rcar_cmm.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * R-Car Display Unit Color Management Module
  4 *
  5 * Copyright (C) 2019 Jacopo Mondi <jacopo+renesas@jmondi.org>
  6 */
  7
  8#include <linux/io.h>
  9#include <linux/module.h>
 10#include <linux/of.h>
 11#include <linux/platform_device.h>
 12#include <linux/pm_runtime.h>
 13
 14#include <drm/drm_color_mgmt.h>
 15
 16#include "rcar_cmm.h"
 17
 18#define CM2_LUT_CTRL		0x0000
 19#define CM2_LUT_CTRL_LUT_EN	BIT(0)
 20#define CM2_LUT_TBL_BASE	0x0600
 21#define CM2_LUT_TBL(__i)	(CM2_LUT_TBL_BASE + (__i) * 4)
 22
 23struct rcar_cmm {
 24	void __iomem *base;
 25
 26	/*
 27	 * @lut:		1D-LUT state
 28	 * @lut.enabled:	1D-LUT enabled flag
 29	 */
 30	struct {
 31		bool enabled;
 32	} lut;
 33};
 34
 35static inline void rcar_cmm_write(struct rcar_cmm *rcmm, u32 reg, u32 data)
 36{
 37	iowrite32(data, rcmm->base + reg);
 38}
 39
 40/*
 41 * rcar_cmm_lut_write() - Scale the DRM LUT table entries to hardware precision
 42 *			  and write to the CMM registers
 43 * @rcmm: Pointer to the CMM device
 44 * @drm_lut: Pointer to the DRM LUT table
 45 */
 46static void rcar_cmm_lut_write(struct rcar_cmm *rcmm,
 47			       const struct drm_color_lut *drm_lut)
 48{
 49	unsigned int i;
 50
 51	for (i = 0; i < CM2_LUT_SIZE; ++i) {
 52		u32 entry = drm_color_lut_extract(drm_lut[i].red, 8) << 16
 53			  | drm_color_lut_extract(drm_lut[i].green, 8) << 8
 54			  | drm_color_lut_extract(drm_lut[i].blue, 8);
 55
 56		rcar_cmm_write(rcmm, CM2_LUT_TBL(i), entry);
 57	}
 58}
 59
 60/*
 61 * rcar_cmm_setup() - Configure the CMM unit
 62 * @pdev: The platform device associated with the CMM instance
 63 * @config: The CMM unit configuration
 64 *
 65 * Configure the CMM unit with the given configuration. Currently enabling,
 66 * disabling and programming of the 1-D LUT unit is supported.
 67 *
 68 * As rcar_cmm_setup() accesses the CMM registers the unit should be powered
 69 * and its functional clock enabled. To guarantee this, before any call to
 70 * this function is made, the CMM unit has to be enabled by calling
 71 * rcar_cmm_enable() first.
 72 *
 73 * TODO: Add support for LUT double buffer operations to avoid updating the
 74 * LUT table entries while a frame is being displayed.
 75 */
 76int rcar_cmm_setup(struct platform_device *pdev,
 77		   const struct rcar_cmm_config *config)
 78{
 79	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
 80
 81	/* Disable LUT if no table is provided. */
 82	if (!config->lut.table) {
 83		if (rcmm->lut.enabled) {
 84			rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0);
 85			rcmm->lut.enabled = false;
 86		}
 87
 88		return 0;
 89	}
 90
 91	/* Enable LUT and program the new gamma table values. */
 92	if (!rcmm->lut.enabled) {
 93		rcar_cmm_write(rcmm, CM2_LUT_CTRL, CM2_LUT_CTRL_LUT_EN);
 94		rcmm->lut.enabled = true;
 95	}
 96
 97	rcar_cmm_lut_write(rcmm, config->lut.table);
 98
 99	return 0;
100}
101EXPORT_SYMBOL_GPL(rcar_cmm_setup);
102
103/*
104 * rcar_cmm_enable() - Enable the CMM unit
105 * @pdev: The platform device associated with the CMM instance
106 *
107 * When the output of the corresponding DU channel is routed to the CMM unit,
108 * the unit shall be enabled before the DU channel is started, and remain
109 * enabled until the channel is stopped. The CMM unit shall be disabled with
110 * rcar_cmm_disable().
