Re: [PATCH v2 3/4] clk: ti: Driver for DRA7 ATL (Audio Tracking Logic)
From: Mike Turquette
Date: Tue May 20 2014 - 13:45:40 EST
Quoting Peter Ujfalusi (2014-05-07 03:20:47)
> Audio Tracking Logic is designed to be used by HD Radio applications to
> synchronize the audio output clocks to the baseband clock. ATL can be also
> used to track errors between two reference clocks (BWS, AWS) and generate a modulated
> clock output which averages to some desired frequency.
> In essence ATL is generating a clock to be used by an audio codec and also
> to be used by the SoC as MCLK.
>
> To be able to integrate the ATL provided clocks to the clock tree we need
> two types of DT binding:
> - DT clock nodes to represent the ATL clocks towards the CCF
> - binding for the ATL IP itself which is going to handle the hw
> configuration
>
> The reason for this type of setup is that ATL itself is a separate device
> in the SoC, it has it's own address space and clock domain. Other IPs can
> use the ATL generated clock as their functional clock (McASPs for example)
> and external components like audio codecs can also use the very same clock
> as their MCLK.
>
> The ATL IP in DRA7 contains 4 ATL instences.
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
Looks good to me.
Regards,
Mike
> ---
> drivers/clk/ti/Makefile | 3 +-
> drivers/clk/ti/clk-dra7-atl.c | 313 ++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 315 insertions(+), 1 deletion(-)
> create mode 100644 drivers/clk/ti/clk-dra7-atl.c
>
> diff --git a/drivers/clk/ti/Makefile b/drivers/clk/ti/Makefile
> index 4319d4031aa3..18e2443224e6 100644
> --- a/drivers/clk/ti/Makefile
> +++ b/drivers/clk/ti/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_SOC_AM33XX) += $(clk-common) clk-33xx.o
> obj-$(CONFIG_ARCH_OMAP3) += $(clk-common) interface.o clk-3xxx.o
> obj-$(CONFIG_ARCH_OMAP4) += $(clk-common) clk-44xx.o
> obj-$(CONFIG_SOC_OMAP5) += $(clk-common) clk-54xx.o
> -obj-$(CONFIG_SOC_DRA7XX) += $(clk-common) clk-7xx.o
> +obj-$(CONFIG_SOC_DRA7XX) += $(clk-common) clk-7xx.o \
> + clk-dra7-atl.o
> obj-$(CONFIG_SOC_AM43XX) += $(clk-common) clk-43xx.o
> endif
> diff --git a/drivers/clk/ti/clk-dra7-atl.c b/drivers/clk/ti/clk-dra7-atl.c
> new file mode 100644
> index 000000000000..97a8992eebb7
> --- /dev/null
> +++ b/drivers/clk/ti/clk-dra7-atl.c
> @@ -0,0 +1,313 @@
> +/*
> + * DRA7 ATL (Audio Tracking Logic) clock driver
> + *
> + * Copyright (C) 2013 Texas Instruments, Inc.
> + *
> + * Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/clk-provider.h>
> +#include <linux/slab.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +
> +#define DRA7_ATL_INSTANCES 4
> +
> +#define DRA7_ATL_PPMR_REG(id) (0x200 + (id * 0x80))
> +#define DRA7_ATL_BBSR_REG(id) (0x204 + (id * 0x80))
> +#define DRA7_ATL_ATLCR_REG(id) (0x208 + (id * 0x80))
> +#define DRA7_ATL_SWEN_REG(id) (0x210 + (id * 0x80))
> +#define DRA7_ATL_BWSMUX_REG(id) (0x214 + (id * 0x80))
> +#define DRA7_ATL_AWSMUX_REG(id) (0x218 + (id * 0x80))
> +#define DRA7_ATL_PCLKMUX_REG(id) (0x21c + (id * 0x80))
> +
> +#define DRA7_ATL_SWEN BIT(0)
> +#define DRA7_ATL_DIVIDER_MASK (0x1f)
> +#define DRA7_ATL_PCLKMUX BIT(0)
> +struct dra7_atl_clock_info;
> +
> +struct dra7_atl_desc {
> + struct clk *clk;
> + struct clk_hw hw;
> + struct dra7_atl_clock_info *cinfo;
> + int id;
> +
> + bool probed; /* the driver for the IP has been loaded */
