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Message-ID: <8c224e1e-9871-dce9-89d0-3dad8218a747@samsung.com>
Date: Wed, 14 Mar 2018 09:42:36 +0100
From: Andrzej Hajda <a.hajda@...sung.com>
To: Jacopo Mondi <jacopo+renesas@...ndi.org>, architt@...eaurora.org,
Laurent.pinchart@...asonboard.com, airlied@...ux.ie,
horms@...ge.net.au, magnus.damm@...il.com, geert@...ux-m68k.org,
niklas.soderlund@...natech.se, sergei.shtylyov@...entembedded.com,
robh+dt@...nel.org, mark.rutland@....com
Cc: dri-devel@...ts.freedesktop.org, linux-renesas-soc@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/3] drm: bridge: Add thc63lvd1024 LVDS decoder
driver
On 13.03.2018 15:30, Jacopo Mondi wrote:
> Add DRM bridge driver for Thine THC63LVD1024 LVDS to digital parallel
> output decoder.
IMO converter suits here better, but it is just suggestion.
>
> Signed-off-by: Jacopo Mondi <jacopo+renesas@...ndi.org>
> ---
> drivers/gpu/drm/bridge/Kconfig | 7 +
> drivers/gpu/drm/bridge/Makefile | 1 +
> drivers/gpu/drm/bridge/thc63lvd1024.c | 241 ++++++++++++++++++++++++++++++++++
> 3 files changed, 249 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/thc63lvd1024.c
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 3b99d5a..facf6bd 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -92,6 +92,13 @@ config DRM_SII9234
> It is an I2C driver, that detects connection of MHL bridge
> and starts encapsulation of HDMI signal.
>
> +config DRM_THINE_THC63LVD1024
> + tristate "Thine THC63LVD1024 LVDS decoder bridge"
> + depends on OF
> + select DRM_PANEL_BRIDGE
You don't use PANEL_BRIDGE, it should be possible to drop the select.
> + ---help---
> + Thine THC63LVD1024 LVDS decoder bridge driver.
Decoder to what?
Maybe it would be better to say it is LVDS/parallel or LVDS/RGB
converter or bridge.
> +
> config DRM_TOSHIBA_TC358767
> tristate "Toshiba TC358767 eDP bridge"
> depends on OF
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 373eb28..fd90b16 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
> obj-$(CONFIG_DRM_SIL_SII8620) += sil-sii8620.o
> obj-$(CONFIG_DRM_SII902X) += sii902x.o
> obj-$(CONFIG_DRM_SII9234) += sii9234.o
> +obj-$(CONFIG_DRM_THINE_THC63LVD1024) += thc63lvd1024.o
> obj-$(CONFIG_DRM_TOSHIBA_TC358767) += tc358767.o
> obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix/
> obj-$(CONFIG_DRM_I2C_ADV7511) += adv7511/
> diff --git a/drivers/gpu/drm/bridge/thc63lvd1024.c b/drivers/gpu/drm/bridge/thc63lvd1024.c
> new file mode 100644
> index 0000000..4b059c0
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/thc63lvd1024.c
> @@ -0,0 +1,241 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * THC63LVD1024 LVDS to parallel data DRM bridge driver.
> + *
> + * Copyright (C) 2018 Jacopo Mondi <jacopo+renesas@...ndi.org>
> + */
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_panel.h>
> +
> +#include <linux/gpio/consumer.h>
> +#include <linux/of_graph.h>
> +#include <linux/regulator/consumer.h>
> +
> +static const char * const thc63_reg_names[] = {
> + "vcc", "lvcc", "pvcc", "cvcc", };
> +
> +struct thc63_dev {
> + struct device *dev;
> +
> + struct regulator *vccs[ARRAY_SIZE(thc63_reg_names)];
> +
> + struct gpio_desc *pwdn;
> + struct gpio_desc *oe;
> +
> + struct drm_bridge bridge;
> + struct drm_bridge *next;
> +};
> +
> +static inline struct thc63_dev *to_thc63(struct drm_bridge *bridge)
> +{
> + return container_of(bridge, struct thc63_dev, bridge);
> +}
> +
> +static int thc63_attach(struct drm_bridge *bridge)
> +{
> + struct thc63_dev *thc63 = to_thc63(bridge);
> +
> + return drm_bridge_attach(bridge->encoder, thc63->next, bridge);
> +}
> +
> +static void thc63_enable(struct drm_bridge *bridge)
> +{
> + struct thc63_dev *thc63 = to_thc63(bridge);
> + struct regulator *vcc;
> + unsigned int i;
> + int ret;
> +
> + for (i = 0; i < ARRAY_SIZE(thc63->vccs); i++) {
> + vcc = thc63->vccs[i];
> + if (vcc) {
> + ret = regulator_enable(vcc);
> + if (ret)
> + goto error_vcc_enable;
> + }
> + }
> +
> + if (thc63->pwdn)
> + gpiod_set_value(thc63->pwdn, 0);
> +
> + if (thc63->oe)
> + gpiod_set_value(thc63->oe, 1);
> +
> + return;
> +
> +error_vcc_enable:
> + dev_err(thc63->dev, "Failed to enable regulator %u\n", i);
> +}
> +
> +static void thc63_disable(struct drm_bridge *bridge)
> +{
> + struct thc63_dev *thc63 = to_thc63(bridge);
> + struct regulator *vcc;
> + unsigned int i;
> + int ret;
> +
> + for (i = 0; i < ARRAY_SIZE(thc63->vccs); i++) {
> + vcc = thc63->vccs[i];
> + if (vcc) {
> + ret = regulator_disable(vcc);
> + if (ret)
> + goto error_vcc_disable;
I think in disable path you can report an error and continue - should be
safer.
