On Mon, Feb 22, 2021 at 3:12 PM Daniel Scally [off-list ref] wrote:

ACPI devices with _HID INT3472 are currently matched to the tps68470
driver, however this does not cover all situations in which that _HID
occurs. We've encountered three possibilities:

1. On Chrome OS devices, an ACPI device with _HID INT3472 (representing
a physical TPS68470 device) that requires a GPIO and OpRegion driver
2. On devices designed for Windows, an ACPI device with _HID INT3472
(again representing a physical TPS68470 device) which requires GPIO,
Clock and Regulator drivers.
3. On other devices designed for Windows, an ACPI device with _HID
INT3472 which does **not** represent a physical TPS68470, and is instead
used as a dummy device to group some system GPIO lines which are meant
to be consumed by the sensor that is dependent on this entry.

This commit adds a new module, registering a platform driver to deal
with the 3rd scenario plus an i2c driver to deal with #1 and #2, by
querying the CLDB buffer found against INT3472 entries to determine
which is most appropriate.

Can you split CLK parts (and maybe regulators as well) to something
like intel_skl_int3472_clk.c?

...

+#include <linux/acpi.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>

+               dev_err(&adev->dev, "%s object is not an ACPI buffer\n", id);

Perhaps acpi_handle_err() et al. instead of dev_*(&adev->dev, ...)
where it's applicable?

...

+       if (obj->buffer.length > sizeof(*cldb)) {
+               dev_err(&adev->dev, "The CLDB buffer is too large\n");
+               ret = -EINVAL;

ENOSPC? ENOMEM?

+               goto out_free_obj;
+       }

...

+static int skl_int3472_init(void)
+{

+       int ret = 0;

Redundant assignment.

+       ret = platform_driver_register(&int3472_discrete);
+       if (ret)
+               return ret;
+
+       ret = i2c_register_driver(THIS_MODULE, &int3472_tps68470);
+       if (ret)
+               platform_driver_unregister(&int3472_discrete);

Not a fan of the above, but let's see what others will say...

+       return ret;
+}
+module_init(skl_int3472_init);

...

+#include <linux/clk-provider.h>

This is definitely not for *.h. (Not all C files needed this)

+#include <linux/gpio/machine.h>

Ditto.

+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>

Ditto.

...

+/*
+ * 79234640-9e10-4fea-a5c1-b5aa8b19756f
+ * This _DSM GUID returns information about the GPIO lines mapped to a
+ * discrete INT3472 device. Function number 1 returns a count of the GPIO
+ * lines that are mapped. Subsequent functions return 32 bit ints encoding
+ * information about the GPIO line, including its purpose.
+ */
+static const guid_t int3472_gpio_guid =
+       GUID_INIT(0x79234640, 0x9e10, 0x4fea,
+                 0xa5, 0xc1, 0xb5, 0xaa, 0x8b, 0x19, 0x75, 0x6f);

uuid.h ?

...

+/*
+ * The regulators have to have .ops to be valid, but the only ops we actually
+ * support are .enable and .disable which are handled via .ena_gpiod. Pass an
+ * empty struct to clear the check without lying about capabilities.
+ */
+static const struct regulator_ops int3472_gpio_regulator_ops = { 0 };

{ 0 } is implied by the static keyword and C standard.

...

+static int skl_int3472_clk_prepare(struct clk_hw *hw)
+{
+       struct int3472_gpio_clock *clk = to_int3472_clk(hw);
+
+       gpiod_set_value(clk->ena_gpio, 1);

+       if (clk->led_gpio)

Make it optional and drop this check. Same for other places of use of this GPIO.

+               gpiod_set_value(clk->led_gpio, 1);
+
+       return 0;
+}

...

+static int skl_int3472_clk_enable(struct clk_hw *hw)
+{
+       /*
+        * We're just turning a GPIO on to enable, which operation has the
+        * potential to sleep. Given enable cannot sleep, but prepare can,
+        * we toggle the GPIO in prepare instead. Thus, nothing to do here.
+        */

Missed . and / or  () in some words? (Describing callbacks, personally
I use the form "->callback()" in such cases)

+       return 0;
+}

...

+static unsigned int skl_int3472_get_clk_frequency(struct int3472_discrete_device *int3472)
+{
+       union acpi_object *obj;

+       unsigned int ret = 0;

unsigned for ret is unusual. Looking into the code, first of all it
doesn't need this assignment; second, it probably can gain a better
name: "frequency"?

+       obj = skl_int3472_get_acpi_buffer(int3472->sensor, "SSDB");
+       if (IS_ERR(obj))
+               return 0; /* report rate as 0 on error */
+
+       if (obj->buffer.length < CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET + sizeof(u32)) {
+               dev_err(int3472->dev, "The buffer is too small\n");
+               goto out_free_buff;
+       }
+
+       ret = *(u32 *)(obj->buffer.pointer + CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET);
+
+out_free_buff:
+       kfree(obj);
+       return ret;
+}

...

+       sensor_config = int3472->sensor_config;

+       if (!IS_ERR_OR_NULL(sensor_config) && sensor_config->function_maps) {

Hmm...

Would

if (IS_ERR_OR_NULL(sensor_config))
  return 0;

if (!_maps)
  return 0;

with respective comments working here?

+               const struct int3472_gpio_function_remap *remap =
+                       sensor_config->function_maps;

Split assignment so we can see what is the initial for-loop iterator value.

