJS-$(CONFIG_OMAP3_SPI) += omap3_spi.o
 COBJS-$(CONFIG_SOFT_SPI) += soft_spi.o
diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c
new file mode 100644
index 0000000..b9c2f06
--- /dev/null
+++ b/drivers/spi/mxs_spi.c
@@ -0,0 +1,174 @@ 
+/*
+ * Freescale i.MX28 SPI driver
+ *
+ * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
+ * on behalf of DENX Software Engineering GmbH
+ *
+ * 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/errno.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/regs-common.h>
+#include <asm/arch/regs-base.h>
+#include <asm/arch/regs-clkctrl.h>
+#include <asm/arch/regs-ssp.h>
+#include <asm/arch/iomux-mx28.h>
+#include <asm/arch/gpio.h>
+#include <asm/arch/mx28.h>
+
+#define	MXS_SPI_MAX_TIMEOUT	1000000
+
+static inline struct mx28_ssp_regs *to_mxs_regs(struct spi_slave *slave)
+{
+	return (struct mx28_ssp_regs *)(MXS_SSP0_BASE + (slave->bus * 0x2000));
+}
+
+void spi_init(void)
+{
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+				  unsigned int max_hz, unsigned int mode)
+{
+	struct spi_slave *slave;
+	struct mx28_ssp_regs *ssp_regs;
+	uint32_t reg = 0;
+
+	if (bus > 3) {
+		printf("MXS SPI: Max bus number is 3\n");
+		return NULL;
+	}
+
+	slave = malloc(sizeof(struct spi_slave));
+	if (!slave)
+		return NULL;
+
+	slave->bus = bus;
+	slave->cs = cs;
+
+	ssp_regs = to_mxs_regs(slave);
+
+	mx28_reset_block(&ssp_regs->hw_ssp_ctrl0_reg);
+
+	writel(SSP_CTRL0_BUS_WIDTH_ONE_BIT, &ssp_regs->hw_ssp_ctrl0);
+
+	reg = SSP_CTRL1_SSP_MODE_SPI | SSP_CTRL1_WORD_LENGTH_EIGHT_BITS;
+	reg |= (mode & SPI_CPOL) ? SSP_CTRL1_POLARITY : 0;
+	reg |= (mode & SPI_CPHA) ? SSP_CTRL1_PHASE : 0;
+	writel(reg, &ssp_regs->hw_ssp_ctrl1);
+
+	writel(0, &ssp_regs->hw_ssp_cmd0);
+
+	mx28_set_ssp_busclock(bus, max_hz / 1000);
+
+	return slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	free(slave);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+}
+
+void mxs_spi_start_xfer(struct spi_slave *slave)
+{
+	struct mx28_ssp_regs *ssp_regs = to_mxs_regs(slave);
+	writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_set);
+	writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_clr);
+}
+
+void mxs_spi_end_xfer(struct spi_slave *slave)
+{
+	struct mx28_ssp_regs *ssp_regs = to_mxs_regs(slave);
+	writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_clr);
+	writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_set);
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+		const void *dout, void *din, unsigned long flags)
+{
+	struct mx28_ssp_regs *ssp_regs = to_mxs_regs(slave);
+	int len = bitlen / 8;
+	const char *tx = dout;
+	char *rx = din;
+
+	if (bitlen == 0)
+		return 0;
+
+	if (!rx && !tx)
+		return 0;
+
+	if (flags & SPI_XFER_BEGIN)
+		mxs_spi_start_xfer(slave);
+
+	while (len--) {
+		/* We transfer 1 byte */
+		writel(1, &ssp_regs->hw_ssp_xfer_size);
+
+		if ((flags & SPI_XFER_END) && !len)
+			mxs_spi_end_xfer(slave);
+
+		if (tx)
+			writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_clr);
+		else
+			writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_set);
+
+		writel(SSP_CTRL0_RUN, &ssp_regs->hw_ssp_ctrl0_set);
+
+		if (mx28_wait_mask_set(&ssp_regs->hw_ssp_ctrl0_reg,
+			SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) {
+			printf("MXS SPI: Timeout waiting for start\n");
+			return -1;
+		}
+
+		if (tx)
+			writel(*tx++, &ssp_regs->hw_ssp_data);
+
+		writel(SSP_CTRL0_DATA_XFER, &ssp_regs->hw_ssp_ctrl0_set);
+
+		if (rx) {
+			if (mx28_wait_mask_clr(&ssp_regs->hw_ssp_status_reg,
+				SSP_STATUS_FIFO_EMPTY, MXS_SPI_MAX_TIMEOUT)) {
+				printf("MXS SPI: Timeout waiting for data\n");
+				return -1;
+			}
+
+			*rx = readl(&ssp_regs->hw_ssp_data);
+			rx++;
+		}
+
+		if (mx28_wait_mask_clr(&ssp_regs->hw_ssp_ctrl0_reg,
+			SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) {
+			printf("MXS SPI: Timeout waiting for finish\n");
+			return -1;
+		}
+	}
+
+	return 0;
+}