1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * DRM driver for Ilitek ILI9486 panels
4 *
5 * Copyright 2020 Kamlesh Gurudasani <kamlesh.gurudasani@gmail.com>
6 */
7
8#include <linux/backlight.h>
9#include <linux/delay.h>
10#include <linux/gpio/consumer.h>
11#include <linux/module.h>
12#include <linux/property.h>
13#include <linux/spi/spi.h>
14
15#include <video/mipi_display.h>
16
17#include <drm/drm_atomic_helper.h>
18#include <drm/drm_drv.h>
19#include <drm/drm_fbdev_generic.h>
20#include <drm/drm_gem_atomic_helper.h>
21#include <drm/drm_gem_dma_helper.h>
22#include <drm/drm_managed.h>
23#include <drm/drm_mipi_dbi.h>
24#include <drm/drm_modeset_helper.h>
25
26#define ILI9486_ITFCTR1 0xb0
27#define ILI9486_PWCTRL1 0xc2
28#define ILI9486_VMCTRL1 0xc5
29#define ILI9486_PGAMCTRL 0xe0
30#define ILI9486_NGAMCTRL 0xe1
31#define ILI9486_DGAMCTRL 0xe2
32#define ILI9486_MADCTL_BGR BIT(3)
33#define ILI9486_MADCTL_MV BIT(5)
34#define ILI9486_MADCTL_MX BIT(6)
35#define ILI9486_MADCTL_MY BIT(7)
36
37/*
38 * The PiScreen/waveshare rpi-lcd-35 has a SPI to 16-bit parallel bus converter
39 * in front of the display controller. This means that 8-bit values have to be
40 * transferred as 16-bit.
41 */
42static int waveshare_command(struct mipi_dbi *mipi, u8 *cmd, u8 *par,
43 size_t num)
44{
45 struct spi_device *spi = mipi->spi;
46 unsigned int bpw = 8;
47 void *data = par;
48 u32 speed_hz;
49 int i, ret;
50 __be16 *buf;
51
52 buf = kmalloc(size: 32 * sizeof(u16), GFP_KERNEL);
53 if (!buf)
54 return -ENOMEM;
55
56 /*
57 * The displays are Raspberry Pi HATs and connected to the 8-bit only
58 * SPI controller, so 16-bit command and parameters need byte swapping
59 * before being transferred as 8-bit on the big endian SPI bus.
60 */
61 buf[0] = cpu_to_be16(*cmd);
62 spi_bus_lock(ctlr: spi->controller);
63 gpiod_set_value_cansleep(desc: mipi->dc, value: 0);
64 speed_hz = mipi_dbi_spi_cmd_max_speed(spi, len: 2);
65 ret = mipi_dbi_spi_transfer(spi, speed_hz, bpw: 8, buf, len: 2);
66 spi_bus_unlock(ctlr: spi->controller);
67 if (ret || !num)
68 goto free;
69
70 /* 8-bit configuration data, not 16-bit pixel data */
71 if (num <= 32) {
72 for (i = 0; i < num; i++)
73 buf[i] = cpu_to_be16(par[i]);
74 num *= 2;
75 data = buf;
76 }
77
78 /*
79 * Check whether pixel data bytes needs to be swapped or not
80 */
81 if (*cmd == MIPI_DCS_WRITE_MEMORY_START && !mipi->swap_bytes)
82 bpw = 16;
83
84 spi_bus_lock(ctlr: spi->controller);
85 gpiod_set_value_cansleep(desc: mipi->dc, value: 1);
86 speed_hz = mipi_dbi_spi_cmd_max_speed(spi, len: num);
87 ret = mipi_dbi_spi_transfer(spi, speed_hz, bpw, buf: data, len: num);
88 spi_bus_unlock(ctlr: spi->controller);
89 free:
90 kfree(objp: buf);
91
92 return ret;
93}
94
95static void waveshare_enable(struct drm_simple_display_pipe *pipe,
96 struct drm_crtc_state *crtc_state,
97 struct drm_plane_state *plane_state)
98{
99 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(drm: pipe->crtc.dev);
100 struct mipi_dbi *dbi = &dbidev->dbi;
101 u8 addr_mode;
102 int ret, idx;
103
104 if (!drm_dev_enter(dev: pipe->crtc.dev, idx: &idx))
105 return;
106
107 DRM_DEBUG_KMS("\n");
108
109 ret = mipi_dbi_poweron_conditional_reset(dbidev);
110 if (ret < 0)
111 goto out_exit;
112 if (ret == 1)
113 goto out_enable;
114
115 mipi_dbi_command(dbi, ILI9486_ITFCTR1);
116 mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
117 msleep(msecs: 250);
118
119 mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT, 0x55);
120
121 mipi_dbi_command(dbi, ILI9486_PWCTRL1, 0x44);
122
123 mipi_dbi_command(dbi, ILI9486_VMCTRL1, 0x00, 0x00, 0x00, 0x00);
124
125 mipi_dbi_command(dbi, ILI9486_PGAMCTRL,
126 0x0F, 0x1F, 0x1C, 0x0C, 0x0F, 0x08, 0x48, 0x98,
127 0x37, 0x0A, 0x13, 0x04, 0x11, 0x0D, 0x0);
128 mipi_dbi_command(dbi, ILI9486_NGAMCTRL,
129 0x0F, 0x32, 0x2E, 0x0B, 0x0D, 0x05, 0x47, 0x75,
130 0x37, 0x06, 0x10, 0x03, 0x24, 0x20, 0x00);
131 mipi_dbi_command(dbi, ILI9486_DGAMCTRL,
132 0x0F, 0x32, 0x2E, 0x0B, 0x0D, 0x05, 0x47, 0x75,
133 0x37, 0x06, 0x10, 0x03, 0x24, 0x20, 0x00);
134
135 mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
