[PATCH v4] clk: at91: add generated clock driver
Nicolas Ferre
nicolas.ferre at atmel.com
Tue Jul 28 09:08:05 PDT 2015
Add a new type of clocks that can be provided to a peripheral.
In addition to the peripheral clock, this new clock that can use several
input clocks as parents can generate divided rates.
This would allow a peripheral to have finer grained clocks for generating
a baud rate, clocking an asynchronous part or having more
options in frequency.
Signed-off-by: Nicolas Ferre <nicolas.ferre at atmel.com>
Acked-by: Boris Brezillon <boris.brezillon at free-electrons.com>
---
Changes in v4:
- protect stored parent_id from incoherency
- use of of_count_phandle_with_args()
- collect Ack tag from Boris
Changes in v3:
- rebase on top of next-20150727
- make use of of_clk_parent_fill helper function
- change determine_rate() according to new prototype
Changes in v2:
- adapt to new xxx_determine_rate() callback prototype
- fix checkpatch errors and use __func__
- fix handling of clocks without clk-output-range property specified.
Test if range.max is present before using it
- test clock id only at probe time instead of at each API call
- remove useless tests in clk_generated_set_rate()
- change the meaningless config HAVE_AT91_GENERATED to HAVE_AT91_GENERATED_CLK
- wrap some lines over 80 characters
.../devicetree/bindings/clock/at91-clock.txt | 35 +++
arch/arm/mach-at91/Kconfig | 3 +
drivers/clk/at91/Makefile | 1 +
drivers/clk/at91/clk-generated.c | 313 +++++++++++++++++++++
drivers/clk/at91/pmc.c | 6 +
drivers/clk/at91/pmc.h | 3 +
include/linux/clk/at91_pmc.h | 7 +
7 files changed, 368 insertions(+)
create mode 100644 drivers/clk/at91/clk-generated.c
diff --git a/Documentation/devicetree/bindings/clock/at91-clock.txt b/Documentation/devicetree/bindings/clock/at91-clock.txt
index 5ba6450693b9..5e737d2cd05d 100644
--- a/Documentation/devicetree/bindings/clock/at91-clock.txt
+++ b/Documentation/devicetree/bindings/clock/at91-clock.txt
@@ -77,6 +77,9 @@ Required properties:
"atmel,sama5d4-clk-h32mx":
at91 h32mx clock
+ "atmel,sama5d2-clk-generated":
+ at91 generated clock
+
Required properties for SCKC node:
- reg : defines the IO memory reserved for the SCKC.
- #size-cells : shall be 0 (reg is used to encode clk id).
@@ -461,3 +464,35 @@ For example:
compatible = "atmel,sama5d4-clk-h32mx";
clocks = <&mck>;
};
+
+Required properties for generated clocks:
+- #size-cells : shall be 0 (reg is used to encode clk id).
+- #address-cells : shall be 1 (reg is used to encode clk id).
+- clocks : shall be the generated clock source phandles.
+ e.g. clocks = <&clk32k>, <&main>, <&plladiv>, <&utmi>, <&mck>;
+- name: device tree node describing a specific generated clock.
+ * #clock-cells : from common clock binding; shall be set to 0.
+ * reg: peripheral id. See Atmel's datasheets to get a full
+ list of peripheral ids.
+ * atmel,clk-output-range : minimum and maximum clock frequency
+ (two u32 fields).
+
+For example:
+ gck {
+ compatible = "atmel,sama5d2-clk-generated";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ clocks = <&clk32k>, <&main>, <&plladiv>, <&utmi>, <&mck>;
+
+ tcb0_gclk: tcb0_gclk {
+ #clock-cells = <0>;
+ reg = <35>;
+ atmel,clk-output-range = <0 83000000>;
+ };
+
+ pwm_gclk: pwm_gclk {
+ #clock-cells = <0>;
+ reg = <38>;
+ atmel,clk-output-range = <0 83000000>;
+ };
+ };
diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
index fd95f34945f4..e8273e79f6ba 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -90,6 +90,9 @@ config HAVE_AT91_SMD
config HAVE_AT91_H32MX
bool
+config HAVE_AT91_GENERATED_CLK
+ bool
+
config SOC_SAM_V4_V5
bool
diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index 89a48a7bd5df..13e67bd35cff 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_HAVE_AT91_UTMI) += clk-utmi.o
obj-$(CONFIG_HAVE_AT91_USB_CLK) += clk-usb.o
obj-$(CONFIG_HAVE_AT91_SMD) += clk-smd.o
obj-$(CONFIG_HAVE_AT91_H32MX) += clk-h32mx.o
+obj-$(CONFIG_HAVE_AT91_GENERATED_CLK) += clk-generated.o
diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
new file mode 100644
index 000000000000..642366f45742
--- /dev/null
+++ b/drivers/clk/at91/clk-generated.c
@@ -0,0 +1,313 @@
+/*
+ * Copyright (C) 2015 Atmel Corporation,
+ * Nicolas Ferre <nicolas.ferre at atmel.com>
+ *
+ * Based on clk-programmable & clk-peripheral drivers by Boris BREZILLON.
