Hi Jacopo, On Fri, Jun 07, 2019 at 02:35:40PM +0300, Laurent Pinchart wrote: > Hi Jacopo, > > Thank you for the patch. > > On Thu, Jun 06, 2019 at 04:22:14PM +0200, Jacopo Mondi wrote: > > Add a driver for the R-Car Display Unit Color Correction Module. > > > > Each DU output channel is provided with a CMM unit to perform image > > enhancement and color correction. > > I would say "On most Gen3 SoCs, each DU ..." as V3* SoCs have no CMM. > > > > > Add support for CMM through a driver that supports configuration of > > the 1-dimensional LUT table. More advanced CMM feature could be > > implemented on top of this basic one. > > s/could be/will be/ ? :-) > > > > > Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx> > > --- > > drivers/gpu/drm/rcar-du/Kconfig | 7 + > > drivers/gpu/drm/rcar-du/Makefile | 1 + > > drivers/gpu/drm/rcar-du/rcar_cmm.c | 197 +++++++++++++++++++++++++++++ > > drivers/gpu/drm/rcar-du/rcar_cmm.h | 38 ++++++ > > 4 files changed, 243 insertions(+) > > create mode 100644 drivers/gpu/drm/rcar-du/rcar_cmm.c > > create mode 100644 drivers/gpu/drm/rcar-du/rcar_cmm.h > > > > diff --git a/drivers/gpu/drm/rcar-du/Kconfig b/drivers/gpu/drm/rcar-du/Kconfig > > index 1529849e217e..539d232790d1 100644 > > --- a/drivers/gpu/drm/rcar-du/Kconfig > > +++ b/drivers/gpu/drm/rcar-du/Kconfig > > @@ -13,6 +13,13 @@ config DRM_RCAR_DU > > Choose this option if you have an R-Car chipset. > > If M is selected the module will be called rcar-du-drm. > > > > +config DRM_RCAR_CMM > > + bool "R-Car DU Color Management Module (CMM) Support" > > + depends on DRM && OF > > + depends on DRM_RCAR_DU > > + help > > + Enable support for R-Car Color Management Module (CMM). > > + > > config DRM_RCAR_DW_HDMI > > tristate "R-Car DU Gen3 HDMI Encoder Support" > > depends on DRM && OF > > diff --git a/drivers/gpu/drm/rcar-du/Makefile b/drivers/gpu/drm/rcar-du/Makefile > > index 6c2ed9c46467..4d1187ccc3e5 100644 > > --- a/drivers/gpu/drm/rcar-du/Makefile > > +++ b/drivers/gpu/drm/rcar-du/Makefile > > @@ -15,6 +15,7 @@ rcar-du-drm-$(CONFIG_DRM_RCAR_LVDS) += rcar_du_of.o \ > > rcar-du-drm-$(CONFIG_DRM_RCAR_VSP) += rcar_du_vsp.o > > rcar-du-drm-$(CONFIG_DRM_RCAR_WRITEBACK) += rcar_du_writeback.o > > > > +obj-$(CONFIG_DRM_RCAR_CMM) += rcar_cmm.o > > obj-$(CONFIG_DRM_RCAR_DU) += rcar-du-drm.o > > obj-$(CONFIG_DRM_RCAR_DW_HDMI) += rcar_dw_hdmi.o > > obj-$(CONFIG_DRM_RCAR_LVDS) += rcar_lvds.o > > diff --git a/drivers/gpu/drm/rcar-du/rcar_cmm.c b/drivers/gpu/drm/rcar-du/rcar_cmm.c > > new file mode 100644 > > index 000000000000..5d9d917b91f4 > > --- /dev/null > > +++ b/drivers/gpu/drm/rcar-du/rcar_cmm.c > > @@ -0,0 +1,197 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * rcar_cmm.c -- R-Car Display Unit Color Management Module > > + * > > + * Copyright (C) 2019 Jacopo Mondi <jacopo+renesas@xxxxxxxxxx> > > + */ > > + > > +#include <linux/clk.h> > > +#include <linux/io.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/platform_device.h> > > + > > +#include <drm/drm_atomic.h> > > + > > +#include "rcar_cmm.h" > > + > > +#define CM2_LUT_CTRL 0x00 > > I would write all register addresses with 3 (or 4) digits. > > > +#define CM2_LUT_CTRL_EN BIT(0) > > +#define CM2_LUT_TBLA 0x600 > > I would define this as > > #define CM2_LUT_TBLA(n) (0x600 + (n) * 4) > > > + > > +struct rcar_cmm { > > + struct clk *clk; > > + void __iomem *base; > > + bool enabled; > > + > > + /* LUT table scratch buffer. */ > > + struct { > > + bool restore; > > + unsigned int size; > > + uint32_t table[CMM_GAMMA_LUT_SIZE]; > > + } lut; > > +}; > > + > > +static inline int rcar_cmm_read(struct rcar_cmm *rcmm, u32 reg) > > +{ > > + return ioread32(rcmm->base + reg); > > +} > > + > > +static