[PATCH 03/14] ARM: LPC32XX: Clock driver

[Uwe Kleine-König]

On Mon, Feb 08, 2010 at 04:11:24PM -0800, wellsk40 at gmail.com wrote:
> From: Kevin Wells <wellsk40 at gmail.com>
> 
> Clock driver for the LPC32XX architecture
> 
> Signed-off-by: Kevin Wells <wellsk40 at gmail.com>
> ---
>  arch/arm/mach-lpc32xx/clock.c | 1078 +++++++++++++++++++++++++++++++++++++++++
>  arch/arm/mach-lpc32xx/clock.h |   37 ++
>  2 files changed, 1115 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/mach-lpc32xx/clock.c b/arch/arm/mach-lpc32xx/clock.c
> new file mode 100644
> index 0000000..4f0b882
> --- /dev/null
> +++ b/arch/arm/mach-lpc32xx/clock.c
> @@ -0,0 +1,1078 @@
> +/*
> + * arch/arm/mach-lpc32xx/clock.c
> + *
> + * Author: Kevin Wells <kevin.wells at nxp.com>
> + *
> + * Copyright (C) 2010 NXP Semiconductors
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +/*
> + * LPC32xx clock mamagement driver overview
s/mamagement/management/

> + *
> + * The LPC32XX contains a number of high level system clocks that can be
> + * generated from different sources. These system clocks are used to
> + * generate the CPU and bus rates and the individual peripheral clocks in
> + * the system. When Linux is started by the boot loader, the system
> + * clocks are already running. Stopping a system clock during normal
> + * Linux operation should never be attempted, as peripherals that require
> + * those clocks will quit working (ie, DRAM).
> + *
> + * The LPC32xx high level clock tree looks as follows. Clocks marked with
> + * an asterisk are always on and cannot be disabled. Clocks marked with
> + * an ampersand can only be disabled in CPU suspend mode. Clocks marked
> + * with a carot are always on if it is the selected clock for the SYSCLK
s/carot/caret/

> + * source. The clock that isn't used for SYSCLK can be enabled and
> + * disabled normally.
> + *                               32KHz oscillator*
> + *                               /      |      \
> + *                             RTC*   PLL397^ TOUCH
> + *                                     /
> + *               Main oscillator^     /
> + *                   |        \      /
> + *                   |         SYSCLK&
> + *                   |            \
> + *                   |             \
> + *                USB_PLL       HCLK_PLL&
> + *                   |           |    |
> + *            USB host/device  PCLK&  |
> + *                               |    |
> + *                             Peripherals
> + *
> + * The CPU and chip bus rates are derived from the HCLK PLL, which can
> + * generate various clock rates up to 266MHz and beyond. The internal bus
> + * rates (PCLK and HCLK) are generated from dividers based on the HCLK
> + * PLL rate. HCLK can be a ratio of 1:1, 1:2, or 1:4 or HCLK PLL rate,
> + * while PCLK can be 1:1 to 1:32 of HCLK PLL rate. Most peripherals high
> + * level clocks are based on either HCLK or PCLK, but have their own
> + * dividers as part of the IP itself. Because of this, the system clock
> + * rates should not be changed.
> + *
> + * The HCLK PLL is clocked from SYSCLK, which can be derived from the
> + * main oscillator or PLL397. PLL397 generates a rate that is 397 times
> + * the 32KHz oscillator rate. The main oscillator runs at the selected
> + * oscillator/crystal rate on the mosc_in pin of the LPC32xx. This rate
> + * is normally 13MHz, but depends on the selection of external crystals
> + * or oscillators. If USB operation is required, the main oscillator must
> + * be used in the system.
> + *
> + * Switching SYSCLK between sources during normal Linux operation is not
> + * supported. SYSCLK is preset in the bootloader. Because of the
> + * complexities of clock management during clock frequency changes,
> + * there are some limitations to the clock driver explained below:
> + * - The PLL397 and main oscillator can be enabled and disabled by the
> + *   clk_enable() and clk_disable() functions unless SYSCLK is based
> + *   on that clock. This allows the other oscillator that isn't driving
> + *   the HCLK PLL to be used as another system clock that can be routed
> + *   to an external pin.
> + * - The muxed SYSCLK input and HCLK_PLL rate cannot be changed with
> + *   this driver.
> + * - HCLK and PCLK rates cannot be changed as part of this driver.
> + * - Most peripherals have their own dividers are part of the peripheral
> + *   block. Changing SYSCLK, HCLK PLL, HCLK, or PCLK sources or rates
> + *   will also impact the individual peripheral rates.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/errno.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/clk.h>
> +#include <linux/amba/bus.h>
> +#include <linux/amba/clcd.h>
> +
> +#include <mach/hardware.h>
> +#include <asm/clkdev.h>
> +#include <mach/clkdev.h>
> +#include <mach/platform.h>
> +#include "clock.h"
> +#include "common.h"
> +
> +static struct clk clk_armpll;
> +static struct clk clk_usbpll;
> +static struct mutex clkm_lock;
static DEFINE_MUTEX(clkm_lock);

then you don't need to mutex_init below.

