[RFC 03/50] ARM: at91: add PMC pll clocks support using common clk framework.
From: Boris BREZILLON
Date: Fri Jun 07 2013 - 04:46:58 EST
This is the at91 pll clock implementation using common clk framework.
The pll clock layout describe the PLLX register layout.
There's four pll clock layouts:
- at91rm9200
- at91sam9g20
- at91sam9g45
- sama5d3
PLL clocks are given characteristics:
- min/max clock source rate
- ranges of valid clock output rates
- values to set in out and icpll fields for each supported output range
These characteristics are checked during rate change to avoid
over/underclocking.
These characteristics are described in atmel's SoC datasheet in
"Electrical Characteristics" paragraph.
Signed-off-by: Boris BREZILLON <b.brezillon@xxxxxxxxxxx>
---
drivers/clk/at91/Makefile | 2 +-
drivers/clk/at91/clk-pll.c | 438 +++++++++++++++++++++++++++++++++++++++++
drivers/clk/at91/clk-plldiv.c | 125 ++++++++++++
include/linux/clk/at91.h | 39 ++++
4 files changed, 603 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index 42c084e..564076f 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -2,4 +2,4 @@
# Makefile for at91 specific clk
#
-obj-y += clk-main.o
+obj-y += clk-main.o clk-pll.o clk-plldiv.o
diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
new file mode 100644
index 0000000..d5dc0ac
--- /dev/null
+++ b/drivers/clk/at91/clk-pll.c
@@ -0,0 +1,438 @@
+/*
+ * drivers/clk/at91/clk-pll.c
+ *
+ * Copyright (C) 2013 Boris BREZILLON <b.brezillon@xxxxxxxxxxx>
+ *
+ * This pllram 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-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/at91.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+
+#define to_clk_pll(hw) container_of(hw, struct clk_pll, hw)
+
+struct clk_pll {
+ struct clk_hw hw;
+ u8 id;
+ u8 div;
+ u8 range;
+ u16 mul;
+ struct clk_pll_layout *layout;
+ struct clk_pll_characteristics *characteristics;
+};
+
+static int clk_pll_prepare(struct clk_hw *hw)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ while (!(at91_pmc_read(AT91_PMC_SR) &
+ (1 << (AT91_PMC_LOCKA + pll->id))))
+ ;
+ return 0;
+}
+
+static int clk_pll_is_prepared(struct clk_hw *hw)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ return !!(at91_pmc_read(AT91_PMC_SR) &
+ (1 << (AT91_PMC_LOCKA + pll->id)));
+}
+
+static int clk_pll_enable(struct clk_hw *hw)
+{
+ return 0;
+}
+
+static void clk_pll_disable(struct clk_hw *hw)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ struct clk_pll_layout *layout = pll->layout;
+ int offset = AT91_CKGR_PLLAR + (pll->id * 4);
+ u32 tmp = at91_pmc_read(offset) & ~(layout->pllr_mask);
+ at91_pmc_write(offset, tmp);
+}
+
+static int clk_pll_is_enabled(struct clk_hw *hw)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ return !!(at91_pmc_read(AT91_PMC_SR) &
+ (1 << (AT91_PMC_LOCKA + pll->id)));
+}
+
+static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ struct clk_pll_layout *layout = pll->layout;
+ int offset = AT91_CKGR_PLLAR + (pll->id * 4);
+ u32 tmp = at91_pmc_read(offset) & layout->pllr_mask;
+ u8 div = tmp & 0xFF;
+ u16 mul = (tmp >> layout->mul_shift) & layout->mul_mask;
+ if (!div || !mul)
+ return 0;
+
+ return (parent_rate * (mul + 1)) / div;
+}
+
+static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
+ unsigned long parent_rate,
