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![Andy Shevchenko](/assets/img/avatar_default.png)
The infamous commitc440eee1a7
("Staging: staging: fbtft: Switch to the GPIO descriptor interface") broke GPIO handling completely. It has already four commits to rectify and it seems not enough. In order to fix the mess here we: 1) Set default to "inactive" for all requested pins 2) Fix CS#, RD#, and WR# pins polarity since it's active low and GPIO descriptor interface takes it into consideration from the Device Tree or ACPI 3) Consolidate chip activation (CS# assertion) under default ->reset() callback To summarize the expectations about polarity for GPIOs: RD# Low WR# Low CS# Low RESET# Low DC or RS High RW High Data 0 .. 15 High See also Adafruit learning course [1] for the example of the schematics. While at it, drop unneeded NULL checks, since GPIO API is tolerant to that. [1]: https://learn.adafruit.com/adafruit-2-8-and-3-2-color-tft-touchscreen-breakout-v2/downloads Fixes:92e3e88488
("Staging: fbtft: Fix GPIO handling") Fixes:b918d1c270
("Staging: fbtft: Fix reset assertion when using gpio descriptor") Fixes:dbc4f989c8
("Staging: fbtft: Fix probing of gpio descriptor") Fixes:c440eee1a7
("Staging: fbtft: Switch to the gpio descriptor interface") Cc: Jan Sebastian Götte <linux@jaseg.net> Cc: Nishad Kamdar <nishadkamdar@gmail.com> Reviewed-by: Phil Reid <preid@electromag.com.au> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20210503172114.27891-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
204 lines
5.5 KiB
C
204 lines
5.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/gpio/consumer.h>
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#include <linux/spi/spi.h>
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#include <linux/delay.h>
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#include "fbtft.h"
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#define DRVNAME "fb_ssd1331"
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#define WIDTH 96
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#define HEIGHT 64
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#define GAMMA_NUM 1
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#define GAMMA_LEN 63
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#define DEFAULT_GAMMA "0 2 2 2 2 2 2 2 " \
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"2 2 2 2 2 2 2 2 " \
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"2 2 2 2 2 2 2 2 " \
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"2 2 2 2 2 2 2 2 " \
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"2 2 2 2 2 2 2 2 " \
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"2 2 2 2 2 2 2 2 " \
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"2 2 2 2 2 2 2 2 " \
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"2 2 2 2 2 2 2" \
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static int init_display(struct fbtft_par *par)
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{
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par->fbtftops.reset(par);
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write_reg(par, 0xae); /* Display Off */
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/* Set Column Address Mapping, COM Scan Direction and Colour Depth */
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if (par->info->var.rotate == 180)
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write_reg(par, 0xa0, 0x60 | (par->bgr << 2));
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else
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write_reg(par, 0xa0, 0x72 | (par->bgr << 2));
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write_reg(par, 0x72); /* RGB colour */
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write_reg(par, 0xa1, 0x00); /* Set Display Start Line */
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write_reg(par, 0xa2, 0x00); /* Set Display Offset */
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write_reg(par, 0xa4); /* NORMALDISPLAY */
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write_reg(par, 0xa8, 0x3f); /* Set multiplex */
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write_reg(par, 0xad, 0x8e); /* Set master */
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/* write_reg(par, 0xb0, 0x0b); Set power mode */
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write_reg(par, 0xb1, 0x31); /* Precharge */
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write_reg(par, 0xb3, 0xf0); /* Clock div */
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write_reg(par, 0x8a, 0x64); /* Precharge A */
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write_reg(par, 0x8b, 0x78); /* Precharge B */
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write_reg(par, 0x8c, 0x64); /* Precharge C */
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write_reg(par, 0xbb, 0x3a); /* Precharge level */
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write_reg(par, 0xbe, 0x3e); /* vcomh */
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write_reg(par, 0x87, 0x06); /* Master current */
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write_reg(par, 0x81, 0x91); /* Contrast A */
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write_reg(par, 0x82, 0x50); /* Contrast B */
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write_reg(par, 0x83, 0x7d); /* Contrast C */
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write_reg(par, 0xaf); /* Set Sleep Mode Display On */
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return 0;
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}
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static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
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{
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write_reg(par, 0x15, xs, xe);
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write_reg(par, 0x75, ys, ye);
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}
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static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
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{
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va_list args;
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int i, ret;
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u8 *buf = par->buf;
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if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {
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va_start(args, len);
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for (i = 0; i < len; i++)
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buf[i] = (u8)va_arg(args, unsigned int);
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va_end(args);
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fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par, par->info->device,
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u8, buf, len, "%s: ", __func__);
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}
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va_start(args, len);
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*buf = (u8)va_arg(args, unsigned int);
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gpiod_set_value(par->gpio.dc, 0);
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ret = par->fbtftops.write(par, par->buf, sizeof(u8));
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if (ret < 0) {
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va_end(args);
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dev_err(par->info->device,
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"write() failed and returned %d\n", ret);
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return;
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}
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len--;
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if (len) {
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i = len;
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while (i--)
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*buf++ = (u8)va_arg(args, unsigned int);
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ret = par->fbtftops.write(par, par->buf, len * (sizeof(u8)));
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if (ret < 0) {
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va_end(args);
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dev_err(par->info->device,
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"write() failed and returned %d\n", ret);
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return;
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}
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}
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gpiod_set_value(par->gpio.dc, 1);
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va_end(args);
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}
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/*
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* Grayscale Lookup Table
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* GS1 - GS63
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* The driver Gamma curve contains the relative values between the entries
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* in the Lookup table.
