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 
23 struct 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 
35 static inline int rcar_cmm_read(struct rcar_cmm *rcmm, u32 reg)
36 {
37 	return ioread32(rcmm->base + reg);
38 }
39 
40 static 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  */
51 static 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  */
81 int 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 }
106 EXPORT_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  */
121 int 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 }
131 EXPORT_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  */
143 void 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 }
152 EXPORT_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  */
161 int 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 }
170 EXPORT_SYMBOL_GPL(rcar_cmm_init);
171 
172 static 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 
190 static void rcar_cmm_remove(struct platform_device *pdev)
191 {
192 	pm_runtime_disable(&pdev->dev);
193 }
194 
195 static const struct of_device_id rcar_cmm_of_table[] = {
196 	{ .compatible = "renesas,rcar-gen3-cmm", },
197 	{ .compatible = "renesas,rcar-gen2-cmm", },
198 	{ },
199 };
200 MODULE_DEVICE_TABLE(of, rcar_cmm_of_table);
201 
202 static struct platform_driver rcar_cmm_platform_driver = {
203 	.probe		= rcar_cmm_probe,
204 	.remove_new	= rcar_cmm_remove,
205 	.driver		= {
206 		.name	= "rcar-cmm",
207 		.of_match_table = rcar_cmm_of_table,
208 	},
209 };
210 
211 module_platform_driver(rcar_cmm_platform_driver);
212 
213 MODULE_AUTHOR("Jacopo Mondi <jacopo+renesas@jmondi.org>");
214 MODULE_DESCRIPTION("Renesas R-Car CMM Driver");
215 MODULE_LICENSE("GPL v2");
216