> +
> +/*
> + * Post divider values for PLLs based on selected register value
> + */
> +const u32 pll_postdivs[4] = {1, 2, 4, 8};
make this static, too?

> +
> +static u32 local_return_parent_rate(struct clk *clk)
> +{
> +	/*
> +	 * If a clock has a rate of 0, then it inherits it's parent
> +	 * clock rate
> +	 */
> +	if (clk->rate == 0)
> +		return local_return_parent_rate(clk->parent);
> +
> +	return clk->rate;
> +}
> +
> +/* 32KHz clock has a fixed rate and is not stoppable */
> +static struct clk osc_32KHz = {
> +	.rate		= LPC32XX_CLOCK_OSC_FREQ,
> +	.get_rate	= &local_return_parent_rate,
The address operator -----^ isn't needed and commonly omitted.

> +};
> +
> +static int local_pll397_enable(struct clk *clk, int enable)
> +{
> +	u32 reg;
> +	unsigned long timeout = 1 + msecs_to_jiffies(10);
> +
> +	reg = __raw_readl(LPC32XX_CLKPWR_PLL397_CTRL);
> +
> +	if (enable == 0) 	{
> +		reg |= LPC32XX_CLKPWR_SYSCTRL_PLL397_DIS;
> +		__raw_writel(reg, LPC32XX_CLKPWR_PLL397_CTRL);
> +		clk->rate = 0;
I think you don't need to zero rate here.  get_rate isn't guaranteed to
return the right value if the clock is off, but you don't need to
"destroy" the right value on purpose.

> +	} else {
> +		/* Enable PLL397 */
> +		reg &= ~LPC32XX_CLKPWR_SYSCTRL_PLL397_DIS;
> +		__raw_writel(reg, LPC32XX_CLKPWR_PLL397_CTRL);
> +		clk->rate = LPC32XX_CLOCK_OSC_FREQ * 397;
> +
> +		/* Wait for PLL397 lock */
> +		while (((__raw_readl(LPC32XX_CLKPWR_PLL397_CTRL) &
> +			LPC32XX_CLKPWR_SYSCTRL_PLL397_STS) == 0) &&
> +			(timeout > jiffies))
> +			cpu_relax();
> +
> +		if ((__raw_readl(LPC32XX_CLKPWR_PLL397_CTRL) &
> +			LPC32XX_CLKPWR_SYSCTRL_PLL397_STS) == 0)
> +			return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static int local_oscmain_enable(struct clk *clk, int enable)
> +{
> +	u32 reg;
> +	unsigned long timeout = 1 + msecs_to_jiffies(10);
> +
> +	reg = __raw_readl(LPC32XX_CLKPWR_MAIN_OSC_CTRL);
> +
> +	if (enable == 0) {
> +		reg |= LPC32XX_CLKPWR_MOSC_DISABLE;
> +		__raw_writel(reg, LPC32XX_CLKPWR_MAIN_OSC_CTRL);
> +		clk->rate = 0;
> +	} else {
> +		/* Enable main oscillator */
> +		reg &= ~LPC32XX_CLKPWR_MOSC_DISABLE;
> +		__raw_writel(reg, LPC32XX_CLKPWR_MAIN_OSC_CTRL);
> +		clk->rate = LPC32XX_MAIN_OSC_FREQ;
> +
> +		/* Wait for main oscillator to start */
> +		while (((__raw_readl(LPC32XX_CLKPWR_MAIN_OSC_CTRL) &
> +			LPC32XX_CLKPWR_MOSC_DISABLE) != 0) &&
> +			(timeout > jiffies))
> +			cpu_relax();
> +
> +		if ((__raw_readl(LPC32XX_CLKPWR_MAIN_OSC_CTRL) &
> +			LPC32XX_CLKPWR_MOSC_DISABLE) != 0)
> +			return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct clk osc_pll397 = {
> +	.parent		= &osc_32KHz,
> +	.enable		= &local_pll397_enable,
> +	.rate		= LPC32XX_CLOCK_OSC_FREQ * 397,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk osc_main = {
> +	.enable		= &local_oscmain_enable,
> +	.rate		= LPC32XX_MAIN_OSC_FREQ,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_sys;
> +
> +/*
> + * Setup the HCLK PLL with a PLL structure
> + */
> +static u32 local_clk_pll_setup(struct clk_pll_setup *PllSetup)
> +{
> +	u32 tv, tmp = 0;
> +
> +	if (PllSetup->analog_on != 0)
> +		tmp |= LPC32XX_CLKPWR_HCLKPLL_POWER_UP;
> +	if (PllSetup->cco_bypass_b15 != 0)
> +		tmp |= LPC32XX_CLKPWR_HCLKPLL_CCO_BYPASS;
> +	if (PllSetup->direct_output_b14 != 0)
> +		tmp |= LPC32XX_CLKPWR_HCLKPLL_POSTDIV_BYPASS;
> +	if (PllSetup->fdbk_div_ctrl_b13 != 0)
> +		tmp |= LPC32XX_CLKPWR_HCLKPLL_FDBK_SEL_FCLK;
> +
> +	switch (PllSetup->pll_p) {
> +	case 1:
> +		tv = 0;
> +		break;
> +
> +	case 2:
> +		tv = 1;
> +		break;
> +
> +	case 4:
> +		tv = 2;
> +		break;
> +
> +	case 8:
> +		tv = 3;
> +		break;
> +
> +	default:
> +		return 0;
> +	}
I don't know the hardware details here, but maybe using ffs and
is_power_of_2 is more efficient?