> + bool valid; /* configured */
> + bool enabled;
> + u32 bws; /* Baseband Word Select Mux */
> + u32 aws; /* Audio Word Select Mux */
> + u32 divider; /* Cached divider value */
> +};
> +
> +struct dra7_atl_clock_info {
> + struct device *dev;
> + void __iomem *iobase;
> +
> + struct dra7_atl_desc *cdesc;
> +};
> +
> +#define to_atl_desc(_hw) container_of(_hw, struct dra7_atl_desc, hw)
> +
> +static inline void atl_write(struct dra7_atl_clock_info *cinfo, u32 reg,
> + u32 val)
> +{
> + __raw_writel(val, cinfo->iobase + reg);
> +}
> +
> +static inline int atl_read(struct dra7_atl_clock_info *cinfo, u32 reg)
> +{
> + return __raw_readl(cinfo->iobase + reg);
> +}
> +
> +static int atl_clk_enable(struct clk_hw *hw)
> +{
> + struct dra7_atl_desc *cdesc = to_atl_desc(hw);
> +
> + if (!cdesc->probed)
> + goto out;
> +
> + if (unlikely(!cdesc->valid))
> + dev_warn(cdesc->cinfo->dev, "atl%d has not been configured\n",
> + cdesc->id);
> + pm_runtime_get_sync(cdesc->cinfo->dev);
> +
> + atl_write(cdesc->cinfo, DRA7_ATL_ATLCR_REG(cdesc->id),
> + cdesc->divider - 1);
> + atl_write(cdesc->cinfo, DRA7_ATL_SWEN_REG(cdesc->id), DRA7_ATL_SWEN);
> +
> +out:
> + cdesc->enabled = true;
> +
> + return 0;
> +}
> +
> +static void atl_clk_disable(struct clk_hw *hw)
> +{
> + struct dra7_atl_desc *cdesc = to_atl_desc(hw);
> +
> + if (!cdesc->probed)
> + goto out;
> +
> + atl_write(cdesc->cinfo, DRA7_ATL_SWEN_REG(cdesc->id), 0);
> + pm_runtime_put_sync(cdesc->cinfo->dev);
> +
> +out:
> + cdesc->enabled = false;
> +}
> +
> +static int atl_clk_is_enabled(struct clk_hw *hw)
> +{
> + struct dra7_atl_desc *cdesc = to_atl_desc(hw);
> +
> + return cdesc->enabled;
> +}
> +
> +static unsigned long atl_clk_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct dra7_atl_desc *cdesc = to_atl_desc(hw);
> +
> + return parent_rate / cdesc->divider;
> +}
> +
> +static long atl_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long *parent_rate)
> +{
> + unsigned divider;
> +
> + divider = (*parent_rate + rate / 2) / rate;
> + if (divider > DRA7_ATL_DIVIDER_MASK + 1)
> + divider = DRA7_ATL_DIVIDER_MASK + 1;
> +
> + return *parent_rate / divider;
> +}
> +
> +static int atl_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct dra7_atl_desc *cdesc = to_atl_desc(hw);
> + u32 divider;
> +
> + divider = ((parent_rate + rate / 2) / rate) - 1;
> + if (divider > DRA7_ATL_DIVIDER_MASK)
> + divider = DRA7_ATL_DIVIDER_MASK;
> +
> + cdesc->divider = divider + 1;
> +
> + return 0;
> +}
> +
> +const struct clk_ops atl_clk_ops = {
> + .enable = atl_clk_enable,
> + .disable = atl_clk_disable,
> + .is_enabled = atl_clk_is_enabled,
> + .recalc_rate = atl_clk_recalc_rate,
> + .round_rate = atl_clk_round_rate,
> + .set_rate = atl_clk_set_rate,
> +};
> +
> +static void __init of_dra7_atl_clock_setup(struct device_node *node)
> +{
> + struct dra7_atl_desc *clk_hw = NULL;
> + struct clk_init_data init = { 0 };
> + const char **parent_names = NULL;
> + struct clk *clk;
> +
> + clk_hw = kzalloc(sizeof(*clk_hw), GFP_KERNEL);
> + if (!clk_hw) {
> + pr_err("%s: could not allocate dra7_atl_desc\n", __func__);
> + return;
> + }
> +
> + clk_hw->hw.init = &init;
> + clk_hw->divider = 1;
> + init.name = node->name;
> + init.ops = &atl_clk_ops;
> + init.flags = CLK_IGNORE_UNUSED;
> + init.num_parents = of_clk_get_parent_count(node);
> +
> + if (init.num_parents != 1) {
