Re: [PATCH v6 2/2] drm/bridge: Add I2C based driver for ps8640 bridge

On Tue, Dec 15, 2015 at 11:30 AM, Jitao Shi jitao.shi@mediatek.com wrote:

This patch adds drm_bridge driver for parade DSI to eDP bridge chip.

Signed-off-by: Jitao Shi jitao.shi@mediatek.com

Changes since v5

-fix compile errors when CONFIG_GPIOLIB=n

drivers/gpu/drm/bridge/Kconfig | 10 + drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/parade-ps8640.c | 472 ++++++++++++++++++++++++++++++++ 3 files changed, 483 insertions(+) create mode 100644 drivers/gpu/drm/bridge/parade-ps8640.c

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index 6dddd39..dcfdbc9 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -41,4 +41,14 @@ config DRM_PARADE_PS8622 ---help--- Parade eDP-LVDS bridge chip driver.

+config DRM_PARADE_PS8640

•   tristate "Parade PS8640 MIPI DSI to eDP Converter"
  

•   depends on OF
  

•   select DRM_KMS_HELPER
  

•   select DRM_PANEL
  

•   ---help---
  

•     Choose this option if you have PS8640 for display
  

•     The PS8640 is a high-performance and low-power
  

•     MIPI DSI to eDP converter
  

endmenu diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index d4e28be..272e3c01 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_DW_HDMI) += dw_hdmi.o obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw_hdmi-ahb-audio.o obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o +obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c new file mode 100644 index 0000000..bf0c3c37 --- /dev/null +++ b/drivers/gpu/drm/bridge/parade-ps8640.c @@ -0,0 +1,472 @@ +/*

• • Copyright (c) 2014 MediaTek Inc.
• • This program is free software; you can redistribute it and/or modify
• • it under the terms of the GNU General Public License version 2 as
• • published by the Free Software Foundation.
• • This program is distributed in the hope that it will be useful,
• • but WITHOUT ANY WARRANTY; without even the implied warranty of
• • MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
• • GNU General Public License for more details.
• */

+#include <linux/delay.h> +#include <linux/err.h> +#include <linux/gpio.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_gpio.h> +#include <linux/of_graph.h> +#include <linux/regulator/consumer.h>

+#include <drm/drm_panel.h>

+#include <drmP.h> +#include <drm_crtc_helper.h> +#include <drm_crtc.h> +#include <drm_mipi_dsi.h> +#include <drm_atomic_helper.h>

+#define PAGE2_GPIO_L 0xa6 +#define PAGE2_GPIO_H 0xa7 +#define PS_GPIO9 BIT(1) +#define PAGE2_I2C_BYPASS 0xea +#define I2C_BYPASS_EN 0xd0

+#define PAGE3_SET_ADD 0xfe +#define PAGE3_SET_VAL 0xff +#define VDO_CTL_ADD 0x13 +#define VDO_DIS 0x18 +#define VDO_EN 0x1c

+#define PAGE4_REV_L 0xf0 +#define PAGE4_REV_H 0xf1 +#define PAGE4_CHIP_L 0xf2 +#define PAGE4_CHIP_H 0xf3

+#define bridge_to_ps8640(e) container_of(e, struct ps8640, bridge) +#define connector_to_ps8640(e) container_of(e, struct ps8640, connector)

+struct ps8640 {

•   struct drm_connector connector;
  

•   struct drm_bridge bridge;
  

•   struct i2c_client *page[6];
  

•   struct ps8640_driver_data *driver_data;
  

•   struct regulator *pwr_1v2_supply;
  

•   struct regulator *pwr_3v3_supply;
  

•   struct drm_panel *panel;
  

•   struct gpio_desc *gpio_rst_n;
  

•   struct gpio_desc *gpio_slp_n;
  

•   struct gpio_desc *gpio_mode_sel_n;
  

•   bool enabled;
  

+};

+static int ps8640_regr(struct i2c_client *client, u8 reg, u8 *value) +{

•   int ret;
  

•   ret = i2c_master_send(client, &reg, 1);
  

•   if (ret <= 0) {
  

•           dev_err(&client->dev, "Failed to send i2c command, ret=%d\n",
  

•                   ret);
  

•           return ret;
  

•   }
  

•   ret = i2c_master_recv(client, value, 1);
  

•   if (ret <= 0) {
  

•           dev_err(&client->dev, "Failed to recv i2c data, ret=%d\n", ret);
  

•           return ret;
  

•   }
  

i2c_transfer should be a bit more efficient for reading one byte.