> +	tmp |= LPC32XX_CLKPWR_HCLKPLL_POSTDIV_2POW(tv);
> +	tmp |= LPC32XX_CLKPWR_HCLKPLL_PREDIV_PLUS1(PllSetup->pll_n - 1);
> +	tmp |= LPC32XX_CLKPWR_HCLKPLL_PLLM(PllSetup->pll_m - 1);
> +
> +	return tmp;
> +}
> +
> +/*
> + * Update the ARM core PLL frequency rate variable from the actual PLL setting
> + */
> +static void local_update_armpll_rate(void)
> +{
> +	u32 clkin, pllreg;
> +
> +	clkin = clk_armpll.parent->rate;
> +	pllreg = __raw_readl(LPC32XX_CLKPWR_HCLKPLL_CTRL) & 0x1FFFF;
> +
> +	clk_armpll.rate = clk_get_pllrate_from_reg(clkin, pllreg);
> +}
> +
> +/*
> + * Find a PLL configuration for the selected input frequency
> + */
> +static u32 local_clk_find_pll_cfg(u32 pllin_freq, u32 target_freq,
> +	struct clk_pll_setup *pllsetup)
> +{
> +	u32 ifreq, freqtol, m, n, p, fclkout;
> +
> +	/* Determine frequency tolerance limits */
> +	freqtol = target_freq / 250;
> +	ifreq = pllin_freq;
> +
> +	/* Is direct bypass mode possible? */
> +	if (abs(pllin_freq - target_freq) <= freqtol) {
> +		pllsetup->analog_on = 0;
> +		pllsetup->cco_bypass_b15 = 1;
> +		pllsetup->direct_output_b14 = 1;
> +		pllsetup->fdbk_div_ctrl_b13 = 1;
> +		pllsetup->pll_p = pll_postdivs[0];
> +		pllsetup->pll_n = 1;
> +		pllsetup->pll_m = 1;
> +		return clk_check_pll_setup(ifreq, pllsetup);
> +	} else if (target_freq <= ifreq) {
> +		pllsetup->analog_on = 0;
> +		pllsetup->cco_bypass_b15 = 1;
> +		pllsetup->direct_output_b14 = 0;
> +		pllsetup->fdbk_div_ctrl_b13 = 1;
> +		pllsetup->pll_n = 1;
> +		pllsetup->pll_m = 1;
> +		for (p = 0; p <= 3; p++) {
> +			pllsetup->pll_p = pll_postdivs[p];
> +			fclkout = clk_check_pll_setup(ifreq, pllsetup);
> +			if (abs(target_freq - fclkout) <= freqtol)
> +				return fclkout;
> +		}
> +	}
> +
> +	/* Is direct mode possible? */
> +	pllsetup->analog_on = 1;
> +	pllsetup->cco_bypass_b15 = 0;
> +	pllsetup->direct_output_b14 = 1;
> +	pllsetup->fdbk_div_ctrl_b13 = 0;
> +	pllsetup->pll_p = pll_postdivs[0];
> +	for (m = 1; m <= 256; m++) {
> +		for (n = 1; n <= 4; n++) {
> +			/* Compute output frequency for this value */
> +			pllsetup->pll_n = n;
> +			pllsetup->pll_m = m;
> +			fclkout = clk_check_pll_setup(ifreq,
> +				pllsetup);
> +			if (abs(target_freq - fclkout) <=
> +				freqtol)
> +				return fclkout;
> +		}
> +	}
> +
> +	/* Is integer mode possible? */
> +	pllsetup->analog_on = 1;
> +	pllsetup->cco_bypass_b15 = 0;
> +	pllsetup->direct_output_b14 = 0;
> +	pllsetup->fdbk_div_ctrl_b13 = 1;
> +	for (m = 1; m <= 256; m++) {
> +		for (n = 1; n <= 4; n++) {
> +			for (p = 0; p < 4; p++) {
> +				/* Compute output frequency */
> +				pllsetup->pll_p = pll_postdivs[p];
> +				pllsetup->pll_n = n;
> +				pllsetup->pll_m = m;
> +				fclkout = clk_check_pll_setup(
> +					ifreq, pllsetup);
> +				if (abs(target_freq - fclkout) <= freqtol)
> +					return fclkout;
> +			}
> +		}
> +	}
> +
> +	/* Try non-integer mode */
> +	pllsetup->analog_on = 1;
> +	pllsetup->cco_bypass_b15 = 0;
> +	pllsetup->direct_output_b14 = 0;
> +	pllsetup->fdbk_div_ctrl_b13 = 0;
> +	for (m = 1; m <= 256; m++) {
> +		for (n = 1; n <= 4; n++) {
> +			for (p = 0; p < 4; p++) {
> +				/* Compute output frequency */
> +				pllsetup->pll_p = pll_postdivs[p];
> +				pllsetup->pll_n = n;
> +				pllsetup->pll_m = m;
> +				fclkout = clk_check_pll_setup(
> +					ifreq, pllsetup);
> +				if (abs(target_freq - fclkout) <= freqtol)
> +					return fclkout;
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static struct clk clk_armpll = {
> +	.parent		= &clk_sys,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +/*
> + * Update the USB PLL frequency rate variable from the actual PLL setting
> + */
> +static void local_update_usbpll_rate(void)
> +{
> +	u32 clkin, pllreg;
> +
> +	clkin = clk_usbpll.get_rate(&clk_usbpll);
> +	pllreg = __raw_readl(LPC32XX_CLKPWR_USB_CTRL) & 0x1FFFF;
> +
> +	if ((pllreg & LPC32XX_CLKPWR_USBCTRL_PLL_PWRUP) == 0)
> +		clk_usbpll.rate = 0;
> +	else
> +		clk_usbpll.rate = clk_get_pllrate_from_reg(clkin,