+               for (; remap->documented; ++remap)

remap++

+                       if (!strcmp(func, remap->documented)) {
+                               func = remap->actual;
+                               break;
+                       }
+       }
+
+       /* Functions mapped to NULL should not be mapped to the sensor */
+       if (!func)
+               return 0;

...

+static int skl_int3472_register_clock(struct int3472_discrete_device *int3472)
+{
+       struct clk_init_data init = {
+               .ops = &skl_int3472_clock_ops,
+               .flags = CLK_GET_RATE_NOCACHE,
+       };
+       int ret = 0;
+
+       init.name = kasprintf(GFP_KERNEL, "%s-clk",
+                             acpi_dev_name(int3472->adev));

devm_*() ? Or is the lifetime different?

+       if (!init.name)
+               return -ENOMEM;
+
+       int3472->clock.frequency = skl_int3472_get_clk_frequency(int3472);
+
+       int3472->clock.clk_hw.init = &init;
+       int3472->clock.clk = clk_register(&int3472->adev->dev,
+                                         &int3472->clock.clk_hw);
+       if (IS_ERR(int3472->clock.clk)) {
+               ret = PTR_ERR(int3472->clock.clk);
+               goto out_free_init_name;
+       }
+
+       int3472->clock.cl = clkdev_create(int3472->clock.clk, NULL,
+                                         int3472->sensor_name);
+       if (!int3472->clock.cl) {
+               ret = -ENOMEM;
+               goto err_unregister_clk;
+       }
+
+       goto out_free_init_name;
+
+err_unregister_clk:
+       clk_unregister(int3472->clock.clk);
+out_free_init_name:
+       kfree(init.name);
+
+       return ret;
+}

...

+       sensor_config = int3472->sensor_config;
+       if (IS_ERR_OR_NULL(sensor_config)) {
+               dev_err(int3472->dev, "No sensor module config\n");

+               return PTR_ERR(sensor_config);

NULL -> 0. Is it okay?

+       }

...

+       int ret = 0;

Seems redundant assignment.
...

+       if (ares->type != ACPI_RESOURCE_TYPE_GPIO ||
+           ares->data.gpio.connection_type != ACPI_RESOURCE_GPIO_TYPE_IO)
+               return 1; /* Deliberately positive so parsing continues */

I don't like to lose control over ACPI_RESOURCE_TYPE_GPIO, i.e.
spreading it over kernel code (yes, I know about one existing TS
case).
Consider to provide a helper in analogue to acpi_gpio_get_irq_resource().

...

+       if (ret < 0 && ret != -EPROBE_DEFER)
+               dev_err(int3472->dev, err_msg);

dev_err_probe() will make the above conditional go away. And you may even do...

+       int3472->n_gpios++;
+       ACPI_FREE(obj);

+       return ret;

...here

return dev_err_probe(...);

...

+       struct list_head resource_list;

+       INIT_LIST_HEAD(&resource_list);

LIST_HEAD(resource_list);

will do two in one.

...

+       if (int3472->clock.ena_gpio) {

Not sure you need this here.

+               ret = skl_int3472_register_clock(int3472);
+               if (ret)
+                       goto out_free_res_list;

+       } else {
+               if (int3472->clock.led_gpio)

Ditto.

+                       dev_warn(int3472->dev,
+                                "No clk GPIO. The privacy LED won't work\n");
+       }

...

+       /* Max num GPIOs we've seen plus a terminator */
+       int3472 = kzalloc(struct_size(int3472, gpios.table,
+                         INT3472_MAX_SENSOR_GPIOS + 1), GFP_KERNEL);

Wonder of you can use devm_*() APIs in this function.

+       if (!int3472)
+               return -ENOMEM;

...

+       int3472->sensor = acpi_dev_get_dependent_dev(adev);
+       if (IS_ERR_OR_NULL(int3472->sensor)) {
+               dev_err(&pdev->dev,
+                       "INT3472 seems to have no dependents.\n");

+               ret = -ENODEV;

Don't shadow error code when you got IS_ERR() case.

+               goto err_free_int3472;
+       }

...

+int skl_int3472_discrete_remove(struct platform_device *pdev)
+{
+       struct int3472_discrete_device *int3472 = platform_get_drvdata(pdev);

+       if (int3472->gpios.dev_id)
+               gpiod_remove_lookup_table(&int3472->gpios);

gpiod_remove_lookup_table() is now NULL-aware.
But in any case I guess you don't need the above check.

+       if (!IS_ERR(int3472->regulator.rdev))

+               regulator_unregister(int3472->regulator.rdev);

Shouldn't it be the pointer to the regulator itself?

+       if (!IS_ERR(int3472->clock.clk))

If you get it optional, you won't need this additional check.

+               clk_unregister(int3472->clock.clk);
+
+       if (int3472->clock.cl)
+               clkdev_drop(int3472->clock.cl);
+
+       gpiod_put(int3472->regulator.gpio);
+       gpiod_put(int3472->clock.ena_gpio);
+       gpiod_put(int3472->clock.led_gpio);
+
+       acpi_dev_put(int3472->sensor);
+
+       kfree(int3472->sensor_name);
+       kfree(int3472);
+
+       return 0;
+}

...

+       ret = skl_int3472_fill_cldb(adev, &cldb);
+       if (!ret && cldb.control_logic_type != 2) {
+               dev_err(&client->dev, "Unsupported control logic type %u\n",
+                       cldb.control_logic_type);
+               return -EINVAL;
+       }
+
+       if (ret)
+               cldb_present = false;

if (ret)
  ...
else if (...)  {
  ...
  return ...;
}

-- 
With Best Regards,
Andy Shevchenko