drivers/clk/clk-fsl-sai.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Freescale SAI BCLK as a generic clock driver
   4  *
   5  * Copyright 2020 Michael Walle <michael@walle.cc>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/clk-provider.h>
  11 #include <linux/err.h>
  12 #include <linux/of.h>
  13 #include <linux/of_address.h>
  14 #include <linux/slab.h>
  15
  16 #define I2S_CSR         0x00
  17 #define I2S_CR2         0x08
  18 #define CSR_BCE_BIT     28
  19 #define CR2_BCD         BIT(24)
  20 #define CR2_DIV_SHIFT   0
  21 #define CR2_DIV_WIDTH   8
  22
  23 struct fsl_sai_clk {
  24         struct clk_divider div;
  25         struct clk_gate gate;
  26         spinlock_t lock;
  27 };
  28
  29 static int fsl_sai_clk_probe(struct platform_device *pdev)
  30 {
  31         struct device *dev = &pdev->dev;
  32         struct fsl_sai_clk *sai_clk;
  33         struct clk_parent_data pdata = { .index = 0 };
  34         void __iomem *base;
  35         struct clk_hw *hw;
  36
  37         sai_clk = devm_kzalloc(dev, sizeof(*sai_clk), GFP_KERNEL);
  38         if (!sai_clk)
  39                 return -ENOMEM;
  40
  41         base = devm_platform_ioremap_resource(pdev, 0);
  42         if (IS_ERR(base))
  43                 return PTR_ERR(base);
  44
  45         spin_lock_init(&sai_clk->lock);
  46
  47         sai_clk->gate.reg = base + I2S_CSR;
  48         sai_clk->gate.bit_idx = CSR_BCE_BIT;
  49         sai_clk->gate.lock = &sai_clk->lock;
  50
  51         sai_clk->div.reg = base + I2S_CR2;
  52         sai_clk->div.shift = CR2_DIV_SHIFT;
  53         sai_clk->div.width = CR2_DIV_WIDTH;
  54         sai_clk->div.lock = &sai_clk->lock;
  55
  56         /* set clock direction, we are the BCLK master */
  57         writel(CR2_BCD, base + I2S_CR2);
  58
  59         hw = devm_clk_hw_register_composite_pdata(dev, dev->of_node->name,
  60                                                   &pdata, 1, NULL, NULL,
  61                                                   &sai_clk->div.hw,
  62                                                   &clk_divider_ops,
  63                                                   &sai_clk->gate.hw,
  64                                                   &clk_gate_ops,
  65                                                   CLK_SET_RATE_GATE);
  66         if (IS_ERR(hw))
  67                 return PTR_ERR(hw);
  68
  69         return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, hw);
  70 }
  71
  72 static const struct of_device_id of_fsl_sai_clk_ids[] = {
  73         { .compatible = "fsl,vf610-sai-clock" },
  74         { }
  75 };
  76 MODULE_DEVICE_TABLE(of, of_fsl_sai_clk_ids);
  77
  78 static struct platform_driver fsl_sai_clk_driver = {
  79         .probe = fsl_sai_clk_probe,
  80         .driver         = {
  81                 .name   = "fsl-sai-clk",
  82                 .of_match_table = of_fsl_sai_clk_ids,
  83         },
  84 };
  85 module_platform_driver(fsl_sai_clk_driver);
  86
  87 MODULE_DESCRIPTION("Freescale SAI bitclock-as-a-clock driver");
  88 MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
  89 MODULE_ALIAS("platform:fsl-sai-clk");