> +			pllreg);
> +}
> +
> +/*
> + * Setup the USB PLL with a PLL structure
> + */
> +static u32 local_clk_usbpll_setup(struct clk_pll_setup *pHCLKPllSetup)
> +{
> +	u32 reg, tmp = local_clk_pll_setup(pHCLKPllSetup);
> +
> +	reg = __raw_readl(LPC32XX_CLKPWR_USB_CTRL) & ~0x1FFFF;
> +	reg |= tmp;
> +	__raw_writel(reg, LPC32XX_CLKPWR_USB_CTRL);
> +
> +	return clk_check_pll_setup(clk_usbpll.parent->rate,
> +		pHCLKPllSetup);
> +}
> +
> +static int local_usbpll_enable(struct clk *clk, int enable)
> +{
> +	u32 reg;
> +	int ret = -ENODEV;
> +	unsigned long timeout = 1 + msecs_to_jiffies(10);
> +
> +	reg = __raw_readl(LPC32XX_CLKPWR_USB_CTRL);
> +
> +	if (enable == 0) {
> +		reg &= ~(LPC32XX_CLKPWR_USBCTRL_CLK_EN1 |
> +			LPC32XX_CLKPWR_USBCTRL_CLK_EN2);
> +		__raw_writel(reg, LPC32XX_CLKPWR_USB_CTRL);
> +	} else if (reg & LPC32XX_CLKPWR_USBCTRL_PLL_PWRUP) {
> +		reg |= LPC32XX_CLKPWR_USBCTRL_CLK_EN1;
> +		__raw_writel(reg, LPC32XX_CLKPWR_USB_CTRL);
> +
> +		/* Wait for PLL lock */
> +		while ((timeout > jiffies) & (ret == -ENODEV)) {
> +			reg = __raw_readl(LPC32XX_CLKPWR_USB_CTRL);
> +			if (reg & LPC32XX_CLKPWR_USBCTRL_PLL_STS)
> +				ret = 0;
> +		}
> +
> +		if (ret == 0) {
> +			reg |= LPC32XX_CLKPWR_USBCTRL_CLK_EN2;
> +			__raw_writel(reg, LPC32XX_CLKPWR_USB_CTRL);
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int local_usbpll_set_rate(struct clk *clk, u32 rate)
> +{
> +	u32 clkin, reg, usbdiv;
> +	struct clk_pll_setup pllsetup;
> +
> +	/*
> +	 * Unlike other clocks, this clock has a KHz input rate, so bump
> +	 * it up to work with the PLL function
> +	 */
> +	rate = rate * 1000;
> +
> +	local_usbpll_enable(clk, 0);
> +
> +	if (rate == 0)
> +		return 0;
> +
> +	clkin = clk->parent->rate;
> +	usbdiv = __raw_readl(LPC32XX_CLKPWR_USBCLK_PDIV) + 1;
> +	clkin = clkin / usbdiv;
> +
> +	/* Try to find a good rate setup */
> +	if (local_clk_find_pll_cfg(clkin, rate, &pllsetup) == 0)
> +		return -EINVAL;
> +
> +	reg = __raw_readl(LPC32XX_CLKPWR_USB_CTRL);
> +	reg |= LPC32XX_CLKPWR_USBCTRL_CLK_EN1;
> +	__raw_writel(reg, LPC32XX_CLKPWR_USB_CTRL);
> +
> +	pllsetup.analog_on = 1;
> +	local_clk_usbpll_setup(&pllsetup);
> +
> +	clk->rate = clk_check_pll_setup(clkin, &pllsetup);
> +
> +	reg = __raw_readl(LPC32XX_CLKPWR_USB_CTRL);
> +	reg |= LPC32XX_CLKPWR_USBCTRL_CLK_EN2;
> +	__raw_writel(reg, LPC32XX_CLKPWR_USB_CTRL);
> +
> +	return 0;
> +}
> +
> +static struct clk clk_usbpll = {
> +	.parent		= &osc_main,
> +	.set_rate	= &local_usbpll_set_rate,
> +	.enable		= &local_usbpll_enable,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static u32 clk_get_hclk_div(void)
> +{
> +	static const u32 hclkdivs[4] = {1, 2, 4, 4};
> +	return hclkdivs[LPC32XX_CLKPWR_HCLKDIV_DIV_2POW(
> +		__raw_readl(LPC32XX_CLKPWR_HCLK_DIV))];
> +}
> +
> +static struct clk clk_hclk = {
> +	.parent		= &clk_armpll,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_pclk = {
> +	.parent		= &clk_armpll,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static int local_onoff_enable(struct clk *clk, int enable)
> +{
> +	u32 tmp;
> +
> +	tmp = __raw_readl(clk->enable_reg);
> +
> +	if (enable == 0)
> +		tmp &= ~clk->enable_mask;
> +	else
> +		tmp |= clk->enable_mask;
> +
> +	__raw_writel(tmp, clk->enable_reg);
> +
> +	return 0;
> +}
> +
> +/* Peripheral clock sources */
> +static struct clk clk_timer0 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1,
> +	.enable_mask	= LPC32XX_CLKPWR_TMRPWMCLK_TIMER0_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +static struct clk clk_timer1 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1,
> +	.enable_mask	= LPC32XX_CLKPWR_TMRPWMCLK_TIMER1_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +static struct clk clk_timer2 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1,
> +	.enable_mask	= LPC32XX_CLKPWR_TMRPWMCLK_TIMER2_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +static struct clk clk_timer3 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1,
