Re: [PATCH v2 2/7] i3c: Add core I3C infrastructure

Boris Brezillon
2017-12-18T08:37:40Z

On Sun, 17 Dec 2017 14:32:04 -0800
Randy Dunlap <rdunlap@infradead.org> wrote:

> On 12/14/17 07:16, Boris Brezillon wrote:
> > Add core infrastructure to support I3C in Linux and document it.
> >
> > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> > ---
> > drivers/Kconfig | 2 +
> > drivers/Makefile | 2 +-
> > drivers/i3c/Kconfig | 24 +
> > drivers/i3c/Makefile | 4 +
> > drivers/i3c/core.c | 573 ++++++++++++++++
> > drivers/i3c/device.c | 344 ++++++++++
> > drivers/i3c/internals.h | 34 +
> > drivers/i3c/master.c | 1433 +++++++++++++++++++++++++++++++++++++++
> > drivers/i3c/master/Kconfig | 0
> > drivers/i3c/master/Makefile | 0
> > include/linux/i3c/ccc.h | 380 +++++++++++
> > include/linux/i3c/device.h | 321 +++++++++
> > include/linux/i3c/master.h | 564 +++++++++++++++
> > include/linux/mod_devicetable.h | 17 +
> > 14 files changed, 3697 insertions(+), 1 deletion(-)
> > create mode 100644 drivers/i3c/Kconfig
> > create mode 100644 drivers/i3c/Makefile
> > create mode 100644 drivers/i3c/core.c
> > create mode 100644 drivers/i3c/device.c
> > create mode 100644 drivers/i3c/internals.h
> > create mode 100644 drivers/i3c/master.c
> > create mode 100644 drivers/i3c/master/Kconfig
> > create mode 100644 drivers/i3c/master/Makefile
> > create mode 100644 include/linux/i3c/ccc.h
> > create mode 100644 include/linux/i3c/device.h
> > create mode 100644 include/linux/i3c/master.h
> >
> > diff --git a/drivers/i3c/Kconfig b/drivers/i3c/Kconfig
> > new file mode 100644
> > index 000000000000..cf3752412ae9
> > --- /dev/null
> > +++ b/drivers/i3c/Kconfig
> > @@ -0,0 +1,24 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +
> > +menuconfig I3C
> > + tristate "I3C support"
> > + select I2C
> > + help
> > + I3C is a serial protocol standardized by the MIPI alliance.
> > +
> > + It's supposed to be backward compatible with I2C while providing
> > + support for high speed transfers and native interrupt support
> > + without the need for extra pins.
> > +
> > + The I3C protocol also standardizes the slave device types and is
> > + mainly design to communicate with sensors.
> > +
> > + If you want I3C support, you should say Y here and also to the
> > + specific driver for your bus adapter(s) below.
> > +
> > + This I3C support can also be built as a module. If so, the module
> > + will be called i3c.
> > +
> > +if I3C
> > +source "drivers/i3c/master/Kconfig"
> > +endif # I3C
>
> > diff --git a/drivers/i3c/core.c b/drivers/i3c/core.c
> > new file mode 100644
> > index 000000000000..7eb8e84acd33
> > --- /dev/null
> > +++ b/drivers/i3c/core.c
> > @@ -0,0 +1,573 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2017 Cadence Design Systems Inc.
> > + *
> > + * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
> > + */
> > +
> > +#include <linux/idr.h>
> > +#include <linux/module.h>
> > +#include <linux/of_device.h>
> > +#include <linux/slab.h>
>
> #include <linux/device.h>
> #include <linux/init.h>
> #include <linux/list.h>
> #include <linux/mutex.h>
> #include <linux/rwsem.h>

Do you have a tool to detect those missing inclusions?

>
>
> > +#include "internals.h"
> > +
> > +static DEFINE_IDR(i3c_bus_idr);
> > +static DEFINE_MUTEX(i3c_core_lock);
> > +
>
> > +/**
> > + * i3c_bus_maintenance_lock - Release the bus lock after a maintenance
>
> unlock
>

Will fix that.

> > + * operation
> > + * @bus: I3C bus to release the lock on
> > + *
> > + * Should be called when the bus maintenance operation is done. See
> > + * i3c_bus_maintenance_lock() for more details on what these maintenance
> > + * operations are.
> > + */
> > +void i3c_bus_maintenance_unlock(struct i3c_bus *bus)
> > +{
> > + up_write(&bus->lock);
> > +}
> > +EXPORT_SYMBOL_GPL(i3c_bus_maintenance_unlock);
> > +
>
> > +/**
> > + * i3c_bus_normaluse_lock - Release the bus lock after a normal operation
>
> unlock

Ditto.

