Hi Simon,
My review is still under way,
but I have some comments below:
On Mon, 24 Nov 2014 11:57:15 -0700
Simon Glass <s...@chromium.org> wrote:
> +static bool i2c_setup_offset(struct dm_i2c_chip *chip, uint offset,
> + uint8_t offset_buf[], struct i2c_msg *msg)
> +{
> + if (!chip->offset_len)
> + return false;
> + msg->addr = chip->chip_addr;
> + msg->flags = chip->flags;
> + msg->len = chip->offset_len;
> + msg->buf = offset_buf;
You directly copy
from (struct dm_i2c_chip *)->flags
to (struct i2c_msg *)->flags.
But you define completely different flags for them:
DM_I2C_CHIP_10BIT is defined as 0x1.
I2C_M_TEN is defined as 0x10.
It would not work.
> +
> +static int i2c_read_bytewise(struct udevice *dev, uint offset,
> + const uint8_t *buffer, int len)
> +{
> + struct dm_i2c_chip *chip = dev_get_parentdata(dev);
> + struct udevice *bus = dev_get_parent(dev);
> + struct dm_i2c_ops *ops = i2c_get_ops(bus);
> + struct i2c_msg msg[1];
> + uint8_t buf[5];
> + int ret;
> + int i;
> +
> + for (i = 0; i < len; i++) {
> + i2c_setup_offset(chip, offset, buf, msg);
> + msg->len++;
> + buf[chip->offset_len] = buffer[i];
> +
> + ret = ops->xfer(bus, msg, 1);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
I could not understand how this works.
It seems to send only write transactions.
> +
> +static int i2c_bind_driver(struct udevice *bus, uint chip_addr,
> + struct udevice **devp)
> +{
> + struct dm_i2c_chip *chip;
> + char name[30], *str;
> + struct udevice *dev;
> + int ret;
> +
> + snprintf(name, sizeof(name), "generic_%x", chip_addr);
> + str = strdup(name);
> + ret = device_bind_driver(bus, "i2c_generic_drv", str, &dev);
> + debug("%s: device_bind_driver: ret=%d\n", __func__, ret);
> + if (ret)
> + goto err_bind;
> +
> + /* Tell the device what we know about it */
> + chip = calloc(1, sizeof(struct dm_i2c_chip));
> + if (!chip) {
> + ret = -ENOMEM;
> + goto err_mem;
> + }
> + chip->chip_addr = chip_addr;
> + chip->offset_len = 1; /* we assume */
> + ret = device_probe_child(dev, chip);
> + debug("%s: device_probe_child: ret=%d\n", __func__, ret);
> + free(chip);
Why do you need calloc() & free() here?
I think you can use the stack area for "struct dm_i2c_chip chip;"
> +
> +UCLASS_DRIVER(i2c) = {
> + .id = UCLASS_I2C,
> + .name = "i2c",
> + .per_device_auto_alloc_size = sizeof(struct dm_i2c_bus),
> + .post_bind = i2c_post_bind,
> + .post_probe = i2c_post_probe,
> +};
> +
> +UCLASS_DRIVER(i2c_generic) = {
> + .id = UCLASS_I2C_GENERIC,
> + .name = "i2c_generic",
> +};
> +
> +U_BOOT_DRIVER(i2c_generic_drv) = {
Perhaps isn't "i2c_generic_chip" clearer than "i2c_generic_drv"?
> + .name = "i2c_generic_drv",
> + .id = UCLASS_I2C_GENERIC,
> +};
Can we move "i2c_generic" to a different file?
maybe, drivers/i2c/i2c-generic.c or drivers/i2c/i2c-generic-chip.c ?
UCLASS_DRIVER(i2c) is a bus, whereas UCLASS_DRIVER(i2c_generic) is a chip.
Mixing up a bus and a chip-device together in the same file
looks confusing to me.
>
> /*
> + * For now there are essentially two parts to this file - driver model
> + * here at the top, and the older code below (with CONFIG_SYS_I2C being
> + * most recent). The plan is to migrate everything to driver model.
> + * The driver model structures and API are separate as they are different
> + * enough as to be incompatible for compilation purposes.
> + */
> +
> +#ifdef CONFIG_DM_I2C
> +
> +enum dm_i2c_chip_flags {
> + DM_I2C_CHIP_10BIT = 1 << 0, /* Use 10-bit addressing */
> + DM_I2C_CHIP_RE_ADDRESS = 1 << 1, /* Send address for every byte */
> +};
As I mentioned above, you define DM_I2C_CHIP_10BIT as 0x1
whereas you define I2C_M_TEN as 0x0010.
These flags should be shared with struct i2c_msg.
> +/*
> + * Not all of these flags are implemented in the U-Boot API
> + */
> +enum dm_i2c_msg_flags {
> + I2C_M_TEN = 0x0010, /* ten-bit chip address */
> + I2C_M_RD = 0x0001, /* read data, from slave to master */
> + I2C_M_STOP = 0x8000, /* send stop after this message */
> + I2C_M_NOSTART = 0x4000, /* no start before this message */
> + I2C_M_REV_DIR_ADDR = 0x2000, /* invert polarity of R/W bit */
> + I2C_M_IGNORE_NAK = 0x1000, /* continue after NAK */
> + I2C_M_NO_RD_ACK = 0x0800, /* skip the Ack bit on reads */
> + I2C_M_RECV_LEN = 0x0400, /* length is first received byte */
> +};
I think this enum usage is odd.
If you want to allocate specific values such as 0x8000, 0x4000, etc.
you should use #define instead of enum.
If you do not care which value is assigned, you can use enum.
arch/arm/include/asm/spl.h is a good example of usage of enum.
> +};
> +
> +/**
> + * struct dm_i2c_ops - driver operations for I2C uclass
> + *
> + * Drivers should support these operations unless otherwise noted. These
> + * operations are intended to be used by uclass code, not directly from
> + * other code.
> + */
> +struct dm_i2c_ops {
> + /**
> + * xfer() - transfer a list of I2C messages
> + *
> + * @bus: Bus to read from
> + * @chip_addr: Chip address to read from
> + * @offset: Offset within chip to start reading
> + * @olen: Length of chip offset in bytes
> + * @buffer: Place to put data
> + * @len: Number of bytes to read
> + * @return 0 if OK, -EREMOTEIO if the slave did not ACK a byte,
> + * other -ve value on some other error
> + */
> + int (*xfer)(struct udevice *bus, struct i2c_msg *msg, int nmsgs);
This comment block does not reflect the actual prototype;
chip_addr, offset, ... etc. do not exist any more.
Best Regards
Masahiro Yamada
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