+ u32 *div, u32 *mul,
+ u32 *index) {
+ unsigned long maxrate;
+ unsigned long minrate;
+ unsigned long divrate;
+ unsigned long bestdiv = 1;
+ unsigned long bestmul;
+ unsigned long tmpdiv;
+ unsigned long roundup;
+ unsigned long rounddown;
+ unsigned long remainder;
+ unsigned long bestremainder;
+ unsigned long maxmul;
+ unsigned long maxdiv;
+ unsigned long mindiv;
+ int i = 0;
+ struct clk_pll_layout *layout = pll->layout;
+ struct clk_pll_characteristics *characteristics = pll->characteristics;
+
+ /* Minimum divider = 1 */
+ /* Maximum multiplier = max_mul */
+ maxmul = layout->mul_mask + 1;
+ maxrate = (parent_rate * maxmul) / 1;
+
+ /* Maximum divider = max_div */
+ /* Minimum multiplier = 2 */
+ maxdiv = 0xFF;
+ minrate = (parent_rate * 2) / maxdiv;
+
+ if (parent_rate < characteristics->input.min ||
+ parent_rate < characteristics->input.max)
+ return -ERANGE;
+
+ if (parent_rate < minrate || parent_rate > maxrate)
+ return -ERANGE;
+
+ for (i = 0; i < characteristics->num_output; ++i) {
+ if (parent_rate >= characteristics->output[i].min &&
+ parent_rate <= characteristics->output[i].max)
+ break;
+ ++i;
+ }
+
+ if (i >= characteristics->num_output)
+ return -ERANGE;
+
+ bestmul = rate / parent_rate;
+ rounddown = parent_rate % rate;
+ roundup = rate - rounddown;
+ bestremainder = roundup < rounddown ? roundup : rounddown;
+
+ if (!bestremainder) {
+ if (div)
+ *div = bestdiv;
+ if (mul)
+ *mul = bestmul;
+ if (index)
+ *index = i;
+ return rate;
+ }
+
+ maxdiv = 255 / (bestmul + 1);
+ if (parent_rate / maxdiv < characteristics->input.min)
+ maxdiv = parent_rate / characteristics->input.min;
+ mindiv = parent_rate / characteristics->input.max;
+ if (parent_rate % characteristics->input.max)
+ mindiv++;
+
+ for (tmpdiv = mindiv; tmpdiv < maxdiv; tmpdiv++) {
+ divrate = parent_rate / tmpdiv;
+
+ rounddown = rate % divrate;
+ roundup = divrate - rounddown;
+ remainder = roundup < rounddown ? roundup : rounddown;
+
+ if (remainder < bestremainder) {
+ bestremainder = remainder;
+ bestmul = rate / divrate;
+ bestdiv = tmpdiv;
+ }
+
+ if (!remainder)
+ break;
+ }
+
+ rate = (parent_rate / bestdiv) * bestmul;
+
+ if (div)
+ *div = bestdiv;
+ if (mul)
+ *mul = bestmul;
+ if (index)
+ *index = i;
+
+ return rate;
+}
+
+static long clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ return clk_pll_get_best_div_mul(pll, rate, *parent_rate,
+ NULL, NULL, NULL);
+
+}
+
+static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ struct clk_pll_layout *layout = pll->layout;
+ struct clk_pll_characteristics *characteristics = pll->characteristics;
+ int offset = AT91_CKGR_PLLAR + (pll->id * 4);
+ long ret;
+ u32 div;
+ u32 mul;
+ u32 index;
+ u32 tmp;
+ u8 out = 0;
+ ret = clk_pll_get_best_div_mul(pll, rate, parent_rate,
+ &div, &mul, &index);
+
+ if (ret < 0)
+ return ret;
+
+ if (characteristics->out)
+ out = characteristics->out[pll->range];
+ if (characteristics->icpll) {
+ tmp = at91_pmc_read(AT91_PMC_PLLICPR) &
+ ~(0xFFFF << (16 * pll->id));
+ tmp |= characteristics->icpll[pll->range] << (16 * pll->id);
+ at91_pmc_write(AT91_PMC_PLLICPR, tmp);
+ }
+ tmp = at91_pmc_read(offset) & ~(layout->pllr_mask);
+ tmp |= layout->pllr_mask & (div | 0x3F << 8 | out << 14 |
+ (mul & layout->mul_mask) <<
+ layout->mul_shift);