> +	.enable_mask	= LPC32XX_CLKPWR_TMRPWMCLK_TIMER3_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +static struct clk clk_wdt = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_TIMER_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_PWMCLK_WDOG_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +static struct clk clk_vfp9 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_DEBUG_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_VFP_CLOCK_ENABLE_BIT,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +static struct clk clk_dma = {
> +	.parent		= &clk_hclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_DMA_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_DMACLKCTRL_CLK_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_uart3 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_UART_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_UARTCLKCTRL_UART3_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_uart4 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_UART_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_UARTCLKCTRL_UART4_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_uart5 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_UART_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_UARTCLKCTRL_UART5_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_uart6 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_UART_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_UARTCLKCTRL_UART6_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_i2c0 = {
> +	.parent		= &clk_hclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_I2C_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_I2CCLK_I2C1CLK_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_i2c1 = {
> +	.parent		= &clk_hclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_I2C_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_I2CCLK_I2C2CLK_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_i2c2 = {
> +	.parent		= &clk_pclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= io_p2v(LPC32XX_USB_BASE + 0xFF4),
> +	.enable_mask	= 0x4,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_ssp0 = {
> +	.parent		= &clk_hclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_SSP_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_SSPCTRL_SSPCLK0_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_ssp1 = {
> +	.parent		= &clk_hclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_SSP_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_SSPCTRL_SSPCLK1_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_kscan = {
> +	.parent		= &osc_32KHz,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_KEY_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_KEYCLKCTRL_CLK_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_nand = {
> +	.parent		= &clk_hclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_NAND_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_NANDCLK_SLCCLK_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_i2s0 = {
> +	.parent		= &clk_hclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_I2S_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_I2SCTRL_I2SCLK0_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_i2s1 = {
> +	.parent		= &clk_hclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_I2S_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_I2SCTRL_I2SCLK1_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_net = {
> +	.parent		= &clk_hclk,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_MACCLK_CTRL,
> +	.enable_mask	= (LPC32XX_CLKPWR_MACCTRL_DMACLK_EN |
> +		LPC32XX_CLKPWR_MACCTRL_MMIOCLK_EN |
> +		LPC32XX_CLKPWR_MACCTRL_HRCCLK_EN),
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_rtc = {
> +	.parent		= &osc_32KHz,
> +	.rate		= 1, /* 1 Hz */
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static struct clk clk_usbd = {
