Re: [Qemu-devel] [PATCH v3 2/9] ppc4xx_i2c: Implement directcntl register

[David Gibson]

On Thu, Jun 14, 2018 at 02:17:00AM +0200, BALATON Zoltan wrote:
> Signed-off-by: BALATON Zoltan <address@hidden>

Patch looks good, but it needs a commit message.  What is the
directcntl register?  Now does the bitbang interface play into that?
(Note that I know the answer to those questions right now, but it
needs to be in the commit message for the benefit of people looking
back in the future).

> ---
>  default-configs/ppc-softmmu.mak    |  1 +
>  default-configs/ppcemb-softmmu.mak |  1 +
>  hw/i2c/ppc4xx_i2c.c                | 13 ++++++++++++-
>  include/hw/i2c/ppc4xx_i2c.h        |  4 ++++
>  4 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/default-configs/ppc-softmmu.mak b/default-configs/ppc-softmmu.mak
> index 4d7be45..7d0dc2f 100644
> --- a/default-configs/ppc-softmmu.mak
> +++ b/default-configs/ppc-softmmu.mak
> @@ -26,6 +26,7 @@ CONFIG_USB_EHCI_SYSBUS=y
>  CONFIG_SM501=y
>  CONFIG_IDE_SII3112=y
>  CONFIG_I2C=y
> +CONFIG_BITBANG_I2C=y
>  
>  # For Macs
>  CONFIG_MAC=y
> diff --git a/default-configs/ppcemb-softmmu.mak 
> b/default-configs/ppcemb-softmmu.mak
> index 67d18b2..37af193 100644
> --- a/default-configs/ppcemb-softmmu.mak
> +++ b/default-configs/ppcemb-softmmu.mak
> @@ -19,3 +19,4 @@ CONFIG_USB_EHCI_SYSBUS=y
>  CONFIG_SM501=y
>  CONFIG_IDE_SII3112=y
>  CONFIG_I2C=y
> +CONFIG_BITBANG_I2C=y
> diff --git a/hw/i2c/ppc4xx_i2c.c b/hw/i2c/ppc4xx_i2c.c
> index 4e0aaae..c0a1930 100644
> --- a/hw/i2c/ppc4xx_i2c.c
> +++ b/hw/i2c/ppc4xx_i2c.c
> @@ -30,6 +30,7 @@
>  #include "cpu.h"
>  #include "hw/hw.h"
>  #include "hw/i2c/ppc4xx_i2c.h"
> +#include "bitbang_i2c.h"
>  
>  #define PPC4xx_I2C_MEM_SIZE 18
>  
> @@ -46,6 +47,11 @@
>  
>  #define IIC_XTCNTLSS_SRST   (1 << 0)
>  
> +#define IIC_DIRECTCNTL_SDAC (1 << 3)
> +#define IIC_DIRECTCNTL_SCLC (1 << 2)
> +#define IIC_DIRECTCNTL_MSDA (1 << 1)
> +#define IIC_DIRECTCNTL_MSCL (1 << 0)
> +
>  static void ppc4xx_i2c_reset(DeviceState *s)
>  {
>      PPC4xxI2CState *i2c = PPC4xx_I2C(s);
> @@ -289,7 +295,11 @@ static void ppc4xx_i2c_writeb(void *opaque, hwaddr addr, 
> uint64_t value,
>          i2c->xtcntlss = value;
>          break;
>      case 16:
> -        i2c->directcntl = value & 0x7;
> +        i2c->directcntl = value & (IIC_DIRECTCNTL_SDAC & 
> IIC_DIRECTCNTL_SCLC);
> +        i2c->directcntl |= (value & IIC_DIRECTCNTL_SCLC ? 1 : 0);
> +        bitbang_i2c_set(i2c->bitbang, BITBANG_I2C_SCL, i2c->directcntl & 1);
> +        i2c->directcntl |= bitbang_i2c_set(i2c->bitbang, BITBANG_I2C_SDA,
> +                               (value & IIC_DIRECTCNTL_SDAC) != 0) << 1;
>          break;
>      default:
>          if (addr < PPC4xx_I2C_MEM_SIZE) {
> @@ -322,6 +332,7 @@ static void ppc4xx_i2c_init(Object *o)
>      sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
>      sysbus_init_irq(SYS_BUS_DEVICE(s), &s->irq);
>      s->bus = i2c_init_bus(DEVICE(s), "i2c");
> +    s->bitbang = bitbang_i2c_init(s->bus);
>  }
>  
>  static void ppc4xx_i2c_class_init(ObjectClass *klass, void *data)
> diff --git a/include/hw/i2c/ppc4xx_i2c.h b/include/hw/i2c/ppc4xx_i2c.h
> index e4b6ded..ea6c8e1 100644
> --- a/include/hw/i2c/ppc4xx_i2c.h
> +++ b/include/hw/i2c/ppc4xx_i2c.h
> @@ -31,6 +31,9 @@
>  #include "hw/sysbus.h"
>  #include "hw/i2c/i2c.h"
>  
> +/* from hw/i2c/bitbang_i2c.h */
> +typedef struct bitbang_i2c_interface bitbang_i2c_interface;
> +
>  #define TYPE_PPC4xx_I2C "ppc4xx-i2c"
>  #define PPC4xx_I2C(obj) OBJECT_CHECK(PPC4xxI2CState, (obj), TYPE_PPC4xx_I2C)
>  
> @@ -42,6 +45,7 @@ typedef struct PPC4xxI2CState {
>      I2CBus *bus;
>      qemu_irq irq;
>      MemoryRegion iomem;
> +    bitbang_i2c_interface *bitbang;
>      uint8_t mdata;
>      uint8_t lmadr;
>      uint8_t hmadr;

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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