2 * FB driver for the HX8340BN LCD Controller
4 * This display uses 9-bit SPI: Data/Command bit + 8 data bits
5 * For platforms that doesn't support 9-bit, the driver is capable
6 * of emulating this using 8-bit transfer.
7 * This is done by transferring eight 9-bit words in 9 bytes.
9 * Copyright (C) 2013 Noralf Tronnes
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 #include <linux/module.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/vmalloc.h>
30 #include <linux/spi/spi.h>
31 #include <linux/delay.h>
35 #define DRVNAME "fb_hx8340bn"
38 #define TXBUFLEN (4 * PAGE_SIZE)
39 #define DEFAULT_GAMMA "1 3 0E 5 0 2 09 0 6 1 7 1 0 2 2\n" \
40 "3 3 17 8 4 7 05 7 6 0 3 1 6 0 0 "
44 module_param(emulate, bool, 0);
45 MODULE_PARM_DESC(emulate, "Force emulation in 9-bit mode");
48 static int init_display(struct fbtft_par *par)
50 par->fbtftops.reset(par);
52 /* BTL221722-276L startup sequence, from datasheet */
54 /* SETEXTCOM: Set extended command set (C1h)
55 This command is used to set extended command set access enable.
56 Enable: After command (C1h), must write: ffh,83h,40h */
57 write_reg(par, 0xC1, 0xFF, 0x83, 0x40);
60 This command turns off sleep mode.
61 In this mode the DC/DC converter is enabled, Internal oscillator
62 is started, and panel scanning is started. */
66 /* Undoc'd register? */
67 write_reg(par, 0xCA, 0x70, 0x00, 0xD9);
69 /* SETOSC: Set Internal Oscillator (B0h)
70 This command is used to set internal oscillator related settings */
71 /* OSC_EN: Enable internal oscillator */
72 /* Internal oscillator frequency: 125% x 2.52MHz */
73 write_reg(par, 0xB0, 0x01, 0x11);
75 /* Drive ability setting */
76 write_reg(par, 0xC9, 0x90, 0x49, 0x10, 0x28, 0x28, 0x10, 0x00, 0x06);
79 /* SETPWCTR5: Set Power Control 5(B5h)
80 This command is used to set VCOM Low and VCOM High Voltage */
81 /* VCOMH 0110101 : 3.925 */
82 /* VCOML 0100000 : -1.700 */
83 /* 45h=69 VCOMH: "VMH" + 5d VCOML: "VMH" + 5d */
84 write_reg(par, 0xB5, 0x35, 0x20, 0x45);
86 /* SETPWCTR4: Set Power Control 4(B4h)
87 VRH[4:0]: Specify the VREG1 voltage adjusting.
88 VREG1 voltage is for gamma voltage setting.
89 BT[2:0]: Switch the output factor of step-up circuit 2
90 for VGH and VGL voltage generation. */
91 write_reg(par, 0xB4, 0x33, 0x25, 0x4C);
94 /* Interface Pixel Format (3Ah)
95 This command is used to define the format of RGB picture data,
96 which is to be transfer via the system and RGB interface. */
97 /* RGB interface: 16 Bit/Pixel */
98 write_reg(par, 0x3A, 0x05);
101 This command is used to recover from DISPLAY OFF mode.
102 Output from the Frame Memory is enabled. */
103 write_reg(par, 0x29);
109 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
111 write_reg(par, FBTFT_CASET, 0x00, xs, 0x00, xe);
112 write_reg(par, FBTFT_RASET, 0x00, ys, 0x00, ye);
113 write_reg(par, FBTFT_RAMWR);
116 static int set_var(struct fbtft_par *par)
118 /* MADCTL - Memory data access control */
119 /* RGB/BGR can be set with H/W pin SRGB and MADCTL BGR bit */
123 switch (par->info->var.rotate) {
125 write_reg(par, 0x36, par->bgr << 3);
128 write_reg(par, 0x36, MX | MV | (par->bgr << 3));
131 write_reg(par, 0x36, MX | MY | (par->bgr << 3));
134 write_reg(par, 0x36, MY | MV | (par->bgr << 3));
142 Gamma Curve selection, GC (only GC0 can be customized):
143 0 = 2.2, 1 = 1.8, 2 = 2.5, 3 = 1.0
145 OP0 OP1 CP0 CP1 CP2 CP3 CP4 MP0 MP1 MP2 MP3 MP4 MP5 CGM0 CGM1
146 ON0 ON1 CN0 CN1 CN2 CN3 CN4 MN0 MN1 MN2 MN3 MN4 MN5 XXXX GC
148 #define CURVE(num, idx) curves[num*par->gamma.num_values + idx]
149 static int set_gamma(struct fbtft_par *par, unsigned long *curves)
151 unsigned long mask[] = {
152 0x0f, 0x0f, 0x1f, 0x0f, 0x0f, 0x0f, 0x1f, 0x07, 0x07, 0x07,
153 0x07, 0x07, 0x07, 0x03, 0x03, 0x0f, 0x0f, 0x1f, 0x0f, 0x0f,
154 0x0f, 0x1f, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x00, 0x00,
159 for (i = 0; i < par->gamma.num_curves; i++)
160 for (j = 0; j < par->gamma.num_values; j++)
161 CURVE(i, j) &= mask[i * par->gamma.num_values + j];
163 write_reg(par, 0x26, 1 << CURVE(1, 14)); /* Gamma Set (26h) */
166 return 0; /* only GC0 can be customized */
169 (CURVE(0, 8) << 4) | CURVE(0, 7),
170 (CURVE(0, 10) << 4) | CURVE(0, 9),
171 (CURVE(0, 12) << 4) | CURVE(0, 11),
173 (CURVE(0, 4) << 4) | CURVE(0, 3),
176 (CURVE(0, 1) << 4) | CURVE(0, 0),
177 (CURVE(0, 14) << 2) | CURVE(0, 13));
180 (CURVE(1, 8) << 4) | CURVE(1, 7),
181 (CURVE(1, 10) << 4) | CURVE(1, 9),
182 (CURVE(1, 12) << 4) | CURVE(1, 11),
184 (CURVE(1, 4) << 4) | CURVE(1, 3),
187 (CURVE(1, 1) << 4) | CURVE(1, 0));
196 static struct fbtft_display display = {
200 .txbuflen = TXBUFLEN,
203 .gamma = DEFAULT_GAMMA,
205 .init_display = init_display,
206 .set_addr_win = set_addr_win,
208 .set_gamma = set_gamma,
211 FBTFT_REGISTER_DRIVER(DRVNAME, "himax,hx8340bn", &display);
213 MODULE_ALIAS("spi:" DRVNAME);
214 MODULE_ALIAS("platform:" DRVNAME);
215 MODULE_ALIAS("spi:hx8340bn");
216 MODULE_ALIAS("platform:hx8340bn");
218 MODULE_DESCRIPTION("FB driver for the HX8340BN LCD Controller");
219 MODULE_AUTHOR("Noralf Tronnes");
220 MODULE_LICENSE("GPL");