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 OCOTP_CFG3_MKT_SEGMENT_SHIFT    6
  20 #define OCOTP_CFG3_MKT_SEGMENT_MASK     (0x3 << 6)
  21
  22 /* cpufreq-dt device registered by imx-cpufreq-dt */
  23 static struct platform_device *cpufreq_dt_pdev;
  24 static struct opp_table *cpufreq_opp_table;
  25
  26 static int imx_cpufreq_dt_probe(struct platform_device *pdev)
  27 {
  28         struct device *cpu_dev = get_cpu_device(0);
  29         u32 cell_value, supported_hw[2];
  30         int speed_grade, mkt_segment;
  31         int ret;
  32
  33         ret = nvmem_cell_read_u32(cpu_dev, "speed_grade", &cell_value);
  34         if (ret)
  35                 return ret;
  36
  37         speed_grade = (cell_value & OCOTP_CFG3_SPEED_GRADE_MASK) >> OCOTP_CFG3_SPEED_GRADE_SHIFT;
  38         mkt_segment = (cell_value & OCOTP_CFG3_MKT_SEGMENT_MASK) >> OCOTP_CFG3_MKT_SEGMENT_SHIFT;
  39
  40         /*
  41          * Early samples without fuses written report "0 0" which means
  42          * consumer segment and minimum speed grading.
  43          *
  44          * According to datasheet minimum speed grading is not supported for
  45          * consumer parts so clamp to 1 to avoid warning for "no OPPs"
  46          *
  47          * Applies to i.MX8M series SoCs.
  48          */
  49         if (mkt_segment == 0 && speed_grade == 0 && (
  50                         of_machine_is_compatible("fsl,imx8mm") ||
  51                         of_machine_is_compatible("fsl,imx8mn") ||
  52                         of_machine_is_compatible("fsl,imx8mq")))
  53                 speed_grade = 1;
  54
  55         supported_hw[0] = BIT(speed_grade);
  56         supported_hw[1] = BIT(mkt_segment);
  57         dev_info(&pdev->dev, "cpu speed grade %d mkt segment %d supported-hw %#x %#x\n",
  58                         speed_grade, mkt_segment, supported_hw[0], supported_hw[1]);
  59
  60         cpufreq_opp_table = dev_pm_opp_set_supported_hw(cpu_dev, supported_hw, 2);
  61         if (IS_ERR(cpufreq_opp_table)) {
  62                 ret = PTR_ERR(cpufreq_opp_table);
  63                 dev_err(&pdev->dev, "Failed to set supported opp: %d\n", ret);
  64                 return ret;
  65         }
  66
  67         cpufreq_dt_pdev = platform_device_register_data(
  68                         &pdev->dev, "cpufreq-dt", -1, NULL, 0);
  69         if (IS_ERR(cpufreq_dt_pdev)) {
  70                 dev_pm_opp_put_supported_hw(cpufreq_opp_table);
  71                 ret = PTR_ERR(cpufreq_dt_pdev);
  72                 dev_err(&pdev->dev, "Failed to register cpufreq-dt: %d\n", ret);
  73                 return ret;
  74         }
  75
  76         return 0;
  77 }
  78
  79 static int imx_cpufreq_dt_remove(struct platform_device *pdev)
  80 {
  81         platform_device_unregister(cpufreq_dt_pdev);
  82         dev_pm_opp_put_supported_hw(cpufreq_opp_table);
  83
  84         return 0;
  85 }
  86
  87 static struct platform_driver imx_cpufreq_dt_driver = {
  88         .probe = imx_cpufreq_dt_probe,
  89         .remove = imx_cpufreq_dt_remove,
  90         .driver = {
  91                 .name = "imx-cpufreq-dt",
  92         },
  93 };
  94 module_platform_driver(imx_cpufreq_dt_driver);
  95
  96 MODULE_ALIAS("platform:imx-cpufreq-dt");
  97 MODULE_DESCRIPTION("Freescale i.MX cpufreq speed grading driver");
  98 MODULE_LICENSE("GPL v2");