1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * clk-synthesizer.c
4 *
5 * Clock synthesizer apis
6 *
7 * Copyright (C) 2016, Texas Instruments, Incorporated - http://www.ti.com/
8 */
9
10
11 #include <common.h>
12 #include <asm/arch/clk_synthesizer.h>
13 #include <i2c.h>
14
15 /**
16 * clk_synthesizer_reg_read - Read register from synthesizer.
17 * @addr: addr within the i2c device
18 * buf: Buffer to which value is to be read.
19 *
20 * For reading the register from this clock synthesizer, a command needs to
21 * be send along with enabling byte read more, and then read can happen.
22 * Returns 0 on success
23 */
clk_synthesizer_reg_read(int addr,uint8_t * buf)24 static int clk_synthesizer_reg_read(int addr, uint8_t *buf)
25 {
26 int rc;
27
28 /* Enable Bye read */
29 addr = addr | CLK_SYNTHESIZER_BYTE_MODE;
30
31 /* Send the command byte */
32 rc = i2c_write(CLK_SYNTHESIZER_I2C_ADDR, addr, 1, buf, 1);
33 if (rc)
34 printf("Failed to send command to clock synthesizer\n");
35
36 /* Read the Data */
37 return i2c_read(CLK_SYNTHESIZER_I2C_ADDR, addr, 1, buf, 1);
38 }
39
40 /**
41 * clk_synthesizer_reg_write - Write a value to register in synthesizer.
42 * @addr: addr within the i2c device
43 * val: Value to be written in the addr.
44 *
45 * Enable the byte read mode in the address and start the i2c transfer.
46 * Returns 0 on success
47 */
clk_synthesizer_reg_write(int addr,uint8_t val)48 static int clk_synthesizer_reg_write(int addr, uint8_t val)
49 {
50 uint8_t cmd[2];
51 int rc = 0;
52
53 /* Enable byte write */
54 cmd[0] = addr | CLK_SYNTHESIZER_BYTE_MODE;
55 cmd[1] = val;
56
57 rc = i2c_write(CLK_SYNTHESIZER_I2C_ADDR, addr, 1, cmd, 2);
58 if (rc)
59 printf("Clock synthesizer reg write failed at addr = 0x%x\n",
60 addr);
61 return rc;
62 }
63
64 /**
65 * setup_clock_syntherizer - Program the clock synthesizer to get the desired
66 * frequency.
67 * @data: Data containing the desired output
68 *
69 * This is a PLL-based high performance synthesizer which gives 3 outputs
70 * as per the PLL_DIV and load capacitor programmed.
71 */
setup_clock_synthesizer(struct clk_synth * data)72 int setup_clock_synthesizer(struct clk_synth *data)
73 {
74 int rc;
75 uint8_t val;
76
77 rc = i2c_probe(CLK_SYNTHESIZER_I2C_ADDR);
78 if (rc) {
79 printf("i2c probe failed at address 0x%x\n",
80 CLK_SYNTHESIZER_I2C_ADDR);
81 return rc;
82 }
83
84 rc = clk_synthesizer_reg_read(CLK_SYNTHESIZER_ID_REG, &val);
85 if (val != data->id)
86 return rc;
87
88 /* Crystal Load capacitor selection */
89 rc = clk_synthesizer_reg_write(CLK_SYNTHESIZER_XCSEL, data->capacitor);
90 if (rc)
91 return rc;
92 rc = clk_synthesizer_reg_write(CLK_SYNTHESIZER_MUX_REG, data->mux);
93 if (rc)
94 return rc;
95 rc = clk_synthesizer_reg_write(CLK_SYNTHESIZER_PDIV2_REG, data->pdiv2);
96 if (rc)
97 return rc;
98 rc = clk_synthesizer_reg_write(CLK_SYNTHESIZER_PDIV3_REG, data->pdiv3);
99 if (rc)
100 return rc;
101
102 return 0;
103 }
104