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

From: Archit Taneja
Date: Tue Dec 15 2015 - 02:18:23 EST


Hi,

On 12/15/2015 09:00 AM, Jitao Shi wrote:
This patch adds drm_bridge driver for parade DSI to eDP bridge chip.

Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
---
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>

This doesn't seem to be used at the moment.

<snip>

+
+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;
+ }

The driver retrieves the panel from the output port via DT, but doesn't
retrieve the DSI host from the input port?

Wouldn't this driver need to call a "mipi_dsi_attach" at some point to
link with the DSI host (and pass parameters like number of lanes, color
format etc)?

I've been working on a patchset[1] which lets i2c drivers create mipi
dsi devices. I think this would be needed for the ps8640 driver too.

[1] https://lkml.org/lkml/2015/12/10/283

Archit

+
+ ps_bridge->page[0] = client;
+ for (i = 1; i < 6; i++)
+ ps_bridge->page[i] = i2c_new_dummy(client->adapter,
+ client->addr + i);
+
+ 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);
+
+ 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@xxxxxxxxxxxx>");
+MODULE_AUTHOR("CK Hu <ck.hu@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("PARADE ps8640 DSI-eDP converter driver");
+MODULE_LICENSE("GPL v2");


--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/