Re: [RFC v2 2/2] drm/bridge: Add I2C based driver for ps8640 bridge

From: jitao shi
Date: Wed Nov 04 2015 - 20:22:57 EST

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In reply to: Philipp Zabel: "Re: [RFC v2 2/2] drm/bridge: Add I2C based driver for ps8640 bridge"
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Hi Philipp

I'll fixed those comments on V3.

Thank you very much.

Best Regards.

On Mon, 2015-11-02 at 12:34 +0100, Philipp Zabel wrote:
> Hi Jitao,
>
> a few comments below.
>
> Am Montag, den 02.11.2015, 11:54 +0800 schrieb jitao shi:
> [...]
> > > +static int ps8640_check_valid_id(struct ps8640 *ps_bridge)
>
> This could be bool and return true/false.
>
> > > +{
> > > + struct i2c_client *client = ps_bridge->client;
> > > + u8 rev_id_low, rev_id_high, chip_id_low, chip_id_high;
> > > + int retry_cnt = 0;
> > > +
> > > + do {
> > > + ps8640_regr(client, ps_bridge->base_reg + 4, PAGE4_CHIP_H,
> > > + &chip_id_high);
> > > + if (chip_id_high != 0x30)
> > > + DRM_INFO("chip_id_high = 0x%x\n", chip_id_high);
> > > + } while ((retry_cnt++ < 2) && (chip_id_high != 0x30));
> > > +
> > > + ps8640_regr(client, ps_bridge->base_reg + 4, PAGE4_REV_L, &rev_id_low);
> > > + ps8640_regr(client, ps_bridge->base_reg + 4, PAGE4_REV_H, &rev_id_high);
> > > + ps8640_regr(client, ps_bridge->base_reg + 4, PAGE4_CHIP_L,
> > > + &chip_id_low);
> > > +
> > > + if ((rev_id_low == 0x00) && (rev_id_high == 0x0a) &&
> > > + (chip_id_low == 0x00) && (chip_id_high == 0x30))
> > > + return 1;
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static void ps8640_show_mcu_fw_version(struct ps8640 *ps_bridge)
> > > +{
> > > + struct i2c_client *client = ps_bridge->client;
> > > + u8 major_ver, minor_ver;
> > > +
> > > + ps8640_regr(client, ps_bridge->base_reg + 5, 0x4, &major_ver);
> > > + ps8640_regr(client, ps_bridge->base_reg + 5, 0x5, &minor_ver);
> > > +
> > > + DRM_INFO_ONCE("ps8640 rom fw version %d.%d\n", major_ver, minor_ver);
> > > +}
> > > +
> > > +static int ps8640_bdg_enable(struct ps8640 *ps_bridge)
> > > +{
> > > + struct i2c_client *client = ps_bridge->client;
> > > +
> > > + if (ps8640_check_valid_id(ps_bridge)) {
> > > + ps8640_regw(client, ps_bridge->base_reg + 3, 0xfe, 0x13);
> > > + ps8640_regw(client, ps_bridge->base_reg + 3, 0xff, 0x18);
> > > + ps8640_regw(client, ps_bridge->base_reg + 3, 0xfe, 0x13);
> > > + ps8640_regw(client, ps_bridge->base_reg + 3, 0xff, 0x1c);
>
> Can you introduce #defines with descriptive names for those magic
> constants and register offsets, and maybe also i2c address offsets?
>
> > > +
> > > + return 0;
> > > + }
> > > +
> > > + return -1;
>
> Never return -1 to signal a problem.
> If there was an error, use a proper error code.
>
> > > +}
> > > +
> > > +static void ps8640_prepare(struct ps8640 *ps_bridge)
> > > +{
> > > + struct i2c_client *client = ps_bridge->client;
> > > + int err, retry_cnt = 0;
> > > + u8 set_vdo_done;
> > > +
> > > + if (ps_bridge->enabled)
> > > + return;
> > > +
> > > + if (drm_panel_prepare(ps_bridge->panel)) {
> > > + DRM_ERROR("failed to prepare panel\n");
> > > + return;
> > > + }
> > > +
> > > + err = regulator_enable(ps_bridge->pwr_1v2_supply);
> > > + if (err < 0) {
> > > + DRM_ERROR("failed to enable pwr_1v2_supply: %d\n", err);
>
> Missing panel unprepare.
>
> > > + return;
> > > + }
> > > +
> > > + err = regulator_enable(ps_bridge->pwr_3v3_supply);
> > > + if (err < 0) {
> > > + DRM_ERROR("failed to enable pwr_3v3_supply: %d\n", err);
>
> Missing panel unprepare and vdd12 regulator disable.
>
> > > + return;
> > > + }
> > > +
> > > + gpiod_set_value(ps_bridge->gpio_slp_n, 1);