+ at91_pmc_write(offset, tmp);
+
+ return 0;
+}
+
+static const struct clk_ops pll_ops = {
+ .prepare = clk_pll_prepare,
+ .is_prepared = clk_pll_is_prepared,
+ .enable = clk_pll_enable,
+ .disable = clk_pll_disable,
+ .is_enabled = clk_pll_is_enabled,
+ .recalc_rate = clk_pll_recalc_rate,
+ .round_rate = clk_pll_round_rate,
+ .set_rate = clk_pll_set_rate,
+};
+
+struct clk * __init
+at91_clk_register_pll(const char *name, const char *parent_name, u8 id,
+ struct clk_pll_layout *layout,
+ struct clk_pll_characteristics *characteristics)
+{
+ struct clk_pll *pll;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ id &= 3;
+
+ pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+ if (!pll)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &pll_ops;
+ init.parent_names = parent_name ? &parent_name : NULL;
+ init.num_parents = parent_name ? 1 : 0;
+ init.flags = CLK_SET_RATE_GATE;
+
+ pll->id = id;
+ pll->hw.init = &init;
+ pll->layout = layout;
+ pll->characteristics = characteristics;
+
+ clk = clk_register(NULL, &pll->hw);
+
+ if (IS_ERR(clk))
+ kfree(pll);
+
+ return clk;
+}
+
+
+struct clk_pll_layout at91rm9200_pll_layout = {
+ .pllr_mask = 0x7FFFFFF,
+ .mul_shift = 16,
+ .mul_mask = 0x7FF,
+};
+
+struct clk_pll_layout at91sam9g45_pll_layout = {
+ .pllr_mask = 0xFFFFFF,
+ .mul_shift = 16,
+ .mul_mask = 0xFF,
+};
+
+struct clk_pll_layout at91sam9g20_pllb_layout = {
+ .pllr_mask = 0x3FFFFF,
+ .mul_shift = 16,
+ .mul_mask = 0x3F,
+};
+
+struct clk_pll_layout sama5d3_pll_layout = {
+ .pllr_mask = 0x1FFFFFF,
+ .mul_shift = 18,
+ .mul_mask = 0x7F,
+};
+
+
+#if defined(CONFIG_OF)
+static struct clk_pll_characteristics * __init
+of_at91_clk_pll_get_characteristics(struct device_node *np)
+{
+ int i;
+ u32 tmp;
+ int num_output;
+ struct clk_range *output = NULL;
+ u8 *out = NULL;
+ u16 *icpll = NULL;
+ struct clk_pll_characteristics *characteristics = NULL;
+ characteristics = kzalloc(sizeof(*characteristics), GFP_KERNEL);
+ if (!characteristics)
+ return NULL;
+
+ if (of_property_read_u32_index(np, "input", 0, &tmp))
+ goto out_free_characteristics;
+
+ characteristics->input.min = tmp;
+
+ if (of_property_read_u32_index(np, "input", 1, &tmp))
+ goto out_free_characteristics;
+
+ characteristics->input.max = tmp;
+
+ if (!of_get_property(np, "output", &num_output))
+ goto out_free_characteristics;
+ num_output /= (sizeof(u32) * 2);
+
+ output = kzalloc(sizeof(*output) * num_output, GFP_KERNEL);
+ for (i = 0; i < num_output; i++) {
+ if (of_property_read_u32_index(np, "output", i * 2, &tmp))
+ goto out_free_output;
+ output[i].min = tmp;
+ if (of_property_read_u32_index(np, "output", (i * 2) + 1, &tmp))
+ goto out_free_output;
+ output[i].max = tmp;
+ }
+
+ if (of_get_property(np, "out", NULL)) {
+ out = kzalloc(sizeof(*out) * num_output, GFP_KERNEL);
+ if (!out)
+ goto out_free_output;
+ for (i = 0; i < num_output; i++) {
+ if (of_property_read_u32_index(np, "out", i, &tmp))
+ goto out_free_out;
+ out[i] = tmp;
+ }
+ }
+
+ if (of_get_property(np, "icpll", NULL)) {
+ icpll = kzalloc(sizeof(*icpll) * num_output, GFP_KERNEL);
+ if (!icpll)
+ goto out_free_out;
+ for (i = 0; i < num_output; i++) {
+ if (of_property_read_u32_index(np, "icpll", i, &tmp))
+ goto out_free_icpll;
+ icpll[i] = tmp;
+ }
+ }
+
+ characteristics->num_output = num_output;
