Date:   Mon, 10 Jan 2022 12:19:05 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Lucas Tanure <tanureal@...nsource.cirrus.com>,
        Tom Rix <trix@...hat.com>
Cc:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <markgross@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Mark Brown <broonie@...nel.org>, Takashi Iwai <tiwai@...e.com>,
        ALSA Development Mailing List <alsa-devel@...a-project.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        patches@...nsource.cirrus.com,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 07/10] hda: cs35l41: Add support for CS35L41 in HDA systems

Tom,below my review where you may find a lot to be improved in the
code, including the place where you should fix it instead of your
approach.

On Thu, Jan 6, 2022 at 2:29 PM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
>
> On Fri, Dec 17, 2021 at 5:45 PM Lucas Tanure
> <tanureal@...nsource.cirrus.com> wrote:
> >
> > Add support for CS35L41 using a new separated driver
> > that can be used in all upcoming designs
>
>
>
> > +config SND_HDA_SCODEC_CS35L41_I2C
> > +       tristate "Build CS35L41 HD-audio side codec support for I2C Bus"
> > +       depends on ACPI
> > +       select SND_HDA_GENERIC
> > +       select SND_SOC_CS35L41_LIB
> > +       select SND_HDA_SCODEC_CS35L41
> > +       help
> > +         Say Y or M here to include CS35L41 I2C HD-audio side codec support
> > +         in snd-hda-intel driver, such as ALC287.
> > +
> > +comment "Set to Y if you want auto-loading the side codec driver"
> > +       depends on SND_HDA=y && SND_HDA_SCODEC_CS35L41_I2C=m
> > +
> > +config SND_HDA_SCODEC_CS35L41_SPI
> > +       tristate "Build CS35L41 HD-audio codec support for SPI Bus"
> > +       depends on ACPI
> > +       select SND_HDA_GENERIC
> > +       select SND_SOC_CS35L41_LIB
> > +       select SND_HDA_SCODEC_CS35L41
> > +       help
> > +         Say Y or M here to include CS35L41 SPI HD-audio side codec support
> > +         in snd-hda-intel driver, such as ALC287.
>
> ...
>
> > +// cs35l41.c -- CS35l41 ALSA HDA audio driver
>
> It's an additional burden in case the file will be renamed. i..o.w.
> drop the names of the files from the files.
>
>
> > +#include <linux/acpi.h>
> > +#include <linux/module.h>
> > +#include <sound/hda_codec.h>
> > +#include "hda_local.h"
> > +#include "hda_auto_parser.h"
> > +#include "hda_jack.h"
> > +#include "hda_generic.h"
> > +#include "hda_component.h"
> > +#include "cs35l41_hda.h"
>
> ...
>
> > +       { CS35L41_PWR_CTRL1,            0x00000001, 2000 }, //GLOBAL_EN = 1
>
> Here and everywhere else, missed space after //
>
> ...
>
> > +static void cs35l41_hda_playback_hook(struct device *dev, int action)
> > +{
> > +       struct cs35l41_hda *cs35l41 = dev_get_drvdata(dev);
> > +       const struct cs35l41_hda_reg_sequence *reg_seq = cs35l41->reg_seq;
> > +       struct regmap *reg = cs35l41->regmap;
> > +       int ret = 0;
> > +
> > +       switch (action) {
> > +       case HDA_GEN_PCM_ACT_OPEN:
> > +               if (reg_seq->open)
> > +                       ret = regmap_multi_reg_write(reg, reg_seq->open, reg_seq->num_open);
> > +               break;
> > +       case HDA_GEN_PCM_ACT_PREPARE:
> > +               if (reg_seq->prepare)
> > +                       ret = regmap_multi_reg_write(reg, reg_seq->prepare, reg_seq->num_prepare);
> > +               break;
> > +       case HDA_GEN_PCM_ACT_CLEANUP:
> > +               if (reg_seq->cleanup)
> > +                       ret = regmap_multi_reg_write(reg, reg_seq->cleanup, reg_seq->num_cleanup);
> > +               break;
> > +       case HDA_GEN_PCM_ACT_CLOSE:
> > +               if (reg_seq->close)
> > +                       ret = regmap_multi_reg_write(reg, reg_seq->close, reg_seq->num_close);
> > +               break;
>
> default case?