> +	.parent		= &clk_usbpll,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_USB_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_USBCTRL_HCLK_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static int tsc_onoff_enable(struct clk *clk, int enable)
> +{
> +	u32 tmp;
> +
> +	/* Make sure 32KHz clock is the selected clock */
> +	tmp = __raw_readl(LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
> +	tmp &= ~LPC32XX_CLKPWR_ADCCTRL1_PCLK_SEL;
> +	__raw_writel(tmp, LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
> +
> +	if (enable == 0)
> +		__raw_writel(0, clk->enable_reg);
> +	else
> +		__raw_writel(clk->enable_mask, clk->enable_reg);
> +
> +	return 0;
> +}
> +
> +static struct clk clk_tsc = {
> +	.parent		= &osc_32KHz,
> +	.enable		= &tsc_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_ADC_CLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_ADC32CLKCTRL_CLK_EN,
> +	.get_rate	= &local_return_parent_rate,
> +};
> +
> +static int mmc_onoff_enable(struct clk *clk, int enable)
> +{
> +	u32 tmp;
> +
> +	tmp = __raw_readl(LPC32XX_CLKPWR_MS_CTRL) &
> +		~(LPC32XX_CLKPWR_MSCARD_SDCARD_EN |
> +		LPC32XX_CLKPWR_MSCARD_SDCARD_DIV(15));
> +
> +	/* If rate is 0, disable clock */
> +	if (enable != 0)
> +		tmp |= LPC32XX_CLKPWR_MSCARD_SDCARD_EN |
> +			LPC32XX_CLKPWR_MSCARD_SDCARD_DIV(1);
> +
> +	__raw_writel(tmp, LPC32XX_CLKPWR_MS_CTRL);
> +
> +	return 0;
> +}
> +
> +static u32 mmc_get_rate(struct clk *clk)
> +{
> +	u32 div, tmp, rate;
> +
> +	div = __raw_readl(LPC32XX_CLKPWR_MS_CTRL);
> +	tmp = div & LPC32XX_CLKPWR_MSCARD_SDCARD_EN;
> +
> +	if (!tmp)
> +		return 0;
> +
> +	/* Get the parent clock rate */
> +	rate = clk->parent->get_rate(clk->parent);
> +
> +	/* Get the LCD controller clock divider value */
> +	div = div & 0xF;
> +
> +	if (!div)
> +		return 0;
> +
> +	tmp = rate / div;
> +
> +	return tmp;
> +}
> +
> +static int mmc_set_rate(struct clk *clk, u32 rate)
> +{
> +	if (rate == 0)
> +		mmc_onoff_enable(clk, 0);
> +	else
> +		mmc_onoff_enable(clk, 1);
> +
> +	return 0;
> +}
> +
> +static struct clk clk_mmc = {
> +	.parent		= &clk_armpll,
> +	.set_rate	= &mmc_set_rate,
> +	.get_rate	= &mmc_get_rate,
> +	.enable		= &mmc_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_MS_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_MSCARD_SDCARD_EN,
> +};
> +
> +static u32 clcd_get_rate(struct clk *clk)
> +{
> +	u32 tmp, div, rate;
> +
> +	tmp = __raw_readl(LPC32XX_CLKPWR_LCDCLK_CTRL) &
> +		LPC32XX_CLKPWR_LCDCTRL_CLK_EN;
> +
> +	if (!tmp)
> +		return 0;
> +
> +	rate = clk->parent->get_rate(clk->parent);
> +	tmp = __raw_readl(io_p2v(LPC32XX_LCD_BASE + CLCD_TIM2));
> +
> +	/* Only supports internal clocking */
> +	if (tmp & TIM2_BCD)
> +		return rate;
> +
> +	div = (tmp & 0x1F) | ((tmp & 0xF8) >> 22);
> +	tmp = rate / (2 + div);
> +
> +	return tmp;
> +}
> +
> +static int clcd_set_rate(struct clk *clk, u32 rate)
> +{
> +	u32 tmp, prate, div;
> +
> +	tmp = __raw_readl(io_p2v(LPC32XX_LCD_BASE + CLCD_TIM2));
> +	prate = clk->parent->get_rate(clk->parent);
> +
> +	if (rate == prate) {
> +		tmp |= TIM2_BCD;
> +		local_onoff_enable(clk, 1);
> +	} else {
> +		/* Find closest divider */
> +		div = prate / rate;
> +		if (div == 1)
> +			div = 0;
> +		else
> +			div -= 2;
> +
> +		tmp &= ~(0xF800001F);
> +		tmp &= ~TIM2_BCD;
> +		tmp |= (div & 0x1F);
> +		tmp |= (((div >> 5) & 0x1F) << 27);
> +		__raw_writel(tmp, io_p2v(LPC32XX_LCD_BASE + CLCD_TIM2));
> +		local_onoff_enable(clk, 1);
> +	}
> +
> +	return 0;
> +}
> +
> +static struct clk clk_lcd = {
> +	.parent		= &clk_hclk,
> +	.set_rate	= &clcd_set_rate,
> +	.get_rate	= &clcd_get_rate,
> +	.enable		= &local_onoff_enable,
> +	.enable_reg	= LPC32XX_CLKPWR_LCDCLK_CTRL,
> +	.enable_mask	= LPC32XX_CLKPWR_LCDCTRL_CLK_EN,
> +};
> +
> +static inline void clk_lock(void)
> +{
> +	mutex_lock(&clkm_lock);
> +}
> +
> +static inline void clk_unlock(void)
> +{
> +	mutex_unlock(&clkm_lock);
> +}
> +
> +static void local_clk_disable(struct clk *clk)
> +{
> +	/* Don't attempt to disable clock if it has no users */
WARN_ON(clk->usecount <= 0)?

