diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-nomadik.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-nomadik.c | 40 |
1 files changed, 28 insertions, 12 deletions
diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c index 8bf9ac01301a..51e61d8127cb 100644 --- a/drivers/i2c/busses/i2c-nomadik.c +++ b/drivers/i2c/busses/i2c-nomadik.c @@ -340,6 +340,8 @@ static void setup_i2c_controller(struct nmk_i2c_dev *dev) { u32 brcr1, brcr2; u32 i2c_clk, div; + u32 ns; + u16 slsu; writel(0x0, dev->virtbase + I2C_CR); writel(0x0, dev->virtbase + I2C_HSMCR); @@ -347,18 +349,38 @@ static void setup_i2c_controller(struct nmk_i2c_dev *dev) writel(0x0, dev->virtbase + I2C_RFTR); writel(0x0, dev->virtbase + I2C_DMAR); + i2c_clk = clk_get_rate(dev->clk); + /* * set the slsu: * * slsu defines the data setup time after SCL clock - * stretching in terms of i2c clk cycles. The - * needed setup time for the three modes are 250ns, - * 100ns, 10ns respectively thus leading to the values - * of 14, 6, 2 for a 48 MHz i2c clk. + * stretching in terms of i2c clk cycles + 1 (zero means + * "wait one cycle"), the needed setup time for the three + * modes are 250ns, 100ns, 10ns respectively. + * + * As the time for one cycle T in nanoseconds is + * T = (1/f) * 1000000000 => + * slsu = cycles / (1000000000 / f) + 1 */ - writel(dev->cfg.slsu << 16, dev->virtbase + I2C_SCR); + ns = DIV_ROUND_UP_ULL(1000000000ULL, i2c_clk); + switch (dev->cfg.sm) { + case I2C_FREQ_MODE_FAST: + case I2C_FREQ_MODE_FAST_PLUS: + slsu = DIV_ROUND_UP(100, ns); /* Fast */ + break; + case I2C_FREQ_MODE_HIGH_SPEED: + slsu = DIV_ROUND_UP(10, ns); /* High */ + break; + case I2C_FREQ_MODE_STANDARD: + default: + slsu = DIV_ROUND_UP(250, ns); /* Standard */ + break; + } + slsu += 1; - i2c_clk = clk_get_rate(dev->clk); + dev_dbg(&dev->adev->dev, "calculated SLSU = %04x\n", slsu); + writel(slsu << 16, dev->virtbase + I2C_SCR); /* * The spec says, in case of std. mode the divider is @@ -915,11 +937,6 @@ static const struct i2c_algorithm nmk_i2c_algo = { }; static struct nmk_i2c_controller u8500_i2c = { - /* - * Slave data setup time; 250ns, 100ns, and 10ns, which - * is 14, 6 and 2 respectively for a 48Mhz i2c clock. - */ - .slsu = 0xe, .tft = 1, /* Tx FIFO threshold */ .rft = 8, /* Rx FIFO threshold */ .clk_freq = 400000, /* fast mode operation */ @@ -1027,7 +1044,6 @@ static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id) /* fetch the controller configuration from machine */ dev->cfg.clk_freq = pdata->clk_freq; - dev->cfg.slsu = pdata->slsu; dev->cfg.tft = pdata->tft; dev->cfg.rft = pdata->rft; dev->cfg.sm = pdata->sm; |