Re: [PATCH v4 2/3] drm: bridge: Add thc63lvd1024 LVDS decoder driver

From: jacopo mondi
Date: Thu Mar 15 2018 - 11:49:38 EST

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Hi Andrzej,
thanks for your patience in reviewing this series

On Thu, Mar 15, 2018 at 02:37:00PM +0100, Andrzej Hajda wrote:
> On 15.03.2018 11:56, Jacopo Mondi wrote:
> > Add DRM bridge driver for Thine THC63LVD1024 LVDS to digital parallel
> > output converter.
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> > ---
> > drivers/gpu/drm/bridge/Kconfig | 6 +
> > drivers/gpu/drm/bridge/Makefile | 1 +
> > drivers/gpu/drm/bridge/thc63lvd1024.c | 255 ++++++++++++++++++++++++++++++++++
> > 3 files changed, 262 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..5815a20 100644
> > --- a/drivers/gpu/drm/bridge/Kconfig
> > +++ b/drivers/gpu/drm/bridge/Kconfig
> > @@ -92,6 +92,12 @@ 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
> > + ---help---
> > + Thine THC63LVD1024 LVDS/parallel converter driver.
> > +
> > 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..067f231
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/thc63lvd1024.c
> > @@ -0,0 +1,255 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * THC63LVD1024 LVDS to parallel data DRM bridge driver.
> > + *
> > + * Copyright (C) 2018 Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> > + */
> > +
> > +#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>
> > +
> > +enum {
> > + THC63_LVDS_IN0,
> > + THC63_LVDS_IN1,
> > + THC63_DIGITAL_OUT0,
> > + THC63_DIGITAL_OUT1,
> > +};
> > +
> > +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 *pdwn;
> > + 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;
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(thc63->vccs); i++) {
> > + vcc = thc63->vccs[i];
> > + if (!vcc)
> > + continue;
> > +
> > + if (regulator_enable(vcc))
> > + goto error_vcc_enable;
> > + }
> > +
> > + if (thc63->pdwn)
> > + gpiod_set_value(thc63->pdwn, 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);
>
> It would be better to use supply or regulator name instead of index.
>

Yeah, now it's easy as I have the array with names in the driver
global scope...

> > +
> > + for (i = i - 1; i >= 0; i--) {
> > + vcc = thc63->vccs[i];
> > + if (!vcc)
> > + continue;
> > +
> > + regulator_disable(vcc);
> > + }
> > +}
> > +
> > +static void thc63_disable(struct drm_bridge *bridge)
> > +{
> > + struct thc63_dev *thc63 = to_thc63(bridge);
> > + struct regulator *vcc;
> > + int i;
> > +
> > + if (thc63->oe)
> > + gpiod_set_value(thc63->oe, 0);
> > +
> > + if (thc63->pdwn)
> > + gpiod_set_value(thc63->pdwn, 1);
> > +
> > + for (i = ARRAY_SIZE(thc63->vccs) - 1; i >= 0; i--) {
> > + vcc = thc63->vccs[i];
> > + if (!vcc)
> > + continue;
> > +
> > + if (regulator_disable(vcc))
> > + dev_dbg(thc63->dev,
> > + "Failed to disable regulator %u\n", i);
>
> ditto
>
> > + }
> > +}
> > +
> > +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,
> > + THC63_DIGITAL_OUT0, -1);
> > + if (!thc63_out) {
> > + dev_err(thc63->dev, "Missing endpoint in Port@%u\n",
> > + THC63_DIGITAL_OUT0);
> > + return -ENODEV;
> > + }
> > +
> > + remote = of_graph_get_remote_port_parent(thc63_out);
> > + if (!remote) {
> > + dev_err(thc63->dev, "Endpoint in Port@%u unconnected\n",
> > + THC63_DIGITAL_OUT0);
> > + ret = -ENODEV;
> > + goto error_put_out_node;
> > + }
> > +
> > + if (!of_device_is_available(remote)) {
> > + dev_err(thc63->dev, "Port@%u remote endpoint is disabled\n",
> > + THC63_DIGITAL_OUT0);
> > + 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->oe = devm_gpiod_get_optional(thc63->dev, "oe", GPIOD_OUT_LOW);
> > + if (IS_ERR(thc63->oe)) {
> > + dev_err(thc63->dev, "Unable to get \"oe-gpios\"\n");
> > + return PTR_ERR(thc63->oe);
> > + }
> > +
> > + thc63->pdwn = devm_gpiod_get_optional(thc63->dev, "pdwn",
> > + GPIOD_OUT_HIGH);
> > + if (IS_ERR(thc63->pdwn)) {
> > + dev_err(thc63->dev, "Unable to get \"pdwn-gpios\"\n");
> > + return PTR_ERR(thc63->pdwn);
> > + }
> > +
> > + 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;
> > + }
>
> You could use "if (!...) continue", to avoid nesting.

(unfortunately) regulator_get_optional() does not return NULL as
gpiod_get_optional() does (I'm sure there are good reasons) but
returns ERR_PTR(-ENODEV), instead of a dummy regulator returned by the
non _optional() version. If I got your comment right, I cannot simply
check for a NULL value here, but instead make sure the 'reg' pointer
is set to NULL so that I can skip it during enable/disable.

>
> With or without suggested changes:
> Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>

Thanks, v5 will have your Reviewed-by tag on all patches!

Thanks
j
>
> Â--
> Regards
> Andrzej
>
> > + }
> > +
> > + 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@xxxxxxxxxx>");
> > +MODULE_DESCRIPTION("Thine THC63LVD1024 LVDS decoder DRM bridge driver");
> > +MODULE_LICENSE("GPL v2");
>
>

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In reply to: Andrzej Hajda: "Re: [PATCH v4 2/3] drm: bridge: Add thc63lvd1024 LVDS decoder driver"
Next in thread: Jacopo Mondi: "[PATCH v4 3/3] arm64: dts: renesas: Add LVDS decoder to R-Car V3M Eagle"
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