> > > + gpiod_set_value(ps_bridge->gpio_rst_n, 0);
> > > + usleep_range(500, 700);
> > > + gpiod_set_value(ps_bridge->gpio_rst_n, 1);
> > > +
> > > + do {
> > > + msleep(50);
> > > + ps8640_regr(client, ps_bridge->base_reg + 2, PAGE2_GPIO_H,
> > > + &set_vdo_done);
> > > + } while ((retry_cnt++ < 70) && ((set_vdo_done & PS_GPIO9) != PS_GPIO9));
> > > +
> > > + ps8640_show_mcu_fw_version(ps_bridge);
> > > + ps_bridge->enabled = true;
> > > +}
> > > +
> > > +static void ps8640_pre_enable(struct drm_bridge *bridge)
> > > +{
> > > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
> > > +
> > > + ps8640_prepare(ps_bridge);
> > > +}
> > > +
> > > +static void ps8640_enable(struct drm_bridge *bridge)
> > > +{
> > > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
> > > +
> > > + ps8640_bdg_enable(ps_bridge);
> > > +
> > > + if (drm_panel_enable(ps_bridge->panel)) {
> > > + DRM_ERROR("failed to enable panel\n");
> > > + return;
>
> The return is superfluous.
>
> > > + }
> > > +}
> > > +
> > > +static void ps8640_disable(struct drm_bridge *bridge)
> > > +{
> > > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
> > > +
> > > + if (!ps_bridge->enabled)
> > > + return;
> > > +
> > > + ps_bridge->enabled = false;
> > > +
> > > + if (drm_panel_disable(ps_bridge->panel)) {
> > > + DRM_ERROR("failed to disable panel\n");
> > > + return;
>
> Shouldn't we still disable the bridge, even if panel disable fails?
>
> > > + }
> > > +
> > > + regulator_disable(ps_bridge->pwr_1v2_supply);
> > > + regulator_disable(ps_bridge->pwr_3v3_supply);
> > > + gpiod_set_value(ps_bridge->gpio_rst_n, 0);
> > > + gpiod_set_value(ps_bridge->gpio_slp_n, 0);
> > > +}
> > > +
> > > +static void ps8640_post_disable(struct drm_bridge *bridge)
> > > +{
> > > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
> > > +
> > > + if (drm_panel_unprepare(ps_bridge->panel)) {
> > > + DRM_ERROR("failed to unprepare panel\n");
> > > + return;
>
> Drop the return.
>
> > > + }
> > > +}
> > > +
> > > +static int ps8640_get_modes(struct drm_connector *connector)
> > > +{
> > > + struct ps8640 *ps_bridge = connector_to_ps8640(connector);
> > > + struct i2c_client *client = ps_bridge->client;
> > > +
> > > + ps8640_prepare(ps_bridge);
> > > + ps8640_regw(client, ps_bridge->base_reg + 2, 0xea, 0xd0);
> > > +
> > > + return drm_panel_get_modes(ps_bridge->panel);
> > > +}
> > > +
> > > +static struct drm_encoder *ps8640_best_encoder(struct drm_connector *connector)
> > > +{
> > > + struct ps8640 *ps_bridge;
> > > +
> > > + ps_bridge = connector_to_ps8640(connector);
> > > + return ps_bridge->bridge.encoder;
> > > +}
> > > +
> > > +static const struct drm_connector_helper_funcs
> > > + ps8640_connector_helper_funcs = {
> > > + .get_modes = ps8640_get_modes,
> > > + .best_encoder = ps8640_best_encoder,
> > > +};
> > > +
> > > +static enum drm_connector_status ps8640_detect(struct drm_connector *connector,
> > > + bool force)
> > > +{
> > > + return connector_status_connected;
> > > +}
> > > +
> > > +static void ps8640_connector_destroy(struct drm_connector *connector)
> > > +{
> > > + drm_connector_unregister(connector);
> > > + drm_connector_cleanup(connector);
> > > +}
> > > +
> > > +static const struct drm_connector_funcs ps8640_connector_funcs = {
> > > + .dpms = drm_atomic_helper_connector_dpms,
> > > + .fill_modes = drm_helper_probe_single_connector_modes,
> > > + .detect = ps8640_detect,
> > > + .destroy = ps8640_connector_destroy,
> > > + .reset = drm_atomic_helper_connector_reset,
> > > + .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> > > + .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> > > +};
