From 5deaa530280fda91b8fef632c62c94e7bfd89561 Mon Sep 17 00:00:00 2001 From: Wadim Egorov Date: Thu, 3 Aug 2017 13:48:11 +0200 Subject: [PATCH] rockchip: i2c: fix >32 byte reads The hw can read up to 32 bytes at a time. If we need more than one chunk, we have to enter the plain RX mode. Signed-off-by: Wadim Egorov Acked-by: Philipp Tomsich --- drivers/i2c/rk_i2c.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/i2c/rk_i2c.c b/drivers/i2c/rk_i2c.c index 8bc045a1a0..68e66536e4 100644 --- a/drivers/i2c/rk_i2c.c +++ b/drivers/i2c/rk_i2c.c @@ -164,6 +164,7 @@ static int rk_i2c_read(struct rk_i2c *i2c, uchar chip, uint reg, uint r_len, uint rxdata; uint i, j; int err; + bool snd_chunk = false; debug("rk_i2c_read: chip = %d, reg = %d, r_len = %d, b_len = %d\n", chip, reg, r_len, b_len); @@ -184,15 +185,26 @@ static int rk_i2c_read(struct rk_i2c *i2c, uchar chip, uint reg, uint r_len, while (bytes_remain_len) { if (bytes_remain_len > RK_I2C_FIFO_SIZE) { - con = I2C_CON_EN | I2C_CON_MOD(I2C_MODE_TRX); + con = I2C_CON_EN; bytes_xferred = 32; } else { - con = I2C_CON_EN | I2C_CON_MOD(I2C_MODE_TRX) | - I2C_CON_LASTACK; + /* + * The hw can read up to 32 bytes at a time. If we need + * more than one chunk, send an ACK after the last byte. + */ + con = I2C_CON_EN | I2C_CON_LASTACK; bytes_xferred = bytes_remain_len; } words_xferred = DIV_ROUND_UP(bytes_xferred, 4); + /* + * make sure we are in plain RX mode if we read a second chunk + */ + if (snd_chunk) + con |= I2C_CON_MOD(I2C_MODE_RX); + else + con |= I2C_CON_MOD(I2C_MODE_TRX); + writel(con, ®s->con); writel(bytes_xferred, ®s->mrxcnt); writel(I2C_MBRFIEN | I2C_NAKRCVIEN, ®s->ien); @@ -227,6 +239,7 @@ static int rk_i2c_read(struct rk_i2c *i2c, uchar chip, uint reg, uint r_len, } bytes_remain_len -= bytes_xferred; + snd_chunk = true; debug("I2C Read bytes_remain_len %d\n", bytes_remain_len); } -- 2.30.2