diff options
| -rw-r--r-- | drivers/i2c/busses/i2c-bcm2835.c | 51 |
1 files changed, 32 insertions, 19 deletions
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c index d2085dd3742e..c3436f627028 100644 --- a/drivers/i2c/busses/i2c-bcm2835.c +++ b/drivers/i2c/busses/i2c-bcm2835.c @@ -58,6 +58,7 @@ struct bcm2835_i2c_dev { void __iomem *regs; struct clk *clk; int irq; + u32 bus_clk_rate; struct i2c_adapter adapter; struct completion completion; struct i2c_msg *curr_msg; @@ -78,6 +79,30 @@ static inline u32 bcm2835_i2c_readl(struct bcm2835_i2c_dev *i2c_dev, u32 reg) return readl(i2c_dev->regs + reg); } +static int bcm2835_i2c_set_divider(struct bcm2835_i2c_dev *i2c_dev) +{ + u32 divider; + + divider = DIV_ROUND_UP(clk_get_rate(i2c_dev->clk), + i2c_dev->bus_clk_rate); + /* + * Per the datasheet, the register is always interpreted as an even + * number, by rounding down. In other words, the LSB is ignored. So, + * if the LSB is set, increment the divider to avoid any issue. + */ + if (divider & 1) + divider++; + if ((divider < BCM2835_I2C_CDIV_MIN) || + (divider > BCM2835_I2C_CDIV_MAX)) { + dev_err_ratelimited(i2c_dev->dev, "Invalid clock-frequency\n"); + return -EINVAL; + } + + bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DIV, divider); + + return 0; +} + static void bcm2835_fill_txfifo(struct bcm2835_i2c_dev *i2c_dev) { u32 val; @@ -224,7 +249,7 @@ static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], { struct bcm2835_i2c_dev *i2c_dev = i2c_get_adapdata(adap); unsigned long time_left; - int i; + int i, ret; for (i = 0; i < (num - 1); i++) if (msgs[i].flags & I2C_M_RD) { @@ -233,6 +258,10 @@ static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], return -EOPNOTSUPP; } + ret = bcm2835_i2c_set_divider(i2c_dev); + if (ret) + return ret; + i2c_dev->curr_msg = msgs; i2c_dev->num_msgs = num; reinit_completion(&i2c_dev->completion); @@ -282,7 +311,6 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) { struct bcm2835_i2c_dev *i2c_dev; struct resource *mem, *irq; - u32 bus_clk_rate, divider; int ret; struct i2c_adapter *adap; @@ -306,27 +334,12 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) } ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency", - &bus_clk_rate); + &i2c_dev->bus_clk_rate); if (ret < 0) { dev_warn(&pdev->dev, "Could not read clock-frequency property\n"); - bus_clk_rate = 100000; - } - - divider = DIV_ROUND_UP(clk_get_rate(i2c_dev->clk), bus_clk_rate); - /* - * Per the datasheet, the register is always interpreted as an even - * number, by rounding down. In other words, the LSB is ignored. So, - * if the LSB is set, increment the divider to avoid any issue. - */ - if (divider & 1) - divider++; - if ((divider < BCM2835_I2C_CDIV_MIN) || - (divider > BCM2835_I2C_CDIV_MAX)) { - dev_err(&pdev->dev, "Invalid clock-frequency\n"); - return -ENODEV; + i2c_dev->bus_clk_rate = 100000; } - bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DIV, divider); irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (!irq) { |