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drm/bridge: Add PTN3460 bridge driver
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This patch adds a drm_bridge driver for the PTN3460 DisplayPort to LVDS
bridge chip.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
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Sean Paul authored and Inki Dae committed Mar 23, 2014
1 parent ce6cb55 commit a9fe713
Showing 7 changed files with 423 additions and 0 deletions.
27 changes: 27 additions & 0 deletions Documentation/devicetree/bindings/drm/bridge/ptn3460.txt
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ptn3460 bridge bindings

Required properties:
- compatible: "nxp,ptn3460"
- reg: i2c address of the bridge
- powerdown-gpio: OF device-tree gpio specification
- reset-gpio: OF device-tree gpio specification
- edid-emulation: The EDID emulation entry to use
+-------+------------+------------------+
| Value | Resolution | Description |
| 0 | 1024x768 | NXP Generic |
| 1 | 1920x1080 | NXP Generic |
| 2 | 1920x1080 | NXP Generic |
| 3 | 1600x900 | Samsung LTM200KT |
| 4 | 1920x1080 | Samsung LTM230HT |
| 5 | 1366x768 | NXP Generic |
| 6 | 1600x900 | ChiMei M215HGE |
+-------+------------+------------------+

Example:
lvds-bridge@20 {
compatible = "nxp,ptn3460";
reg = <0x20>;
powerdown-gpio = <&gpy2 5 1 0 0>;
reset-gpio = <&gpx1 5 1 0 0>;
edid-emulation = <5>;
};
2 changes: 2 additions & 0 deletions drivers/gpu/drm/Kconfig
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@@ -199,3 +199,5 @@ source "drivers/gpu/drm/msm/Kconfig"
source "drivers/gpu/drm/tegra/Kconfig"

source "drivers/gpu/drm/panel/Kconfig"

source "drivers/gpu/drm/bridge/Kconfig"
1 change: 1 addition & 0 deletions drivers/gpu/drm/Makefile
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@@ -63,3 +63,4 @@ obj-$(CONFIG_DRM_MSM) += msm/
obj-$(CONFIG_DRM_TEGRA) += tegra/
obj-y += i2c/
obj-y += panel/
obj-y += bridge/
4 changes: 4 additions & 0 deletions drivers/gpu/drm/bridge/Kconfig
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config DRM_PTN3460
tristate "PTN3460 DP/LVDS bridge"
depends on DRM && I2C
---help---
3 changes: 3 additions & 0 deletions drivers/gpu/drm/bridge/Makefile
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ccflags-y := -Iinclude/drm

obj-$(CONFIG_DRM_PTN3460) += ptn3460.o
349 changes: 349 additions & 0 deletions drivers/gpu/drm/bridge/ptn3460.c
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/*
* NXP PTN3460 DP/LVDS bridge driver
*
* Copyright (C) 2013 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/delay.h>

#include "drmP.h"
#include "drm_edid.h"
#include "drm_crtc.h"
#include "drm_crtc_helper.h"

#include "bridge/ptn3460.h"

#define PTN3460_EDID_ADDR 0x0
#define PTN3460_EDID_EMULATION_ADDR 0x84
#define PTN3460_EDID_ENABLE_EMULATION 0
#define PTN3460_EDID_EMULATION_SELECTION 1
#define PTN3460_EDID_SRAM_LOAD_ADDR 0x85

struct ptn3460_bridge {
struct drm_connector connector;
struct i2c_client *client;
struct drm_encoder *encoder;
struct drm_bridge *bridge;
struct edid *edid;
int gpio_pd_n;
int gpio_rst_n;
u32 edid_emulation;
bool enabled;
};

static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
u8 *buf, int len)
{
int ret;

ret = i2c_master_send(ptn_bridge->client, &addr, 1);
if (ret <= 0) {
DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
return ret;
}

ret = i2c_master_recv(ptn_bridge->client, buf, len);
if (ret <= 0) {
DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
return ret;
}

return 0;
}

static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
char val)
{
int ret;
char buf[2];

buf[0] = addr;
buf[1] = val;

ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
if (ret <= 0) {
DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
return ret;
}

return 0;
}

static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
{
int ret;
char val;

/* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
ptn_bridge->edid_emulation);
if (ret) {
DRM_ERROR("Failed to transfer edid to sram, ret=%d\n", ret);
return ret;
}

/* Enable EDID emulation and select the desired EDID */
val = 1 << PTN3460_EDID_ENABLE_EMULATION |
ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;

ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
if (ret) {
DRM_ERROR("Failed to write edid value, ret=%d\n", ret);
return ret;
}

return 0;
}

static void ptn3460_pre_enable(struct drm_bridge *bridge)
{
struct ptn3460_bridge *ptn_bridge = bridge->driver_private;
int ret;

if (ptn_bridge->enabled)
return;

if (gpio_is_valid(ptn_bridge->gpio_pd_n))
gpio_set_value(ptn_bridge->gpio_pd_n, 1);

if (gpio_is_valid(ptn_bridge->gpio_rst_n)) {
gpio_set_value(ptn_bridge->gpio_rst_n, 0);
udelay(10);
gpio_set_value(ptn_bridge->gpio_rst_n, 1);
}

/*
* There's a bug in the PTN chip where it falsely asserts hotplug before
* it is fully functional. We're forced to wait for the maximum start up
* time specified in the chip's datasheet to make sure we're really up.
*/
msleep(90);

ret = ptn3460_select_edid(ptn_bridge);
if (ret)
DRM_ERROR("Select edid failed ret=%d\n", ret);

ptn_bridge->enabled = true;
}

static void ptn3460_enable(struct drm_bridge *bridge)
{
}

static void ptn3460_disable(struct drm_bridge *bridge)
{
struct ptn3460_bridge *ptn_bridge = bridge->driver_private;

if (!ptn_bridge->enabled)
return;

ptn_bridge->enabled = false;

if (gpio_is_valid(ptn_bridge->gpio_rst_n))
gpio_set_value(ptn_bridge->gpio_rst_n, 1);

if (gpio_is_valid(ptn_bridge->gpio_pd_n))
gpio_set_value(ptn_bridge->gpio_pd_n, 0);
}

static void ptn3460_post_disable(struct drm_bridge *bridge)
{
}

void ptn3460_bridge_destroy(struct drm_bridge *bridge)
{
struct ptn3460_bridge *ptn_bridge = bridge->driver_private;

drm_bridge_cleanup(bridge);
if (gpio_is_valid(ptn_bridge->gpio_pd_n))
gpio_free(ptn_bridge->gpio_pd_n);
if (gpio_is_valid(ptn_bridge->gpio_rst_n))
gpio_free(ptn_bridge->gpio_rst_n);
/* Nothing else to free, we've got devm allocated memory */
}

struct drm_bridge_funcs ptn3460_bridge_funcs = {
.pre_enable = ptn3460_pre_enable,
.enable = ptn3460_enable,
.disable = ptn3460_disable,
.post_disable = ptn3460_post_disable,
.destroy = ptn3460_bridge_destroy,
};

int ptn3460_get_modes(struct drm_connector *connector)
{
struct ptn3460_bridge *ptn_bridge;
u8 *edid;
int ret, num_modes;
bool power_off;

ptn_bridge = container_of(connector, struct ptn3460_bridge, connector);

if (ptn_bridge->edid)
return drm_add_edid_modes(connector, ptn_bridge->edid);

power_off = !ptn_bridge->enabled;
ptn3460_pre_enable(ptn_bridge->bridge);

edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
if (!edid) {
DRM_ERROR("Failed to allocate edid\n");
return 0;
}

ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
EDID_LENGTH);
if (ret) {
kfree(edid);
num_modes = 0;
goto out;
}

ptn_bridge->edid = (struct edid *)edid;
drm_mode_connector_update_edid_property(connector, ptn_bridge->edid);

num_modes = drm_add_edid_modes(connector, ptn_bridge->edid);

out:
if (power_off)
ptn3460_disable(ptn_bridge->bridge);

return num_modes;
}

static int ptn3460_mode_valid(struct drm_connector *connector,
struct drm_display_mode *mode)
{
return MODE_OK;
}

struct drm_encoder *ptn3460_best_encoder(struct drm_connector *connector)
{
struct ptn3460_bridge *ptn_bridge;

ptn_bridge = container_of(connector, struct ptn3460_bridge, connector);

return ptn_bridge->encoder;
}

struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
.get_modes = ptn3460_get_modes,
.mode_valid = ptn3460_mode_valid,
.best_encoder = ptn3460_best_encoder,
};

enum drm_connector_status ptn3460_detect(struct drm_connector *connector,
bool force)
{
return connector_status_connected;
}

void ptn3460_connector_destroy(struct drm_connector *connector)
{
drm_connector_cleanup(connector);
}

struct drm_connector_funcs ptn3460_connector_funcs = {
.dpms = drm_helper_connector_dpms,
.fill_modes = drm_helper_probe_single_connector_modes,
.detect = ptn3460_detect,
.destroy = ptn3460_connector_destroy,
};

int ptn3460_init(struct drm_device *dev, struct drm_encoder *encoder,
struct i2c_client *client, struct device_node *node)
{
int ret;
struct drm_bridge *bridge;
struct ptn3460_bridge *ptn_bridge;

bridge = devm_kzalloc(dev->dev, sizeof(*bridge), GFP_KERNEL);
if (!bridge) {
DRM_ERROR("Failed to allocate drm bridge\n");
return -ENOMEM;
}

ptn_bridge = devm_kzalloc(dev->dev, sizeof(*ptn_bridge), GFP_KERNEL);
if (!ptn_bridge) {
DRM_ERROR("Failed to allocate ptn bridge\n");
return -ENOMEM;
}

ptn_bridge->client = client;
ptn_bridge->encoder = encoder;
ptn_bridge->bridge = bridge;
ptn_bridge->gpio_pd_n = of_get_named_gpio(node, "powerdown-gpio", 0);
if (gpio_is_valid(ptn_bridge->gpio_pd_n)) {
ret = gpio_request_one(ptn_bridge->gpio_pd_n,
GPIOF_OUT_INIT_HIGH, "PTN3460_PD_N");
if (ret) {
DRM_ERROR("Request powerdown-gpio failed (%d)\n", ret);
return ret;
}
}

ptn_bridge->gpio_rst_n = of_get_named_gpio(node, "reset-gpio", 0);
if (gpio_is_valid(ptn_bridge->gpio_rst_n)) {
/*
* Request the reset pin low to avoid the bridge being
* initialized prematurely
*/
ret = gpio_request_one(ptn_bridge->gpio_rst_n,
GPIOF_OUT_INIT_LOW, "PTN3460_RST_N");
if (ret) {
DRM_ERROR("Request reset-gpio failed (%d)\n", ret);
gpio_free(ptn_bridge->gpio_pd_n);
return ret;
}
}

ret = of_property_read_u32(node, "edid-emulation",
&ptn_bridge->edid_emulation);
if (ret) {
DRM_ERROR("Can't read edid emulation value\n");
goto err;
}

ret = drm_bridge_init(dev, bridge, &ptn3460_bridge_funcs);
if (ret) {
DRM_ERROR("Failed to initialize bridge with drm\n");
goto err;
}

bridge->driver_private = ptn_bridge;
encoder->bridge = bridge;

ret = drm_connector_init(dev, &ptn_bridge->connector,
&ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
if (ret) {
DRM_ERROR("Failed to initialize connector with drm\n");
goto err;
}
drm_connector_helper_add(&ptn_bridge->connector,
&ptn3460_connector_helper_funcs);
drm_sysfs_connector_add(&ptn_bridge->connector);
drm_mode_connector_attach_encoder(&ptn_bridge->connector, encoder);

return 0;

err:
if (gpio_is_valid(ptn_bridge->gpio_pd_n))
gpio_free(ptn_bridge->gpio_pd_n);
if (gpio_is_valid(ptn_bridge->gpio_rst_n))
gpio_free(ptn_bridge->gpio_rst_n);
return ret;
}
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