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Subject[PATCH] staging: panel: change struct bits to a bit array
Date
From: isaky <illeida@openaliasbox.org>

This path implements a bit array representing the LCD signal states instead of the old "struct bits", which used char to represent a single bit. This will reduce the memory usage.

Signed-off-by: Isaac Lleida <illeida@openaliasbox.org>
---
drivers/staging/panel/panel.c | 86 ++++++++++++++++++++++++-------------------
1 file changed, 49 insertions(+), 37 deletions(-)

diff --git a/drivers/staging/panel/panel.c b/drivers/staging/panel/panel.c
index 3339633..7deb092 100644
--- a/drivers/staging/panel/panel.c
+++ b/drivers/staging/panel/panel.c
@@ -310,6 +310,25 @@ static int selected_lcd_type = NOT_SET;
#define LCD_BITS 6

/*
+ * LCD signal states
+ */
+#define LCD_BIT_E_MASK 0x1 /* E (data latch on falling edge) */
+#define LCD_BIT_RS_MASK 0x2 /* RS (0 = cmd, 1 = data) */
+#define LCD_BIT_RW_MASK 0x4 /* R/W (0 = W, 1 = R) */
+#define LCD_BIT_BL_MASK 0x8 /* backlight (0 = off, 1 = on) */
+#define LCD_BIT_CL_MASK 0x10 /* clock (latch on rising edge) */
+#define LCD_BIT_DA_MASK 0x20 /* data */
+
+/*
+ * Bit array operations
+ */
+#define BIT_ON(b, m) (b |= m)
+#define BIT_OFF(b, m) (b &= ~m)
+#define BIT_CHK(b, m) (b & m)
+#define BIT_MOD(b, m, v) \
+ ((v) ? BIT_ON(b, m) : BIT_OFF(b, m)) \
+
+/*
* each bit can be either connected to a DATA or CTRL port
*/
#define LCD_PORT_C 0
@@ -653,15 +672,8 @@ static const char nexcom_keypad_profile[][4][9] = {

static const char (*keypad_profile)[4][9] = old_keypad_profile;

-/* FIXME: this should be converted to a bit array containing signals states */
-static struct {
- unsigned char e; /* parallel LCD E (data latch on falling edge) */
- unsigned char rs; /* parallel LCD RS (0 = cmd, 1 = data) */
- unsigned char rw; /* parallel LCD R/W (0 = W, 1 = R) */
- unsigned char bl; /* parallel LCD backlight (0 = off, 1 = on) */
- unsigned char cl; /* serial LCD clock (latch on rising edge) */
- unsigned char da; /* serial LCD data */
-} bits;
+/* Bit array containing signals states */
+static char bits;

static void init_scan_timer(void);

@@ -674,12 +686,12 @@ static int set_data_bits(void)
for (bit = 0; bit < LCD_BITS; bit++)
val &= lcd_bits[LCD_PORT_D][bit][BIT_MSK];

- val |= lcd_bits[LCD_PORT_D][LCD_BIT_E][bits.e]
- | lcd_bits[LCD_PORT_D][LCD_BIT_RS][bits.rs]
- | lcd_bits[LCD_PORT_D][LCD_BIT_RW][bits.rw]
- | lcd_bits[LCD_PORT_D][LCD_BIT_BL][bits.bl]
- | lcd_bits[LCD_PORT_D][LCD_BIT_CL][bits.cl]
- | lcd_bits[LCD_PORT_D][LCD_BIT_DA][bits.da];
+ val |= lcd_bits[LCD_PORT_D][LCD_BIT_E][BIT_CHK(bits, LCD_BIT_E_MASK)]
+ | lcd_bits[LCD_PORT_D][LCD_BIT_RS][BIT_CHK(bits, LCD_BIT_RS_MASK)]
+ | lcd_bits[LCD_PORT_D][LCD_BIT_RW][BIT_CHK(bits, LCD_BIT_RW_MASK)]
+ | lcd_bits[LCD_PORT_D][LCD_BIT_BL][BIT_CHK(bits, LCD_BIT_BL_MASK)]
+ | lcd_bits[LCD_PORT_D][LCD_BIT_CL][BIT_CHK(bits, LCD_BIT_CL_MASK)]
+ | lcd_bits[LCD_PORT_D][LCD_BIT_DA][BIT_CHK(bits, LCD_BIT_DA_MASK)];

w_dtr(pprt, val);
return val;
@@ -694,12 +706,12 @@ static int set_ctrl_bits(void)
for (bit = 0; bit < LCD_BITS; bit++)
val &= lcd_bits[LCD_PORT_C][bit][BIT_MSK];