•   return 0;
  

+}

+static int ps8640_regw(struct i2c_client *client, u8 reg, u8 value) +{

•   int ret;
  

•   char buf[2];
  

•   buf[0] = reg;
  

•   buf[1] = value;
  

•   ret = i2c_master_send(client, buf, ARRAY_SIZE(buf));
  

•   if (ret <= 0) {
  

•           dev_err(&client->dev, "Failed to send i2c command, ret=%d\n",
  

•                   ret);
  

•           return ret;
  

•   }
  

•   return 0;
  

+}

+static bool ps8640_check_valid_id(struct ps8640 *ps_bridge) +{

•   struct i2c_client *client = ps_bridge->page[4];
  

•   u8 rev_id_low, rev_id_high, chip_id_low, chip_id_high;
  

•   int retry_cnt = 0;
  

•   do {
  

•           ps8640_regr(client, PAGE4_CHIP_H, &chip_id_high);
  

Check return value and propagate if non-zero.

•           if (chip_id_high != 0x30)
  

•                   dev_info(&client->dev, "chip_id_high = 0x%x\n",
  

•                            chip_id_high);
  

•   } while ((retry_cnt++ < 2) && (chip_id_high != 0x30));
  

Why is this loop retrying? What could be happening here? Please add a comment.

•   ps8640_regr(client, PAGE4_REV_L, &rev_id_low);
  

•   ps8640_regr(client, PAGE4_REV_H, &rev_id_high);
  

•   ps8640_regr(client, PAGE4_CHIP_L, &chip_id_low);
  

Can you just read all 4 bytes in a single i2c transaction?

•   if ((rev_id_low == 0x00) && (rev_id_high == 0x0a) &&
  

•       (chip_id_low == 0x00) && (chip_id_high == 0x30))
  

•           return true;
  

•   return false;
  

return -ENODEV if no device is found?

+}

+static void ps8640_show_mcu_fw_version(struct ps8640 *ps_bridge) +{

•   struct i2c_client *client = ps_bridge->page[5];
  

•   u8 major_ver, minor_ver;
  

•   ps8640_regr(client, 0x4, &major_ver);
  

•   ps8640_regr(client, 0x5, &minor_ver);
  

Please #define these FW version registers. Also, can you read them in a single i2c transaction?

•   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->page[3];
  

•   if (ps8640_check_valid_id(ps_bridge)) {
  

Usually it is prefered to fail fast, so:

ret = ps8640_check_valid_id(ps_bridge); if (ret) return ret; ... return 0;

•           ps8640_regw(client, PAGE3_SET_ADD, VDO_CTL_ADD);
  

•           ps8640_regw(client, PAGE3_SET_VAL, VDO_DIS);
  

Combine into 1 i2c transaction.

•           ps8640_regw(client, PAGE3_SET_ADD, VDO_CTL_ADD);
  

•           ps8640_regw(client, PAGE3_SET_VAL, VDO_DIS);
  

Why are you doing this twice? Add a comment.

•           return 0;
  

•   }
  

•   return -EINVAL;
  

+}

+static void ps8640_prepare(struct ps8640 *ps_bridge) +{

•   struct i2c_client *client = ps_bridge->page[2];
  

•   int err, retry_cnt = 0;
  

•   u8 set_vdo_done;
  

•   if (ps_bridge->enabled)
  

•           return;
  

•   err = drm_panel_prepare(ps_bridge->panel);
  

•   if (err < 0) {
  

•           DRM_ERROR("failed to prepare panel: %d\n", err);
  

•           return;
  

•   }
  

•   /* delay for power stable */
  

•   usleep_range(500, 700);
  

•   err = regulator_enable(ps_bridge->pwr_1v2_supply);
  

•   if (err < 0) {
  

•           DRM_ERROR("failed to enable vdd12-supply: %d\n", err);
  

•           goto err_panel_unprepare;
  

•   }
  

•   err = regulator_enable(ps_bridge->pwr_3v3_supply);
  

•   if (err < 0) {
  

•           DRM_ERROR("failed to enable vdd33-supply: %d\n", err);
  

•           goto err_regulator_disable;
  

Slightly less confusing:

goto err_regulator_1v2_disable;

•   }
  

•   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);
  

50 ms seems pretty slow polling interval. How long is this expected to take?

•           ps8640_regr(client, 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;
  

•   return;
  

+err_regulator_disable:

•   regulator_disable(ps_bridge->pwr_1v2_supply);
  

+err_panel_unprepare:

•   drm_panel_unprepare(ps_bridge->panel);
  

+}

+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);
  

•   int err;
  

•   ps8640_bdg_enable(ps_bridge);
  

•   err = drm_panel_enable(ps_bridge->panel);
  

•   if (err < 0)
  

•           DRM_ERROR("failed to enable panel: %d\n", err);
  

+}

+static void ps8640_disable(struct drm_bridge *bridge) +{

•   struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
  

•   int err;
  

•   if (!ps_bridge->enabled)
  

•           return;
  

•   ps_bridge->enabled = false;
  

•   err = drm_panel_disable(ps_bridge->panel);
  

•   if (err < 0)
  

•           DRM_ERROR("failed to disable panel: %d\n", err);
  

•   regulator_disable(ps_bridge->pwr_1v2_supply);
  

•   regulator_disable(ps_bridge->pwr_3v3_supply);
  

Not sure if it matters, but... since you enabled them 1v2 then 3v3, its usually better to turn them off in opposite order, so: 3v3 then 1v2.