inline void rcar_cmm_write(struct rcar_cmm *rcmm, u32 reg, u32 data) > > +{ > > + iowrite32(data, rcmm->base + reg); > > +} > > + > > +int rcar_cmm_setup(struct platform_device *pdev, struct rcar_cmm_config *config) > > Please document the functions exposed to the DU driver. It's hard to > understand the setup vs. enable/disable split by just reading this > driver. > > > +{ > > + struct rcar_cmm *rcmm = platform_get_drvdata(pdev); > > + unsigned int i; > > + > > + if (config->lut.size > CMM_GAMMA_LUT_SIZE) > > + return -EINVAL; > > + > > + /* > > + * As cmm_setup is called by atomic commit tail helper, it might be > > + * called before the enabling the CRTC (which calls cmm_enable()). > > + * > > + * Store the LUT table entries in the scratch buffer to be later > > + * programmed at enable time. > > + */ > > + if (!rcmm->enabled) { > > + if (!config->lut.enable) > > + return 0; > > + > > + for (i = 0; i < config->lut.size; ++i) { > > + struct drm_color_lut *lut = &config->lut.table[i]; > > + > > + rcmm->lut.table[i] = (lut->red & 0xff) << 16 | > > + (lut->green & 0xff) << 8 | > > + (lut->blue & 0xff); > > + } > > + > > + rcmm->lut.restore = true; > > + rcmm->lut.size = config->lut.size; > > + > > + return 0; > > + } > > + > > + if (rcar_cmm_read(rcmm, CM2_LUT_CTRL) & CM2_LUT_CTRL_EN && > > + !config->lut.enable) { > > + rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0); > > + return 0; > > + } > > + > > + /* Enable LUT and program the new gamma table values. */ > > + rcar_cmm_write(rcmm, CM2_LUT_CTRL, CM2_LUT_CTRL_EN); > > Shouldn't you write the LUT contents before enabling it (same below) ? > > > + for (i = 0; i < config->lut.size; ++i) { > > + struct drm_color_lut *lut = &config->lut.table[i]; > > + u32 val = (lut->red & 0xff) << 16 | (lut->green & 0xff) << 8 | > > + (lut->blue & 0xff); > > Do you need to recompute the value, can't you use rcmm->lut.table ? > > > + > > + rcar_cmm_write(rcmm, CM2_LUT_TBLA + i * 4, val); > > + } > > + > > + return 0; > > +} > > You need to export this and the next two functions. > > > + > > +int rcar_cmm_enable(struct platform_device *pdev) > > +{ > > + struct rcar_cmm *rcmm = platform_get_drvdata(pdev); > > + unsigned int i; > > + int ret; > > + > > + if (rcmm->enabled) > > + return 0; > > Can this happen without a bug in the caller ? If it can, and assuming > the caller balances the enable and disable calls, you will have > unbalanced clk_prepare_enable() and clk_disable_unprepare() calls. > > > + > > + ret = clk_prepare_enable(rcmm->clk); > > + if (ret) > > + return ret; > > Could you use pm_runtime_get_sync() instead ? > > > + > > + /* Apply the LUT table values saved at cmm_setup time. */ > > + if (rcmm->lut.restore) { > > + rcar_cmm_write(rcmm, CM2_LUT_CTRL, CM2_LUT_CTRL_EN); > > + for (i = 0; i < rcmm->lut.size; ++i) > > + rcar_cmm_write(rcmm, CM2_LUT_TBLA + i * 4, > > + rcmm->lut.table[i]); > > + > > + rcmm->lut.restore = false; > > + rcmm->lut.size = 0; > > + } > > + > > + rcmm->enabled = true; > > + > > + return 0; > > +} > > + > > +void rcar_cmm_disable(struct platform_device *pdev) > > +{ > > + struct rcar_cmm *rcmm = platform_get_drvdata(pdev); > > + > > + rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0); > > + > > + clk_disable_unprepare(rcmm->clk); > > + > > + rcmm->lut.restore = false; > > + rcmm->lut.size = 0; > > + rcmm->enabled = false; > > +} > > + > > +static int rcar_cmm_probe(struct platform_device *pdev) > > +{ > > + struct rcar_cmm *rcmm; > > + struct resource *res; > > + resource_size_t size; > > + > > + rcmm = devm_kzalloc(&pdev->dev, sizeof(*rcmm), GFP_KERNEL); > > + if (!rcmm) > > + return -ENOMEM; > > + > > + platform_set_drvdata(pdev, rcmm); > > + > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + size = resource_size(res); > > + if (!devm_request_mem_region(&pdev->dev, res->start, size, > > + dev_name(&pdev->dev))) { > > + dev_err(&pdev->dev, > > + "can't request region for resource %pR\n", res); > > + return -EBUSY; > > + } > > + > > + rcmm->base = devm_ioremap_nocache(&pdev->dev, res->start, size); > > + if (IS_ERR(rcmm->base)) > > + return PTR_ERR(rcmm->base); > > Anything wrong with devm_ioremap_resource() ? > > > + > > + rcmm->clk = devm_clk_get(&pdev->dev, NULL); > > + if (IS_ERR(rcmm->clk)) { > > + dev_err(&pdev->dev, "Failed to get CMM clock"); > > + return PTR_ERR(rcmm->clk); > > + } > > + > > + rcmm->lut.restore = false; > > + rcmm->lut.size = 0; > > + rcmm->enabled = false; > > As you allocate memory with kzalloc() you could skip this. > > > + > > + return 0; > > +} > > + > > +static const struct of_device_id rcar_cmm_of_table[] = { > > + { .compatible = "renesas,cmm-gen3" }, > > + { .compatible = "renesas,cmm-gen2" }, > > + { }, > > +}; > > + > > +MODULE_DEVICE_TABLE(of, rcar_cmm_of_table); > > + > > +static struct platform_driver rcar_cmm_platform_driver = { > > + .probe = rcar_cmm_probe, > > + .driver = { > > + .name = "rcar-cmm", > > + .of_match_table = rcar_cmm_of_table, > > + }, > > No need for suspend/resume support ? The DU driver should disable/enable > the CMM in its suspend/resume paths, so this should be fine, but won't > the LUT contents be lost and need to be restored ? > > > +}; > > + > > +module_platform_driver(rcar_cmm_platform_driver); > > + > > +MODULE_AUTHOR("Jacopo Mondi <jacopo+renesas@xxxxxxxxxx"); > > Missing >. > > > +MODULE_DESCRIPTION("Renesas R-Car CMM Driver"); > > +MODULE_LICENSE("GPL v2"); > > diff --git a/drivers/gpu/drm/rcar-du/rcar_cmm.h b/drivers/gpu/drm/rcar-du/rcar_cmm.h > > new file mode 100644 > > index 000000000000..da61a145dc5c > > --- /dev/null > > +++ b/drivers/gpu/drm/rcar-du/rcar_cmm.h > > @@ -0,0 +1,38 @@ > > +/* SPDX-License-Identifier: GPL-2.0+ */ > > The .c and .h file licenses don't match. > > > +/* > > + * rcar_cmm.h -- R-Car Display Unit Color Management Module > > + * > > + * Copyright (C) 2019 Jacopo Mondi <jacopo+renesas@xxxxxxxxxx> > > + */ > > + > > +#ifndef __RCAR_CMM_H__ > > +#define __RCAR_CMM_H__ > > + > > +#include <linux/platform_device.h> > > You can forward-declare struct platform_device instead. > > > + > > +#define CMM_GAMMA_LUT_SIZE 256 > > + > > +struct drm_color_lut; > > + > > +/** > > + * struct rcar_cmm_config - CMM configuration > > + * > > + * @lut: 1D-LUT configuration > > + * @lut.enable: 1D-LUT enable flag > > + * @lut.table: 1D-LUT table entries. > > + * @lut.size 1D-LUT number of entries. Max is 256 > > The last line is missing a colon. > > > + */ > > +struct rcar_cmm_config { > > + struct { > > + bool enable; > > + struct drm_color_lut *table; > > + unsigned int size; > > + } lut; > > +}; > > + > > +int rcar_cmm_enable(struct platform_device *); > > As the OF API looks up a struct device from a device_node, should we use > struct device here ? My bad, the API actually returns a struct platform_device. I would still prefer using struct device, but it then becomes more of a personal preference. > > +void rcar_cmm_disable(struct platform_device *); > > I find headers more readable when function arguments are named. In this > case the types probably provide enough information, but good luck trying > to read a function such as > > int foo(int, int, bool); > > > + > > +int rcar_cmm_setup(struct platform_device *, struct rcar_cmm_config *); > > Can the second argument be const ? > > > + > > +#endif /* __RCAR_CMM_H__ */ -- Regards, Laurent Pinchart