drivers/cpufreq/imx-cpufreq-dt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2019 NXP
   4  */
   5
   6 #include <linux/cpu.h>
   7 #include <linux/err.h>
   8 #include <linux/init.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/nvmem-consumer.h>
  12 #include <linux/of.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/pm_opp.h>
  15 #include <linux/slab.h>
  16
  17 #define OCOTP_CFG3_SPEED_GRADE_SHIFT    8
  18 #define OCOTP_CFG3_SPEED_GRADE_MASK     (0x3 << 8)
  19 #define IMX8MN_OCOTP_CFG3_SPEED_GRADE_MASK      (0xf << 8)
  20 #define OCOTP_CFG3_MKT_SEGMENT_SHIFT    6
  21 #define OCOTP_CFG3_MKT_SEGMENT_MASK     (0x3 << 6)
  22
  23 /* cpufreq-dt device registered by imx-cpufreq-dt */
  24 static struct platform_device *cpufreq_dt_pdev;
  25 static struct opp_table *cpufreq_opp_table;
  26
  27 static int imx_cpufreq_dt_probe(struct platform_device *pdev)
  28 {
  29         struct device *cpu_dev = get_cpu_device(0);
  30         u32 cell_value, supported_hw[2];
  31         int speed_grade, mkt_segment;
  32         int ret;
  33
  34         ret = nvmem_cell_read_u32(cpu_dev, "speed_grade", &cell_value);
  35         if (ret)
  36                 return ret;
  37
  38         if (of_machine_is_compatible("fsl,imx8mn") ||
  39             of_machine_is_compatible("fsl,imx8mp"))
  40                 speed_grade = (cell_value & IMX8MN_OCOTP_CFG3_SPEED_GRADE_MASK)
  41                               >> OCOTP_CFG3_SPEED_GRADE_SHIFT;
  42         else
  43                 speed_grade = (cell_value & OCOTP_CFG3_SPEED_GRADE_MASK)
  44                               >> OCOTP_CFG3_SPEED_GRADE_SHIFT;
  45         mkt_segment = (cell_value & OCOTP_CFG3_MKT_SEGMENT_MASK) >> OCOTP_CFG3_MKT_SEGMENT_SHIFT;
  46
  47         /*
  48          * Early samples without fuses written report "0 0" which may NOT
  49          * match any OPP defined in DT. So clamp to minimum OPP defined in
  50          * DT to avoid warning for "no OPPs".
  51          *
  52          * Applies to i.MX8M series SoCs.
  53          */
  54         if (mkt_segment == 0 && speed_grade == 0) {
  55                 if (of_machine_is_compatible("fsl,imx8mm") ||
  56                     of_machine_is_compatible("fsl,imx8mq"))
  57                         speed_grade = 1;
  58                 if (of_machine_is_compatible("fsl,imx8mn") ||
  59                     of_machine_is_compatible("fsl,imx8mp"))
  60                         speed_grade = 0xb;
  61         }
  62
  63         supported_hw[0] = BIT(speed_grade);
  64         supported_hw[1] = BIT(mkt_segment);
  65         dev_info(&pdev->dev, "cpu speed grade %d mkt segment %d supported-hw %#x %#x\n",
  66                         speed_grade, mkt_segment, supported_hw[0], supported_hw[1]);
  67
  68         cpufreq_opp_table = dev_pm_opp_set_supported_hw(cpu_dev, supported_hw, 2);
  69         if (IS_ERR(cpufreq_opp_table)) {
  70                 ret = PTR_ERR(cpufreq_opp_table);
  71                 dev_err(&pdev->dev, "Failed to set supported opp: %d\n", ret);
  72                 return ret;
  73         }
  74
  75         cpufreq_dt_pdev = platform_device_register_data(
  76                         &pdev->dev, "cpufreq-dt", -1, NULL, 0);
  77         if (IS_ERR(cpufreq_dt_pdev)) {
  78                 dev_pm_opp_put_supported_hw(cpufreq_opp_table);
  79                 ret = PTR_ERR(cpufreq_dt_pdev);
  80                 dev_err(&pdev->dev, "Failed to register cpufreq-dt: %d\n", ret);
  81                 return ret;
  82         }
  83
  84         return 0;
  85 }
  86
  87 static int imx_cpufreq_dt_remove(struct platform_device *pdev)
  88 {
  89         platform_device_unregister(cpufreq_dt_pdev);
  90         dev_pm_opp_put_supported_hw(cpufreq_opp_table);
  91
  92         return 0;
  93 }
  94
  95 static struct platform_driver imx_cpufreq_dt_driver = {
  96         .probe = imx_cpufreq_dt_probe,
  97         .remove = imx_cpufreq_dt_remove,
  98         .driver = {
  99                 .name = "imx-cpufreq-dt",
 100         },
 101 };
 102 module_platform_driver(imx_cpufreq_dt_driver);
 103
 104 MODULE_ALIAS("platform:imx-cpufreq-dt");
 105 MODULE_DESCRIPTION("Freescale i.MX cpufreq speed grading driver");
 106 MODULE_LICENSE("GPL v2");