•   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);
  

•   int err;
  

•   err = drm_panel_unprepare(ps_bridge->panel);
  

•   if (err)
  

•           DRM_ERROR("failed to unprepare panel: %d\n", err);
  

+}

+static int ps8640_get_modes(struct drm_connector *connector) +{

•   struct ps8640 *ps_bridge = connector_to_ps8640(connector);
  

•   struct i2c_client *client = ps_bridge->page[2];
  

•   ps8640_prepare(ps_bridge);
  

•   ps8640_regw(client, PAGE2_I2C_BYPASS, I2C_BYPASS_EN);
  

Do you need to unset bypass mode after getting modes? If not, perhaps you can just set this once during prepare?

•   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 = {
  

Indentation looks a bit funny. I think you want another tab here.

•   .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;
  

Always?

+}

+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: %d\n", ret);
  

•           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 *port, *out_ep;
  

•   struct device_node *panel_node = NULL;
  

•   int i, ret;
  

•   ps_bridge = devm_kzalloc(dev, sizeof(*ps_bridge), GFP_KERNEL);
  

•   if (!ps_bridge)
  

•           return -ENOMEM;
  

•   /* port@1 is ps8640 output port */
  

•   port = of_graph_get_port_by_id(np, 1);
  

•   if (port) {
  

•           out_ep = of_get_child_by_name(port, "endpoint");
  

•           of_node_put(port);
  

•           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->page[0] = client;
  

•   for (i = 1; i < 6; i++)
  

•           ps_bridge->page[i] = i2c_new_dummy(client->adapter,
  

•                                              client->addr + i);
  

Can you add a comment somewhere explaining what these extra i2c clients are for?

Also, if after this in probe() fails, unregister our these i2c_clients. Or, move this after the devm_*() calls.

•   ps_bridge->pwr_3v3_supply = devm_regulator_get(dev, "vdd33");
  

•   if (IS_ERR(ps_bridge->pwr_3v3_supply)) {
  

•           ret = PTR_ERR(ps_bridge->pwr_3v3_supply);
  

•           dev_err(dev, "cannot get vdd33 supply: %d\n", ret);
  

•           return ret;
  

•   }
  

•   ps_bridge->pwr_1v2_supply = devm_regulator_get(dev, "vdd12");
  

•   if (IS_ERR(ps_bridge->pwr_1v2_supply)) {
  

•           ret = PTR_ERR(ps_bridge->pwr_1v2_supply);
  

•           dev_err(dev, "cannot get vdd12 supply: %d\n", ret);
  

•           return ret;
  

•   }
  

•   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);
  

•           dev_err(dev, "cannot get gpio_mode_sel_n %d\n", ret);
  

•           return ret;
  

•   }
  

•   ps_bridge->gpio_slp_n = devm_gpiod_get(&client->dev, "sleep",
  

•                                          GPIOD_OUT_HIGH);
  

•   if (IS_ERR(ps_bridge->gpio_slp_n)) {
  

•           ret = PTR_ERR(ps_bridge->gpio_slp_n);
  

•           dev_err(dev, "cannot get gpio_slp_n: %d\n", ret);
  

•           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);
  

•           dev_err(dev, "cannot get gpio_rst_n: %d\n", ret);
  

•           return ret;
  

•   }
  

•   ps_bridge->bridge.funcs = &ps8640_bridge_funcs;
  

•   ps_bridge->bridge.of_node = dev->of_node;
  

•   ret = drm_bridge_add(&ps_bridge->bridge);
  

•   if (ret) {
  

•           dev_err(dev, "Failed to add bridge: %d\n", ret);
  

•           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);
  

i2c_unregister_device() the pages.

•   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",
  

•           .of_match_table = ps8640_match,
  

•   },
  

+}; +module_i2c_driver(ps8640_driver);

+MODULE_AUTHOR("Jitao Shi jitao.shi@mediatek.com"); +MODULE_AUTHOR("CK Hu ck.hu@mediatek.com"); +MODULE_DESCRIPTION("PARADE ps8640 DSI-eDP converter driver");

+MODULE_LICENSE("GPL v2");

1.7.9.5

---

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