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| author | Beniamino Galvani <b.galvani@gmail.com> | 2017-11-26 17:40:57 +0100 |
|---|---|---|
| committer | Heiko Schocher <hs@denx.de> | 2017-12-07 09:28:42 +0100 |
| commit | 50a69095cbcaa0e17aebc3ec6a502017f6fed55a (patch) | |
| tree | dfc3caa2c88b4a5fac00a447d928e7db9216ab91 /drivers/i2c | |
| parent | 989bb924c464f08ddac9c8ccb4bf6babbb9083f3 (diff) | |
| download | u-boot-50a69095cbcaa0e17aebc3ec6a502017f6fed55a.zip u-boot-50a69095cbcaa0e17aebc3ec6a502017f6fed55a.tar.gz u-boot-50a69095cbcaa0e17aebc3ec6a502017f6fed55a.tar.bz2 | |
i2c: meson: add some comments
Add some comment describing the purpose of struct members and
functions.
Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/meson_i2c.c | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/drivers/i2c/meson_i2c.c b/drivers/i2c/meson_i2c.c index 2f39214..4f37d2f 100644 --- a/drivers/i2c/meson_i2c.c +++ b/drivers/i2c/meson_i2c.c @@ -44,12 +44,12 @@ struct i2c_regs { struct meson_i2c { struct i2c_regs *regs; - struct i2c_msg *msg; - bool last; - uint count; - uint pos; - u32 tokens[2]; - uint num_tokens; + struct i2c_msg *msg; /* Current I2C message */ + bool last; /* Whether the message is the last */ + uint count; /* Number of bytes in the current transfer */ + uint pos; /* Position of current transfer in message */ + u32 tokens[2]; /* Sequence of tokens to be written */ + uint num_tokens; /* Number of tokens to be written */ }; static void meson_i2c_reset_tokens(struct meson_i2c *i2c) @@ -69,6 +69,10 @@ static void meson_i2c_add_token(struct meson_i2c *i2c, int token) i2c->num_tokens++; } +/* + * Retrieve data for the current transfer (which can be at most 8 + * bytes) from the device internal buffer. + */ static void meson_i2c_get_data(struct meson_i2c *i2c, u8 *buf, int len) { u32 rdata0, rdata1; @@ -86,6 +90,10 @@ static void meson_i2c_get_data(struct meson_i2c *i2c, u8 *buf, int len) *buf++ = (rdata1 >> (i - 4) * 8) & 0xff; } +/* + * Write data for the current transfer (which can be at most 8 bytes) + * to the device internal buffer. + */ static void meson_i2c_put_data(struct meson_i2c *i2c, u8 *buf, int len) { u32 wdata0 = 0, wdata1 = 0; @@ -103,6 +111,11 @@ static void meson_i2c_put_data(struct meson_i2c *i2c, u8 *buf, int len) debug("meson i2c: write data %08x %08x len %d\n", wdata0, wdata1, len); } +/* + * Prepare the next transfer: pick the next 8 bytes in the remaining + * part of message and write tokens and data (if needed) to the + * device. + */ static void meson_i2c_prepare_xfer(struct meson_i2c *i2c) { bool write = !(i2c->msg->flags & I2C_M_RD); |