microchip-lvds.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2023 Microchip Technology Inc. and its subsidiaries
  4 *
  5 * Author: Manikandan Muralidharan <manikandan.m@microchip.com>
  6 * Author: Dharma Balasubiramani <dharma.b@microchip.com>
  7 *
  8 */
  9
 10#include <linux/clk.h>
 11#include <linux/component.h>
 12#include <linux/delay.h>
 13#include <linux/jiffies.h>
 14#include <linux/mfd/syscon.h>
 15#include <linux/of_graph.h>
 16#include <linux/pinctrl/devinfo.h>
 17#include <linux/phy/phy.h>
 18#include <linux/platform_device.h>
 19#include <linux/pm_runtime.h>
 20#include <linux/regmap.h>
 21#include <linux/reset.h>
 22
 23#include <drm/drm_atomic_helper.h>
 24#include <drm/drm_bridge.h>
 25#include <drm/drm_of.h>
 26#include <drm/drm_panel.h>
 27#include <drm/drm_print.h>
 28#include <drm/drm_probe_helper.h>
 29#include <drm/drm_simple_kms_helper.h>
 30
 31#define LVDS_POLL_TIMEOUT_MS 1000
 32
 33/* LVDSC register offsets */
 34#define LVDSC_CR	0x00
 35#define LVDSC_CFGR	0x04
 36#define LVDSC_SR	0x0C
 37#define LVDSC_WPMR	0xE4
 38
 39/* Bitfields in LVDSC_CR (Control Register) */
 40#define LVDSC_CR_SER_EN	BIT(0)
 41
 42/* Bitfields in LVDSC_CFGR (Configuration Register) */
 43#define LVDSC_CFGR_PIXSIZE_24BITS	0
 44#define LVDSC_CFGR_DEN_POL_HIGH		0
 45#define LVDSC_CFGR_DC_UNBALANCED	0
 46#define LVDSC_CFGR_MAPPING_JEIDA	BIT(6)
 47
 48/*Bitfields in LVDSC_SR */
 49#define LVDSC_SR_CS	BIT(0)
 50
 51/* Bitfields in LVDSC_WPMR (Write Protection Mode Register) */
 52#define LVDSC_WPMR_WPKEY_MASK	GENMASK(31, 8)
 53#define LVDSC_WPMR_WPKEY_PSSWD	0x4C5644
 54
 55struct mchp_lvds {
 56	struct device *dev;
 57	void __iomem *regs;
 58	struct clk *pclk;
 59	struct drm_panel *panel;
 60	struct drm_bridge bridge;
 61	struct drm_bridge *panel_bridge;
 62};
 63
 64static inline struct mchp_lvds *bridge_to_lvds(struct drm_bridge *bridge)
 65{
 66	return container_of(bridge, struct mchp_lvds, bridge);
 67}
 68
 69static inline u32 lvds_readl(struct mchp_lvds *lvds, u32 offset)
 70{
 71	return readl_relaxed(lvds->regs + offset);
 72}
 73
 74static inline void lvds_writel(struct mchp_lvds *lvds, u32 offset, u32 val)
 75{
 76	writel_relaxed(val, lvds->regs + offset);
 77}
 78
 79static void lvds_serialiser_on(struct mchp_lvds *lvds)
 80{
 81	unsigned long timeout = jiffies + msecs_to_jiffies(LVDS_POLL_TIMEOUT_MS);
 82
 83	/* The LVDSC registers can only be written if WPEN is cleared */
 84	lvds_writel(lvds, LVDSC_WPMR, (LVDSC_WPMR_WPKEY_PSSWD &
 85				LVDSC_WPMR_WPKEY_MASK));
 86
 87	/* Wait for the status of configuration registers to be changed */
 88	while (lvds_readl(lvds, LVDSC_SR) & LVDSC_SR_CS) {
 89		if (time_after(jiffies, timeout)) {
 90			dev_err(lvds->dev, "%s: timeout error\n", __func__);
 91			return;
 92		}
 93		usleep_range(1000, 2000);
 94	}
 95
 96	/* Configure the LVDSC */
 97	lvds_writel(lvds, LVDSC_CFGR, (LVDSC_CFGR_MAPPING_JEIDA |
 98				LVDSC_CFGR_DC_UNBALANCED |
 99				LVDSC_CFGR_DEN_POL_HIGH |
100				LVDSC_CFGR_PIXSIZE_24BITS));
101
102	/* Enable the LVDS serializer */
103	lvds_writel(lvds, LVDSC_CR, LVDSC_CR_SER_EN);
104}
105
106static int mchp_lvds_attach(struct drm_bridge *bridge,
107			    struct drm_encoder *encoder,
108			    enum drm_bridge_attach_flags flags)
