diff options
Diffstat (limited to 'arch/arm/plat-s3c24xx/pwm-clock.c')
| -rw-r--r-- | arch/arm/plat-s3c24xx/pwm-clock.c | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/arch/arm/plat-s3c24xx/pwm-clock.c b/arch/arm/plat-s3c24xx/pwm-clock.c new file mode 100644 index 000000000000..2cda3e3c6786 --- /dev/null +++ b/arch/arm/plat-s3c24xx/pwm-clock.c @@ -0,0 +1,437 @@ +/* linux/arch/arm/plat-s3c24xx/pwm-clock.c + * + * Copyright (c) 2007 Simtec Electronics + * Copyright (c) 2007, 2008 Ben Dooks + * Ben Dooks <ben-linux@fluff.org> + * + * 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. +*/ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/errno.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> + +#include <asm/hardware.h> +#include <asm/irq.h> + +#include <asm/arch/regs-clock.h> +#include <asm/arch/regs-gpio.h> + +#include <asm/plat-s3c24xx/clock.h> +#include <asm/plat-s3c24xx/cpu.h> + +#include <asm/plat-s3c/regs-timer.h> + +/* Each of the timers 0 through 5 go through the following + * clock tree, with the inputs depending on the timers. + * + * pclk ---- [ prescaler 0 ] -+---> timer 0 + * +---> timer 1 + * + * pclk ---- [ prescaler 1 ] -+---> timer 2 + * +---> timer 3 + * \---> timer 4 + * + * Which are fed into the timers as so: + * + * prescaled 0 ---- [ div 2,4,8,16 ] ---\ + * [mux] -> timer 0 + * tclk 0 ------------------------------/ + * + * prescaled 0 ---- [ div 2,4,8,16 ] ---\ + * [mux] -> timer 1 + * tclk 0 ------------------------------/ + * + * + * prescaled 1 ---- [ div 2,4,8,16 ] ---\ + * [mux] -> timer 2 + * tclk 1 ------------------------------/ + * + * prescaled 1 ---- [ div 2,4,8,16 ] ---\ + * [mux] -> timer 3 + * tclk 1 ------------------------------/ + * + * prescaled 1 ---- [ div 2,4,8, 16 ] --\ + * [mux] -> timer 4 + * tclk 1 ------------------------------/ + * + * Since the mux and the divider are tied together in the + * same register space, it is impossible to set the parent + * and the rate at the same time. To avoid this, we add an + * intermediate 'prescaled-and-divided' clock to select + * as the parent for the timer input clock called tdiv. + * + * prescaled clk --> pwm-tdiv ---\ + * [ mux ] --> timer X + * tclk -------------------------/ +*/ + +static unsigned long clk_pwm_scaler_getrate(struct clk *clk) +{ + unsigned long tcfg0 = __raw_readl(S3C2410_TCFG0); + + if (clk->id == 1) { + tcfg0 &= S3C2410_TCFG_PRESCALER1_MASK; + tcfg0 >>= S3C2410_TCFG_PRESCALER1_SHIFT; + } else { + tcfg0 &= S3C2410_TCFG_PRESCALER0_MASK; + } + + return clk_get_rate(clk->parent) / (tcfg0 + 1); +} + +/* TODO - add set rate calls. */ + +struct clk clk_timer_scaler[] = { + [0] = { + .name = "pwm-scaler0", + .id = -1, + .get_rate = clk_pwm_scaler_getrate, + }, + [1] = { + .name = "pwm-scaler1", + .id = -1, + .get_rate = clk_pwm_scaler_getrate, + }, +}; + +struct clk clk_timer_tclk[] = { + [0] = { + .name = "pwm-tclk0", + .id = -1, + }, + [1] = { + .name = "pwm-tclk1", + .id = -1, + }, +}; + +struct pwm_tdiv_clk { + struct clk clk; + unsigned int divisor; +}; + +static inline struct pwm_tdiv_clk *to_tdiv(struct clk *clk) +{ + return container_of(clk, struct pwm_tdiv_clk, clk); +} + +static inline unsigned long tcfg_to_divisor(unsigned long tcfg1) +{ + return 1 << (1 + tcfg1); +} + +static unsigned long clk_pwm_tdiv_get_rate(struct clk *clk) +{ + unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1); + unsigned int divisor; + + tcfg1 >>= S3C2410_TCFG1_SHIFT(clk->id); + tcfg1 &= S3C2410_TCFG1_MUX_MASK; + + if (tcfg1 == S3C2410_TCFG1_MUX_TCLK) + divisor = to_tdiv(clk)->divisor; + else + divisor = tcfg_to_divisor(tcfg1); + + return clk_get_rate(clk->parent) / divisor; +} + +static unsigned long clk_pwm_tdiv_round_rate(struct clk *clk, + unsigned long rate) +{ + unsigned long parent_rate; + unsigned long divisor; + + parent_rate = clk_get_rate(clk->parent); + divisor = parent_rate / rate; + + if (divisor <= 2) + divisor = 2; + else if (divisor <= 4) + divisor = 4; + else if (divisor <= 8) + divisor = 8; + else + divisor = 16; + + return parent_rate / divisor; +} + +static unsigned long clk_pwm_tdiv_bits(struct pwm_tdiv_clk *divclk) +{ + unsigned long bits; + + switch (divclk->divisor) { + case 2: + bits = S3C2410_TCFG1_MUX_DIV2; + break; + case 4: + bits = S3C2410_TCFG1_MUX_DIV4; + break; + case 8: + bits = S3C2410_TCFG1_MUX_DIV8; + break; + case 16: + default: + bits = S3C2410_TCFG1_MUX_DIV16; + break; + } + + return bits; +} + +static void clk_pwm_tdiv_update(struct pwm_tdiv_clk *divclk) +{ + unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1); + unsigned long bits = clk_pwm_tdiv_bits(divclk); + unsigned long flags; + unsigned long shift = S3C2410_TCFG1_SHIFT(divclk->clk.id); + + local_irq_save(flags); + + tcfg1 = __raw_readl(S3C2410_TCFG1); + tcfg1 &= ~(S3C2410_TCFG1_MUX_MASK << shift); + tcfg1 |= bits << shift; + __raw_writel(tcfg1, S3C2410_TCFG1); + + local_irq_restore(flags); +} + +static int clk_pwm_tdiv_set_rate(struct clk *clk, unsigned long rate) +{ + struct pwm_tdiv_clk *divclk = to_tdiv(clk); + unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1); + unsigned long parent_rate = clk_get_rate(clk->parent); + unsigned long divisor; + + tcfg1 >>= S3C2410_TCFG1_SHIFT(clk->id); + tcfg1 &= S3C2410_TCFG1_MUX_MASK; + + rate = clk_round_rate(clk, rate); + divisor = parent_rate / rate; + + if (divisor > 16) + return -EINVAL; + + divclk->divisor = divisor; + + /* Update the current MUX settings if we are currently + * selected as the clock source for this clock. */ + + if (tcfg1 != S3C2410_TCFG1_MUX_TCLK) + clk_pwm_tdiv_update(divclk); + + return 0; +} + +struct pwm_tdiv_clk clk_timer_tdiv[] = { + [0] = { + .clk = { + .name = "pwm-tdiv", + .parent = &clk_timer_scaler[0], + .get_rate = clk_pwm_tdiv_get_rate, + .set_rate = clk_pwm_tdiv_set_rate, + .round_rate = clk_pwm_tdiv_round_rate, + }, + }, + [1] = { + .clk = { + .name = "pwm-tdiv", + .parent = &clk_timer_scaler[0], + .get_rate = clk_pwm_tdiv_get_rate, + .set_rate = clk_pwm_tdiv_set_rate, + .round_rate = clk_pwm_tdiv_round_rate, + } + }, + [2] = { + .clk = { + .name = "pwm-tdiv", + .parent = &clk_timer_scaler[1], + .get_rate = clk_pwm_tdiv_get_rate, + .set_rate = clk_pwm_tdiv_set_rate, + .round_rate = clk_pwm_tdiv_round_rate, + }, + }, + [3] = { + .clk = { + .name = "pwm-tdiv", + .parent = &clk_timer_scaler[1], + .get_rate = clk_pwm_tdiv_get_rate, + .set_rate = clk_pwm_tdiv_set_rate, + .round_rate = clk_pwm_tdiv_round_rate, + }, + }, + [4] = { + .clk = { + .name = "pwm-tdiv", + .parent = &clk_timer_scaler[1], + .get_rate = clk_pwm_tdiv_get_rate, + .set_rate = clk_pwm_tdiv_set_rate, + .round_rate = clk_pwm_tdiv_round_rate, + }, + }, +}; + +static int __init clk_pwm_tdiv_register(unsigned int id) +{ + struct