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SubjectRe: [PATCH v22 2/2] drm/bridge: Add I2C based driver for ps8640 bridge
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Hi Nicolas,

Many thanks for you review. Just preparing a new version with your comments
addressed.

On 20/12/19 9:44, Nicolas Boichat wrote:
> On Fri, Dec 20, 2019 at 4:17 PM Enric Balletbo i Serra
> <enric.balletbo@collabora.com> wrote:
>>
>> From: Jitao Shi <jitao.shi@mediatek.com>
>>
>> This patch adds drm_bridge driver for parade DSI to eDP bridge chip.
>>
>> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
>> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
>> Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> [uli: followed API changes, removed FW update feature]
>> Signed-off-by: Ulrich Hecht <uli@fpond.eu>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> ---
>> [snip]
>>
>> drivers/gpu/drm/bridge/Kconfig | 11 +
>> drivers/gpu/drm/bridge/Makefile | 1 +
>> drivers/gpu/drm/bridge/parade-ps8640.c | 354 +++++++++++++++++++++++++
>
> Half the size! Sounds great.
>
> Mostly nits below.
>
>> 3 files changed, 366 insertions(+)
>> create mode 100644 drivers/gpu/drm/bridge/parade-ps8640.c
>>
>> diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
>> new file mode 100644
>> index 000000000000..aa0045037f44
>> --- /dev/null
>> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
>> @@ -0,0 +1,354 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (c) 2016 MediaTek Inc.
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/err.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/of_graph.h>
>> +#include <linux/regulator/consumer.h>
>> +
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_mipi_dsi.h>
>> +#include <drm/drm_of.h>
>> +#include <drm/drm_panel.h>
>> +#include <drm/drm_print.h>
>> +
>> +#define PAGE2_GPIO_H 0xa7
>> +#define PS_GPIO9 BIT(1)
>> +#define PAGE2_I2C_BYPASS 0xea
>> +#define I2C_BYPASS_EN 0xd0
>> +#define PAGE2_MCS_EN 0xf3
>> +#define MCS_EN BIT(0)
>> +#define PAGE3_SET_ADD 0xfe
>> +#define VDO_CTL_ADD 0x13
>> +#define VDO_DIS 0x18
>> +#define VDO_EN 0x1c
>> +
>> +/*
>> + * PS8640 uses multiple addresses:
>> + * page[0]: for DP control
>> + * page[1]: for VIDEO Bridge
>> + * page[2]: for control top
>> + * page[3]: for DSI Link Control1
>> + * page[4]: for MIPI Phy
>> + * page[5]: for VPLL
>> + * page[6]: for DSI Link Control2
>> + * page[7]: for SPI ROM mapping
>> + */
>> +enum page_addr_offset {
>> + PAGE0_DP_CNTL = 0,
>> + PAGE1_VDO_BDG,
>> + PAGE2_TOP_CNTL,
>> + PAGE3_DSI_CNTL1,
>> + PAGE4_MIPI_PHY,
>> + PAGE5_VPLL,
>> + PAGE6_DSI_CNTL2,
>> + PAGE7_SPI_CNTL,
>> + MAX_DEVS
>> +};
>> +
>> +struct ps8640 {
>> + struct drm_bridge bridge;
>> + struct drm_bridge *panel_bridge;
>> + struct mipi_dsi_device *dsi;
>> + struct i2c_client *page[MAX_DEVS];
>> + struct regulator_bulk_data supplies[2];
>> + struct gpio_desc *gpio_reset;
>> + struct gpio_desc *gpio_powerdown;
>> +};
>> +
>> +static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e)
>> +{
>> + return container_of(e, struct ps8640, bridge);
>> +}
>> +
>> +static int ps8640_bridge_unmute(struct ps8640 *ps_bridge)
>> +{
>> + struct i2c_client *client = ps_bridge->page[PAGE3_DSI_CNTL1];
>> + u8 vdo_ctrl_buf[] = { VDO_CTL_ADD, VDO_EN };
>
> nit: const?
>
>> + int ret;
>> +
>> + ret = i2c_smbus_write_i2c_block_data(client, PAGE3_SET_ADD,
>> + sizeof(vdo_ctrl_buf),
>> + vdo_ctrl_buf);
>> + if (ret < 0)
>> + return ret;
>> +
>> + return 0;
>> +}
>> +
>> +static int ps8640_bridge_mute(struct ps8640 *ps_bridge)
>> +{
>> + struct i2c_client *client = ps_bridge->page[PAGE3_DSI_CNTL1];
>> + u8 vdo_ctrl_buf[] = { VDO_CTL_ADD, VDO_DIS };
>
> ditto
>
>> + int ret;
>> +
>> + ret = i2c_smbus_write_i2c_block_data(client, PAGE3_SET_ADD,
>> + sizeof(vdo_ctrl_buf),
>> + vdo_ctrl_buf);
>> + if (ret < 0)
>> + return ret;
>> +
>> + return 0;
>> +}
>
> Since the 2 functions are almost the same, you could shrink the driver
> a bit further by merging them into one with a boolean parameter? (then
> maybe give up on the const u8 comment).
>

I decided to merge the two functions and use and enum instead of a boolean
parameter, so the "bool" value is more understandable.