>
> > +       }
> > +
> > +       if (ret)
> > +               dev_warn(cs35l41->dev, "Failed to apply multi reg write: %d\n", ret);
>
> > +
>
> Redundant blank line.
>
> > +}
>
>
> ...
>
> > +       if (comps && cs35l41->index >= 0 && cs35l41->index < HDA_MAX_COMPONENTS)
> > +               comps = &comps[cs35l41->index];
> > +       else
> > +               return -EINVAL;
>
> Can you check first? In such a case you won't need the 'else' branch at all.
>
> ...
>
> > +       if (!comps->dev) {
>
> Why not a positive check and standard pattern as per above?
>
>
> > +               comps->dev = dev;
> > +               strscpy(comps->name, dev_name(dev), sizeof(comps->name));
> > +               comps->playback_hook = cs35l41_hda_playback_hook;
> > +               comps->set_channel_map = cs35l41_hda_channel_map;
> > +               return 0;
> > +       }
> > +
> > +       return -EBUSY;
> > +}
>
> ...
>
> > +       switch (hw_cfg->gpio1_func) {
> > +       case CS35l41_VSPK_SWITCH:
> > +               regmap_update_bits(cs35l41->regmap, CS35L41_GPIO_PAD_CONTROL,
> > +                                  CS35L41_GPIO1_CTRL_MASK, 1 << CS35L41_GPIO1_CTRL_SHIFT);
> > +               break;
> > +       case CS35l41_SYNC:
> > +               regmap_update_bits(cs35l41->regmap, CS35L41_GPIO_PAD_CONTROL,
> > +                                  CS35L41_GPIO1_CTRL_MASK, 2 << CS35L41_GPIO1_CTRL_SHIFT);
> > +               break;
>
> default case?
>
> Same for all switch-cases in your code.
>
> > +       }
>
> ...
>
> > +       ret = cs35l41_hda_channel_map(cs35l41->dev, 0, NULL, 1, (unsigned int *)&hw_cfg->spk_pos);
> > +       if (ret)
> > +               return ret;
> > +
> > +       return 0;
>
> return cs35l41_hda_...(...);
>
> ...
>
> > +       property = "cirrus,dev-index";
> > +       ret = device_property_count_u32(acpi_dev, property);
>
> Please, name adev the pointer to ACPI device. Ah, what a mess, you
> have named acpi_dev the pointer to the struct device. Please, find a
> better name, like dev, or physdev or so.
>
> > +       if (ret <= 0)
>
> Shouldn't you override the error code for the 0 case?
>
> > +               goto no_acpi_dsd;
>
> ...
>
> > +       if (ret > ARRAY_SIZE(values)) {
> > +               ret = -EINVAL;
> > +               goto err;
> > +       }
>
> Is it really the issue? I would expect the issue when you have less
> than expected, and not otherwise.
>
> ...
>
> > +       /* No devm_ version as CLSA0100, in no_acpi_dsd case, can't use devm version */
>
> Can you elaborate why devm can't be used?
>
> > +       cs35l41->reset_gpio = fwnode_gpiod_get_index(&adev->fwnode, "reset", cs35l41->index,
>
> Please, do not dereference fwnode pointers.
> Also, why can't you use the device instead of fwnode?
>
> > +                                                    GPIOD_OUT_LOW, "cs35l41-reset");
>
> ...
>
> > +       hw_cfg = kzalloc(sizeof(*hw_cfg), GFP_KERNEL);
>
> Why not devm?
>
> > +       if (!hw_cfg) {
> > +               ret = -ENOMEM;
> > +               goto err;
> > +       }
>
> ...
>
> > +       property = "cirrus,speaker-position";
> > +       ret = device_property_read_u32_array(acpi_dev, property, values, nval);
> > +       if (ret)
> > +               goto err_free;
> > +       hw_cfg->spk_pos = values[cs35l41->index];
>
> This and further is weird. Why do you need to retrieve all values for
> just one? Use indexed APIs for that. If there are none, create them.
>
> ...
>
> > +no_acpi_dsd:
> > +       /*
> > +        * Device CLSA0100 doesn't have _DSD so a gpiod_get by the label reset won't work.
>
> So, you need to add mapping tables and switch to regular APIs, tell
> me, why it won't work.
