drivers/clk/h8300/clk-div.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * H8/300 divide clock driver
   4  *
   5  * Copyright 2015 Yoshinori Sato <ysato@users.sourceforge.jp>
   6  */
   7
   8 #include <linux/clk-provider.h>
   9 #include <linux/err.h>
  10 #include <linux/io.h>
  11 #include <linux/of.h>
  12 #include <linux/of_address.h>
  13
  14 static DEFINE_SPINLOCK(clklock);
  15
  16 static void __init h8300_div_clk_setup(struct device_node *node)
  17 {
  18         unsigned int num_parents;
  19         struct clk_hw *hw;
  20         const char *clk_name = node->name;
  21         const char *parent_name;
  22         void __iomem *divcr = NULL;
  23         int width;
  24         int offset;
  25
  26         num_parents = of_clk_get_parent_count(node);
  27         if (!num_parents) {
  28                 pr_err("%s: no parent found\n", clk_name);
  29                 return;
  30         }
  31
  32         divcr = of_iomap(node, 0);
  33         if (divcr == NULL) {
  34                 pr_err("%s: failed to map divide register\n", clk_name);
  35                 goto error;
  36         }
  37         offset = (unsigned long)divcr & 3;
  38         offset = (3 - offset) * 8;
  39         divcr = (void __iomem *)((unsigned long)divcr & ~3);
  40
  41         parent_name = of_clk_get_parent_name(node, 0);
  42         of_property_read_u32(node, "renesas,width", &width);
  43         hw = clk_hw_register_divider(NULL, clk_name, parent_name,
  44                                    CLK_SET_RATE_GATE, divcr, offset, width,
  45                                    CLK_DIVIDER_POWER_OF_TWO, &clklock);
  46         if (!IS_ERR(hw)) {
  47                 of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
  48                 return;
  49         }
  50         pr_err("%s: failed to register %s div clock (%ld)\n",
  51                __func__, clk_name, PTR_ERR(hw));
  52 error:
  53         if (divcr)
  54                 iounmap(divcr);
  55 }
  56
  57 CLK_OF_DECLARE(h8300_div_clk, "renesas,h8300-div-clock", h8300_div_clk_setup);