>
> > + * @bus: I3C bus to release the lock on
> > + *
> > + * Should be called when a normal operation is done. See
> > + * i3c_bus_normaluse_lock() for more details on what these normal operations
> > + * are.
> > + */
> > +void i3c_bus_normaluse_unlock(struct i3c_bus *bus)
> > +{
> > + up_read(&bus->lock);
> > +}
> > +EXPORT_SYMBOL_GPL(i3c_bus_normaluse_unlock);
>
>
>
> > +static int i3c_device_match(struct device *dev, struct device_driver *drv)
>
> bool?
>
> > +{
> > + struct i3c_device *i3cdev;
> > + struct i3c_driver *i3cdrv;
> > +
> > + if (dev->type != &i3c_device_type)
> > + return 0;
> > +
> > + i3cdev = dev_to_i3cdev(dev);
> > + i3cdrv = drv_to_i3cdrv(drv);
> > + if (i3c_device_match_id(i3cdev, i3cdrv->id_table))
> > + return 1;
> > +
> > + return 0;
> > +}
>
>
> > diff --git a/drivers/i3c/device.c b/drivers/i3c/device.c
> > new file mode 100644
> > index 000000000000..dcf51150b7cb
> > --- /dev/null
> > +++ b/drivers/i3c/device.c
> > @@ -0,0 +1,344 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2017 Cadence Design Systems Inc.
> > + *
> > + * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
> > + */
> > +
> > +#include <linux/slab.h>
>
> #include <linux/atomic.h>
> #include <linux/bug.h>
> #include <linux/completion.h>
> #include <linux/device.h>
> #include <linux/mutex.h>
>
> > +#include "internals.h"
>
>
>
> > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> > new file mode 100644
> > index 000000000000..1c85abac08d5
> > --- /dev/null
> > +++ b/drivers/i3c/master.c
> > @@ -0,0 +1,1433 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2017 Cadence Design Systems Inc.
> > + *
> > + * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
> > + */
>
> #include <linux/atomic.h>
> #include <linux/device.h>
> #include <linux/err.h>
> #include <linux/export.h>
> #include <linux/kernel.h>
> #include <linux/list.h>
> #include <linux/of.h>
>
> > +#include <linux/slab.h>
>
> #include <linux/spinlock.h>
> #include <linux/workqueue.h>
>
> #include <asm-generic/bug.h>
>
> > +#include "internals.h"
>
>
> and I probably missed a few.
>
>
>
>
> > diff --git a/include/linux/i3c/ccc.h b/include/linux/i3c/ccc.h
> > new file mode 100644
> > index 000000000000..ff3e1a3e2c4c
> > --- /dev/null
> > +++ b/include/linux/i3c/ccc.h
> > @@ -0,0 +1,380 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2017 Cadence Design Systems Inc.
> > + *
> > + * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
> > + */
>
> > +/**
> > + * struct i3c_ccc_dev_desc - I3C/I3C device descriptor used for DEFSLVS
>
> Is one of those I3C above supposed to be I2C?

Indeed, should be I2C/I3C.

>
> > + *
> > + * @dyn_addr: dynamic address assigned to the I3C slave or 0 if the entry is
> > + * describing an I2C slave.
> > + * @dcr: DCR value (not applicable to entries describing I2C devices)
> > + * @lvr: LVR value (not applicable to entries describing I3C devices)
> > + * @bcr: BCR value or 0 if this entry is describing an I2C slave
> > + * @static_addr: static address or 0 if the device does not have a static
> > + * address
> > + *
> > + * The DEFSLVS command should be passed an array of i3c_ccc_dev_desc
> > + * descriptors (one entry per I3C/I2C dev controlled by the master).
> > + */
> > +struct i3c_ccc_dev_desc {
> > + u8 dyn_addr;
> > + union {
> > + u8 dcr;
> > + u8 lvr;
> > + };
> > + u8 bcr;
> > + u8 static_addr;
> > +} __packed;
>
>
> Needs bitops.h
>
> > diff --git a/include/linux/i3c/device.h b/include/linux/i3c/device.h
> > new file mode 100644
> > index 000000000000..83958d3a02e2
> > --- /dev/null
> > +++ b/include/linux/i3c/device.h
> > @@ -0,0 +1,321 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2017 Cadence Design Systems Inc.
> > + *
> > + * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
> > + */
> > +
> > +#ifndef I3C_DEV_H
> > +#define I3C_DEV_H
> > +
> > +#include <linux/device.h>
> > +#include <linux/i2c.h>
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/module.h>
>
>
> Needs bitops.h, kconfig.h.
>
>
> > diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
> > new file mode 100644
> > index 000000000000..7ec9a4821bac
> > --- /dev/null
> > +++ b/include/linux/i3c/master.h
> > @@ -0,0 +1,564 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2017 Cadence Design Systems Inc.
> > + *
> > + * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
> > + */
> > +
> > +#ifndef I3C_MASTER_H
> > +#define I3C_MASTER_H
> > +
> > +#include <linux/i2c.h>
> > +#include <linux/i3c/ccc.h>
> > +#include <linux/i3c/device.h>
> > +#include <linux/spinlock.h>
> > +
> > +#define I3C_HOT_JOIN_ADDR 0x2
> > +#define I3C_BROADCAST_ADDR 0x7e
> > +#define I3C_MAX_ADDR GENMASK(6, 0)
> > +
>
> Needs bitops.h, workqueue.h, rwsem.h
>
>
> Needs <asm-generic/bitsperlong.h>

Okay, that's really weird to directly include a header from the
asm-generic directory, are you sure this is the right thing to do here?

>
>
>
> > diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> > index abb6dc2ebbf8..e59da92d8ac9 100644
> > --- a/include/linux/mod_devicetable.h
> > +++ b/include/linux/mod_devicetable.h
> > @@ -442,6 +442,23 @@ struct pci_epf_device_id {
> > kernel_ulong_t driver_data;
> > };
> >
> > +/* i3c */
> > +
> > +#define I3C_MATCH_DCR BIT(0)
> > +#define I3C_MATCH_MANUF BIT(1)
> > +#define I3C_MATCH_PART BIT(2)
> > +#define I3C_MATCH_EXTRA_INFO BIT(3)
>
> Needs bitops.h.

I think I'll just avoid using BIT() here, as done for other definitions
in this file.

>
> > +struct i3c_device_id {
> > + __u8 match_flags;
> > + __u8 dcr;
> > + __u16 manuf_id;
> > + __u16 part_id;
> > + __u16 extra_info;
> > +
> > + const void *data;
> > +};
> > +
> > /* spi */
> >
> > #define SPI_NAME_SIZE 32
> >
>
>