109{
110	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
111
112	return drm_bridge_attach(encoder, lvds->panel_bridge,
113				 bridge, flags);
114}
115
116static void mchp_lvds_enable(struct drm_bridge *bridge)
117{
118	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
119	int ret;
120
121	ret = clk_prepare_enable(lvds->pclk);
122	if (ret < 0) {
123		dev_err(lvds->dev, "failed to enable lvds pclk %d\n", ret);
124		return;
125	}
126
127	ret = pm_runtime_get_sync(lvds->dev);
128	if (ret < 0) {
129		dev_err(lvds->dev, "failed to get pm runtime: %d\n", ret);
130		return;
131	}
132
133	lvds_serialiser_on(lvds);
134}
135
136static void mchp_lvds_disable(struct drm_bridge *bridge)
137{
138	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
139
140	pm_runtime_put(lvds->dev);
141	clk_disable_unprepare(lvds->pclk);
142}
143
144static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
145	.attach = mchp_lvds_attach,
146	.enable = mchp_lvds_enable,
147	.disable = mchp_lvds_disable,
148};
149
150static int mchp_lvds_probe(struct platform_device *pdev)
151{
152	struct device *dev = &pdev->dev;
153	struct mchp_lvds *lvds;
154	struct device_node *port;
155	int ret;
156
157	if (!dev->of_node)
158		return -ENODEV;
159
160	lvds = devm_drm_bridge_alloc(&pdev->dev, struct mchp_lvds, bridge,
161				     &mchp_lvds_bridge_funcs);
162	if (IS_ERR(lvds))
163		return PTR_ERR(lvds);
164
165	lvds->dev = dev;
166
167	lvds->regs = devm_platform_ioremap_resource(pdev, 0);
168	if (IS_ERR(lvds->regs))
169		return PTR_ERR(lvds->regs);
170
171	lvds->pclk = devm_clk_get(lvds->dev, "pclk");
172	if (IS_ERR(lvds->pclk))
173		return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
174				"could not get pclk_lvds\n");
175
176	port = of_graph_get_remote_node(dev->of_node, 1, 0);
177	if (!port) {
178		dev_err(dev,
179			"can't find port point, please init lvds panel port!\n");
180		return -ENODEV;
181	}
182
183	lvds->panel = of_drm_find_panel(port);
184	of_node_put(port);
185
186	if (IS_ERR(lvds->panel))
187		return -EPROBE_DEFER;
188
189	lvds->panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
190
191	if (IS_ERR(lvds->panel_bridge))
192		return PTR_ERR(lvds->panel_bridge);
193
194	lvds->bridge.of_node = dev->of_node;
195	lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
196
197	dev_set_drvdata(dev, lvds);
198	ret = devm_pm_runtime_enable(dev);
199	if (ret < 0) {
200		dev_err(lvds->dev, "failed to enable pm runtime: %d\n", ret);
201		return ret;
202	}
203
204	drm_bridge_add(&lvds->bridge);
205
206	return 0;
207}
208
209static const struct of_device_id mchp_lvds_dt_ids[] = {
210	{
211		.compatible = "microchip,sam9x75-lvds",
212	},
213	{},
214};
215MODULE_DEVICE_TABLE(of, mchp_lvds_dt_ids);
216
217static struct platform_driver mchp_lvds_driver = {
218	.probe = mchp_lvds_probe,
219	.driver = {
220		   .name = "microchip-lvds",
221		   .of_match_table = mchp_lvds_dt_ids,
222	},
223};
224module_platform_driver(mchp_lvds_driver);
225
226MODULE_AUTHOR("Manikandan Muralidharan <manikandan.m@microchip.com>");
227MODULE_AUTHOR("Dharma Balasubiramani <dharma.b@microchip.com>");
228MODULE_DESCRIPTION("Low Voltage Differential Signaling Controller Driver");
229MODULE_LICENSE("GPL");