Re: [PATCH] clk: wm831x: Add initial WM831x clock driver
From: Turquette, Mike
Date: Wed May 16 2012 - 01:01:16 EST
On Mon, May 14, 2012 at 7:16 AM, Mark Brown
<broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> The WM831x and WM832x series of PMICs contain a flexible clocking
> subsystem intended to provide always on and system core clocks. It
> features:
>
> - A 32.768kHz crystal oscillator which can optionally be used to pass
> through an externally generated clock.
> - A FLL which can be clocked from either the 32.768kHz oscillator or
> the CLKIN pin.
> - A CLKOUT pin which can bring out either the oscillator or the FLL
> output.
> - The 32.768kHz clock can also optionally be brought out on the GPIO
> pins of the device.
>
> This driver fully supports the 32.768kHz oscillator and CLKOUT. The FLL
> is supported only in AUTO mode, the full flexibility of the FLL cannot
> currently be used.
>
> Due to a lack of access to systems where the core SoC has been converted
> to use the generic clock API this driver has been compile tested only.
>
> Signed-off-by: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Mark,
Do you plan to rebase against my clk-next branch? I've pushed your
clk_unregister patch there.
Regards,
Mike
> ---
> MAINTAINERS | 1 +
> drivers/clk/Kconfig | 7 +
> drivers/clk/Makefile | 3 +
> drivers/clk/clk-wm831x.c | 408 ++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 419 insertions(+)
> create mode 100644 drivers/clk/clk-wm831x.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 577950a..0a1f261 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7567,6 +7567,7 @@ W: http://opensource.wolfsonmicro.com/content/linux-drivers-wolfson-devices
> S: Supported
> F: Documentation/hwmon/wm83??
> F: arch/arm/mach-s3c64xx/mach-crag6410*
> +F: drivers/clk/clk-wm83*.c
> F: drivers/leds/leds-wm83*.c
> F: drivers/hwmon/wm83??-hwmon.c
> F: drivers/input/misc/wm831x-on.c
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index 6835e6a..7f0b5ca 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -33,4 +33,11 @@ config COMMON_CLK_DEBUG
> clk_flags, clk_prepare_count, clk_enable_count &
> clk_notifier_count.
>
> +config COMMON_CLK_WM831X
> + tristate "Clock driver for WM831x/2x PMICs"
> + depends on MFD_WM831X
> + ---help---
> + Supports the clocking subsystem of the WM831x/2x series of
> + PMICs from Wolfson Microlectronics.
> +
> endmenu
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index b9a5158..b679f11 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -5,3 +5,6 @@ obj-$(CONFIG_COMMON_CLK) += clk.o clk-fixed-rate.o clk-gate.o \
> # SoCs specific
> obj-$(CONFIG_ARCH_MXS) += mxs/
> obj-$(CONFIG_PLAT_SPEAR) += spear/
> +
> +# Chip specific
> +obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o
> diff --git a/drivers/clk/clk-wm831x.c b/drivers/clk/clk-wm831x.c
> new file mode 100644
> index 0000000..1a9fd43
> --- /dev/null
> +++ b/drivers/clk/clk-wm831x.c
> @@ -0,0 +1,408 @@
> +/*
> + * WM831x clock control
> + *
> + * Copyright 2011-2 Wolfson Microelectronics PLC.
> + *
> + * Author: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or (at your
> + * option) any later version.
> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/platform_device.h>
> +#include <linux/mfd/wm831x/core.h>
> +
> +struct wm831x_clk {
> + struct wm831x *wm831x;
> + struct clk_hw xtal_hw;
> + struct clk_hw fll_hw;
> + struct clk_hw clkout_hw;
> + bool xtal_ena;
> +};
> +
> +static int wm831x_xtal_is_enabled(struct clk_hw *hw)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + xtal_hw);
> +
> + return clkdata->xtal_ena;
> +}
> +
> +static unsigned long wm831x_xtal_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + xtal_hw);
> +
> + if (clkdata->xtal_ena)
> + return 32768;
> + else
> + return 0;
> +}
> +
> +static const struct clk_ops wm831x_xtal_ops = {
> + .is_enabled = wm831x_xtal_is_enabled,
> + .recalc_rate = wm831x_xtal_recalc_rate,
> +};
> +
> +static struct clk_init_data wm831x_xtal_init = {
> + .name = "xtal",
> + .ops = &wm831x_xtal_ops,
> + .flags = CLK_IS_ROOT,
> +};
> +
> +static const unsigned long wm831x_fll_auto_rates[] = {
> + 2048000,
> + 11289600,
> + 12000000,
> + 12288000,
> + 19200000,
> + 22579600,
> + 24000000,
> + 24576000,
> +};
> +
