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 ? > +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