Re: [PATCH v5 6/9] platform/x86: serial-multi-instantiate: Reorganize I2C functions

Rafael J. Wysocki
2022-01-21T15:27:29Z

On Fri, Jan 21, 2022 at 3:33 PM Stefan Binding
<sbinding@opensource.cirrus.com> wrote:
>
> From: Lucas Tanure <tanureal@opensource.cirrus.com>
>
> Reorganize I2C functions to accommodate SPI support
> Split the probe and factor out parts of the code
> that will be used in the SPI support
>
> Signed-off-by: Lucas Tanure <tanureal@opensource.cirrus.com>
> Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
> ---
> .../platform/x86/serial-multi-instantiate.c | 145 +++++++++++-------
> 1 file changed, 90 insertions(+), 55 deletions(-)
>
> diff --git a/drivers/platform/x86/serial-multi-instantiate.c b/drivers/platform/x86/serial-multi-instantiate.c
> index 32fb3f904547..162ec20a861a 100644
> --- a/drivers/platform/x86/serial-multi-instantiate.c
> +++ b/drivers/platform/x86/serial-multi-instantiate.c
> @@ -29,96 +29,131 @@ struct smi_instance {
>
> struct smi {
> int i2c_num;
> - struct i2c_client *i2c_devs[];
> + struct i2c_client **i2c_devs;
> };
>
> -static int smi_probe(struct platform_device *pdev)
> +static int smi_get_irq(struct platform_device *pdev, struct acpi_device *adev,
> + const struct smi_instance *inst)
> +{
> + int ret;
> +
> + switch (inst->flags & IRQ_RESOURCE_TYPE) {
> + case IRQ_RESOURCE_GPIO:
> + ret = acpi_dev_gpio_irq_get(adev, inst->irq_idx);
> + break;
> + case IRQ_RESOURCE_APIC:
> + ret = platform_get_irq(pdev, inst->irq_idx);
> + break;
> + default:
> + ret = 0;
> + break;

return 0;

would be slightly more efficient here

> + }
> +
> + if (ret < 0)
> + dev_err_probe(&pdev->dev, ret, "Error requesting irq at index %d: %d\n",
> + inst->irq_idx, ret);
> +
> + return ret;
> +}
> +
> +static void smi_devs_unregister(struct smi *smi)
> +{
> + while (smi->i2c_num > 0)
> + i2c_unregister_device(smi->i2c_devs[--smi->i2c_num]);
> +}
> +
> +/**
> + * smi_i2c_probe - Instantiate multiple I2C devices from inst array
> + * @pdev: Platform device
> + * @adev: ACPI device
> + * @smi: Internal struct for Serial multi instantiate driver
> + * @inst: Array of instances to probe

This is called inst_array below.

> + *
> + * Returns the number of I2C devices instantiate, Zero if none is found or a negative error code.
> + */
> +static int smi_i2c_probe(struct platform_device *pdev, struct acpi_device *adev, struct smi *smi,
> + const struct smi_instance *inst_array)
> {
> struct i2c_board_info board_info = {};
> - const struct smi_instance *inst;
> struct device *dev = &pdev->dev;
> - struct acpi_device *adev;
> - struct smi *smi;
> char name[32];
> - int i, ret;
> + int i, ret, count;
>
> - inst = device_get_match_data(dev);
> - if (!inst) {
> - dev_err(dev, "Error ACPI match data is missing\n");
> - return -ENODEV;
> - }
> -
> - adev = ACPI_COMPANION(dev);
> -
> - /* Count number of clients to instantiate */
> ret = i2c_acpi_client_count(adev);
> - if (ret < 0)
> - return ret;
> + if (ret <= 0)
> + return ret == 0 ? -ENODEV : ret;

I would prefer

if ret < 0)
return ret;
else if (!ret)
return -ENODEV;