>> +
>> +static void ps8640_pre_enable(struct drm_bridge *bridge)
>> +{
>> + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
>> + struct i2c_client *client = ps_bridge->page[PAGE2_TOP_CNTL];
>> + unsigned long timeout;
>> + int ret, status;
>> +
>> + ret = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies),
>> + ps_bridge->supplies);
>> + if (ret < 0) {
>> + DRM_ERROR("cannot enable regulators %d\n", ret);
>> + return;
>> + }
>> +
>> + gpiod_set_value(ps_bridge->gpio_powerdown, 1);
>> + gpiod_set_value(ps_bridge->gpio_reset, 0);
>> + usleep_range(2000, 2500);
>> + gpiod_set_value(ps_bridge->gpio_reset, 1);
>> +
>> + /*
>> + * Wait for the ps8640 embedded MCU to be ready
>> + * First wait 200ms and then check the MCU ready flag every 20ms
>> + */
>> + msleep(200);
>> +
>> + timeout = jiffies + msecs_to_jiffies(200) + 1;
>> +
>> + while (time_is_after_jiffies(timeout)) {
>> + status = i2c_smbus_read_byte_data(client, PAGE2_GPIO_H);
>> + if (status < 0) {
>> + DRM_ERROR("failed read PAGE2_GPIO_H: %d\n", status);
>> + goto err_regulators_disable;
>> + }
>> + if ((status & PS_GPIO9) == PS_GPIO9)
>> + break;
>> +
>> + msleep(20);
>> + }
>> +
>> + msleep(50);
>> +
>> + /*
>> + * The Manufacturer Command Set (MCS) is a device dependent interface
>> + * intended for factory programming of the display module default
>> + * parameters. Once the display module is configured, the MCS shall be
>> + * disabled by the manufacturer. Once disabled, all MCS commands are
>> + * ignored by the display interface.
>> + */
>> + status = i2c_smbus_read_byte_data(client, PAGE2_MCS_EN);
>> + if (status < 0) {
>> + DRM_ERROR("failed read PAGE2_MCS_EN: %d\n", status);
>> + goto err_regulators_disable;
>> + }
>> +
>> + ret = i2c_smbus_write_byte_data(client, PAGE2_MCS_EN,
>> + status & ~MCS_EN);
>> + if (ret < 0) {
>> + DRM_ERROR("failed write PAGE2_MCS_EN: %d\n", ret);
>> + goto err_regulators_disable;
>> + }
>> +
>> + ret = ps8640_bridge_unmute(ps_bridge);
>> + if (ret)
>> + DRM_ERROR("failed to enable unmutevideo: %d\n", ret);
>
> failed to unmute? Or failed to enable?
>

failed to unmute sound more clear to me.

>> +
>> + /* Switch access edp panel's edid through i2c */
>> + ret = i2c_smbus_write_byte_data(client, PAGE2_I2C_BYPASS,
>> + I2C_BYPASS_EN);
>> + if (ret < 0) {
>> + DRM_ERROR("failed write PAGE2_I2C_BYPASS: %d\n", ret);
>> + goto err_regulators_disable;
>> + }
>> +
>> + return;
>> +
>> +err_regulators_disable:
>> + regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
>> + ps_bridge->supplies);
>> +}
>> +
>> +static void ps8640_post_disable(struct drm_bridge *bridge)
>> +{
>> + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
>> + int ret;
>> +
>> + ret = ps8640_bridge_mute(ps_bridge);
>> + if (ret < 0)
>> + DRM_ERROR("failed to unmutevideo: %d\n", ret);
>
> ditto
>

Done.