+ characteristics->output = output;
+ characteristics->out = out;
+ characteristics->icpll = icpll;
+ return characteristics;
+
+out_free_icpll:
+ kfree(icpll);
+out_free_out:
+ kfree(out);
+out_free_output:
+ kfree(output);
+out_free_characteristics:
+ kfree(characteristics);
+ return NULL;
+}
+
+static void __init
+of_at91_clk_pll_setup(struct device_node *np,
+ struct clk_pll_layout *layout)
+{
+ u32 id;
+ struct clk *clk;
+ const char *parent_name;
+ const char *name = np->name;
+ struct clk_pll_characteristics *characteristics;
+
+ if (of_property_read_u32(np, "id", &id))
+ return;
+
+ parent_name = of_clk_get_parent_name(np, 0);
+
+ of_property_read_string(np, "clock-output-names", &name);
+
+ characteristics = of_at91_clk_pll_get_characteristics(np);
+ if (!characteristics)
+ return;
+
+ clk = at91_clk_register_pll(name, parent_name, id, layout,
+ characteristics);
+
+ if (IS_ERR(clk))
+ goto out_free_characteristics;
+
+ of_clk_add_provider(np, of_clk_src_simple_get, clk);
+ return;
+
+out_free_characteristics:
+ kfree(characteristics);
+}
+
+static void __init of_at91rm9200_clk_pll_setup(struct device_node *np)
+{
+ of_at91_clk_pll_setup(np, &at91rm9200_pll_layout);
+}
+CLK_OF_DECLARE(at91rm9200_clk_pll, "atmel,at91rm9200-clk-pll",
+ of_at91rm9200_clk_pll_setup);
+
+static void __init of_at91sam9g45_clk_pll_setup(struct device_node *np)
+{
+ of_at91_clk_pll_setup(np, &at91sam9g45_pll_layout);
+}
+CLK_OF_DECLARE(at91sam9g45_clk_pll, "atmel,at91sam9g45-clk-pll",
+ of_at91sam9g45_clk_pll_setup);
+
+static void __init of_at91sam9g20_clk_pllb_setup(struct device_node *np)
+{
+ of_at91_clk_pll_setup(np, &at91sam9g20_pllb_layout);
+}
+CLK_OF_DECLARE(at91sam9g20_clk_pllb, "atmel,at91sam9g20-clk-pllb",
+ of_at91sam9g20_clk_pllb_setup);
+
+static void __init of_sama5d3_clk_pll_setup(struct device_node *np)
+{
+ of_at91_clk_pll_setup(np, &sama5d3_pll_layout);
+}
+CLK_OF_DECLARE(sama5d3_clk_pll, "atmel,sama5d3-clk-pll",
+ of_sama5d3_clk_pll_setup);
+#endif
diff --git a/drivers/clk/at91/clk-plldiv.c b/drivers/clk/at91/clk-plldiv.c
new file mode 100644
index 0000000..430de9b
--- /dev/null
+++ b/drivers/clk/at91/clk-plldiv.c
@@ -0,0 +1,125 @@
+/*
+ * drivers/clk/at91/clk-plldiv.c
+ *
+ * Copyright (C) 2013 Boris BREZILLON <b.brezillon@xxxxxxxxxxx>
+ *
+ * This plldivram 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-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/at91.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+
+#define to_clk_plldiv(hw) container_of(hw, struct clk_plldiv, hw)
+
+struct clk_plldiv {
+ struct clk_hw hw;
+};
+
+static unsigned long clk_plldiv_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ if (at91_pmc_read(AT91_PMC_MCKR) & AT91_PMC_PLLADIV2)
+ return parent_rate / 2;
+ return parent_rate;
+}
+
+static long clk_plldiv_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ unsigned long div;
+ if (rate > *parent_rate)
+ return *parent_rate;
+ div = *parent_rate / 2;
+ if (rate < div)
+ return div;
+
+ if (rate - div < *parent_rate - rate)
+ return div;
+
+ return *parent_rate;
+}
+
+static int clk_plldiv_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ u32 tmp;
+ if (parent_rate != rate && (parent_rate / 2) != rate)
+ return -EINVAL;
+
+ tmp = at91_pmc_read(AT91_PMC_MCKR) & ~AT91_PMC_PLLADIV2;