136 msleep(msecs: 100);
137
138 out_enable:
139 switch (dbidev->rotation) {
140 case 90:
141 addr_mode = ILI9486_MADCTL_MY;
142 break;
143 case 180:
144 addr_mode = ILI9486_MADCTL_MV;
145 break;
146 case 270:
147 addr_mode = ILI9486_MADCTL_MX;
148 break;
149 default:
150 addr_mode = ILI9486_MADCTL_MV | ILI9486_MADCTL_MY |
151 ILI9486_MADCTL_MX;
152 break;
153 }
154 addr_mode |= ILI9486_MADCTL_BGR;
155 mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
156 mipi_dbi_enable_flush(dbidev, crtc_state, plan_state: plane_state);
157 out_exit:
158 drm_dev_exit(idx);
159}
160
161static const struct drm_simple_display_pipe_funcs waveshare_pipe_funcs = {
162 DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(waveshare_enable),
163};
164
165static const struct drm_display_mode waveshare_mode = {
166 DRM_SIMPLE_MODE(480, 320, 73, 49),
167};
168
169DEFINE_DRM_GEM_DMA_FOPS(ili9486_fops);
170
171static const struct drm_driver ili9486_driver = {
172 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
173 .fops = &ili9486_fops,
174 DRM_GEM_DMA_DRIVER_OPS_VMAP,
175 .debugfs_init = mipi_dbi_debugfs_init,
176 .name = "ili9486",
177 .desc = "Ilitek ILI9486",
178 .date = "20200118",
179 .major = 1,
180 .minor = 0,
181};
182
183static const struct of_device_id ili9486_of_match[] = {
184 { .compatible = "waveshare,rpi-lcd-35" },
185 { .compatible = "ozzmaker,piscreen" },
186 {},
187};
188MODULE_DEVICE_TABLE(of, ili9486_of_match);
189
190static const struct spi_device_id ili9486_id[] = {
191 { "ili9486", 0 },
192 { "rpi-lcd-35", 0 },
193 { "piscreen", 0 },
194 { }
195};
196MODULE_DEVICE_TABLE(spi, ili9486_id);
197
198static int ili9486_probe(struct spi_device *spi)
199{
200 struct device *dev = &spi->dev;
201 struct mipi_dbi_dev *dbidev;
202 struct drm_device *drm;
203 struct mipi_dbi *dbi;
204 struct gpio_desc *dc;
205 u32 rotation = 0;
206 int ret;
207
208 dbidev = devm_drm_dev_alloc(dev, &ili9486_driver,
209 struct mipi_dbi_dev, drm);
210 if (IS_ERR(ptr: dbidev))
211 return PTR_ERR(ptr: dbidev);
212
213 dbi = &dbidev->dbi;
214 drm = &dbidev->drm;
215
216 dbi->reset = devm_gpiod_get(dev, con_id: "reset", flags: GPIOD_OUT_HIGH);
217 if (IS_ERR(ptr: dbi->reset))
218 return dev_err_probe(dev, err: PTR_ERR(ptr: dbi->reset), fmt: "Failed to get GPIO 'reset'\n");
219
220 dc = devm_gpiod_get(dev, con_id: "dc", flags: GPIOD_OUT_LOW);
221 if (IS_ERR(ptr: dc))
222 return dev_err_probe(dev, err: PTR_ERR(ptr: dc), fmt: "Failed to get GPIO 'dc'\n");
223
224 dbidev->backlight = devm_of_find_backlight(dev);
225 if (IS_ERR(ptr: dbidev->backlight))
226 return PTR_ERR(ptr: dbidev->backlight);
227
228 device_property_read_u32(dev, propname: "rotation", val: &rotation);
229
230 ret = mipi_dbi_spi_init(spi, dbi, dc);
231 if (ret)
232 return ret;
233
234 dbi->command = waveshare_command;
235 dbi->read_commands = NULL;
236
237 ret = mipi_dbi_dev_init(dbidev, funcs: &waveshare_pipe_funcs,
238 mode: &waveshare_mode, rotation);
239 if (ret)
240 return ret;
241
242 drm_mode_config_reset(dev: drm);
243
244 ret = drm_dev_register(dev: drm, flags: 0);
245 if (ret)
246 return ret;
247
248 spi_set_drvdata(spi, data: drm);
249
250 drm_fbdev_generic_setup(dev: drm, preferred_bpp: 0);
251
252 return 0;
253}
254
255static void ili9486_remove(struct spi_device *spi)
256{
257 struct drm_device *drm = spi_get_drvdata(spi);
258
259 drm_dev_unplug(dev: drm);
260 drm_atomic_helper_shutdown(dev: drm);
261}
262
263static void ili9486_shutdown(struct spi_device *spi)
264{
265 drm_atomic_helper_shutdown(dev: spi_get_drvdata(spi));
266}
267
268static struct spi_driver ili9486_spi_driver = {
269 .driver = {
270 .name = "ili9486",
271 .of_match_table = ili9486_of_match,
272 },
273 .id_table = ili9486_id,
274 .probe = ili9486_probe,
275 .remove = ili9486_remove,
276 .shutdown = ili9486_shutdown,
277};
278module_spi_driver(ili9486_spi_driver);
279
280MODULE_DESCRIPTION("Ilitek ILI9486 DRM driver");
281MODULE_AUTHOR("Kamlesh Gurudasani <kamlesh.gurudasani@gmail.com>");
282MODULE_LICENSE("GPL");
283

source code of linux/drivers/gpu/drm/tiny/ili9486.c