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                 speed_grade = (cell_value & IMX8MN_OCOTP_CFG3_SPEED_GRADE_MASK)
  40                               >> OCOTP_CFG3_SPEED_GRADE_SHIFT;
  41         else
  42                 speed_grade = (cell_value & OCOTP_CFG3_SPEED_GRADE_MASK)
  43                               >> OCOTP_CFG3_SPEED_GRADE_SHIFT;
  44         mkt_segment = (cell_value & OCOTP_CFG3_MKT_SEGMENT_MASK) >> OCOTP_CFG3_MKT_SEGMENT_SHIFT;
  45
  46         /*
  47          * Early samples without fuses written report "0 0" which means
  48          * consumer segment and minimum speed grading.
  49          *
  50          * According to datasheet minimum speed grading is not supported for
  51          * consumer parts so clamp to 1 to avoid warning for "no OPPs"
  52          *
  53          * Applies to i.MX8M series SoCs.
  54          */
  55         if (mkt_segment == 0 && speed_grade == 0 && (
  56                         of_machine_is_compatible("fsl,imx8mm") ||
  57                         of_machine_is_compatible("fsl,imx8mn") ||
  58                         of_machine_is_compatible("fsl,imx8mq")))
  59                 speed_grade = 1;
  60
  61         supported_hw[0] = BIT(speed_grade);
  62         supported_hw[1] = BIT(mkt_segment);
  63         dev_info(&pdev->dev, "cpu speed grade %d mkt segment %d supported-hw %#x %#x\n",
  64                         speed_grade, mkt_segment, supported_hw[0], supported_hw[1]);
  65
  66         cpufreq_opp_table = dev_pm_opp_set_supported_hw(cpu_dev, supported_hw, 2);
  67         if (IS_ERR(cpufreq_opp_table)) {
  68                 ret = PTR_ERR(cpufreq_opp_table);
  69                 dev_err(&pdev->dev, "Failed to set supported opp: %d\n", ret);
  70                 return ret;
  71         }
  72
  73         cpufreq_dt_pdev = platform_device_register_data(
  74                         &pdev->dev, "cpufreq-dt", -1, NULL, 0);
  75         if (IS_ERR(cpufreq_dt_pdev)) {
  76                 dev_pm_opp_put_supported_hw(cpufreq_opp_table);
  77                 ret = PTR_ERR(cpufreq_dt_pdev);
  78                 dev_err(&pdev->dev, "Failed to register cpufreq-dt: %d\n", ret);
  79                 return ret;
  80         }
  81
  82         return 0;
  83 }
  84
  85 static int imx_cpufreq_dt_remove(struct platform_device *pdev)
  86 {
  87         platform_device_unregister(cpufreq_dt_pdev);
  88         dev_pm_opp_put_supported_hw(cpufreq_opp_table);
  89
  90         return 0;
  91 }
  92
  93 static struct platform_driver imx_cpufreq_dt_driver = {
  94         .probe = imx_cpufreq_dt_probe,
  95         .remove = imx_cpufreq_dt_remove,
  96         .driver = {
  97                 .name = "imx-cpufreq-dt",
  98         },
  99 };
 100 module_platform_driver(imx_cpufreq_dt_driver);
 101
 102 MODULE_ALIAS("platform:imx-cpufreq-dt");
 103 MODULE_DESCRIPTION("Freescale i.MX cpufreq speed grading driver");
 104 MODULE_LICENSE("GPL v2");