2 * Atmel AT93C46 serial eeprom driver
4 * Brian Murphy <brian.murphy@eicon.com>
7 #include <linux/kernel.h>
8 #include <linux/delay.h>
9 #include <asm/lasat/lasat.h>
13 #define AT93C_ADDR_SHIFT 7
14 #define AT93C_ADDR_MAX ((1 << AT93C_ADDR_SHIFT) - 1)
15 #define AT93C_RCMD (0x6 << AT93C_ADDR_SHIFT)
16 #define AT93C_WCMD (0x5 << AT93C_ADDR_SHIFT)
17 #define AT93C_WENCMD 0x260
18 #define AT93C_WDSCMD 0x200
20 struct at93c_defs *at93c;
22 static void at93c_reg_write(u32 val)
27 static u32 at93c_reg_read(void)
29 u32 tmp = *at93c->reg;
33 static u32 at93c_datareg_read(void)
35 u32 tmp = *at93c->rdata_reg;
39 static void at93c_cycle_clk(u32 data)
41 at93c_reg_write(data | at93c->clk);
43 at93c_reg_write(data & ~at93c->clk);
47 static void at93c_write_databit(u8 bit)
49 u32 data = at93c_reg_read();
51 data |= 1 << at93c->wdata_shift;
53 data &= ~(1 << at93c->wdata_shift);
55 at93c_reg_write(data);
57 at93c_cycle_clk(data);
60 static unsigned int at93c_read_databit(void)
64 at93c_cycle_clk(at93c_reg_read());
65 data = (at93c_datareg_read() >> at93c->rdata_shift) & 1;
69 static u8 at93c_read_byte(void)
74 for (i = 0; i <= 7; i++) {
76 data |= at93c_read_databit();
81 static void at93c_write_bits(u32 data, int size)
85 u32 mask = (1 << shift);
87 for (i = 0; i < size; i++) {
88 at93c_write_databit((data & mask) >> shift);
93 static void at93c_init_op(void)
95 at93c_reg_write((at93c_reg_read() | at93c->cs) &
96 ~at93c->clk & ~(1 << at93c->rdata_shift));
100 static void at93c_end_op(void)
102 at93c_reg_write(at93c_reg_read() & ~at93c->cs);
106 static void at93c_wait(void)
109 while (!at93c_read_databit())
114 static void at93c_disable_wp(void)
117 at93c_write_bits(AT93C_WENCMD, 10);
121 static void at93c_enable_wp(void)
124 at93c_write_bits(AT93C_WDSCMD, 10);
128 u8 at93c_read(u8 addr)
132 at93c_write_bits((addr & AT93C_ADDR_MAX)|AT93C_RCMD, 10);
133 byte = at93c_read_byte();
138 void at93c_write(u8 addr, u8 data)
142 at93c_write_bits((addr & AT93C_ADDR_MAX)|AT93C_WCMD, 10);
143 at93c_write_bits(data, 8);