From 9cd10205227cbe9bbd48fd6bf78dad88b45526b0 Mon Sep 17 00:00:00 2001 From: Michael Walle Date: Fri, 3 Jan 2020 00:11:01 +0100 Subject: [PATCH] clk: fsl-sai: new driver 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 Link: https://lkml.kernel.org/r/20200102231101.11834-3-michael@walle.cc Signed-off-by: Stephen Boyd --- drivers/clk/Kconfig | 12 +++++++ drivers/clk/Makefile | 1 + drivers/clk/clk-fsl-sai.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 105 insertions(+) create mode 100644 drivers/clk/clk-fsl-sai.c diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index 45653a0..dd1a5ab 100644 --- a/drivers/clk/Kconfig +++ b/drivers/clk/Kconfig @@ -174,6 +174,18 @@ config COMMON_CLK_CS2000_CP help If you say yes here you get support for the CS2000 clock multiplier. +config COMMON_CLK_FSL_SAI + bool "Clock driver for BCLK of Freescale SAI cores" + depends on ARCH_LAYERSCAPE || COMPILE_TEST + help + This driver supports the Freescale SAI (Synchronous Audio Interface) + to be used as a generic clock output. Some SoCs have restrictions + regarding the possible pin multiplexer settings. Eg. on some SoCs + two SAI interfaces can only be enabled together. If just one is + needed, the BCLK pin of the second one can be used as general + purpose clock output. Ideally, it can be used to drive an audio + codec (sometimes known as MCLK). + config COMMON_CLK_GEMINI bool "Clock driver for Cortina Systems Gemini SoC" depends on ARCH_GEMINI || COMPILE_TEST diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 0696a0c..ec23fd9 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -29,6 +29,7 @@ obj-$(CONFIG_ARCH_CLPS711X) += clk-clps711x.o obj-$(CONFIG_COMMON_CLK_CS2000_CP) += clk-cs2000-cp.o obj-$(CONFIG_ARCH_EFM32) += clk-efm32gg.o obj-$(CONFIG_COMMON_CLK_FIXED_MMIO) += clk-fixed-mmio.o +obj-$(CONFIG_COMMON_CLK_FSL_SAI) += clk-fsl-sai.o obj-$(CONFIG_COMMON_CLK_GEMINI) += clk-gemini.o obj-$(CONFIG_COMMON_CLK_ASPEED) += clk-aspeed.o obj-$(CONFIG_MACH_ASPEED_G6) += clk-ast2600.o diff --git a/drivers/clk/clk-fsl-sai.c b/drivers/clk/clk-fsl-sai.c new file mode 100644 index 0000000..0221180 --- /dev/null +++ b/drivers/clk/clk-fsl-sai.c @@ -0,0 +1,92 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Freescale SAI BCLK as a generic clock driver + * + * Copyright 2020 Michael Walle + */ + +#include +#include +#include +#include +#include +#include +#include + +#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 "); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:fsl-sai-clk"); -- 2.7.4