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*
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* From datasheet:
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* 8.8 Gray Scale Decoder
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*
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* there are total 180 Gamma Settings (Setting 0 to Setting 180)
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* available for the Gray Scale table.
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*
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* The gray scale is defined in incremental way, with reference
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* to the length of previous table entry:
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* Setting of GS1 has to be >= 0
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* Setting of GS2 has to be > Setting of GS1 +1
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* Setting of GS3 has to be > Setting of GS2 +1
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* :
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* Setting of GS63 has to be > Setting of GS62 +1
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*
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*/
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static int set_gamma(struct fbtft_par *par, u32 *curves)
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{
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unsigned long tmp[GAMMA_NUM * GAMMA_LEN];
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int i, acc = 0;
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for (i = 0; i < 63; i++) {
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if (i > 0 && curves[i] < 2) {
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dev_err(par->info->device,
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"Illegal value in Grayscale Lookup Table at index %d. Must be greater than 1\n",
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i);
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return -EINVAL;
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}
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acc += curves[i];
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tmp[i] = acc;
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if (acc > 180) {
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dev_err(par->info->device,
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"Illegal value(s) in Grayscale Lookup Table. At index=%d, the accumulated value has exceeded 180\n",
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i);
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return -EINVAL;
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}
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}
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write_reg(par, 0xB8,
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tmp[0], tmp[1], tmp[2], tmp[3], tmp[4], tmp[5], tmp[6],
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tmp[7], tmp[8], tmp[9], tmp[10], tmp[11], tmp[12], tmp[13],
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tmp[14], tmp[15], tmp[16], tmp[17], tmp[18], tmp[19], tmp[20],
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tmp[21], tmp[22], tmp[23], tmp[24], tmp[25], tmp[26], tmp[27],
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tmp[28], tmp[29], tmp[30], tmp[31], tmp[32], tmp[33], tmp[34],
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tmp[35], tmp[36], tmp[37], tmp[38], tmp[39], tmp[40], tmp[41],
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tmp[42], tmp[43], tmp[44], tmp[45], tmp[46], tmp[47], tmp[48],
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tmp[49], tmp[50], tmp[51], tmp[52], tmp[53], tmp[54], tmp[55],
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tmp[56], tmp[57], tmp[58], tmp[59], tmp[60], tmp[61],
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tmp[62]);
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return 0;
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}
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static int blank(struct fbtft_par *par, bool on)
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{
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fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n",
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__func__, on ? "true" : "false");
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if (on)
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write_reg(par, 0xAE);
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else
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write_reg(par, 0xAF);
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return 0;
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}
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static struct fbtft_display display = {
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.regwidth = 8,
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.width = WIDTH,
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.height = HEIGHT,
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.gamma_num = GAMMA_NUM,
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.gamma_len = GAMMA_LEN,
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.gamma = DEFAULT_GAMMA,
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.fbtftops = {
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.write_register = write_reg8_bus8,
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.init_display = init_display,
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.set_addr_win = set_addr_win,
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.set_gamma = set_gamma,
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.blank = blank,
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},
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};
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FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1331", &display);
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MODULE_ALIAS("spi:" DRVNAME);
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MODULE_ALIAS("platform:" DRVNAME);
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MODULE_ALIAS("spi:ssd1331");
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MODULE_ALIAS("platform:ssd1331");
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MODULE_DESCRIPTION("SSD1331 OLED Driver");
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MODULE_AUTHOR("Alec Smecher (adapted from SSD1351 by James Davies)");
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MODULE_LICENSE("GPL");
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