> > > +
> > > +int ps8640_bridge_attach(struct drm_bridge *bridge)
> > > +{
> > > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
> > > + int ret;
> > > +
> > > + if (!bridge->encoder) {
> > > + DRM_ERROR("Parent encoder object not found");
> > > + return -ENODEV;
> > > + }
> > > +
> > > + ret = drm_connector_init(bridge->dev, &ps_bridge->connector,
> > > + &ps8640_connector_funcs,
> > > + DRM_MODE_CONNECTOR_eDP);
> > > +
> > > + if (ret) {
> > > + DRM_ERROR("Failed to initialize connector with drm\n");
> > > + return ret;
> > > + }
> > > +
> > > + drm_connector_helper_add(&ps_bridge->connector,
> > > + &ps8640_connector_helper_funcs);
> > > + drm_connector_register(&ps_bridge->connector);
> > > +
> > > + ps_bridge->connector.dpms = DRM_MODE_DPMS_ON;
> > > + drm_mode_connector_attach_encoder(&ps_bridge->connector,
> > > + bridge->encoder);
> > > +
> > > + if (ps_bridge->panel)
> > > + drm_panel_attach(ps_bridge->panel, &ps_bridge->connector);
> > > +
> > > + return ret;
> > > +}
> > > +
> > > +static bool ps8640_bridge_mode_fixup(struct drm_bridge *bridge,
> > > + const struct drm_display_mode *mode,
> > > + struct drm_display_mode *adjusted_mode)
> > > +{
> > > + return true;
> > > +}
> > > +
> > > +static const struct drm_bridge_funcs ps8640_bridge_funcs = {
> > > + .attach = ps8640_bridge_attach,
> > > + .mode_fixup = ps8640_bridge_mode_fixup,
> > > + .disable = ps8640_disable,
> > > + .post_disable = ps8640_post_disable,
> > > + .pre_enable = ps8640_pre_enable,
> > > + .enable = ps8640_enable,
> > > +};
> > > +
> > > +static int ps8640_probe(struct i2c_client *client,
> > > + const struct i2c_device_id *id)
> > > +{
> > > + struct device *dev = &client->dev;
> > > + struct ps8640 *ps_bridge;
> > > + struct device_node *np = dev->of_node;
> > > + struct device_node *in_ep, *out_ep;
> > > + struct device_node *panel_node = NULL;
> > > + int ret;
> > > + u32 temp_reg;
> > > +
> > > + ps_bridge = devm_kzalloc(dev, sizeof(*ps_bridge), GFP_KERNEL);
> > > + if (!ps_bridge)
> > > + return -ENOMEM;
> > > +
> > > + in_ep = of_graph_get_next_endpoint(np, NULL);
> > > + if (in_ep) {
> > > + out_ep = of_graph_get_next_endpoint(np, in_ep);
>
> Better use:
> port = of_graph_get_port_by_id(np, 1);
> out_ep = of_get_child_by_name(port, "endpoint");
>
> > > + of_node_put(in_ep);
> > > + if (out_ep) {
> > > + panel_node = of_graph_get_remote_port_parent(out_ep);
> > > + of_node_put(out_ep);
> > > + }
> > > + }
> > > + if (panel_node) {
> > > + ps_bridge->panel = of_drm_find_panel(panel_node);
> > > + of_node_put(panel_node);
> > > + if (!ps_bridge->panel)
> > > + return -EPROBE_DEFER;
> > > + }
> > > +
> > > + ps_bridge->client = client;
> > > +
> > > + ps_bridge->pwr_3v3_supply = devm_regulator_get(dev, "vdd33-supply");
> > > + if (IS_ERR(ps_bridge->pwr_3v3_supply)) {
> > > + dev_err(dev, "cannot get ps_bridge->pwr_3v3_supply\n");
>
> Instead of printing the variable name, just say "vdd3-supply". Also, it
> is good practice to print the actual error value.
>
> > > + return PTR_ERR(ps_bridge->pwr_3v3_supply);
> > > + }
> > > +
> > > + ps_bridge->pwr_1v2_supply = devm_regulator_get(dev, "vdd12-supply");
> > > + if (IS_ERR(ps_bridge->pwr_1v2_supply)) {
> > > + dev_err(dev, "cannot get ps_bridge->pwr_1v2_supply\n");
>
> Same as above.
>
> > > + return PTR_ERR(ps_bridge->pwr_1v2_supply);
> > > + }
> > > +
> > > + ps_bridge->gpio_mode_sel_n = devm_gpiod_get(&client->dev, "mode-sel",
> > > + GPIOD_OUT_HIGH);
> > > + if (IS_ERR(ps_bridge->gpio_mode_sel_n)) {
> > > + ret = PTR_ERR(ps_bridge->gpio_mode_sel_n);
