[PATCH v4 3/6] lib: utils/i2c: Add generic I2C configuration library

[Xiang W]

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

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
> 
>