staging: fbtft: core support

This commit adds the core fbtft framework from
https://github.com/notro/fbtft.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Noralf Tronnes <notro@tronnes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/Kconfig

@@ -106,4 +106,6 @@ source "drivers/staging/unisys/Kconfig"
 
 source "drivers/staging/clocking-wizard/Kconfig"
 
+source "drivers/staging/fbtft/Kconfig"
+
 endif # STAGING

drivers/staging/Makefile

@@ -45,3 +45,4 @@ obj-$(CONFIG_GS_FPGABOOT)	+= gs_fpgaboot/
 obj-$(CONFIG_CRYPTO_SKEIN)	+= skein/
 obj-$(CONFIG_UNISYSSPAR)	+= unisys/
 obj-$(CONFIG_COMMON_CLK_XLNX_CLKWZRD)	+= clocking-wizard/
+obj-$(CONFIG_FB_TFT)		+= fbtft/

drivers/staging/fbtft/Kconfig

@@ -0,0 +1,9 @@
+menuconfig FB_TFT
+	tristate "Support for small TFT LCD display modules"
+	depends on FB && SPI && GPIOLIB
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA
+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_DEFERRED_IO
+	select FB_BACKLIGHT

drivers/staging/fbtft/Makefile

@@ -0,0 +1,3 @@
+# Core module
+obj-$(CONFIG_FB_TFT)             += fbtft.o
+fbtft-y                          += fbtft-core.o fbtft-sysfs.o fbtft-bus.o fbtft-io.o

drivers/staging/fbtft/README

@@ -0,0 +1,32 @@
+  FBTFT
+=========
+
+Linux Framebuffer drivers for small TFT LCD display modules.
+The module 'fbtft' makes writing drivers for some of these displays very easy.
+
+Development is done on a Raspberry Pi running the Raspbian "wheezy" distribution.
+
+INSTALLATION
+  Download kernel sources
+
+  From Linux 3.15  
+    cd drivers/video/fbdev/fbtft
+    git clone https://github.com/notro/fbtft.git
+
+    Add to drivers/video/fbdev/Kconfig:   source "drivers/video/fbdev/fbtft/Kconfig"
+    Add to drivers/video/fbdev/Makefile:  obj-y += fbtft/
+
+  Before Linux 3.15  
+    cd drivers/video
+    git clone https://github.com/notro/fbtft.git
+
+    Add to drivers/video/Kconfig:   source "drivers/video/fbtft/Kconfig"
+    Add to drivers/video/Makefile:  obj-y += fbtft/
+
+  Enable driver(s) in menuconfig and build the kernel
+
+
+See wiki for more information: https://github.com/notro/fbtft/wiki
+
+
+Source: https://github.com/notro/fbtft/

