Input: goodix-berlin - add SPI support for Goodix Berlin Touchscreen IC

Add initial support for the new Goodix "Berlin" touchscreen ICs
over the SPI interface.

The driver doesn't use the regmap_spi code since the SPI messages
needs to be prefixed, thus this custom regmap code.

This initial driver is derived from the Goodix goodix_ts_berlin
available at [1] and [2] and only supports the GT9916 IC
present on the Qualcomm SM8550 MTP & QRD touch panel.

The current implementation only supports BerlinD, aka GT9916.

[1] https://github.com/goodix/goodix_ts_berlin
[2] https://git.codelinaro.org/clo/la/platform/vendor/opensource/touch-drivers

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240129-topic-goodix-berlin-upstream-initial-v15-4-6f7d096c0a0a@linaro.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index cc7b8811815863aaa99d6a1e7a213030f1b46f8e..c821fe3ee794e3db7a68a44dec3c23747b8ba5f6 100644 (file)
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -433,6 +433,20 @@ config TOUCHSCREEN_GOODIX_BERLIN_I2C
          To compile this driver as a module, choose M here: the
          module will be called goodix_berlin_i2c.
 
+config TOUCHSCREEN_GOODIX_BERLIN_SPI
+       tristate "Goodix Berlin SPI touchscreen"
+       depends on SPI_MASTER
+       select REGMAP
+       select TOUCHSCREEN_GOODIX_BERLIN_CORE
+       help
+         Say Y here if you have a Goodix Berlin IC connected to
+         your system via SPI.
+
+         If unsure, say N.
+
+         To compile this driver as a module, choose M here: the
+         module will be called goodix_berlin_spi.
+
 config TOUCHSCREEN_HIDEEP
        tristate "HiDeep Touch IC"
        depends on I2C

diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 7ef677cf7a1048afdc9135c84019fa2b226a30a8..a81cb5aa21a5b931b8bb91bfaab27241e9967a77 100644 (file)
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_TOUCHSCREEN_FUJITSU)     += fujitsu_ts.o
 obj-$(CONFIG_TOUCHSCREEN_GOODIX)       += goodix_ts.o
 obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_CORE)   += goodix_berlin_core.o
 obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_I2C)    += goodix_berlin_i2c.o
+obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_SPI)    += goodix_berlin_spi.o
 obj-$(CONFIG_TOUCHSCREEN_HIDEEP)       += hideep.o
 obj-$(CONFIG_TOUCHSCREEN_HYNITRON_CSTXXX)      += hynitron_cstxxx.o
 obj-$(CONFIG_TOUCHSCREEN_ILI210X)      += ili210x.o