> +	if (clk->usecount > 0) {
> +		clk->usecount--;
> +
> +		/* Only disable clock when it has no more users */
> +		if ((clk->usecount == 0) && (clk->enable))
> +			clk->enable(clk, 0);
> +
> +		/* Check parent clocks, they may need to be disabled too */
> +		if (clk->parent)
> +			local_clk_disable(clk->parent);
> +	}
> +}
> +
> +static int local_clk_enable(struct clk *clk)
> +{
> +	int ret = 0;
> +
> +	if (clk->usecount == 0) {
> +		/* Enable parent clocks first */
> +		if (clk->parent)
> +			ret = local_clk_enable(clk->parent);
> +
> +		/* Enable clock on first use */
> +		if ((ret == 0) && (clk->enable)) {
> +			ret = clk->enable(clk, 1);
> +			clk->usecount++;
> +		}
> +
> +		/* Back out use counters if enable fails */
> +		if (ret < 0)
> +			local_clk_disable(clk);
if enable failed there is no need to disable, is it?

And I think the reference counting is broken.

After

	clk_enable(aclk);
	clk_enable(aclk);
	clk_disable(aclk);

aclk is disabled because usecount isn't increased if it is already >0!?


> +	}
> +
> +	return ret;
> +}
> +
> +/*
> + * clk_enable - inform the system when the clock source should be running.
> + */
> +int clk_enable(struct clk *clk)
> +{
> +	int ret;
> +
> +	clk_lock();
> +	ret = local_clk_enable(clk);
> +	clk_unlock();
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(clk_enable);
> +
> +/*
> + * clk_disable - inform the system when the clock source is no longer required
> + */
> +void clk_disable(struct clk *clk)
> +{
> +	clk_lock();
> +	local_clk_disable(clk);
> +	clk_unlock();
> +}
> +EXPORT_SYMBOL(clk_disable);
> +
> +/*
> + * clk_get_rate - obtain the current clock rate (in Hz) for a clock source
> + */
> +unsigned long clk_get_rate(struct clk *clk)
> +{
> +	unsigned long rate;
> +
> +	clk_lock();
> +	rate = (clk->get_rate)(clk);
> +	clk_unlock();
> +
> +	return rate;
> +}
> +EXPORT_SYMBOL(clk_get_rate);
> +
> +/*
> + * clk_set_rate - set the clock rate for a clock source
> + */
> +int clk_set_rate(struct clk *clk, unsigned long rate)
> +{
> +	int ret = -EINVAL;
> +
> +	/*
> +	 * Most system clocks can only be enabled or disabled, with
> +	 * the actual rate set as part of the peripheral dividers
> +	 * instead of high level clock control
> +	 */
> +	if (clk->set_rate) {
> +		clk_lock();
> +		ret = (clk->set_rate)(clk, rate);
> +		clk_unlock();
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(clk_set_rate);
> +
> +/*
> + * clk_round_rate - adjust a rate to the exact rate a clock can provide
> + */
> +long clk_round_rate(struct clk *clk, unsigned long rate)
> +{
> +	int ret;
> +
> +	/* Use set_rate to try to adjust the rate if it supports it */
> +	ret = clk_set_rate(clk, rate);
> +	if (ret < 0)
> +		return ret;
> +
> +	return clk->rate;
> +}
> +EXPORT_SYMBOL(clk_round_rate);
> +
> +/*
> + * clk_set_parent - set the parent clock source for this clock
> + */
> +int clk_set_parent(struct clk *clk, struct clk *parent)
> +{
> +	/* Clock re-parenting is not supported */
> +	return -EINVAL;
> +}
> +EXPORT_SYMBOL(clk_set_parent);
> +
> +/*
> + * clk_get_parent - get the parent clock source for this clock
> + */
> +struct clk *clk_get_parent(struct clk *clk)
> +{
> +	return clk->parent;
> +}
> +EXPORT_SYMBOL(clk_get_parent);
> +
> +#define _REGISTER_CLOCK(d, n, c) \
> +	{ \
> +		.dev_id = (d), \
> +		.con_id = (n), \
> +		.clk = &(c), \
> +	},
> +
> +static struct clk_lookup lookups[] = {
> +	_REGISTER_CLOCK(NULL, "osc_32KHz", osc_32KHz)
> +	_REGISTER_CLOCK(NULL, "osc_pll397", osc_pll397)
> +	_REGISTER_CLOCK(NULL, "osc_main", osc_main)
> +	_REGISTER_CLOCK(NULL, "sys_ck", clk_sys)
> +	_REGISTER_CLOCK(NULL, "arm_pll_ck", clk_armpll)
> +	_REGISTER_CLOCK(NULL, "ck_pll5", clk_usbpll)
> +	_REGISTER_CLOCK(NULL, "hclk_ck", clk_hclk)
> +	_REGISTER_CLOCK(NULL, "pclk_ck", clk_pclk)
> +	_REGISTER_CLOCK(NULL, "timer0_ck", clk_timer0)
> +	_REGISTER_CLOCK(NULL, "timer1_ck", clk_timer1)
