diff options
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-octeon.c | 126 |
1 files changed, 63 insertions, 63 deletions
diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c index c4abf16468ca..f647667a3a47 100644 --- a/drivers/i2c/busses/i2c-octeon.c +++ b/drivers/i2c/busses/i2c-octeon.c @@ -214,6 +214,69 @@ static int octeon_i2c_wait(struct octeon_i2c *i2c) return 0; } +/* calculate and set clock divisors */ +static void octeon_i2c_set_clock(struct octeon_i2c *i2c) +{ + int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff; + int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000; + + for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) { + /* + * An mdiv value of less than 2 seems to not work well + * with ds1337 RTCs, so we constrain it to larger values. + */ + for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) { + /* + * For given ndiv and mdiv values check the + * two closest thp values. + */ + tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10; + tclk *= (1 << ndiv_idx); + thp_base = (i2c->sys_freq / (tclk * 2)) - 1; + + for (inc = 0; inc <= 1; inc++) { + thp_idx = thp_base + inc; + if (thp_idx < 5 || thp_idx > 0xff) + continue; + + foscl = i2c->sys_freq / (2 * (thp_idx + 1)); + foscl = foscl / (1 << ndiv_idx); + foscl = foscl / (mdiv_idx + 1) / 10; + diff = abs(foscl - i2c->twsi_freq); + if (diff < delta_hz) { + delta_hz = diff; + thp = thp_idx; + mdiv = mdiv_idx; + ndiv = ndiv_idx; + } + } + } + } + octeon_i2c_write_sw(i2c, SW_TWSI_OP_TWSI_CLK, thp); + octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv); +} + +static int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c) +{ + u8 status; + int tries; + + /* disable high level controller, enable bus access */ + octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB); + + /* reset controller */ + octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_RST, 0); + + for (tries = 10; tries; tries--) { + udelay(1); + status = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT); + if (status == STAT_IDLE) + return 0; + } + dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n", __func__, status); + return -EIO; +} + /** * octeon_i2c_start - send START to the bus * @i2c: The struct octeon_i2c @@ -428,69 +491,6 @@ static struct i2c_adapter octeon_i2c_ops = { .algo = &octeon_i2c_algo, }; -/* calculate and set clock divisors */ -static void octeon_i2c_set_clock(struct octeon_i2c *i2c) -{ - int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff; - int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000; - - for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) { - /* - * An mdiv value of less than 2 seems to not work well - * with ds1337 RTCs, so we constrain it to larger values. - */ - for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) { - /* - * For given ndiv and mdiv values check the - * two closest thp values. - */ - tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10; - tclk *= (1 << ndiv_idx); - thp_base = (i2c->sys_freq / (tclk * 2)) - 1; - - for (inc = 0; inc <= 1; inc++) { - thp_idx = thp_base + inc; - if (thp_idx < 5 || thp_idx > 0xff) - continue; - - foscl = i2c->sys_freq / (2 * (thp_idx + 1)); - foscl = foscl / (1 << ndiv_idx); - foscl = foscl / (mdiv_idx + 1) / 10; - diff = abs(foscl - i2c->twsi_freq); - if (diff < delta_hz) { - delta_hz = diff; - thp = thp_idx; - mdiv = mdiv_idx; - ndiv = ndiv_idx; - } - } - } - } - octeon_i2c_write_sw(i2c, SW_TWSI_OP_TWSI_CLK, thp); - octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv); -} - -static int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c) -{ - u8 status; - int tries; - - /* disable high level controller, enable bus access */ - octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB); - - /* reset controller */ - octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_RST, 0); - - for (tries = 10; tries; tries--) { - udelay(1); - status = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT); - if (status == STAT_IDLE) - return 0; - } - dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n", __func__, status); - return -EIO; -} - static int octeon_i2c_probe(struct platform_device *pdev) { struct device_node *node = pdev->dev.of_node; |