diff options
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-imx.c | 93 |
1 files changed, 49 insertions, 44 deletions
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 5f4bc7008251..fe53207a6ebb 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -183,6 +183,8 @@ struct imx_i2c_struct { unsigned int disable_delay; int stopped; unsigned int ifdr; /* IMX_I2C_IFDR */ + unsigned int cur_clk; + unsigned int bitrate; const struct imx_i2c_hwdata *hwdata; }; @@ -305,6 +307,48 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx) return 0; } +static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx) +{ + struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div; + unsigned int i2c_clk_rate; + unsigned int div; + int i; + + /* Divider value calculation */ + i2c_clk_rate = clk_get_rate(i2c_imx->clk); + if (i2c_imx->cur_clk == i2c_clk_rate) + return; + else + i2c_imx->cur_clk = i2c_clk_rate; + + div = (i2c_clk_rate + i2c_imx->bitrate - 1) / i2c_imx->bitrate; + if (div < i2c_clk_div[0].div) + i = 0; + else if (div > i2c_clk_div[i2c_imx->hwdata->ndivs - 1].div) + i = i2c_imx->hwdata->ndivs - 1; + else + for (i = 0; i2c_clk_div[i].div < div; i++); + + /* Store divider value */ + i2c_imx->ifdr = i2c_clk_div[i].val; + + /* + * There dummy delay is calculated. + * It should be about one I2C clock period long. + * This delay is used in I2C bus disable function + * to fix chip hardware bug. + */ + i2c_imx->disable_delay = (500000U * i2c_clk_div[i].div + + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2); + +#ifdef CONFIG_I2C_DEBUG_BUS + dev_dbg(&i2c_imx->adapter.dev, "I2C_CLK=%d, REQ DIV=%d\n", + i2c_clk_rate, div); + dev_dbg(&i2c_imx->adapter.dev, "IFDR[IC]=0x%x, REAL DIV=%d\n", + i2c_clk_div[i].val, i2c_clk_div[i].div); +#endif +} + static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) { unsigned int temp = 0; @@ -312,6 +356,8 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); + i2c_imx_set_clk(i2c_imx); + result = clk_prepare_enable(i2c_imx->clk); if (result) return result; @@ -367,45 +413,6 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) clk_disable_unprepare(i2c_imx->clk); } -static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx, - unsigned int rate) -{ - struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div; - unsigned int i2c_clk_rate; - unsigned int div; - int i; - - /* Divider value calculation */ - i2c_clk_rate = clk_get_rate(i2c_imx->clk); - div = (i2c_clk_rate + rate - 1) / rate; - if (div < i2c_clk_div[0].div) - i = 0; - else if (div > i2c_clk_div[i2c_imx->hwdata->ndivs - 1].div) - i = i2c_imx->hwdata->ndivs - 1; - else - for (i = 0; i2c_clk_div[i].div < div; i++); - - /* Store divider value */ - i2c_imx->ifdr = i2c_clk_div[i].val; - - /* - * There dummy delay is calculated. - * It should be about one I2C clock period long. - * This delay is used in I2C bus disable function - * to fix chip hardware bug. - */ - i2c_imx->disable_delay = (500000U * i2c_clk_div[i].div - + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2); - - /* dev_dbg() can't be used, because adapter is not yet registered */ -#ifdef CONFIG_I2C_DEBUG_BUS - dev_dbg(&i2c_imx->adapter.dev, "<%s> I2C_CLK=%d, REQ DIV=%d\n", - __func__, i2c_clk_rate, div); - dev_dbg(&i2c_imx->adapter.dev, "<%s> IFDR[IC]=0x%x, REAL DIV=%d\n", - __func__, i2c_clk_div[i].val, i2c_clk_div[i].div); -#endif -} - static irqreturn_t i2c_imx_isr(int irq, void *dev_id) { struct imx_i2c_struct *i2c_imx = dev_id; @@ -644,7 +651,6 @@ static int i2c_imx_probe(struct platform_device *pdev) struct imxi2c_platform_data *pdata = dev_get_platdata(&pdev->dev); void __iomem *base; int irq, ret; - u32 bitrate; dev_dbg(&pdev->dev, "<%s>\n", __func__); @@ -708,12 +714,11 @@ static int i2c_imx_probe(struct platform_device *pdev) i2c_set_adapdata(&i2c_imx->adapter, i2c_imx); /* Set up clock divider */ - bitrate = IMX_I2C_BIT_RATE; + i2c_imx->bitrate = IMX_I2C_BIT_RATE; ret = of_property_read_u32(pdev->dev.of_node, - "clock-frequency", &bitrate); + "clock-frequency", &i2c_imx->bitrate); if (ret < 0 && pdata && pdata->bitrate) - bitrate = pdata->bitrate; - i2c_imx_set_clk(i2c_imx, bitrate); + i2c_imx->bitrate = pdata->bitrate; /* Set up chip registers to defaults */ imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN, |