111 *
112 * Calls to rcar_cmm_enable() and rcar_cmm_disable() are not reference-counted.
113 * It is an error to attempt to enable an already enabled CMM unit, or to
114 * attempt to disable a disabled unit.
115 */
116int rcar_cmm_enable(struct platform_device *pdev)
117{
118	int ret;
119
120	ret = pm_runtime_resume_and_get(&pdev->dev);
121	if (ret < 0)
122		return ret;
123
124	return 0;
125}
126EXPORT_SYMBOL_GPL(rcar_cmm_enable);
127
128/*
129 * rcar_cmm_disable() - Disable the CMM unit
130 * @pdev: The platform device associated with the CMM instance
131 *
132 * See rcar_cmm_enable() for usage information.
133 *
134 * Disabling the CMM unit disable all the internal processing blocks. The CMM
135 * state shall thus be restored with rcar_cmm_setup() when re-enabling the CMM
136 * unit after the next rcar_cmm_enable() call.
137 */
138void rcar_cmm_disable(struct platform_device *pdev)
139{
140	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
141
142	rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0);
143	rcmm->lut.enabled = false;
144
145	pm_runtime_put(&pdev->dev);
146}
147EXPORT_SYMBOL_GPL(rcar_cmm_disable);
148
149/*
150 * rcar_cmm_init() - Initialize the CMM unit
151 * @pdev: The platform device associated with the CMM instance
152 *
153 * Return: 0 on success, -EPROBE_DEFER if the CMM is not available yet,
154 *         -ENODEV if the DRM_RCAR_CMM config option is disabled
155 */
156int rcar_cmm_init(struct platform_device *pdev)
157{
158	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
159
160	if (!rcmm)
161		return -EPROBE_DEFER;
162
163	return 0;
164}
165EXPORT_SYMBOL_GPL(rcar_cmm_init);
166
167static int rcar_cmm_probe(struct platform_device *pdev)
168{
169	struct rcar_cmm *rcmm;
170
171	rcmm = devm_kzalloc(&pdev->dev, sizeof(*rcmm), GFP_KERNEL);
172	if (!rcmm)
173		return -ENOMEM;
174	platform_set_drvdata(pdev, rcmm);
175
176	rcmm->base = devm_platform_ioremap_resource(pdev, 0);
177	if (IS_ERR(rcmm->base))
178		return PTR_ERR(rcmm->base);
179
180	pm_runtime_enable(&pdev->dev);
181
182	return 0;
183}
184
185static void rcar_cmm_remove(struct platform_device *pdev)
186{
187	pm_runtime_disable(&pdev->dev);
188}
189
190static const struct of_device_id rcar_cmm_of_table[] = {
191	{ .compatible = "renesas,rcar-gen3-cmm", },
192	{ .compatible = "renesas,rcar-gen2-cmm", },
193	{ },
194};
195MODULE_DEVICE_TABLE(of, rcar_cmm_of_table);
196
197static struct platform_driver rcar_cmm_platform_driver = {
198	.probe		= rcar_cmm_probe,
199	.remove		= rcar_cmm_remove,
200	.driver		= {
201		.name	= "rcar-cmm",
202		.of_match_table = rcar_cmm_of_table,
203	},
204};
205
206module_platform_driver(rcar_cmm_platform_driver);
207
208MODULE_AUTHOR("Jacopo Mondi <jacopo+renesas@jmondi.org>");
209MODULE_DESCRIPTION("Renesas R-Car CMM Driver");
210MODULE_LICENSE("GPL v2");