> + pr_err("%s: atl clock %s must have 1 parent\n", __func__,
> + node->name);
> + goto cleanup;
> + }
> +
> + parent_names = kzalloc(sizeof(char *), GFP_KERNEL);
> +
> + if (!parent_names)
> + goto cleanup;
> +
> + parent_names[0] = of_clk_get_parent_name(node, 0);
> +
> + init.parent_names = parent_names;
> +
> + clk = clk_register(NULL, &clk_hw->hw);
> +
> + if (!IS_ERR(clk)) {
> + of_clk_add_provider(node, of_clk_src_simple_get, clk);
> + return;
> + }
> +cleanup:
> + kfree(parent_names);
> + kfree(clk_hw);
> +}
> +CLK_OF_DECLARE(dra7_atl_clock, "ti,dra7-atl-clock", of_dra7_atl_clock_setup);
> +
> +static int of_dra7_atl_clk_probe(struct platform_device *pdev)
> +{
> + struct device_node *node = pdev->dev.of_node;
> + struct dra7_atl_clock_info *cinfo;
> + int i;
> + int ret = 0;
> +
> + if (!node)
> + return -ENODEV;
> +
> + cinfo = devm_kzalloc(&pdev->dev, sizeof(*cinfo), GFP_KERNEL);
> + if (!cinfo)
> + return -ENOMEM;
> +
> + cinfo->iobase = of_iomap(node, 0);
> + cinfo->dev = &pdev->dev;
> + pm_runtime_enable(cinfo->dev);
> +
> + pm_runtime_get_sync(cinfo->dev);
> + atl_write(cinfo, DRA7_ATL_PCLKMUX_REG(0), DRA7_ATL_PCLKMUX);
> +
> + for (i = 0; i < DRA7_ATL_INSTANCES; i++) {
> + struct device_node *cfg_node;
> + char prop[5];
> + struct dra7_atl_desc *cdesc;
> + struct of_phandle_args clkspec;
> + struct clk *clk;
> + int rc;
> +
> + rc = of_parse_phandle_with_args(node, "ti,provided-clocks",
> + NULL, i, &clkspec);
> +
> + if (rc) {
> + pr_err("%s: failed to lookup atl clock %d\n", __func__,
> + i);
> + return -EINVAL;
> + }
> +
> + clk = of_clk_get_from_provider(&clkspec);
> +
> + cdesc = to_atl_desc(__clk_get_hw(clk));
> + cdesc->cinfo = cinfo;
> + cdesc->id = i;
> +
> + /* Get configuration for the ATL instances */
> + snprintf(prop, sizeof(prop), "atl%u", i);
> + cfg_node = of_find_node_by_name(node, prop);
> + if (cfg_node) {
> + ret = of_property_read_u32(cfg_node, "bws",
> + &cdesc->bws);
> + ret |= of_property_read_u32(cfg_node, "aws",
> + &cdesc->aws);
> + if (!ret) {
> + cdesc->valid = true;
> + atl_write(cinfo, DRA7_ATL_BWSMUX_REG(i),
> + cdesc->bws);
> + atl_write(cinfo, DRA7_ATL_AWSMUX_REG(i),
> + cdesc->aws);
> + }
> + }
> +
> + cdesc->probed = true;
> + /*
> + * Enable the clock if it has been asked prior to loading the
> + * hw driver
> + */
> + if (cdesc->enabled)
> + atl_clk_enable(__clk_get_hw(clk));
> + }
> + pm_runtime_put_sync(cinfo->dev);
> +
> + return ret;
> +}
> +
> +static int of_dra7_atl_clk_remove(struct platform_device *pdev)
> +{
> + pm_runtime_disable(&pdev->dev);
> +
> + return 0;
> +}
> +
> +static struct of_device_id of_dra7_atl_clk_match_tbl[] = {
> + { .compatible = "ti,dra7-atl", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, of_dra7_atl_clk_match_tbl);
> +
> +static struct platform_driver dra7_atl_clk_driver = {
> + .driver = {
> + .name = "dra7-atl",
> + .owner = THIS_MODULE,
> + .of_match_table = of_dra7_atl_clk_match_tbl,
> + },
> + .probe = of_dra7_atl_clk_probe,
> + .remove = of_dra7_atl_clk_remove,
> +};
> +
> +module_platform_driver(dra7_atl_clk_driver);
> +
> +MODULE_DESCRIPTION("Clock driver for DRA7 Audio Tracking Logic");
> +MODULE_ALIAS("platform:dra7-atl-clock");
> +MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@xxxxxx>");
> +MODULE_LICENSE("GPL v2");
> +
> --
> 1.9.2
>
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