>
> - smi = devm_kmalloc(dev, struct_size(smi, i2c_devs, ret), GFP_KERNEL);
> - if (!smi)
> - return -ENOMEM;
> + count = ret;
>
> - smi->i2c_num = ret;
> + smi->i2c_devs = devm_kcalloc(dev, count, sizeof(*smi->i2c_devs), GFP_KERNEL);
> + if (!smi->i2c_devs)
> + return -ENOMEM;
>
> - for (i = 0; i < smi->i2c_num && inst[i].type; i++) {
> + for (i = 0; i < count && inst_array[i].type; i++) {
> memset(&board_info, 0, sizeof(board_info));
> - strlcpy(board_info.type, inst[i].type, I2C_NAME_SIZE);
> - snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev), inst[i].type, i);
> + strscpy(board_info.type, inst_array[i].type, I2C_NAME_SIZE);

The switch-over from strlcpy() to strscpy() should be mentioned in the
changelog.

> + snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev), inst_array[i].type, i);
> board_info.dev_name = name;
> - switch (inst[i].flags & IRQ_RESOURCE_TYPE) {
> - case IRQ_RESOURCE_GPIO:
> - ret = acpi_dev_gpio_irq_get(adev, inst[i].irq_idx);
> - if (ret < 0) {
> - dev_err(dev, "Error requesting irq at index %d: %d\n",
> - inst[i].irq_idx, ret);
> - goto error;
> - }
> - board_info.irq = ret;
> - break;
> - case IRQ_RESOURCE_APIC:
> - ret = platform_get_irq(pdev, inst[i].irq_idx);
> - if (ret < 0) {
> - dev_dbg(dev, "Error requesting irq at index %d: %d\n",
> - inst[i].irq_idx, ret);
> - goto error;
> - }
> - board_info.irq = ret;
> - break;
> - default:
> - board_info.irq = 0;
> - break;
> - }
> +
> + ret = smi_get_irq(pdev, adev, &inst_array[i]);
> + if (ret < 0)
> + goto error;
> + board_info.irq = ret;
> +
> smi->i2c_devs[i] = i2c_acpi_new_device(dev, i, &board_info);
> if (IS_ERR(smi->i2c_devs[i])) {
> ret = dev_err_probe(dev, PTR_ERR(smi->i2c_devs[i]),
> "Error creating i2c-client, idx %d\n", i);
> goto error;
> }
> + smi->i2c_num++;
> }
> - if (i < smi->i2c_num) {
> + if (smi->i2c_num < count) {
> dev_err(dev, "Error finding driver, idx %d\n", i);

That's not particularly informative and so not particularly useful for
a casual receiver of this message. I'd make it dev_dbg().

> ret = -ENODEV;
> goto error;
> }
>
> - platform_set_drvdata(pdev, smi);
> - return 0;
> + dev_info(dev, "Instantiated %d I2C devices.\n", smi->i2c_num);
>
> + return 0;
> error:
> - while (--i >= 0)
> - i2c_unregister_device(smi->i2c_devs[i]);
> + smi_devs_unregister(smi);
>
> return ret;
> }
>
> +static int smi_probe(struct platform_device *pdev)
> +{
> + const struct smi_instance *inst_array;
> + struct device *dev = &pdev->dev;
> + struct acpi_device *adev;
> + struct smi *smi;
> +
> + inst_array = device_get_match_data(dev);
> + if (!inst_array) {
> + dev_err(dev, "Error ACPI match data is missing\n");

Again, this isn't very informative to someone reading this message on
a random system, so I'd change the log level.

> + return -ENODEV;
> + }
> +
> + adev = ACPI_COMPANION(dev);
> + if (!adev)
> + return -ENODEV;

Since you're at it anyway, I'd check the companion's presence upfront,
because you can't do much without it in any case.

> +
> + smi = devm_kzalloc(dev, sizeof(*smi), GFP_KERNEL);
> + if (!smi)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, smi);
> +
> + return smi_i2c_probe(pdev, adev, smi, inst_array);
> +}
> +
> static int smi_remove(struct platform_device *pdev)
> {
> struct smi *smi = platform_get_drvdata(pdev);
> - int i;
>
> - for (i = 0; i < smi->i2c_num; i++)
> - i2c_unregister_device(smi->i2c_devs[i]);
> + smi_devs_unregister(smi);
>
> return 0;
> }
> --
> 2.25.1
>