On Sat, Oct 31, 2015 at 09:30:41PM -0700, Andrey Smirnov wrote:
> Add a driver for DesignWare I2C controller IP block found on several
> SoCs including Altera SoC products
>
> Tested using Terrasic SoCKit board and GPIO expander board with I2C
> EEPROM on it
>
> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
> ---
Looks mostly fine. Two small nitpicks inside.
> +static int i2c_dw_probe(struct device_d *pdev)
> +{
> + struct dw_i2c_dev *dw;
> + struct i2c_platform_data *pdata;
> + int ret, bitrate;
> + uint32_t ic_con, ic_comp_type_value;
> +
> + pdata = pdev->platform_data;
> +
> + dw = kzalloc(sizeof(*dw), GFP_KERNEL);
kzalloc can fail. You should use xzalloc here which cannot fail.
> +
> + if (IS_ENABLED(CONFIG_COMMON_CLK)) {
> + dw->clk = clk_get(pdev, NULL);
> + if (IS_ERR(dw->clk)) {
> + ret = PTR_ERR(dw->clk);
> + goto fail;
> + }
> + }
> +
> + dw->adapter.master_xfer = i2c_dw_xfer;
> + dw->adapter.nr = pdev->id;
> + dw->adapter.dev.parent = pdev;
> + dw->adapter.dev.device_node = pdev->device_node;
> +
> + dw->base = dev_request_mem_region(pdev, 0);
> + if (IS_ERR(dw->base)) {
> + ret = PTR_ERR(dw->base);
> + goto fail;
> + }
> +
> + ic_comp_type_value = readl(dw->base + DW_IC_COMP_TYPE);
> + if (ic_comp_type_value != DW_IC_COMP_TYPE_VALUE) {
> + dev_err(pdev,
> + "unknown DesignWare IP block 0x%08x",
> + ic_comp_type_value);
> + ret = -ENODEV;
> + goto fail;
> + }
> +
> + i2c_dw_enable(dw, false);
> +
> + if (IS_ENABLED(CONFIG_COMMON_CLK))
> + i2c_dw_setup_timings(dw);
> +
> + bitrate = (pdata && pdata->bitrate) ? pdata->bitrate : DW_I2C_BIT_RATE;
> +
> + /*
> + * We have to clear 'ic_10bitaddr_master' in 'ic_tar'
> + * register, otherwise 'ic_10bitaddr_master' in 'ic_con'
> + * wouldn't clear. We don't care about preserving the contents
> + * of that register so we set it to zero.
> + */
> + writel(0, dw->base + DW_IC_TAR);
> +
> + switch (bitrate) {
> + case 400000:
> + ic_con = DW_IC_CON_SPEED_FAST;
> + break;
> + default:
> + dev_warn(pdev, "requested bitrate (%d) is not supported."
> + " Falling back to 100kHz", bitrate);
> + case 100000: /* FALLTHROUGH */
> + ic_con = DW_IC_CON_SPEED_STD;
> + break;
> + }
> +
> + ic_con |= DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE;
> +
> + writel(ic_con, dw->base + DW_IC_CON);
> +
> + /*
> + * Since we will be working in polling mode set both
> + * thresholds to their minimum
> + */
> + writel(0, dw->base + DW_IC_RX_TL);
> + writel(0, dw->base + DW_IC_TX_TL);
> +
> + /* Disable and clear all interrrupts */
> + writel(0, dw->base + DW_IC_INTR_MASK);
> + readl(dw->base + DW_IC_CLR_INTR);
> +
> + i2c_dw_enable(dw, true);
> +
> + ret = i2c_add_numbered_adapter(&dw->adapter);
> +fail:
> + if (ret < 0) {
> + dev_err(pdev, "registration failed\n");
This message is unnecessary. The driver core will warn you when probe
fails anyway.
Sascha
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