arch/arm/mach-omap2/am33xx/clk_synthesizer.c

   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 }