On Wednesday 29 October 2008, Josh Boyer wrote:
> Looks pretty good. Just a few minor comments/questions below.
Thanks. I also added some comments below.
> Also, do you have a patch for a DTS file that gives an example of how to
> instantiate the SPI stuff in the device tree?
OK, I'll add a DTS patch to the next version.
> >diff --git a/drivers/spi/spi_ppc4xx.c b/drivers/spi/spi_ppc4xx.c
> >new file mode 100644
> >index 0000000..6f94acc
> >--- /dev/null
> >+++ b/drivers/spi/spi_ppc4xx.c
> >+#include <linux/module.h>
> >+#include <linux/init.h>
> >+#include <linux/sched.h>
> >+#include <linux/errno.h>
> >+#include <linux/wait.h>
> >+#include <linux/of_platform.h>
> >+#include <linux/of_spi.h>
> >+#include <linux/of_gpio.h>
> >+#include <linux/interrupt.h>
> >+#include <linux/delay.h>
> >+
> >+#include <linux/gpio.h>
> >+#include <linux/spi/spi.h>
> >+#include <linux/spi/spi_bitbang.h>
> >+
> >+#include <asm/io.h>
> >+#include <asm/dcr-native.h>
>
> Should maybe just be <asm/dcr.h>
Fixed.
> >+#include <asm/dcr-regs.h>
> >+
>
> <snip>
>
> >+/* SPI Controller driver's private data. */
> >+struct ppc4xx_spi {
> >+ /* bitbang has to be first */
> >+ struct spi_bitbang bitbang;
> >+ struct completion done;
> >+
> >+ u64 mapbase;
> >+ u64 mapsize;
> >+ int irqnum;
> >+ /* need this to set the SPI clock */
> >+ unsigned int opb_freq;
> >+
> >+ /* for transfers */
> >+ int len;
> >+ int count;
> >+ /* data buffers */
> >+ const unsigned char *tx;
> >+ unsigned char *rx;
> >+
> >+ int *gpios;
> >+ unsigned int num_gpios;
> >+
> >+ volatile struct spi_ppc4xx_regs __iomem *regs; /* pointer to the
> > registers */
>
> volatile?
Fixed.
> >+ struct spi_master *master;
> >+ struct device *dev;
> >+};
>
> <snip>
>
> >+static int spi_ppc4xx_txrx(struct spi_device *spi, struct spi_transfer
> > *t) +{
> >+ struct ppc4xx_spi *hw;
> >+ u8 data;
> >+
> >+ dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
> >+ t->tx_buf, t->rx_buf, t->len);
> >+
> >+ hw = spi_master_get_devdata(spi->master);
> >+
> >+ hw->tx = t->tx_buf;
> >+ hw->rx = t->rx_buf;
> >+ hw->len = t->len;
> >+ hw->count = 0;
> >+
> >+ /* send the first byte */
> >+ data = hw->tx ? hw->tx[0] : 0;
> >+ out_8(&hw->regs->txd, data);
> >+ out_8(&hw->regs->cr, SPI_PPC4XX_CR_STR);
>
> Maybe iowrite8? Same comment elsewhere.
Why? We use the in_/out_xxx() accessor function for all other 4xx driver as
well.
> >+ wait_for_completion(&hw->done);
> >+
> >+ return hw->count;
> >+}
> >+
>
> <snip>
>
> >+static struct of_device_id spi_ppc4xx_of_match[] = {
> >+ { .compatible = "ibm,spi", },
> >+ {},
> >+};
>
> I'm wondering if that is too generic of a match. In theory,
> IBM could have another SPI controller that isn't for 4xx.
> Maybe "ibm,spi-4xx" ?
Right. I was doing it the same way as already done before, e.g. "ibm,iic". For
the gpio driver we already switched to "ibm,ppc4xx-gpio". So how
about "ibm,ppc4xx-spi"?
Thanks.
Best regards,
Stefan
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-dev
