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 int rcar_cmm_read(struct rcar_cmm *rcmm, u32 reg)
 36{
 37	return ioread32(rcmm->base + reg);
 38}
 39
 40static inline void rcar_cmm_write(struct rcar_cmm *rcmm, u32 reg, u32 data)
 41{
 42	iowrite32(data, rcmm->base + reg);
 43}
 44
 45/*
 46 * rcar_cmm_lut_write() - Scale the DRM LUT table entries to hardware precision
 47 *			  and write to the CMM registers
 48 * @rcmm: Pointer to the CMM device
 49 * @drm_lut: Pointer to the DRM LUT table
 50 */
 51static void rcar_cmm_lut_write(struct rcar_cmm *rcmm,
 52			       const struct drm_color_lut *drm_lut)
 53{
 54	unsigned int i;
 55
 56	for (i = 0; i < CM2_LUT_SIZE; ++i) {
 57		u32 entry = drm_color_lut_extract(drm_lut[i].red, 8) << 16
 58			  | drm_color_lut_extract(drm_lut[i].green, 8) << 8
 59			  | drm_color_lut_extract(drm_lut[i].blue, 8);
 60
 61		rcar_cmm_write(rcmm, CM2_LUT_TBL(i), entry);
 62	}
 63}
 64
 65/*
 66 * rcar_cmm_setup() - Configure the CMM unit
 67 * @pdev: The platform device associated with the CMM instance
 68 * @config: The CMM unit configuration
 69 *
 70 * Configure the CMM unit with the given configuration. Currently enabling,
 71 * disabling and programming of the 1-D LUT unit is supported.
 72 *
 73 * As rcar_cmm_setup() accesses the CMM registers the unit should be powered
 74 * and its functional clock enabled. To guarantee this, before any call to
 75 * this function is made, the CMM unit has to be enabled by calling
 76 * rcar_cmm_enable() first.
 77 *
 78 * TODO: Add support for LUT double buffer operations to avoid updating the
 79 * LUT table entries while a frame is being displayed.
 80 */
 81int rcar_cmm_setup(struct platform_device *pdev,
 82		   const struct rcar_cmm_config *config)
 83{
 84	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
 85
 86	/* Disable LUT if no table is provided. */
 87	if (!config->lut.table) {
 88		if (rcmm->lut.enabled) {
 89			rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0);
 90			rcmm->lut.enabled = false;
 91		}
 92
 93		return 0;
 94	}
 95
 96	/* Enable LUT and program the new gamma table values. */
 97	if (!rcmm->lut.enabled) {
 98		rcar_cmm_write(rcmm, CM2_LUT_CTRL, CM2_LUT_CTRL_LUT_EN);
 99		rcmm->lut.enabled = true;
100	}
101
102	rcar_cmm_lut_write(rcmm, config->lut.table);
103
104	return 0;
105}
106EXPORT_SYMBOL_GPL(rcar_cmm_setup);
107
108/*
109 * rcar_cmm_enable() - Enable the CMM unit
110 * @pdev: The platform device associated with the CMM instance
111 *
112 * When the output of the corresponding DU channel is routed to the CMM unit,
113 * the unit shall be enabled before the DU channel is started, and remain
114 * enabled until the channel is stopped. The CMM unit shall be disabled with
115 * rcar_cmm_disable().
116 *
117 * Calls to rcar_cmm_enable() and rcar_cmm_disable() are not reference-counted.
118 * It is an error to attempt to enable an already enabled CMM unit, or to
119 * attempt to disable a disabled unit.
120 */
121int rcar_cmm_enable(struct platform_device *pdev)
122{
123	int ret;
124
125	ret = pm_runtime_resume_and_get(&pdev->dev);
126	if (ret < 0)
127		return ret;
128
129	return 0;
130}
131EXPORT_SYMBOL_GPL(rcar_cmm_enable);
132
133/*
134 * rcar_cmm_disable() - Disable the CMM unit
135 * @pdev: The platform device associated with the CMM instance
136 *
137 * See rcar_cmm_enable() for usage information.
138 *
139 * Disabling the CMM unit disable all the internal processing blocks. The CMM
140 * state shall thus be restored with rcar_cmm_setup() when re-enabling the CMM
141 * unit after the next rcar_cmm_enable() call.
142 */
143void rcar_cmm_disable(struct platform_device *pdev)
144{
145	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
146
147	rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0);
148	rcmm->lut.enabled = false;
149
150	pm_runtime_put(&pdev->dev);
151}
152EXPORT_SYMBOL_GPL(rcar_cmm_disable);
153
154/*
155 * rcar_cmm_init() - Initialize the CMM unit
156 * @pdev: The platform device associated with the CMM instance
157 *
158 * Return: 0 on success, -EPROBE_DEFER if the CMM is not available yet,
159 *         -ENODEV if the DRM_RCAR_CMM config option is disabled
160 */
161int rcar_cmm_init(struct platform_device *pdev)
162{
163	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
164
165	if (!rcmm)
166		return -EPROBE_DEFER;
167
168	return 0;
169}
170EXPORT_SYMBOL_GPL(rcar_cmm_init);
171
172static int rcar_cmm_probe(struct platform_device *pdev)
173{
174	struct rcar_cmm *rcmm;
175
176	rcmm = devm_kzalloc(&pdev->dev, sizeof(*rcmm), GFP_KERNEL);
177	if (!rcmm)
178		return -ENOMEM;
179	platform_set_drvdata(pdev, rcmm);
180
181	rcmm->base = devm_platform_ioremap_resource(pdev, 0);
182	if (IS_ERR(rcmm->base))
183		return PTR_ERR(rcmm->base);
184
185	pm_runtime_enable(&pdev->dev);
186
187	return 0;
188}
189
190static int rcar_cmm_remove(struct platform_device *pdev)
191{
192	pm_runtime_disable(&pdev->dev);
193
194	return 0;
195}
196
197static const struct of_device_id rcar_cmm_of_table[] = {
198	{ .compatible = "renesas,rcar-gen3-cmm", },
199	{ .compatible = "renesas,rcar-gen2-cmm", },
200	{ },
201};
202MODULE_DEVICE_TABLE(of, rcar_cmm_of_table);
203
204static struct platform_driver rcar_cmm_platform_driver = {
205	.probe		= rcar_cmm_probe,
206	.remove		= rcar_cmm_remove,
207	.driver		= {
208		.name	= "rcar-cmm",
209		.of_match_table = rcar_cmm_of_table,
210	},
211};
212
213module_platform_driver(rcar_cmm_platform_driver);
214
215MODULE_AUTHOR("Jacopo Mondi <jacopo+renesas@jmondi.org>");
216MODULE_DESCRIPTION("Renesas R-Car CMM Driver");
217MODULE_LICENSE("GPL v2");