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  */
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  */
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  */
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