pwm_tdiv_clk *divclk = &clk_timer_tdiv[id]; + unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1); + + tcfg1 >>= S3C2410_TCFG1_SHIFT(id); + tcfg1 &= S3C2410_TCFG1_MUX_MASK; + + divclk->clk.id = id; + divclk->divisor = tcfg_to_divisor(tcfg1); + + return s3c24xx_register_clock(&divclk->clk); +} + +static inline struct clk *s3c24xx_pwmclk_tclk(unsigned int id) +{ + return (id >= 2) ? &clk_timer_tclk[1] : &clk_timer_tclk[0]; +} + +static inline struct clk *s3c24xx_pwmclk_tdiv(unsigned int id) +{ + return &clk_timer_tdiv[id].clk; +} + +static int clk_pwm_tin_set_parent(struct clk *clk, struct clk *parent) +{ + unsigned int id = clk->id; + unsigned long tcfg1; + unsigned long flags; + unsigned long bits; + unsigned long shift = S3C2410_TCFG1_SHIFT(id); + + if (parent == s3c24xx_pwmclk_tclk(id)) + bits = S3C2410_TCFG1_MUX_TCLK << shift; + else if (parent == s3c24xx_pwmclk_tdiv(id)) + bits = clk_pwm_tdiv_bits(to_tdiv(clk)) << shift; + else + return -EINVAL; + + clk->parent = parent; + + local_irq_save(flags); + + tcfg1 = __raw_readl(S3C2410_TCFG1); + tcfg1 &= ~(S3C2410_TCFG1_MUX_MASK << shift); + __raw_writel(tcfg1 | bits, S3C2410_TCFG1); + + local_irq_restore(flags); + + return 0; +} + +static struct clk clk_tin[] = { + [0] = { + .name = "pwm-tin", + .id = 0, + .set_parent = clk_pwm_tin_set_parent, + }, + [1] = { + .name = "pwm-tin", + .id = 1, + .set_parent = clk_pwm_tin_set_parent, + }, + [2] = { + .name = "pwm-tin", + .id = 2, + .set_parent = clk_pwm_tin_set_parent, + }, + [3] = { + .name = "pwm-tin", + .id = 3, + .set_parent = clk_pwm_tin_set_parent, + }, + [4] = { + .name = "pwm-tin", + .id = 4, + .set_parent = clk_pwm_tin_set_parent, + }, +}; + +static __init int clk_pwm_tin_register(struct clk *pwm) +{ + unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1); + unsigned int id = pwm->id; + + struct clk *parent; + int ret; + + ret = s3c24xx_register_clock(pwm); + if (ret < 0) + return ret; + + tcfg1 >>= S3C2410_TCFG1_SHIFT(id); + tcfg1 &= S3C2410_TCFG1_MUX_MASK; + + if (tcfg1 == S3C2410_TCFG1_MUX_TCLK) + parent = s3c24xx_pwmclk_tclk(id); + else + parent = s3c24xx_pwmclk_tdiv(id); + + return clk_set_parent(pwm, parent); +} + +static __init int s3c24xx_pwmclk_init(void) +{ + struct clk *clk_timers; + unsigned int clk; + int ret; + + clk_timers = clk_get(NULL, "timers"); + if (IS_ERR(clk_timers)) { + printk(KERN_ERR "%s: no parent clock\n", __func__); + return -EINVAL; + } + + for (clk = 0; clk < ARRAY_SIZE(clk_timer_scaler); clk++) { + clk_timer_scaler[clk].parent = clk_timers; + ret = s3c24xx_register_clock(&clk_timer_scaler[clk]); + if (ret < 0) { + printk(KERN_ERR "error adding pwm scaler%d clock\n", clk); + goto err; + } + } + + for (clk = 0; clk < ARRAY_SIZE(clk_timer_tclk); clk++) { + ret = s3c24xx_register_clock(&clk_timer_tclk[clk]); + if (ret < 0) { + printk(KERN_ERR "error adding pww tclk%d\n", clk); + goto err; + } + } + + for (clk = 0; clk < ARRAY_SIZE(clk_timer_tdiv); clk++) { + ret = clk_pwm_tdiv_register(clk); + if (ret < 0) { + printk(KERN_ERR "error adding pwm%d tdiv clock\n", clk); + goto err; + } + } + + for (clk = 0; clk < ARRAY_SIZE(clk_tin); clk++) { + ret = clk_pwm_tin_register(&clk_tin[clk]); + if (ret < 0) { + printk(KERN_ERR "error adding pwm%d tin clock\n", clk); + goto err; + } + } + + return 0; + + err: + return ret; +} + +arch_initcall(s3c24xx_pwmclk_init); |