[PATCH v4 3/6] lib: utils/i2c: Add generic I2C configuration library
Anup Patel
anup at brainfault.org
Wed Nov 10 09:00:23 PST 2021
On Wed, Nov 10, 2021 at 6:32 PM Xiang W <wxjstz at 126.com> wrote:
>
> 在 2021-11-10星期三的 12:42 +0300，Nikita Shubin写道：
> > From: Nikita Shubin <n.shubin at yadro.com>
> >
> > Helper library to keep track of registered I2C adapters,
> > identified by dts offset, basic send/read functions and
> > adapter configuration (enable, set dividers, etc...).
> >
> > Tested-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> > Reviewed-by: Alexandre Ghiti <alexandre.ghiti at canonical.com>
> > Tested-by: Alexandre Ghiti <alexandre.ghiti at canonical.com>
> > Signed-off-by: Nikita Shubin <n.shubin at yadro.com>
> The i2c bus does not define register-related operations, these
> interfaces should be renamed smbus
I disagree with this suggestion, the existing read/write interface
names are generic enough to send/receive an array of bytes.
These are also suitable for reading EEPROMs or DDR SPD
data, etc. I don't see why we should explicitly name it SMBUS
and restrict it's use.
Regards,
Anup
>
> Regards,
> Xiang W
> > ---
> > v3->v4:
> > - fixed typo in include/sbi_utils/i2c/i2c.h
> > - fixed inaccurate configure remove, leaked into patch 0004
> > ---
> > include/sbi_utils/i2c/i2c.h | 85
> > +++++++++++++++++++++++++++++++++++++
> > lib/utils/i2c/i2c.c | 75 ++++++++++++++++++++++++++++++++
> > lib/utils/i2c/objects.mk | 10 +++++
> > 3 files changed, 170 insertions(+)
> > create mode 100644 include/sbi_utils/i2c/i2c.h
> > create mode 100644 lib/utils/i2c/i2c.c
> > create mode 100644 lib/utils/i2c/objects.mk
> >
> > diff --git a/include/sbi_utils/i2c/i2c.h
> > b/include/sbi_utils/i2c/i2c.h
> > new file mode 100644
> > index 0000000..79aeeb5
> > --- /dev/null
> > +++ b/include/sbi_utils/i2c/i2c.h
> > @@ -0,0 +1,85 @@
> > +/*
> > + * SPDX-License-Identifier: BSD-2-Clause
> > + *
> > + * Copyright (c) 2021 YADRO
> > + *
> > + * Authors:
> > + * Nikita Shubin <n.shubin at yadro.com>
> > + */
> > +
> > +#ifndef __I2C_H__
> > +#define __I2C_H__
> > +
> > +#include <sbi/sbi_types.h>
> > +#include <sbi/sbi_list.h>
> > +
> > +/** Representation of a I2C adapter */
> > +struct i2c_adapter {
> > + /** Pointer to I2C driver owning this I2C adapter */
> > + void *driver;
> > +
> > + /** Unique ID of the I2C adapter assigned by the driver */
> > + int id;
> > +
> > + /**
> > + * Send buffer to given address, register
> > + *
> > + * @return 0 on success and negative error code on failure
> > + */
> > + int (*write)(struct i2c_adapter *ia, uint8_t addr, uint8_t
> > reg,
> > + uint8_t *buffer, int len);
> > +
> > + /**
> > + * Read buffer from given address, register
> > + *
> > + * @return 0 on success and negative error code on failure
> > + */
> > + int (*read)(struct i2c_adapter *ia, uint8_t addr, uint8_t
> > reg,
> > + uint8_t *buffer, int len);
> > +
> > + /** List */
> > + struct sbi_dlist node;
> > +};
> > +
> > +static inline struct i2c_adapter *to_i2c_adapter(struct sbi_dlist
> > *node)
> > +{
> > + return container_of(node, struct i2c_adapter, node);
> > +}
> > +
> > +/** Find a registered I2C adapter */
> > +struct i2c_adapter *i2c_adapter_find(int id);
> > +
> > +/** Register I2C adapter */
> > +int i2c_adapter_add(struct i2c_adapter *ia);
