drivers/mfd/stm32-timers.c

   1 /*
   2  * Copyright (C) STMicroelectronics 2016
   3  *
   4  * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
   5  *
   6  * License terms:  GNU General Public License (GPL), version 2
   7  */
   8
   9 #include <linux/mfd/stm32-timers.h>
  10 #include <linux/module.h>
  11 #include <linux/of_platform.h>
  12 #include <linux/reset.h>
  13
  14 static const struct regmap_config stm32_timers_regmap_cfg = {
  15         .reg_bits = 32,
  16         .val_bits = 32,
  17         .reg_stride = sizeof(u32),
  18         .max_register = 0x3fc,
  19 };
  20
  21 static void stm32_timers_get_arr_size(struct stm32_timers *ddata)
  22 {
  23         u32 arr;
  24
  25         /* Backup ARR to restore it after getting the maximum value */
  26         regmap_read(ddata->regmap, TIM_ARR, &arr);
  27
  28         /*
  29          * Only the available bits will be written so when readback
  30          * we get the maximum value of auto reload register
  31          */
  32         regmap_write(ddata->regmap, TIM_ARR, ~0L);
  33         regmap_read(ddata->regmap, TIM_ARR, &ddata->max_arr);
  34         regmap_write(ddata->regmap, TIM_ARR, arr);
  35 }
  36
  37 static int stm32_timers_probe(struct platform_device *pdev)
  38 {
  39         struct device *dev = &pdev->dev;
  40         struct stm32_timers *ddata;
  41         struct resource *res;
  42         void __iomem *mmio;
  43
  44         ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
  45         if (!ddata)
  46                 return -ENOMEM;
  47
  48         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  49         mmio = devm_ioremap_resource(dev, res);
  50         if (IS_ERR(mmio))
  51                 return PTR_ERR(mmio);
  52
  53         ddata->regmap = devm_regmap_init_mmio_clk(dev, "int", mmio,
  54                                                   &stm32_timers_regmap_cfg);
  55         if (IS_ERR(ddata->regmap))
  56                 return PTR_ERR(ddata->regmap);
  57
  58         ddata->clk = devm_clk_get(dev, NULL);
  59         if (IS_ERR(ddata->clk))
  60                 return PTR_ERR(ddata->clk);
  61
  62         stm32_timers_get_arr_size(ddata);
  63
  64         platform_set_drvdata(pdev, ddata);
  65
  66         return devm_of_platform_populate(&pdev->dev);
  67 }
  68
  69 static const struct of_device_id stm32_timers_of_match[] = {
  70         { .compatible = "st,stm32-timers", },
  71         { /* end node */ },
  72 };
  73 MODULE_DEVICE_TABLE(of, stm32_timers_of_match);
  74
  75 static struct platform_driver stm32_timers_driver = {
  76         .probe = stm32_timers_probe,
  77         .driver = {
  78                 .name = "stm32-timers",
  79                 .of_match_table = stm32_timers_of_match,
  80         },
  81 };
  82 module_platform_driver(stm32_timers_driver);
  83
  84 MODULE_DESCRIPTION("STMicroelectronics STM32 Timers");
  85 MODULE_LICENSE("GPL v2");