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 #define IMX8MP_OCOTP_CFG3_MKT_SEGMENT_SHIFT    5
  23 #define IMX8MP_OCOTP_CFG3_MKT_SEGMENT_MASK     (0x3 << 5)
  24
  25 /* cpufreq-dt device registered by imx-cpufreq-dt */
  26 static struct platform_device *cpufreq_dt_pdev;
  27 static struct opp_table *cpufreq_opp_table;
  28
  29 static int imx_cpufreq_dt_probe(struct platform_device *pdev)
  30 {
  31         struct device *cpu_dev = get_cpu_device(0);
  32         u32 cell_value, supported_hw[2];
  33         int speed_grade, mkt_segment;
  34         int ret;
  35
  36         if (!of_find_property(cpu_dev->of_node, "cpu-supply", NULL))
  37                 return -ENODEV;
  38
  39         ret = nvmem_cell_read_u32(cpu_dev, "speed_grade", &cell_value);
  40         if (ret)
  41                 return ret;
  42
  43         if (of_machine_is_compatible("fsl,imx8mn") ||
  44             of_machine_is_compatible("fsl,imx8mp"))
  45                 speed_grade = (cell_value & IMX8MN_OCOTP_CFG3_SPEED_GRADE_MASK)
  46                               >> OCOTP_CFG3_SPEED_GRADE_SHIFT;
  47         else
  48                 speed_grade = (cell_value & OCOTP_CFG3_SPEED_GRADE_MASK)
  49                               >> OCOTP_CFG3_SPEED_GRADE_SHIFT;
  50
  51         if (of_machine_is_compatible("fsl,imx8mp"))
  52                 mkt_segment = (cell_value & IMX8MP_OCOTP_CFG3_MKT_SEGMENT_MASK)
  53                                >> IMX8MP_OCOTP_CFG3_MKT_SEGMENT_SHIFT;
  54         else
  55                 mkt_segment = (cell_value & OCOTP_CFG3_MKT_SEGMENT_MASK)
  56                                >> OCOTP_CFG3_MKT_SEGMENT_SHIFT;
  57
  58         /*
  59          * Early samples without fuses written report "0 0" which may NOT
  60          * match any OPP defined in DT. So clamp to minimum OPP defined in
  61          * DT to avoid warning for "no OPPs".
  62          *
  63          * Applies to i.MX8M series SoCs.
  64          */
  65         if (mkt_segment == 0 && speed_grade == 0) {
  66                 if (of_machine_is_compatible("fsl,imx8mm") ||
  67                     of_machine_is_compatible("fsl,imx8mq"))
  68                         speed_grade = 1;
  69                 if (of_machine_is_compatible("fsl,imx8mn") ||
  70                     of_machine_is_compatible("fsl,imx8mp"))
  71                         speed_grade = 0xb;
  72         }
  73
  74         supported_hw[0] = BIT(speed_grade);
  75         supported_hw[1] = BIT(mkt_segment);
  76         dev_info(&pdev->dev, "cpu speed grade %d mkt segment %d supported-hw %#x %#x\n",
  77                         speed_grade, mkt_segment, supported_hw[0], supported_hw[1]);
  78
  79         cpufreq_opp_table = dev_pm_opp_set_supported_hw(cpu_dev, supported_hw, 2);
  80         if (IS_ERR(cpufreq_opp_table)) {
  81                 ret = PTR_ERR(cpufreq_opp_table);
  82                 dev_err(&pdev->dev, "Failed to set supported opp: %d\n", ret);
  83                 return ret;
  84         }
  85
  86         cpufreq_dt_pdev = platform_device_register_data(
  87                         &pdev->dev, "cpufreq-dt", -1, NULL, 0);
  88         if (IS_ERR(cpufreq_dt_pdev)) {
  89                 dev_pm_opp_put_supported_hw(cpufreq_opp_table);
  90                 ret = PTR_ERR(cpufreq_dt_pdev);
  91                 dev_err(&pdev->dev, "Failed to register cpufreq-dt: %d\n", ret);
  92                 return ret;
  93         }
  94
  95         return 0;
  96 }
  97
  98 static int imx_cpufreq_dt_remove(struct platform_device *pdev)
  99 {
 100         platform_device_unregister(cpufreq_dt_pdev);
 101         dev_pm_opp_put_supported_hw(cpufreq_opp_table);
 102
 103         return 0;
 104 }
 105
 106 static struct platform_driver imx_cpufreq_dt_driver = {
 107         .probe = imx_cpufreq_dt_probe,
 108         .remove = imx_cpufreq_dt_remove,
 109         .driver = {
 110                 .name = "imx-cpufreq-dt",
 111         },
 112 };
 113 module_platform_driver(imx_cpufreq_dt_driver);
 114
 115 MODULE_ALIAS("platform:imx-cpufreq-dt");
 116 MODULE_DESCRIPTION("Freescale i.MX cpufreq speed grading driver");
 117 MODULE_LICENSE("GPL v2");