>> +
>> + gpiod_set_value(ps_bridge->gpio_reset, 0);
>> + gpiod_set_value(ps_bridge->gpio_powerdown, 0);
>> + ret = regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
>> + ps_bridge->supplies);
>> + if (ret < 0)
>> + DRM_ERROR("cannot disable regulators %d\n", ret);
>> +}
>> +
>> +int ps8640_bridge_attach(struct drm_bridge *bridge)
>> +{
>> + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
>> + struct device *dev = &ps_bridge->page[0]->dev;
>> + struct device_node *in_ep, *dsi_node;
>> + struct mipi_dsi_device *dsi;
>> + struct mipi_dsi_host *host;
>> + int ret;
>> + const struct mipi_dsi_device_info info = { .type = "ps8640",
>> + .channel = 0,
>> + .node = NULL,
>> + };
>> + /* port@0 is ps8640 dsi input port */
>> + in_ep = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
>> + if (!in_ep)
>> + return -ENODEV;
>> +
>> + dsi_node = of_graph_get_remote_port_parent(in_ep);
>> + of_node_put(in_ep);
>> + if (!dsi_node)
>> + return -ENODEV;
>> +
>> + host = of_find_mipi_dsi_host_by_node(dsi_node);
>> + of_node_put(dsi_node);
>> + if (!host)
>> + return -ENODEV;
>> +
>> + dsi = mipi_dsi_device_register_full(host, &info);
>> + if (IS_ERR(dsi)) {
>> + dev_err(dev, "failed to create dsi device\n");
>> + ret = PTR_ERR(dsi);
>> + return ret;
>> + }
>> +
>> + ps_bridge->dsi = dsi;
>> +
>> + dsi->host = host;
>> + dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
>> + MIPI_DSI_MODE_VIDEO_SYNC_PULSE;
>> + dsi->format = MIPI_DSI_FMT_RGB888;
>> + dsi->lanes = 4;
>> + ret = mipi_dsi_attach(dsi);
>> + if (ret)
>> + goto err_dsi_attach;
>> +
>> + /* Attach the panel-bridge to the dsi bridge */
>> + return drm_bridge_attach(bridge->encoder, ps_bridge->panel_bridge,
>> + &ps_bridge->bridge);
>> +
>> +err_dsi_attach:
>> + mipi_dsi_device_unregister(dsi);
>> + return ret;
>> +}
>> +
>> +static const struct drm_bridge_funcs ps8640_bridge_funcs = {
>> + .attach = ps8640_bridge_attach,
>> + .post_disable = ps8640_post_disable,
>> + .pre_enable = ps8640_pre_enable,
>> +};
>> +
>> +static int ps8640_probe(struct i2c_client *client)
>> +{
>> + struct device *dev = &client->dev;
>> + struct device_node *np = dev->of_node;
>> + struct ps8640 *ps_bridge;
>> + struct drm_panel *panel;
>> + int ret;
>> + u32 i;
>> +
>> + ps_bridge = devm_kzalloc(dev, sizeof(*ps_bridge), GFP_KERNEL);
>> + if (!ps_bridge)
>> + return -ENOMEM;
>> +
>> + /* port@1 is ps8640 output port */
>> + ret = drm_of_find_panel_or_bridge(np, 1, 0, &panel, NULL);
>> + if (ret < 0)
>> + return ret;
>> + if (!panel)
>> + return -ENODEV;
>> +
>> + panel->connector_type = DRM_MODE_CONNECTOR_eDP;
>> +
>> + ps_bridge->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
>> + if (IS_ERR(ps_bridge->panel_bridge))
>> + return PTR_ERR(ps_bridge->panel_bridge);
>> +
>> + ps_bridge->supplies[0].supply = "vdd33";
>> + ps_bridge->supplies[1].supply = "vdd12";
>> + ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ps_bridge->supplies),
>> + ps_bridge->supplies);
>> + if (ret)
>> + return ret;
>> +
>> + ps_bridge->gpio_powerdown = devm_gpiod_get(&client->dev, "powerdown",
>> + GPIOD_OUT_LOW);
>> + if (IS_ERR(ps_bridge->gpio_powerdown))
>> + return PTR_ERR(ps_bridge->gpio_powerdown);
>> +
>> + /*
>> + * Request the reset pin low to avoid the bridge being
>> + * initialized prematurely
>> + */
>> + ps_bridge->gpio_reset = devm_gpiod_get(&client->dev, "reset",
>> + GPIOD_OUT_LOW);
>> + if (IS_ERR(ps_bridge->gpio_reset))
>> + return PTR_ERR(ps_bridge->gpio_reset);
>> +
>> + ps_bridge->bridge.funcs = &ps8640_bridge_funcs;
>> + ps_bridge->bridge.of_node = dev->of_node;
>> +
>> + ps_bridge->page[PAGE0_DP_CNTL] = client;
>> +
>> + for (i = 1; i < ARRAY_SIZE(ps_bridge->page); i++) {
>> + ps_bridge->page[i] = devm_i2c_new_dummy_device(&client->dev,
>> + client->adapter,
>> + client->addr + i);
>> + if (IS_ERR(ps_bridge->page[i])) {
>> + dev_err(dev, "failed i2c dummy device, address%02x\n",
>
> Space after address?
>

Ack and done.

>> + client->addr + i);
>> + return PTR_ERR(ps_bridge->page[i]);
>> + }
>> + }
>> +
>> + i2c_set_clientdata(client, ps_bridge);
>> +
>> + drm_bridge_add(&ps_bridge->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 of_device_id ps8640_match[] = {
>> + { .compatible = "parade,ps8640" },
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(of, ps8640_match);
>> +
>> +static struct i2c_driver ps8640_driver = {
>> + .probe_new = ps8640_probe,
>> + .remove = ps8640_remove,
>> + .driver = {
>> + .name = "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>");
>
> Since you just did a major refactor, do you want to add your name here?
>

Sure.

Thanks,
Enric

>> +MODULE_DESCRIPTION("PARADE ps8640 DSI-eDP converter driver");
>> +MODULE_LICENSE("GPL v2");
>> --
>> 2.20.1
>>
>

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