mirror of
https://github.com/torvalds/linux.git
synced 2024-12-24 20:01:55 +00:00
9cd1020522
With this driver it is possible to use the BCLK pin of the SAI module as a generic clock output. This is esp. useful if you want to drive a clock to an audio codec. Because the output only allows integer divider values the audio codec needs an integrated PLL. Signed-off-by: Michael Walle <michael@walle.cc> Link: https://lkml.kernel.org/r/20200102231101.11834-3-michael@walle.cc Signed-off-by: Stephen Boyd <sboyd@kernel.org>
93 lines
2.3 KiB
C
93 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Freescale SAI BCLK as a generic clock driver
|
|
*
|
|
* Copyright 2020 Michael Walle <michael@walle.cc>
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/clk-provider.h>
|
|
#include <linux/err.h>
|
|
#include <linux/of.h>
|
|
#include <linux/of_address.h>
|
|
#include <linux/slab.h>
|
|
|
|
#define I2S_CSR 0x00
|
|
#define I2S_CR2 0x08
|
|
#define CSR_BCE_BIT 28
|
|
#define CR2_BCD BIT(24)
|
|
#define CR2_DIV_SHIFT 0
|
|
#define CR2_DIV_WIDTH 8
|
|
|
|
struct fsl_sai_clk {
|
|
struct clk_divider div;
|
|
struct clk_gate gate;
|
|
spinlock_t lock;
|
|
};
|
|
|
|
static int fsl_sai_clk_probe(struct platform_device *pdev)
|
|
{
|
|
struct device *dev = &pdev->dev;
|
|
struct fsl_sai_clk *sai_clk;
|
|
struct clk_parent_data pdata = { .index = 0 };
|
|
void __iomem *base;
|
|
struct clk_hw *hw;
|
|
struct resource *res;
|
|
|
|
sai_clk = devm_kzalloc(dev, sizeof(*sai_clk), GFP_KERNEL);
|
|
if (!sai_clk)
|
|
return -ENOMEM;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
base = devm_ioremap_resource(dev, res);
|
|
if (IS_ERR(base))
|
|
return PTR_ERR(base);
|
|
|
|
spin_lock_init(&sai_clk->lock);
|
|
|
|
sai_clk->gate.reg = base + I2S_CSR;
|
|
sai_clk->gate.bit_idx = CSR_BCE_BIT;
|
|
sai_clk->gate.lock = &sai_clk->lock;
|
|
|
|
sai_clk->div.reg = base + I2S_CR2;
|
|
sai_clk->div.shift = CR2_DIV_SHIFT;
|
|
sai_clk->div.width = CR2_DIV_WIDTH;
|
|
sai_clk->div.lock = &sai_clk->lock;
|
|
|
|
/* set clock direction, we are the BCLK master */
|
|
writel(CR2_BCD, base + I2S_CR2);
|
|
|
|
hw = clk_hw_register_composite_pdata(dev, dev->of_node->name,
|
|
&pdata, 1, NULL, NULL,
|
|
&sai_clk->div.hw,
|
|
&clk_divider_ops,
|
|
&sai_clk->gate.hw,
|
|
&clk_gate_ops,
|
|
CLK_SET_RATE_GATE);
|
|
if (IS_ERR(hw))
|
|
return PTR_ERR(hw);
|
|
|
|
return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, hw);
|
|
}
|
|
|
|
static const struct of_device_id of_fsl_sai_clk_ids[] = {
|
|
{ .compatible = "fsl,vf610-sai-clock" },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, of_fsl_sai_clk_ids);
|
|
|
|
static struct platform_driver fsl_sai_clk_driver = {
|
|
.probe = fsl_sai_clk_probe,
|
|
.driver = {
|
|
.name = "fsl-sai-clk",
|
|
.of_match_table = of_fsl_sai_clk_ids,
|
|
},
|
|
};
|
|
module_platform_driver(fsl_sai_clk_driver);
|
|
|
|
MODULE_DESCRIPTION("Freescale SAI bitclock-as-a-clock driver");
|
|
MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:fsl-sai-clk");
|