diff options
| author | Heiner Kallweit <hkallweit1@gmail.com> | 2017-03-25 16:07:57 +0300 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2017-03-30 18:30:54 +0300 |
| commit | 47bb8f71caba9f3c424d35a2ac18428aaa85348a (patch) | |
| tree | 5fca4ee97d8fec8a83e33f3f95228c8e4ed43fa2 /drivers/i2c | |
| parent | 39b2ca68537aaf013ad192eb1c9e6b88e267d257 (diff) | |
| download | linux-47bb8f71caba9f3c424d35a2ac18428aaa85348a.tar.xz | |
i2c: meson: use full 12 bits for clock divider
The clock divider has 12 bits, splitted into a 10 bit field and a
2 bit field. The extra 2 bits aren't used currently.
Change this to use the full 12 bits and warn if the requested
frequency is too low.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-meson.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c index 852db0f0bec2..abaa7cae0936 100644 --- a/drivers/i2c/busses/i2c-meson.c +++ b/drivers/i2c/busses/i2c-meson.c @@ -35,7 +35,9 @@ #define REG_CTRL_STATUS BIT(2) #define REG_CTRL_ERROR BIT(3) #define REG_CTRL_CLKDIV_SHIFT 12 -#define REG_CTRL_CLKDIV_MASK ((BIT(10) - 1) << REG_CTRL_CLKDIV_SHIFT) +#define REG_CTRL_CLKDIV_MASK GENMASK(21, 12) +#define REG_CTRL_CLKDIVEXT_SHIFT 28 +#define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28) #define I2C_TIMEOUT_MS 500 @@ -134,8 +136,18 @@ static void meson_i2c_set_clk_div(struct meson_i2c *i2c, unsigned int freq) unsigned int div; div = DIV_ROUND_UP(clk_rate, freq * 4); + + /* clock divider has 12 bits */ + if (div >= (1 << 12)) { + dev_err(i2c->dev, "requested bus frequency too low\n"); + div = (1 << 12) - 1; + } + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIV_MASK, - div << REG_CTRL_CLKDIV_SHIFT); + (div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT); + + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIVEXT_MASK, + (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT); dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__, clk_rate, freq, div); |