> + }
> + }
> +
> + if (thc63->pwdn)
> + gpiod_set_value(thc63->pwdn, 1);
> +
> + if (thc63->oe)
> + gpiod_set_value(thc63->oe, 0);
Usually disable uses reverse order. Ie first disable oe, then, pwdn,
then regulators, also in reverse order.
Looks more reasonable.
> +
> + return;
> +
> +error_vcc_disable:
> + dev_err(thc63->dev, "Failed to disable regulator %u\n", i);
> +}
> +
> +struct drm_bridge_funcs thc63_bridge_func = {
> + .attach = thc63_attach,
> + .enable = thc63_enable,
> + .disable = thc63_disable,
> +};
> +
> +static int thc63_parse_dt(struct thc63_dev *thc63)
> +{
> + struct device_node *thc63_out;
> + struct device_node *remote;
> + int ret = 0;
> +
> + thc63_out = of_graph_get_endpoint_by_regs(thc63->dev->of_node, 2, -1);
Please define and use enums for port number, it will be more clear.
> + if (!thc63_out) {
> + dev_err(thc63->dev, "Missing endpoint in Port@2\n");
> + return -ENODEV;
> + }
> +
> + remote = of_graph_get_remote_port_parent(thc63_out);
> + if (!remote) {
> + dev_err(thc63->dev, "Endpoint in Port@2 unconnected\n");
> + ret = -ENODEV;
> + goto error_put_out_node;
> + }
> +
> + if (!of_device_is_available(remote)) {
> + dev_err(thc63->dev, "Port@2 remote endpoint is disabled\n");
> + ret = -ENODEV;
> + goto error_put_remote_node;
> + }
> +
> + thc63->next = of_drm_find_bridge(remote);
> + if (!thc63->next)
> + ret = -EPROBE_DEFER;
> +
> +error_put_remote_node:
> + of_node_put(remote);
> +error_put_out_node:
> + of_node_put(thc63_out);
> +
> + return ret;
> +}
> +
> +static int thc63_gpio_init(struct thc63_dev *thc63)
> +{
> + thc63->pwdn = devm_gpiod_get_optional(thc63->dev, "pwdn",
> + GPIOD_OUT_LOW);
Shouldn't be GPIOD_OUT_HIGH - bridge initially disabled?
Regards
Andrzej
> + if (IS_ERR(thc63->pwdn)) {
> + dev_err(thc63->dev, "Unable to get GPIO \"pwdn\"\n");
> + return PTR_ERR(thc63->pwdn);
> + }
> +
> + thc63->oe = devm_gpiod_get_optional(thc63->dev, "oe", GPIOD_OUT_LOW);
> + if (IS_ERR(thc63->oe)) {
> + dev_err(thc63->dev, "Unable to get GPIO \"oe\"\n");
> + return PTR_ERR(thc63->oe);
> + }
> +
> + return 0;
> +}
> +
> +static int thc63_regulator_init(struct thc63_dev *thc63)
> +{
> + struct regulator **reg;
> + int i;
> +
> + reg = &thc63->vccs[0];
> + for (i = 0; i < ARRAY_SIZE(thc63->vccs); i++, reg++) {
> + *reg = devm_regulator_get_optional(thc63->dev,
> + thc63_reg_names[i]);
> + if (IS_ERR(*reg)) {
> + if (PTR_ERR(*reg) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + *reg = NULL;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int thc63_probe(struct platform_device *pdev)
> +{
> + struct thc63_dev *thc63;
> + int ret;
> +
> + thc63 = devm_kzalloc(&pdev->dev, sizeof(*thc63), GFP_KERNEL);
> + if (!thc63)
> + return -ENOMEM;
> +
> + thc63->dev = &pdev->dev;
> + platform_set_drvdata(pdev, thc63);
> +
> + ret = thc63_regulator_init(thc63);
> + if (ret)
> + return ret;
> +
> + ret = thc63_gpio_init(thc63);
> + if (ret)
> + return ret;
> +
> + ret = thc63_parse_dt(thc63);
> + if (ret)
> + return ret;
> +
> + thc63->bridge.driver_private = thc63;
> + thc63->bridge.of_node = pdev->dev.of_node;
> + thc63->bridge.funcs = &thc63_bridge_func;
> +
> + drm_bridge_add(&thc63->bridge);
> +
> + return 0;
> +}
> +
> +static int thc63_remove(struct platform_device *pdev)
> +{
> + struct thc63_dev *thc63 = platform_get_drvdata(pdev);
> +
> + drm_bridge_remove(&thc63->bridge);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id thc63_match[] = {
> + { .compatible = "thine,thc63lvd1024", },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, thc63_match);
> +#endif
> +
> +static struct platform_driver thc63_driver = {
> + .probe = thc63_probe,
> + .remove = thc63_remove,
> + .driver = {
> + .name = "thc63lvd1024",
> + .of_match_table = thc63_match,
> + },
> +};
> +module_platform_driver(thc63_driver);
> +
> +MODULE_AUTHOR("Jacopo Mondi <jacopo@...ndi.org>");
> +MODULE_DESCRIPTION("Thine THC63LVD1024 LVDS decoder DRM bridge driver");
> +MODULE_LICENSE("GPL v2");
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