From 50a69095cbcaa0e17aebc3ec6a502017f6fed55a Mon Sep 17 00:00:00 2001 From: Beniamino Galvani Date: Sun, 26 Nov 2017 17:40:57 +0100 Subject: [PATCH] i2c: meson: add some comments Add some comment describing the purpose of struct members and functions. Signed-off-by: Beniamino Galvani Reviewed-by: Simon Glass Reviewed-by: Heiko Schocher --- drivers/i2c/meson_i2c.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/meson_i2c.c b/drivers/i2c/meson_i2c.c index 2f39214ad2..4f37d2f316 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);