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         /*
  24          * Only the available bits will be written so when readback
  25          * we get the maximum value of auto reload register
  26          */
  27         regmap_write(ddata->regmap, TIM_ARR, ~0L);
  28         regmap_read(ddata->regmap, TIM_ARR, &ddata->max_arr);
  29         regmap_write(ddata->regmap, TIM_ARR, 0x0);
  30 }
  31
  32 static int stm32_timers_probe(struct platform_device *pdev)
  33 {
  34         struct device *dev = &pdev->dev;
  35         struct stm32_timers *ddata;
  36         struct resource *res;
  37         void __iomem *mmio;
  38
  39         ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
  40         if (!ddata)
  41                 return -ENOMEM;
  42
  43         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  44         mmio = devm_ioremap_resource(dev, res);
  45         if (IS_ERR(mmio))
  46                 return PTR_ERR(mmio);
  47
  48         ddata->regmap = devm_regmap_init_mmio_clk(dev, "int", mmio,
  49                                                   &stm32_timers_regmap_cfg);
  50         if (IS_ERR(ddata->regmap))
  51                 return PTR_ERR(ddata->regmap);
  52
  53         ddata->clk = devm_clk_get(dev, NULL);
  54         if (IS_ERR(ddata->clk))
  55                 return PTR_ERR(ddata->clk);
  56
  57         stm32_timers_get_arr_size(ddata);
  58
  59         platform_set_drvdata(pdev, ddata);
  60
  61         return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
  62 }
  63
  64 static int stm32_timers_remove(struct platform_device *pdev)
  65 {
  66         of_platform_depopulate(&pdev->dev);
  67
  68         return 0;
  69 }
  70
  71 static const struct of_device_id stm32_timers_of_match[] = {
  72         { .compatible = "st,stm32-timers", },
  73         { /* end node */ },
  74 };
  75 MODULE_DEVICE_TABLE(of, stm32_timers_of_match);
  76
  77 static struct platform_driver stm32_timers_driver = {
  78         .probe = stm32_timers_probe,
  79         .remove = stm32_timers_remove,
  80         .driver = {
  81                 .name = "stm32-timers",
  82                 .of_match_table = stm32_timers_of_match,
  83         },
  84 };
  85 module_platform_driver(stm32_timers_driver);
  86
  87 MODULE_DESCRIPTION("STMicroelectronics STM32 Timers");
  88 MODULE_LICENSE("GPL v2");