> +static int wm831x_fll_is_enabled(struct clk_hw *hw)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + fll_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int ret;
> +
> + ret = wm831x_reg_read(wm831x, WM831X_FLL_CONTROL_1);
> + if (ret < 0) {
> + dev_err(wm831x->dev, "Unable to read FLL_CONTROL_1: %d\n",
> + ret);
> + return true;
> + }
> +
> + return (ret & WM831X_FLL_ENA) != 0;
> +}
> +
> +static int wm831x_fll_prepare(struct clk_hw *hw)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + fll_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int ret;
> +
> + ret = wm831x_set_bits(wm831x, WM831X_FLL_CONTROL_2,
> + WM831X_FLL_ENA, WM831X_FLL_ENA);
> + if (ret != 0)
> + dev_crit(wm831x->dev, "Failed to enable FLL: %d\n", ret);
> +
> + usleep_range(2000, 2000);
> +
> + return ret;
> +}
> +
> +static void wm831x_fll_unprepare(struct clk_hw *hw)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + fll_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int ret;
> +
> + ret = wm831x_set_bits(wm831x, WM831X_FLL_CONTROL_2, WM831X_FLL_ENA, 0);
> + if (ret != 0)
> + dev_crit(wm831x->dev, "Failed to disaable FLL: %d\n", ret);
> +}
> +
> +static unsigned long wm831x_fll_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + fll_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int ret;
> +
> + ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_2);
> + if (ret < 0) {
> + dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_2: %d\n",
> + ret);
> + return 0;
> + }
> +
> + if (ret & WM831X_FLL_AUTO)
> + return wm831x_fll_auto_rates[ret & WM831X_FLL_AUTO_FREQ_MASK];
> +
> + dev_err(wm831x->dev, "FLL only supported in AUTO mode\n");
> +
> + return 0;
> +}
> +
> +static long wm831x_fll_round_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long *unused)
> +{
> + int best = 0;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(wm831x_fll_auto_rates); i++)
> + if (abs(wm831x_fll_auto_rates[i] - rate) <
> + abs(wm831x_fll_auto_rates[best] - rate))
> + best = i;
> +
> + return wm831x_fll_auto_rates[best];
> +}
> +
> +static int wm831x_fll_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + fll_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(wm831x_fll_auto_rates); i++)
> + if (wm831x_fll_auto_rates[i] == rate)
> + break;
> + if (i == ARRAY_SIZE(wm831x_fll_auto_rates))
> + return -EINVAL;
> +
> + if (wm831x_fll_is_enabled(hw))
> + return -EPERM;
> +
> + return wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_2,
> + WM831X_FLL_AUTO_FREQ_MASK, i);
> +}
> +
> +static const char *wm831x_fll_parents[] = {
> + "xtal",
> + "clkin",
> +};
> +
> +static u8 wm831x_fll_get_parent(struct clk_hw *hw)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + fll_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int ret;
> +
> + /* AUTO mode is always clocked from the crystal */
> + ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_2);
> + if (ret < 0) {
> + dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_2: %d\n",
> + ret);
> + return 0;
> + }
> +
> + if (ret & WM831X_FLL_AUTO)
> + return 0;
> +
> + ret = wm831x_reg_read(wm831x, WM831X_FLL_CONTROL_5);
> + if (ret < 0) {
> + dev_err(wm831x->dev, "Unable to read FLL_CONTROL_5: %d\n",
> + ret);
> + return 0;
> + }
> +
> + switch (ret & WM831X_FLL_CLK_SRC_MASK) {
> + case 0:
> + return 0;
> + case 1:
> + return 1;
> + default:
> + dev_err(wm831x->dev, "Unsupported FLL clock source %d\n",
> + ret & WM831X_FLL_CLK_SRC_MASK);
> + return 0;
> + }
> +}
> +
> +static const struct clk_ops wm831x_fll_ops = {
> + .is_enabled = wm831x_fll_is_enabled,
> + .prepare = wm831x_fll_prepare,
> + .unprepare = wm831x_fll_unprepare,
> + .round_rate = wm831x_fll_round_rate,
> + .recalc_rate = wm831x_fll_recalc_rate,
> + .set_rate = wm831x_fll_set_rate,
> + .get_parent = wm831x_fll_get_parent,
> +};
> +
> +static struct clk_init_data wm831x_fll_init = {
> + .name = "fll",
> + .ops = &wm831x_fll_ops,
> + .parent_names = wm831x_fll_parents,
> + .num_parents = ARRAY_SIZE(wm831x_fll_parents),
> + .flags = CLK_SET_RATE_GATE,
> +};
> +
> +static int wm831x_clkout_is_enabled(struct clk_hw *hw)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + clkout_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int ret;
> +
> + ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_1);
> + if (ret < 0) {
> + dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_1: %d\n",
> + ret);
> + return true;
> + }
> +
> + return (ret & WM831X_CLKOUT_ENA) != 0;
> +}
> +
> +static int wm831x_clkout_prepare(struct clk_hw *hw)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + clkout_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int ret;
> +
> + ret = wm831x_reg_unlock(wm831x);
> + if (ret != 0) {
> + dev_crit(wm831x->dev, "Failed to lock registers: %d\n", ret);
> + return ret;
> + }
> +
> + ret = wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_1,
> + WM831X_CLKOUT_ENA, WM831X_CLKOUT_ENA);
> + if (ret != 0)
> + dev_crit(wm831x->dev, "Failed to enable CLKOUT: %d\n", ret);
> +
> + wm831x_reg_lock(wm831x);
> +
> + return ret;
> +}
> +
> +static void wm831x_clkout_unprepare(struct clk_hw *hw)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + clkout_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int ret;
> +
> + ret = wm831x_reg_unlock(wm831x);
> + if (ret != 0) {
> + dev_crit(wm831x->dev, "Failed to lock registers: %d\n", ret);
> + return;
> + }
> +
> + ret = wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_1,
> + WM831X_CLKOUT_ENA, 0);
> + if (ret != 0)
> + dev_crit(wm831x->dev, "Failed to disable CLKOUT: %d\n", ret);
> +
> + wm831x_reg_lock(wm831x);
> +}
> +
> +static const char *wm831x_clkout_parents[] = {
> + "xtal",
> + "fll",
> +};
> +
> +static u8 wm831x_clkout_get_parent(struct clk_hw *hw)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + clkout_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> + int ret;
> +
> + ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_1);
> + if (ret < 0) {
> + dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_1: %d\n",
> + ret);
> + return 0;
> + }
> +
> + if (ret & WM831X_CLKOUT_SRC)
> + return 0;
> + else
> + return 1;
> +}
> +
> +static int wm831x_clkout_set_parent(struct clk_hw *hw, u8 parent)
> +{
> + struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
> + clkout_hw);
> + struct wm831x *wm831x = clkdata->wm831x;
> +
> + return wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_1,
> + WM831X_CLKOUT_SRC,
> + parent << WM831X_CLKOUT_SRC_SHIFT);
> +}
> +
> +static const struct clk_ops wm831x_clkout_ops = {
> + .is_enabled = wm831x_clkout_is_enabled,
> + .prepare = wm831x_clkout_prepare,
> + .unprepare = wm831x_clkout_unprepare,
> + .get_parent = wm831x_clkout_get_parent,
> + .set_parent = wm831x_clkout_set_parent,
> +};
> +
> +static struct clk_init_data wm831x_clkout_init = {
> + .name = "clkout",
> + .ops = &wm831x_clkout_ops,
> + .parent_names = wm831x_clkout_parents,
> + .num_parents = ARRAY_SIZE(wm831x_clkout_parents),
> + .flags = CLK_SET_RATE_PARENT,
> +};
> +
> +static __devinit int wm831x_clk_probe(struct platform_device *pdev)
> +{
> + struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
> + struct wm831x_clk *clkdata;
> + int ret;
> +
> + clkdata = devm_kzalloc(&pdev->dev, sizeof(*clkdata), GFP_KERNEL);
> + if (!clkdata)
> + return -ENOMEM;
> +
> + /* XTAL_ENA can only be set via OTP/InstantConfig so just read once */
> + ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_2);
> + if (ret < 0) {
> + dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_2: %d\n",
> + ret);
> + return ret;
> + }
> + clkdata->xtal_ena = ret & WM831X_XTAL_ENA;
> +
> + clkdata->xtal_hw.init = &wm831x_xtal_init;
> + if (!clk_register(&pdev->dev, &clkdata->xtal_hw))
> + return -EINVAL;
> +
> + clkdata->fll_hw.init = &wm831x_fll_init;
> + if (!clk_register(&pdev->dev,&clkdata->fll_hw)) {
> + ret = -EINVAL;
> + goto err_xtal;
> + }
> +
> + clkdata->clkout_hw.init = &wm831x_clkout_init;
> + if (!clk_register(&pdev->dev, &clkdata->clkout_hw)) {
> + ret = -EINVAL;
> + goto err_fll;
> + }
> +
> + dev_set_drvdata(&pdev->dev, clkdata);
> +
> + return 0;
> +
> +err_fll:
> +err_xtal:
> + return ret;
> +}
> +
> +static struct platform_driver wm831x_clk_driver = {
> + .probe = wm831x_clk_probe,
> + .driver = {
> + .name = "wm831x-clk",
> + .owner = THIS_MODULE,
> + },
> +};
> +
> +module_platform_driver(wm831x_clk_driver);
> +
> +/* Module information */
> +MODULE_AUTHOR("Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("WM831x clock driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:wm831x-clk");
> --
> 1.7.10
>
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