drivers/staging/fbtft/fbtft-bus.c

@@ -0,0 +1,256 @@
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/gpio.h>
+#include <linux/spi/spi.h>
+#include "fbtft.h"
+
+
+
+
+/*****************************************************************************
+ *
+ *   void (*write_reg)(struct fbtft_par *par, int len, ...);
+ *
+ *****************************************************************************/
+
+#define define_fbtft_write_reg(func, type, modifier)                          \
+void func(struct fbtft_par *par, int len, ...)                                \
+{                                                                             \
+	va_list args;                                                         \
+	int i, ret;                                                           \
+	int offset = 0;                                                       \
+	type *buf = (type *)par->buf;                                         \
+									      \
+	if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {                    \
+		va_start(args, len);                                          \
+		for (i = 0; i < len; i++) {                                   \
+			buf[i] = (type)va_arg(args, unsigned int);            \
+		}                                                             \
+		va_end(args);                                                 \
+		fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par, par->info->device, type, buf, len, "%s: ", __func__);   \
+	}                                                                     \
+									      \
+	va_start(args, len);                                                  \
+									      \
+	if (par->startbyte) {                                                 \
+		*(u8 *)par->buf = par->startbyte;                             \
+		buf = (type *)(par->buf + 1);                                 \
+		offset = 1;                                                   \
+	}                                                                     \
+									      \
+	*buf = modifier((type)va_arg(args, unsigned int));                    \
+	if (par->gpio.dc != -1)                                               \
+		gpio_set_value(par->gpio.dc, 0);                              \
+	ret = par->fbtftops.write(par, par->buf, sizeof(type)+offset);        \
+	if (ret < 0) {                                                        \
+		va_end(args);                                                 \
+		dev_err(par->info->device, "%s: write() failed and returned %d\n", __func__, ret); \
+		return;                                                       \
+	}                                                                     \
+	len--;                                                                \
+									      \
+	if (par->startbyte)                                                   \
+		*(u8 *)par->buf = par->startbyte | 0x2;                       \
+									      \
+	if (len) {                                                            \
+		i = len;                                                      \
+		while (i--) {                                                 \
+			*buf++ = modifier((type)va_arg(args, unsigned int));  \
+		}                                                             \
+		if (par->gpio.dc != -1)                                       \
+			gpio_set_value(par->gpio.dc, 1);                      \
+		ret = par->fbtftops.write(par, par->buf, len * (sizeof(type)+offset)); \
+		if (ret < 0) {                                                \
+			va_end(args);                                         \
+			dev_err(par->info->device, "%s: write() failed and returned %d\n", __func__, ret); \
+			return;                                               \
+		}                                                             \
+	}                                                                     \
+	va_end(args);                                                         \
+}                                                                             \
+EXPORT_SYMBOL(func);
+
+define_fbtft_write_reg(fbtft_write_reg8_bus8, u8, )
+define_fbtft_write_reg(fbtft_write_reg16_bus8, u16, cpu_to_be16)
+define_fbtft_write_reg(fbtft_write_reg16_bus16, u16, )
+
+void fbtft_write_reg8_bus9(struct fbtft_par *par, int len, ...)
+{
+	va_list args;
+	int i, ret;
+	int pad = 0;
+	u16 *buf = (u16 *)par->buf;
+
+	if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {
+		va_start(args, len);