- val |= lcd_bits[LCD_PORT_C][LCD_BIT_E][bits.e]
- | lcd_bits[LCD_PORT_C][LCD_BIT_RS][bits.rs]
- | lcd_bits[LCD_PORT_C][LCD_BIT_RW][bits.rw]
- | lcd_bits[LCD_PORT_C][LCD_BIT_BL][bits.bl]
- | lcd_bits[LCD_PORT_C][LCD_BIT_CL][bits.cl]
- | lcd_bits[LCD_PORT_C][LCD_BIT_DA][bits.da];
+ val |= lcd_bits[LCD_PORT_C][LCD_BIT_E][BIT_CHK(bits, LCD_BIT_E_MASK)]
+ | lcd_bits[LCD_PORT_C][LCD_BIT_RS][BIT_CHK(bits, LCD_BIT_RS_MASK)]
+ | lcd_bits[LCD_PORT_C][LCD_BIT_RW][BIT_CHK(bits, LCD_BIT_RW_MASK)]
+ | lcd_bits[LCD_PORT_C][LCD_BIT_BL][BIT_CHK(bits, LCD_BIT_BL_MASK)]
+ | lcd_bits[LCD_PORT_C][LCD_BIT_CL][BIT_CHK(bits, LCD_BIT_BL_MASK)]
+ | lcd_bits[LCD_PORT_C][LCD_BIT_DA][BIT_CHK(bits, LCD_BIT_DA_MASK)];

w_ctr(pprt, val);
return val;
@@ -794,12 +806,12 @@ static void lcd_send_serial(int byte)
/* the data bit is set on D0, and the clock on STROBE.
* LCD reads D0 on STROBE's rising edge. */
for (bit = 0; bit < 8; bit++) {
- bits.cl = BIT_CLR; /* CLK low */
+ BIT_OFF(bits, LCD_BIT_CL_MASK); /* CLK low */
panel_set_bits();
- bits.da = byte & 1;
+ BIT_MOD(bits, LCD_BIT_DA_MASK, byte & 1);
panel_set_bits();
udelay(2); /* maintain the data during 2 us before CLK up */
- bits.cl = BIT_SET; /* CLK high */
+ BIT_ON(bits, LCD_BIT_CL_MASK); /* CLK high */
panel_set_bits();
udelay(1); /* maintain the strobe during 1 us */
byte >>= 1;
@@ -814,7 +826,7 @@ static void lcd_backlight(int on)

/* The backlight is activated by setting the AUTOFEED line to +5V */
spin_lock_irq(&pprt_lock);
- bits.bl = on;
+ BIT_MOD(bits, LCD_BIT_BL_MASK, on);
panel_set_bits();
spin_unlock_irq(&pprt_lock);
}
@@ -849,14 +861,14 @@ static void lcd_write_cmd_p8(int cmd)
w_dtr(pprt, cmd);
udelay(20); /* maintain the data during 20 us before the strobe */

- bits.e = BIT_SET;
- bits.rs = BIT_CLR;
- bits.rw = BIT_CLR;
+ BIT_ON(bits, LCD_BIT_E_MASK);
+ BIT_OFF(bits, LCD_BIT_RS_MASK);
+ BIT_OFF(bits, LCD_BIT_RW_MASK);
set_ctrl_bits();

udelay(40); /* maintain the strobe during 40 us */

- bits.e = BIT_CLR;
+ BIT_OFF(bits, LCD_BIT_E_MASK);
set_ctrl_bits();

udelay(120); /* the shortest command takes at least 120 us */
@@ -871,14 +883,14 @@ static void lcd_write_data_p8(int data)
w_dtr(pprt, data);
udelay(20); /* maintain the data during 20 us before the strobe */

- bits.e = BIT_SET;
- bits.rs = BIT_SET;
- bits.rw = BIT_CLR;
+ BIT_ON(bits, LCD_BIT_E_MASK);
+ BIT_OFF(bits, LCD_BIT_RS_MASK);
+ BIT_OFF(bits, LCD_BIT_RW_MASK);
set_ctrl_bits();

udelay(40); /* maintain the strobe during 40 us */

- bits.e = BIT_CLR;
+ BIT_OFF(bits, LCD_BIT_E_MASK);
set_ctrl_bits();

udelay(45); /* the shortest data takes at least 45 us */
@@ -968,15 +980,15 @@ static void lcd_clear_fast_p8(void)
/* maintain the data during 20 us before the strobe */
udelay(20);

- bits.e = BIT_SET;
- bits.rs = BIT_SET;
- bits.rw = BIT_CLR;
+ BIT_ON(bits, LCD_BIT_E_MASK);
+ BIT_OFF(bits, LCD_BIT_RS_MASK);
+ BIT_OFF(bits, LCD_BIT_RW_MASK);
set_ctrl_bits();

/* maintain the strobe during 40 us */
udelay(40);

- bits.e = BIT_CLR;
+ BIT_OFF(bits, LCD_BIT_E_MASK);
set_ctrl_bits();

/* the shortest data takes at least 45 us */
--
2.3.2


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