> > > + DRM_ERROR("cannot get gpio_mode_sel_n %d\n", ret);
>
> It would be better to use dev_err instead of DRM_ERROR. The same applies
> to the DRM_ERRORs below.
>
> > > + return ret;
> > > + }
> > > +
> > > + ret = gpiod_direction_output(ps_bridge->gpio_mode_sel_n, 1);
> > > + if (ret) {
> > > + DRM_ERROR("cannot configure gpio_mode_sel_n\n");
> > > + return ret;
> > > + }
> > > +
> > > + ps_bridge->gpio_slp_n = devm_gpiod_get(&client->dev, "sleep-gpios",
> > > + GPIOD_OUT_HIGH);
> > > + if (IS_ERR(ps_bridge->gpio_slp_n)) {
> > > + ret = PTR_ERR(ps_bridge->gpio_slp_n);
> > > + DRM_ERROR("cannot get gpio_slp_n %d\n", ret);
> > > + return ret;
> > > + }
> > > +
> > > + ret = gpiod_direction_output(ps_bridge->gpio_slp_n, 1);
> > > + if (ret) {
> > > + DRM_ERROR("cannot configure gpio_slp_n\n");
> > > + return ret;
> > > + }
> > > +
> > > + ps_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
> > > + GPIOD_OUT_HIGH);
> > > + if (IS_ERR(ps_bridge->gpio_rst_n)) {
> > > + ret = PTR_ERR(ps_bridge->gpio_rst_n);
> > > + DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
> > > + return ret;
> > > + }
> > > +
> > > + ret = gpiod_direction_output(ps_bridge->gpio_rst_n, 1);
> > > + if (ret) {
> > > + DRM_ERROR("cannot configure gpio_rst_n\n");
> > > + return ret;
> > > + }
> > > +
> > > + ret = of_property_read_u32(dev->of_node, "reg", &temp_reg);
> > > + if (ret) {
> > > + DRM_ERROR("Can't read base_reg value\n");
> > > + return ret;
> > > + }
> > > + ps_bridge->base_reg = temp_reg;
>
> No need for this, the i2c address is already stored in client->addr.
>
> > > + ps_bridge->bridge.funcs = &ps8640_bridge_funcs;
> > > + ps_bridge->bridge.of_node = dev->of_node;
> > > + ret = drm_bridge_add(&ps_bridge->bridge);
> > > + if (ret) {
> > > + DRM_ERROR("Failed to add bridge\n");
> > > + return ret;
> > > + }
> > > +
> > > + i2c_set_clientdata(client, ps_bridge);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int ps8640_remove(struct i2c_client *client)
> > > +{
> > > + struct ps8640 *ps_bridge = i2c_get_clientdata(client);
> > > +
> > > + drm_bridge_remove(&ps_bridge->bridge);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static const struct i2c_device_id ps8640_i2c_table[] = {
> > > + {"parade,ps8640", 0},
> > > + {},
> > > +};
> > > +MODULE_DEVICE_TABLE(i2c, ps8640_i2c_table);
> > > +
> > > +static const struct of_device_id ps8640_match[] = {
> > > + { .compatible = "parade,ps8640" },
> > > + {},
> > > +};
> > > +MODULE_DEVICE_TABLE(of, ps8640_match);
> > > +
> > > +static struct i2c_driver ps8640_driver = {
> > > + .id_table = ps8640_i2c_table,
> > > + .probe = ps8640_probe,
> > > + .remove = ps8640_remove,
> > > + .driver = {
> > > + .name = "parade,ps8640",
> > > + .owner = THIS_MODULE,
> > > + .of_match_table = ps8640_match,
> > > + },
> > > +};
> > > +module_i2c_driver(ps8640_driver);
> > > +
> > > +MODULE_AUTHOR("Jitao Shi <jitao.shi@xxxxxxxxxxxx>");
> > > +MODULE_AUTHOR("CK Hu <ck.hu@xxxxxxxxxxxx>");
> > > +MODULE_DESCRIPTION("PARADE ps8640 DSI-eDP converter driver");
> > > +MODULE_LICENSE("GPL v2");
>
> best regards
> Philipp
>

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Next message: Andy Lutomirski: "Re: [PATCH v2 01/13] mm: support madvise(MADV_FREE)"
Previous message: Andrew Morton: "Re: [PATCH 1/1] signal: kill the obsolete SIGNAL_UNKILLABLE check in complete_signal()"
In reply to: Philipp Zabel: "Re: [RFC v2 2/2] drm/bridge: Add I2C based driver for ps8640 bridge"
Next in thread: Philipp Zabel: "Re: [RFC v2 2/2] drm/bridge: Add I2C based driver for ps8640 bridge"
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