+		for (i = 0; i < len; i++)
+			*(((u8 *)buf) + i) = (u8)va_arg(args, unsigned int);
+		va_end(args);
+		fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par,
+			par->info->device, u8, buf, len, "%s: ", __func__);
+	}
+	if (len <= 0)
+		return;
+
+	if (par->spi && (par->spi->bits_per_word == 8)) {
+		/* we're emulating 9-bit, pad start of buffer with no-ops
+		   (assuming here that zero is a no-op) */
+		pad = (len % 4) ? 4 - (len % 4) : 0;
+		for (i = 0; i < pad; i++)
+			*buf++ = 0x000;
+	}
+
+	va_start(args, len);
+	*buf++ = (u8)va_arg(args, unsigned int);
+	i = len - 1;
+	while (i--) {
+		*buf = (u8)va_arg(args, unsigned int);
+		*buf++ |= 0x100; /* dc=1 */
+	}
+	va_end(args);
+	ret = par->fbtftops.write(par, par->buf, (len + pad) * sizeof(u16));
+	if (ret < 0) {
+		dev_err(par->info->device,
+			"%s: write() failed and returned %d\n", __func__, ret);
+		return;
+	}
+}
+EXPORT_SYMBOL(fbtft_write_reg8_bus9);
+
+
+
+
+/*****************************************************************************
+ *
+ *   int (*write_vmem)(struct fbtft_par *par);
+ *
+ *****************************************************************************/
+
+/* 16 bit pixel over 8-bit databus */
+int fbtft_write_vmem16_bus8(struct fbtft_par *par, size_t offset, size_t len)
+{
+	u16 *vmem16;
+	u16 *txbuf16 = (u16 *)par->txbuf.buf;
+	size_t remain;
+	size_t to_copy;
+	size_t tx_array_size;
+	int i;
+	int ret = 0;
+	size_t startbyte_size = 0;
+
+	fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s(offset=%zu, len=%zu)\n",
+		__func__, offset, len);
+
+	remain = len / 2;
+	vmem16 = (u16 *)(par->info->screen_base + offset);
+
+	if (par->gpio.dc != -1)
+		gpio_set_value(par->gpio.dc, 1);
+
+	/* non buffered write */
+	if (!par->txbuf.buf)
+		return par->fbtftops.write(par, vmem16, len);
+
+	/* buffered write */
+	tx_array_size = par->txbuf.len / 2;
+
+	if (par->startbyte) {
+		txbuf16 = (u16 *)(par->txbuf.buf + 1);
+		tx_array_size -= 2;
+		*(u8 *)(par->txbuf.buf) = par->startbyte | 0x2;
+		startbyte_size = 1;
+	}
+
+	while (remain) {
+		to_copy = remain > tx_array_size ? tx_array_size : remain;
+		dev_dbg(par->info->device, "    to_copy=%zu, remain=%zu\n",
+						to_copy, remain - to_copy);
+
+		for (i = 0; i < to_copy; i++)
+			txbuf16[i] = cpu_to_be16(vmem16[i]);
+
+		vmem16 = vmem16 + to_copy;
+		ret = par->fbtftops.write(par, par->txbuf.buf,
+						startbyte_size + to_copy * 2);
+		if (ret < 0)
+			return ret;
+		remain -= to_copy;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(fbtft_write_vmem16_bus8);
+
+/* 16 bit pixel over 9-bit SPI bus: dc + high byte, dc + low byte */
+int fbtft_write_vmem16_bus9(struct fbtft_par *par, size_t offset, size_t len)
+{
+	u8 *vmem8;
+	u16 *txbuf16 = par->txbuf.buf;
+	size_t remain;
+	size_t to_copy;
+	size_t tx_array_size;
+	int i;
+	int ret = 0;
+
+	fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s(offset=%zu, len=%zu)\n",
+		__func__, offset, len);
+
+	if (!par->txbuf.buf) {
+		dev_err(par->info->device, "%s: txbuf.buf is NULL\n", __func__);
+		return -1;
+	}
+
+	remain = len;
+	vmem8 = par->info->screen_base + offset;
+
+	tx_array_size = par->txbuf.len / 2;
+
+	while (remain) {
+		to_copy = remain > tx_array_size ? tx_array_size : remain;
+		dev_dbg(par->info->device, "    to_copy=%zu, remain=%zu\n",
+						to_copy, remain - to_copy);
+
+#ifdef __LITTLE_ENDIAN
+		for (i = 0; i < to_copy; i += 2) {
+			txbuf16[i]   = 0x0100 | vmem8[i+1];
+			txbuf16[i+1] = 0x0100 | vmem8[i];
+		}
+#else
+		for (i = 0; i < to_copy; i++)
+			txbuf16[i]   = 0x0100 | vmem8[i];
+#endif
+		vmem8 = vmem8 + to_copy;
+		ret = par->fbtftops.write(par, par->txbuf.buf, to_copy*2);
+		if (ret < 0)
+			return ret;
+		remain -= to_copy;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(fbtft_write_vmem16_bus9);
+
+int fbtft_write_vmem8_bus8(struct fbtft_par *par, size_t offset, size_t len)
+{
+	dev_err(par->info->device, "%s: function not implemented\n", __func__);
+	return -1;
+}
+EXPORT_SYMBOL(fbtft_write_vmem8_bus8);
+
+/* 16 bit pixel over 16-bit databus */
+int fbtft_write_vmem16_bus16(struct fbtft_par *par, size_t offset, size_t len)
+{
+	u16 *vmem16;
+
+	fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s(offset=%zu, len=%zu)\n",
+		__func__, offset, len);
+
+	vmem16 = (u16 *)(par->info->screen_base + offset);
+
+	if (par->gpio.dc != -1)
+		gpio_set_value(par->gpio.dc, 1);
+
+	/* no need for buffered write with 16-bit bus */
+	return par->fbtftops.write(par, vmem16, len);
+}
+EXPORT_SYMBOL(fbtft_write_vmem16_bus16);