From: Jerome Brunet jbrunet@baylibre.com
commit 28683e847e2f20eed22cdd24f185d7783db396d3 upstream.
When the slave address is written in do_start(), SLAVE_ADDR is written completely. This may overwrite some setting related to the clock rate or signal filtering.
Fix this by writing only the bits related to slave address. To avoid causing unexpected changed, explicitly disable filtering or high/low clock mode which may have been left over by the bootloader.
Fixes: 30021e3707a7 ("i2c: add support for Amlogic Meson I2C controller") Signed-off-by: Jerome Brunet jbrunet@baylibre.com Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/i2c/busses/i2c-meson.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-)
--- a/drivers/i2c/busses/i2c-meson.c +++ b/drivers/i2c/busses/i2c-meson.c @@ -5,6 +5,7 @@ * Copyright (C) 2014 Beniamino Galvani b.galvani@gmail.com */
+#include <linux/bitfield.h> #include <linux/clk.h> #include <linux/completion.h> #include <linux/i2c.h> @@ -38,6 +39,12 @@ #define REG_CTRL_CLKDIVEXT_SHIFT 28 #define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28)
+#define REG_SLV_ADDR GENMASK(7, 0) +#define REG_SLV_SDA_FILTER GENMASK(10, 8) +#define REG_SLV_SCL_FILTER GENMASK(13, 11) +#define REG_SLV_SCL_LOW GENMASK(27, 16) +#define REG_SLV_SCL_LOW_EN BIT(28) + #define I2C_TIMEOUT_MS 500
enum { @@ -147,6 +154,9 @@ static void meson_i2c_set_clk_div(struct meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIVEXT_MASK, (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
+ /* Disable HIGH/LOW mode */ + meson_i2c_set_mask(i2c, REG_SLAVE_ADDR, REG_SLV_SCL_LOW_EN, 0); + dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__, clk_rate, freq, div); } @@ -280,7 +290,10 @@ static void meson_i2c_do_start(struct me token = (msg->flags & I2C_M_RD) ? TOKEN_SLAVE_ADDR_READ : TOKEN_SLAVE_ADDR_WRITE;
- writel(msg->addr << 1, i2c->regs + REG_SLAVE_ADDR); + + meson_i2c_set_mask(i2c, REG_SLAVE_ADDR, REG_SLV_ADDR, + FIELD_PREP(REG_SLV_ADDR, msg->addr << 1)); + meson_i2c_add_token(i2c, TOKEN_START); meson_i2c_add_token(i2c, token); } @@ -461,6 +474,10 @@ static int meson_i2c_probe(struct platfo return ret; }
+ /* Disable filtering */ + meson_i2c_set_mask(i2c, REG_SLAVE_ADDR, + REG_SLV_SDA_FILTER | REG_SLV_SCL_FILTER, 0); + meson_i2c_set_clk_div(i2c, timings.bus_freq_hz);
return 0;