+ if ((parent_rate / 2) == rate)
+ tmp |= AT91_PMC_PLLADIV2;
+ at91_pmc_write(AT91_PMC_MCKR, tmp);
+
+ return 0;
+}
+
+static const struct clk_ops plldiv_ops = {
+ .recalc_rate = clk_plldiv_recalc_rate,
+ .round_rate = clk_plldiv_round_rate,
+ .set_rate = clk_plldiv_set_rate,
+};
+
+struct clk * __init
+at91_clk_register_plldiv(const char *name, const char *parent_name)
+{
+ struct clk_plldiv *plldiv;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ plldiv = kzalloc(sizeof(*plldiv), GFP_KERNEL);
+ if (!plldiv)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &plldiv_ops;
+ init.parent_names = parent_name ? &parent_name : NULL;
+ init.num_parents = parent_name ? 1 : 0;
+ init.flags = CLK_SET_RATE_GATE;
+
+ plldiv->hw.init = &init;
+
+ clk = clk_register(NULL, &plldiv->hw);
+
+ if (IS_ERR(clk))
+ kfree(plldiv);
+
+ return clk;
+}
+
+#if defined(CONFIG_OF)
+static void __init
+of_at91_clk_plldiv_setup(struct device_node *np)
+{
+ struct clk *clk;
+ const char *parent_name;
+ const char *name = np->name;
+
+ parent_name = of_clk_get_parent_name(np, 0);
+
+ of_property_read_string(np, "clock-output-names", &name);
+
+ clk = at91_clk_register_plldiv(name, parent_name);
+
+ if (IS_ERR(clk))
+ return;
+
+ of_clk_add_provider(np, of_clk_src_simple_get, clk);
+ return;
+}
+
+static void __init of_at91sam9x5_clk_plldiv_setup(struct device_node *np)
+{
+ of_at91_clk_plldiv_setup(np);
+}
+CLK_OF_DECLARE(at91sam9x5_clk_plldiv, "atmel,at91sam9x5-clk-plldiv",
+ of_at91sam9x5_clk_plldiv_setup);
+#endif
diff --git a/include/linux/clk/at91.h b/include/linux/clk/at91.h
index c0801e7..7ba038f 100644
--- a/include/linux/clk/at91.h
+++ b/include/linux/clk/at91.h
@@ -163,6 +163,8 @@ extern void __iomem *at91_pmc_base;
#define AT91_PMC_CFDEV (1 << 18) /* Clock Failure Detector Event [some SAM9] */
#define AT91_PMC_IMR 0x6c /* Interrupt Mask Register */
+#define AT91_PMC_PLLICPR 0x80 /* PLL Charge Pump Current Register */
+
#define AT91_PMC_PROT 0xe4 /* Write Protect Mode Register [some SAM9] */
#define AT91_PMC_WPEN (0x1 << 0) /* Write Protect Enable */
#define AT91_PMC_WPKEY (0xffffff << 8) /* Write Protect Key */
@@ -187,6 +189,26 @@ extern void __iomem *at91_pmc_base;
#define AT91_PMC_PCR_EN (0x1 << 28) /* Enable */
+struct clk_range {
+ unsigned long min;
+ unsigned long max;
+};
+
+#define CLK_RANGE(MIN, MAX) {.min = MIN, .max = MAX,}
+
+struct clk_pll_characteristics {
+ struct clk_range input;
+ int num_output;
+ struct clk_range *output;
+ u16 *icpll;
+ u8 *out;
+};
+
+struct clk_pll_layout {
+ u32 pllr_mask;
+ u16 mul_mask;
+ u8 mul_shift;
+};
struct clk * __init
@@ -194,4 +216,21 @@ at91_clk_register_main(const char *name,
const char *parent_name,
unsigned long rate);
+
+extern struct clk_pll_layout at91rm9200_pll_layout;
+
+extern struct clk_pll_layout at91sam9g45_pll_layout;
+
+extern struct clk_pll_layout at91sam9g20_pllb_layout;
+
+extern struct clk_pll_layout sama5d3_pll_layout;
+
+struct clk * __init
+at91_clk_register_pll(const char *name, const char *parent_name, u8 id,
+ struct clk_pll_layout *layout,
+ struct clk_pll_characteristics *characteristics);
+
+struct clk * __init
+at91_clk_register_plldiv(const char *name, const char *parent_name);
+
#endif
--
1.7.9.5
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