>
> > +        * And devices created by i2c-multi-instantiate don't have their device struct pointing to
> > +        * the correct fwnode, so acpi_dev must be used here
> > +        * And devm functions expect that the device requesting the resource has the correct
> > +        * fwnode
>
> You missed grammar periods and what else? Please, update your comments
> to use proper English grammar.
>
> > +        */
> > +       if (strncmp(hid, "CLSA0100", 8) != 0)
> > +               return ERR_PTR(-EINVAL);
> > +
> > +       /* check I2C address to assign the index */
> > +       cs35l41->index = id == 0x40 ? 0 : 1;
> > +       cs35l41->reset_gpio = gpiod_get_index(acpi_dev, NULL, 0, GPIOD_OUT_HIGH);
> > +       cs35l41->vspk_always_on = true;
> > +       put_device(acpi_dev);
> > +
> > +       return NULL;
> > +}
>
> ...
>
> > +int cs35l41_hda_probe(struct device *dev, const char *device_name, int id, int irq,
> > +                     struct regmap *regmap)
>
> > +       if (IS_ERR(regmap))
> > +               return PTR_ERR(regmap);
>
> Why?
>
> ...
>
> > +       if (IS_ERR(cs35l41->reset_gpio)) {
>
> You should use _optinal variants instead,
>
> > +               ret = PTR_ERR(cs35l41->reset_gpio);
> > +               cs35l41->reset_gpio = NULL;
> > +               if (ret == -EBUSY) {
> > +                       dev_info(cs35l41->dev, "Reset line busy, assuming shared reset\n");
> > +               } else {
> > +                       if (ret != -EPROBE_DEFER)
> > +                               dev_err(cs35l41->dev, "Failed to get reset GPIO: %d\n", ret);
> > +                       goto err;
>
> We have dev_err_probe() for a few releases already.
>
> > +               }
> > +       }
>
> ...
>
> > +       ret = regmap_read(cs35l41->regmap, CS35L41_IRQ1_STATUS3, &int_sts);
> > +       if (ret || (int_sts & CS35L41_OTP_BOOT_ERR)) {
> > +               dev_err(cs35l41->dev, "OTP Boot error\n");
> > +               ret = -EIO;
>
> Why shadowing error code?
> Why not use dev_err_probe()?
>
> > +               goto err;
> > +       }
>
> ...
>
> > +EXPORT_SYMBOL_GPL(cs35l41_hda_probe);
>
> Please, use the namespace variant and avoid polluting the global
> namespace with  your symbols.
>
> ...
>
> > + * cs35l41_hda.h -- CS35L41 ALSA HDA audio driver
>
> No file names in the files.
>
> ...
>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/device.h>
> > +#include <sound/cs35l41.h>
>
> Please revisit this. You need to add here only the headers that you
> are a direct user of (or in some cases their top level ones, like
> types.h for compiler_attributes.h).
>
> ...
>
> > +#ifdef CONFIG_ACPI
>
> Drop this ugliness.
>
> > +static const struct acpi_device_id cs35l41_acpi_hda_match[] = {
> > +       {"CLSA0100", 0 },
> > +       {"CSC3551", 0 },
>
> I believe these IDs are officially allocated by the Cirrus Logic, right?
>
> > +       { },
>
> No comma for terminator line here and everywhere else where it's the case.
>
> > +};
> > +MODULE_DEVICE_TABLE(acpi, cs35l41_acpi_hda_match);
> > +#endif
> > +
> > +static struct i2c_driver cs35l41_i2c_driver = {
> > +       .driver = {
> > +               .name           = "cs35l41-hda",
> > +               .acpi_match_table = ACPI_PTR(cs35l41_acpi_hda_match),
>
> ACPI_PTR() as well.
>
> > +       },
> > +       .id_table       = cs35l41_hda_i2c_id,
> > +       .probe          = cs35l41_hda_i2c_probe,
> > +       .remove         = cs35l41_hda_i2c_remove,
> > +};
>
> > +
>
> No need to have a blank line here.
>
> > +module_i2c_driver(cs35l41_i2c_driver);
>
> I stopped here, so this code needs more work and can't be applied like this.
>
> I believe that current Cirrus Logic drivers are written in the same
> (semi-) bad style and have to be fixed in the future. Put this to your
> TODO list, please.
>
> --
> With Best Regards,
> Andy Shevchenko



-- 
With Best Regards,
Andy Shevchenko

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