diff --git a/drivers/input/touchscreen/goodix_berlin_spi.c b/drivers/input/touchscreen/goodix_berlin_spi.c
new file mode 100644 (file)
index 0000000..4cc557d
--- /dev/null
+++ b/drivers/input/touchscreen/goodix_berlin_spi.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Goodix Berlin Touchscreen Driver
+ *
+ * Copyright (C) 2020 - 2021 Goodix, Inc.
+ * Copyright (C) 2023 Linaro Ltd.
+ *
+ * Based on goodix_ts_berlin driver.
+ */
+#include <asm/unaligned.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/input.h>
+
+#include "goodix_berlin.h"
+
+#define GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN     1
+#define GOODIX_BERLIN_REGISTER_WIDTH           4
+#define GOODIX_BERLIN_SPI_READ_DUMMY_LEN       3
+#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN      (GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
+                                                GOODIX_BERLIN_REGISTER_WIDTH + \
+                                                GOODIX_BERLIN_SPI_READ_DUMMY_LEN)
+#define GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN     (GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
+                                                GOODIX_BERLIN_REGISTER_WIDTH)
+
+#define GOODIX_BERLIN_SPI_WRITE_FLAG           0xF0
+#define GOODIX_BERLIN_SPI_READ_FLAG            0xF1
+
+static int goodix_berlin_spi_read(void *context, const void *reg_buf,
+                                 size_t reg_size, void *val_buf,
+                                 size_t val_size)
+{
+       struct spi_device *spi = context;
+       struct spi_transfer xfers;
+       struct spi_message spi_msg;
+       const u32 *reg = reg_buf; /* reg is stored as native u32 at start of buffer */
+       u8 *buf;
+       int error;
+
+       if (reg_size != GOODIX_BERLIN_REGISTER_WIDTH)
+               return -EINVAL;
+
+       buf = kzalloc(GOODIX_BERLIN_SPI_READ_PREFIX_LEN + val_size, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+
+       spi_message_init(&spi_msg);
+       memset(&xfers, 0, sizeof(xfers));
+
+       /* buffer format: 0xF1 + addr(4bytes) + dummy(3bytes) + data */
+       buf[0] = GOODIX_BERLIN_SPI_READ_FLAG;
+       put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
+       memset(buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + GOODIX_BERLIN_REGISTER_WIDTH,
+              0xff, GOODIX_BERLIN_SPI_READ_DUMMY_LEN);
+
+       xfers.tx_buf = buf;
+       xfers.rx_buf = buf;
+       xfers.len = GOODIX_BERLIN_SPI_READ_PREFIX_LEN + val_size;
+       xfers.cs_change = 0;
+       spi_message_add_tail(&xfers, &spi_msg);
+
+       error = spi_sync(spi, &spi_msg);
+       if (error < 0)
+               dev_err(&spi->dev, "spi transfer error, %d", error);
+       else
+               memcpy(val_buf, buf + GOODIX_BERLIN_SPI_READ_PREFIX_LEN, val_size);
+
+       kfree(buf);
+       return error;
+}
+
+static int goodix_berlin_spi_write(void *context, const void *data,
+                                  size_t count)
+{
+       unsigned int len = count - GOODIX_BERLIN_REGISTER_WIDTH;
+       struct spi_device *spi = context;
+       struct spi_transfer xfers;
+       struct spi_message spi_msg;
+       const u32 *reg = data; /* reg is stored as native u32 at start of buffer */
+       u8 *buf;
+       int error;
+
+       buf = kzalloc(GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+
+       spi_message_init(&spi_msg);
+       memset(&xfers, 0, sizeof(xfers));
+
+       buf[0] = GOODIX_BERLIN_SPI_WRITE_FLAG;
+       put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
+       memcpy(buf + GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN,
+              data + GOODIX_BERLIN_REGISTER_WIDTH, len);
+
+       xfers.tx_buf = buf;
+       xfers.len = GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len;
+       xfers.cs_change = 0;
+       spi_message_add_tail(&xfers, &spi_msg);
+
+       error = spi_sync(spi, &spi_msg);
+       if (error < 0)
+               dev_err(&spi->dev, "spi transfer error, %d", error);
+
+       kfree(buf);
+       return error;
+}
+
+static const struct regmap_config goodix_berlin_spi_regmap_conf = {
+       .reg_bits = 32,
+       .val_bits = 8,
+       .read = goodix_berlin_spi_read,
+       .write = goodix_berlin_spi_write,
+};
+
+/* vendor & product left unassigned here, should probably be updated from fw info */
+static const struct input_id goodix_berlin_spi_input_id = {
+       .bustype = BUS_SPI,
+};
+
+static int goodix_berlin_spi_probe(struct spi_device *spi)
+{
+       struct regmap_config regmap_config;
+       struct regmap *regmap;
+       size_t max_size;
+       int error = 0;
+
+       spi->mode = SPI_MODE_0;
+       spi->bits_per_word = 8;
+       error = spi_setup(spi);
+       if (error)
+               return error;
+
+       max_size = spi_max_transfer_size(spi);
+
+       regmap_config = goodix_berlin_spi_regmap_conf;
+       regmap_config.max_raw_read = max_size - GOODIX_BERLIN_SPI_READ_PREFIX_LEN;
+       regmap_config.max_raw_write = max_size - GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN;
+
+       regmap = devm_regmap_init(&spi->dev, NULL, spi, &regmap_config);
+       if (IS_ERR(regmap))
+               return PTR_ERR(regmap);
+
+       error = goodix_berlin_probe(&spi->dev, spi->irq,
+                                   &goodix_berlin_spi_input_id, regmap);
+       if (error)
+               return error;
+
+       return 0;
+}
+
+static const struct spi_device_id goodix_berlin_spi_ids[] = {
+       { "gt9916" },
+       { },
+};
+MODULE_DEVICE_TABLE(spi, goodix_berlin_spi_ids);
+
+static const struct of_device_id goodix_berlin_spi_of_match[] = {
+       { .compatible = "goodix,gt9916", },
+       { }
+};
+MODULE_DEVICE_TABLE(of, goodix_berlin_spi_of_match);
+
+static struct spi_driver goodix_berlin_spi_driver = {
+       .driver = {
+               .name = "goodix-berlin-spi",
+               .of_match_table = goodix_berlin_spi_of_match,
+               .pm = pm_sleep_ptr(&goodix_berlin_pm_ops),
+       },
+       .probe = goodix_berlin_spi_probe,
+       .id_table = goodix_berlin_spi_ids,
+};
+module_spi_driver(goodix_berlin_spi_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Goodix Berlin SPI Touchscreen driver");
+MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");