> +	_REGISTER_CLOCK(NULL, "timer2_ck", clk_timer2)
> +	_REGISTER_CLOCK(NULL, "timer3_ck", clk_timer3)
> +	_REGISTER_CLOCK(NULL, "vfp9_ck", clk_vfp9)
> +	_REGISTER_CLOCK(NULL, "clk_dmac", clk_dma)
> +	_REGISTER_CLOCK("pnx4008-watchdog", NULL, clk_wdt)
> +	_REGISTER_CLOCK(NULL, "uart3_ck", clk_uart3)
> +	_REGISTER_CLOCK(NULL, "uart4_ck", clk_uart4)
> +	_REGISTER_CLOCK(NULL, "uart5_ck", clk_uart5)
> +	_REGISTER_CLOCK(NULL, "uart6_ck", clk_uart6)
> +	_REGISTER_CLOCK("pnx-i2c.0", NULL, clk_i2c0)
> +	_REGISTER_CLOCK("pnx-i2c.1", NULL, clk_i2c1)
> +	_REGISTER_CLOCK("pnx-i2c.2", NULL, clk_i2c2)
> +	_REGISTER_CLOCK("dev:ssp0", NULL, clk_ssp0)
> +	_REGISTER_CLOCK("dev:ssp1", NULL, clk_ssp1)
> +	_REGISTER_CLOCK("lpc32xx_keys.0", NULL, clk_kscan)
> +	_REGISTER_CLOCK("lpc32xx-nand.0", "nand_ck", clk_nand)
> +	_REGISTER_CLOCK("tbd", "i2s0_ck", clk_i2s0)
> +	_REGISTER_CLOCK("tbd", "i2s1_ck", clk_i2s1)
> +	_REGISTER_CLOCK("lpc32xx-ts", NULL, clk_tsc)
> +	_REGISTER_CLOCK("dev:mmc0", "MCLK", clk_mmc)
> +	_REGISTER_CLOCK("lpc-net.0", NULL, clk_net)
> +	_REGISTER_CLOCK("dev:clcd", NULL, clk_lcd)
> +	_REGISTER_CLOCK("lpc32xx_udc", "ck_usbd", clk_usbd)
> +	_REGISTER_CLOCK("lpc32xx_rtc", NULL, clk_rtc)
> +};
> +
> +static int __init clk_init(void)
> +{
> +	int i;
> +
> +	mutex_init(&clkm_lock);
> +
> +	for (i = 0; i < ARRAY_SIZE(lookups); i++)
> +		clkdev_add(&lookups[i]);
> +
> +	/*
> +	 * Setup muxed SYSCLK for HCLK PLL base -this selects the
> +	 * parent clock used for the ARM PLL and is used to derive
> +	 * the many system clock rates in the device.
> +	 */
> +	if (clk_is_sysclk_mainosc() != 0)
> +		clk_sys.parent = &osc_main;
> +	else
> +		clk_sys.parent = &osc_pll397;
> +
> +	clk_sys.rate = clk_sys.parent->rate;
> +
> +	/* Compute the current ARM PLL and USB PLL frequencies */
> +	local_update_armpll_rate();
> +	local_update_usbpll_rate();
> +
> +	/* Compute HCLK and PCLK bus rates */
> +	clk_hclk.rate = clk_hclk.parent->rate / clk_get_hclk_div();
> +	clk_pclk.rate = clk_pclk.parent->rate / clk_get_pclk_div();
> +
> +	/*
> +	 * Enable system clocks - this step is somewhat formal, as the
> +	 * clocks are already running, but it does get the clock data
> +	 * inline with the actual system state. Never disable these
> +	 * clocks as they will only stop if the system is going to sleep.
> +	 * In that case, the chip/system power management functions will
> +	 * handle clock gating.
> +	 */
> +	clk_enable(&clk_hclk);
> +	clk_enable(&clk_pclk);
> +
> +	/*
> +	 * Timers 0 and 1 were enabled and are being used by the high
> +	 * resolution tick function prior to this driver being initialized.
> +	 * Tag them now as used.
> +	 */
> +	clk_enable(&clk_timer0);
> +	clk_enable(&clk_timer1);
> +
> +	return 0;
> +}
> +core_initcall(clk_init);
> +
> diff --git a/arch/arm/mach-lpc32xx/clock.h b/arch/arm/mach-lpc32xx/clock.h
> new file mode 100644
> index 0000000..97789b9
> --- /dev/null
> +++ b/arch/arm/mach-lpc32xx/clock.h
> @@ -0,0 +1,37 @@
> +/*
> + * arch/arm/mach-lpc32xx/clock.h
> + *
> + * Author: Kevin Wells <kevin.wells at nxp.com>
> + *
> + * Copyright (C) 2010 NXP Semiconductors
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __LPC32XX_CLOCK_H
> +#define __LPC32XX_CLOCK_H
> +
> +struct clk {
> +	struct list_head node;
> +	struct clk *parent;
> +	u32 rate;
> +	s8 usecount;
why is usecount a signed value?  You don't save anything here with using
an 8bit quantity because of padding.  So you can use u32 with no cost.

> +
> +	int (*set_rate) (struct clk *, u32);
> +	int (*enable) (struct clk *clk, int);
> +	u32 (*get_rate) (struct clk *clk);
> +
> +	/* Register address and bit mask for simple clocks */
> +	void __iomem *enable_reg;
> +	u32 enable_mask;
> +};
> +
> +#endif

Best regards
Uwe

-- 
Pengutronix e.K.                              | Uwe Kleine-König            |
Industrial Linux Solutions                    | http://www.pengutronix.de/  |