On Tue, Aug 20, 2024 at 08:53:07AM GMT, Christophe JAILLET wrote:
> Le 19/08/2024 à 23:49, Alex Lanzano a écrit :
> > Add support for the monochrome Sharp Memory LCDs.
>
> Hi,
>
> a few nitpick below, should thre be a v5.
>
> ...
>
> > +struct sharp_memory_device {
> > + struct drm_device drm;
> > + struct spi_device *spi;
> > +
> > + const struct drm_display_mode *mode;
> > +
> > + struct drm_crtc crtc;
> > + struct drm_plane plane;
> > + struct drm_encoder encoder;
> > + struct drm_connector connector;
> > +
> > + struct gpio_desc *enable_gpio;
> > +
> > + struct task_struct *sw_vcom_signal;
> > + struct pwm_device *pwm_vcom_signal;
> > +
> > + enum sharp_memory_vcom_mode vcom_mode;
> > + u8 vcom;
> > +
> > + u32 pitch;
> > + u32 tx_buffer_size;
> > + u8 *tx_buffer;
> > +
> > + /* When vcom_mode == "software" a kthread is used to
> > + * periodically send a 'maintain display' message over
> > + * spi. This mutex ensures tx_buffer access and spi bus
> > + * usage is synchronized in this case
>
> This comment could take only 3 lines and still be with < 80 lines.
> A dot could also be added at the end of the 2nd sentence.
>
> > + */
> > + struct mutex tx_mutex;
> > +};
>
> ...
>
> > +static int sharp_memory_probe(struct spi_device *spi)
> > +{
> > + int ret;
> > + struct device *dev;
> > + struct sharp_memory_device *smd;
> > + struct drm_device *drm;
> > + const char *vcom_mode_str;
> > +
> > + ret = spi_setup(spi);
> > + if (ret < 0)
> > + return dev_err_probe(&spi->dev, ret, "Failed to setup spi device\n");
> > +
> > + dev = &spi->dev;
>
> If done earlier (when dev is declared?), it could already be used in the
> dev_err_probe() just above?
>
> > + if (!dev->coherent_dma_mask) {
> > + ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
> > + if (ret)
> > + return dev_err_probe(dev, ret, "Failed to set dma mask\n");
> > + }
> > +
> > + smd = devm_drm_dev_alloc(dev, &sharp_memory_drm_driver,
> > + struct sharp_memory_device, drm);
> > + if (!smd)
> > + return -ENOMEM;
> > +
> > + spi_set_drvdata(spi, smd);
> > +
> > + smd->spi = spi;
> > + drm = &smd->drm;
> > + ret = drmm_mode_config_init(drm);
> > + if (ret)
> > + return dev_err_probe(dev, ret, "Failed to initialize drm config\n");
> > +
> > + smd->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
> > + if (!smd->enable_gpio)
> > + dev_warn(dev, "Enable gpio not defined\n");
> > +
> > + /*
> > + * VCOM is a signal that prevents DC bias from being built up in
> > + * the panel resulting in pixels being forever stuck in one state.
> > + *
> > + * This driver supports three different methods to generate this
> > + * signal depending on EXTMODE pin:
> > + *
> > + * software (EXTMODE = L) - This mode uses a kthread to
> > + * periodically send a "maintain display" message to the display,
> > + * toggling the vcom bit on and off with each message
> > + *
> > + * external (EXTMODE = H) - This mode relies on an external
> > + * clock to generate the signal on the EXTCOMM pin
> > + *
> > + * pwm (EXTMODE = H) - This mode uses a pwm device to generate
> > + * the signal on the EXTCOMM pin
> > + *
> > + */
> > + if (device_property_read_string(&spi->dev, "sharp,vcom-mode", &vcom_mode_str))
>
> just dev?
>
> > + return dev_err_probe(dev, -EINVAL,
> > + "Unable to find sharp,vcom-mode node in device tree\n");
> > +
> > + if (!strcmp("software", vcom_mode_str)) {
> > + smd->vcom_mode = SHARP_MEMORY_SOFTWARE_VCOM;
> > +
> > + } else if (!strcmp("external", vcom_mode_str)) {
> > + smd->vcom_mode = SHARP_MEMORY_EXTERNAL_VCOM;
> > +
> > + } else if (!strcmp("pwm", vcom_mode_str)) {
> > + smd->vcom_mode = SHARP_MEMORY_PWM_VCOM;
> > + ret = sharp_memory_init_pwm_vcom_signal(smd);
> > + if (ret)
> > + return dev_err_probe(dev, ret,
> > + "Failed to initialize external COM signal\n");
> > + } else {
> > + return dev_err_probe(dev, -EINVAL, "Invalid value set for vcom-mode\n");
> > + }
> > +
> > + drm->mode_config.funcs = &sharp_memory_mode_config_funcs;
> > + smd->mode = spi_get_device_match_data(spi);
> > +
> > + smd->pitch = (SHARP_ADDR_PERIOD + smd->mode->hdisplay + SHARP_DUMMY_PERIOD) / 8;
> > + smd->tx_buffer_size = (SHARP_MODE_PERIOD +
> > + (SHARP_ADDR_PERIOD + (smd->mode->hdisplay) + SHARP_DUMMY_PERIOD) *
> > + smd->mode->vdisplay) / 8;
> > +
> > + smd->tx_buffer = devm_kzalloc(&spi->dev, smd->tx_buffer_size, GFP_KERNEL);
>
> Just dev?
>
> > + if (!smd->tx_buffer)
> > + return -ENOMEM;
> > +
> > + mutex_init(&smd->tx_mutex);
> > +
> > + drm->mode_config.min_width = smd->mode->hdisplay;
> > + drm->mode_config.max_width = smd->mode->hdisplay;
> > + drm->mode_config.min_height = smd->mode->vdisplay;
> > + drm->mode_config.max_height = smd->mode->vdisplay;
> > +
> > + ret = sharp_memory_pipe_init(drm, smd, sharp_memory_formats,
> > + ARRAY_SIZE(sharp_memory_formats),
> > + NULL);
> > + if (ret)
> > + return dev_err_probe(dev, ret, "Failed to initialize display pipeline.\n");
> > +
> > + drm_plane_enable_fb_damage_clips(&smd->plane);
> > + drm_mode_config_reset(drm);
> > +
> > + ret = drm_dev_register(drm, 0);
> > + if (ret)
> > + return dev_err_probe(dev, ret, "Failed to register drm device.\n");
> > +
> > + drm_fbdev_dma_setup(drm, 0);
> > +
> > + return 0;
> > +}
>
> ...
>
> CJ
>
Thank you for the review! Will address in v5