> > +
> > +/** Un-register I2C adapter */
> > +void i2c_adapter_remove(struct i2c_adapter *ia);
> > +
> > +/** Send to device on I2C adapter bus */
> > +int i2c_adapter_write(struct i2c_adapter *ia, uint8_t addr, uint8_t
> > reg,
> > + uint8_t *buffer, int len);
> > +
> > +/** Read from device on I2C adapter bus */
> > +int i2c_adapter_read(struct i2c_adapter *ia, uint8_t addr, uint8_t
> > reg,
> > + uint8_t *buffer, int len);
> > +
> > +static inline int i2c_adapter_reg_write(struct i2c_adapter *ia,
> > uint8_t addr,
> > + uint8_t reg, uint8_t val)
> > +{
> > + return i2c_adapter_write(ia, addr, reg, &val, 1);
> > +}
> > +
> > +static inline int i2c_adapter_reg_read(struct i2c_adapter *ia,
> > uint8_t addr,
> > + uint8_t reg, uint8_t *val)
> > +{
> > + uint8_t buf;
> > + int ret = i2c_adapter_read(ia, addr, reg, &buf, 1);
> > +
> > + if (ret)
> > + return ret;
> > +
> > + *val = buf;
> > + return 0;
> > +}
> > +
> > +#endif
> > diff --git a/lib/utils/i2c/i2c.c b/lib/utils/i2c/i2c.c
> > new file mode 100644
> > index 0000000..1f5072c
> > --- /dev/null
> > +++ b/lib/utils/i2c/i2c.c
> > @@ -0,0 +1,75 @@
> > +/*
> > + * SPDX-License-Identifier: BSD-2-Clause
> > + *
> > + * Copyright (c) 2021 YADRO
> > + *
> > + * Authors:
> > + * Nikita Shubin <n.shubin at yadro.com>
> > + *
> > + * derivate: lib/utils/gpio/gpio.c
> > + * Authors:
> > + * Anup Patel <anup.patel at wdc.com>
> > + */
> > +
> > +#include <sbi/sbi_error.h>
> > +#include <sbi_utils/i2c/i2c.h>
> > +
> > +static SBI_LIST_HEAD(i2c_adapters_list);
> > +
> > +struct i2c_adapter *i2c_adapter_find(int id)
> > +{
> > + struct sbi_dlist *pos;
> > +
> > + sbi_list_for_each(pos, &(i2c_adapters_list)) {
> > + struct i2c_adapter *adap = to_i2c_adapter(pos);
> > +
> > + if (adap->id == id)
> > + return adap;
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > +int i2c_adapter_add(struct i2c_adapter *ia)
> > +{
> > + if (!ia)
> > + return SBI_EINVAL;
> > +
> > + if (i2c_adapter_find(ia->id))
> > + return SBI_EALREADY;
> > +
> > + sbi_list_add(&(ia->node), &(i2c_adapters_list));
> > +
> > + return 0;
> > +}
> > +
> > +void i2c_adapter_remove(struct i2c_adapter *ia)
> > +{
> > + if (!ia)
> > + return;
> > +
> > + sbi_list_del(&(ia->node));
> > +}
> > +
> > +int i2c_adapter_write(struct i2c_adapter *ia, uint8_t addr, uint8_t
> > reg,
> > + uint8_t *buffer, int len)
> > +{
> > + if (!ia)
> > + return SBI_EINVAL;
> > + if (!ia->write)
> > + return SBI_ENOSYS;
> > +
> > + return ia->write(ia, addr, reg, buffer, len);
> > +}
> > +
> > +
> > +int i2c_adapter_read(struct i2c_adapter *ia, uint8_t addr, uint8_t
> > reg,
> > + uint8_t *buffer, int len)
> > +{
> > + if (!ia)
> > + return SBI_EINVAL;
> > + if (!ia->read)
> > + return SBI_ENOSYS;
> > +
> > + return ia->read(ia, addr, reg, buffer, len);
> > +}
> > diff --git a/lib/utils/i2c/objects.mk b/lib/utils/i2c/objects.mk
> > new file mode 100644
> > index 0000000..16a70da
> > --- /dev/null
> > +++ b/lib/utils/i2c/objects.mk
> > @@ -0,0 +1,10 @@
> > +#
> > +# SPDX-License-Identifier: BSD-2-Clause
> > +#
> > +# Copyright (c) 2021 YADRO
> > +#
> > +# Authors:
> > +# Nikita Shubin <n.shubin at yadro.com>
> > +#
> > +
> > +libsbiutils-objs-y += i2c/i2c.o
> > --
> > 2.31.1
> >
> >
>
>
>
> --
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