+ *
+ * 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-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/at91_pmc.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+
+#include "pmc.h"
+
+#define PERIPHERAL_MAX 64
+#define PERIPHERAL_ID_MIN 2
+
+#define GENERATED_SOURCE_MAX 6
+#define GENERATED_MAX_DIV 255
+
+struct clk_generated {
+ struct clk_hw hw;
+ struct at91_pmc *pmc;
+ struct clk_range range;
+ u32 id;
+ u32 gckdiv;
+ u8 parent_id;
+};
+
+#define to_clk_generated(hw) \
+ container_of(hw, struct clk_generated, hw)
+
+static int clk_generated_enable(struct clk_hw *hw)
+{
+ struct clk_generated *gck = to_clk_generated(hw);
+ struct at91_pmc *pmc = gck->pmc;
+ u32 tmp;
+
+ pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
+ __func__, gck->gckdiv, gck->parent_id);
+
+ pmc_lock(pmc);
+ pmc_write(pmc, AT91_PMC_PCR, (gck->id & AT91_PMC_PCR_PID_MASK));
+ tmp = pmc_read(pmc, AT91_PMC_PCR) &
+ ~(AT91_PMC_PCR_GCKDIV_MASK | AT91_PMC_PCR_GCKCSS_MASK);
+ pmc_write(pmc, AT91_PMC_PCR, tmp | AT91_PMC_PCR_GCKCSS(gck->parent_id)
+ | AT91_PMC_PCR_CMD
+ | AT91_PMC_PCR_GCKDIV(gck->gckdiv)
+ | AT91_PMC_PCR_GCKEN);
+ pmc_unlock(pmc);
+ return 0;
+}
+
+static void clk_generated_disable(struct clk_hw *hw)
+{
+ struct clk_generated *gck = to_clk_generated(hw);
+ struct at91_pmc *pmc = gck->pmc;
+ u32 tmp;
+
+ pmc_lock(pmc);
+ pmc_write(pmc, AT91_PMC_PCR, (gck->id & AT91_PMC_PCR_PID_MASK));
+ tmp = pmc_read(pmc, AT91_PMC_PCR) & ~AT91_PMC_PCR_GCKEN;
+ pmc_write(pmc, AT91_PMC_PCR, tmp | AT91_PMC_PCR_CMD);
+ pmc_unlock(pmc);
+}
+
+static int clk_generated_is_enabled(struct clk_hw *hw)
+{
+ struct clk_generated *gck = to_clk_generated(hw);
+ struct at91_pmc *pmc = gck->pmc;
+ int ret;
+
+ pmc_lock(pmc);
+ pmc_write(pmc, AT91_PMC_PCR, (gck->id & AT91_PMC_PCR_PID_MASK));
+ ret = !!(pmc_read(pmc, AT91_PMC_PCR) & AT91_PMC_PCR_GCKEN);
+ pmc_unlock(pmc);
+
+ return ret;
+}
+
+static unsigned long
+clk_generated_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_generated *gck = to_clk_generated(hw);
+
+ return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1);
+}
+
+static int clk_generated_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct clk_generated *gck = to_clk_generated(hw);
+ struct clk *parent = NULL;
+ long best_rate = -EINVAL;
+ unsigned long tmp_rate, min_rate;
+ int best_diff = -1;
+ int tmp_diff;
+ int i;
+
+ for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
+ u32 div;
+ unsigned long parent_rate;
+
+ parent = clk_get_parent_by_index(hw->clk, i);
+ if (!parent)
+ continue;
+
+ parent_rate = __clk_get_rate(parent);
+ min_rate = DIV_ROUND_CLOSEST(parent_rate, GENERATED_MAX_DIV + 1);
+ if (!parent_rate ||
+ (gck->range.max && min_rate > gck->range.max))
+ continue;
+
+ for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
+ tmp_rate = DIV_ROUND_CLOSEST(parent_rate, div);
+ tmp_diff = abs(req->rate - tmp_rate);
+
+ if (best_diff < 0 || best_diff > tmp_diff) {
+ best_rate = tmp_rate;
+ best_diff = tmp_diff;
+ req->best_parent_rate = parent_rate;
+ req->best_parent_hw = __clk_get_hw(parent);
+ }
+
+ if (!best_diff || tmp_rate < req->rate)
+ break;
+ }
+
+ if (!best_diff)
+ break;
+ }
+
+ pr_debug("GCLK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
+ __func__, best_rate,
+ __clk_get_name((req->best_parent_hw)->clk),
+ req->best_parent_rate);
+
+ if (best_rate < 0)
+ return best_rate;
+
+ req->rate = best_rate;
+ return 0;
+}
+
+/* No modification of hardware as we have the flag CLK_SET_PARENT_GATE set */
+static int clk_generated_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct clk_generated *gck = to_clk_generated(hw);
+
+ if (index >= __clk_get_num_parents(hw->clk))
+ return -EINVAL;
+
+ gck->parent_id = index;
+ return 0;
+}
+
+static u8 clk_generated_get_parent(struct clk_hw *hw)
+{
+ struct clk_generated *gck = to_clk_generated(hw);
+
+ return gck->parent_id;
+}
+
+/* No modification of hardware as we have the flag CLK_SET_RATE_GATE set */
+static int clk_generated_set_rate(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_generated *gck = to_clk_generated(hw);
+ u32 div;
+
+ if (!rate)
+ return -EINVAL;
+
+ if (gck->range.max && rate > gck->range.max)
+ return -EINVAL;
+
+ div = DIV_ROUND_CLOSEST(parent_rate, rate);
+ if (div > GENERATED_MAX_DIV + 1 || !div)
+ return -EINVAL;
+
+ gck->gckdiv = div - 1;
+ return 0;
+}
+
+static const struct clk_ops generated_ops = {
+ .enable = clk_generated_enable,
+ .disable = clk_generated_disable,
+ .is_enabled = clk_generated_is_enabled,
+ .recalc_rate = clk_generated_recalc_rate,
+ .determine_rate = clk_generated_determine_rate,
+ .get_parent = clk_generated_get_parent,
+ .set_parent = clk_generated_set_parent,
+ .set_rate = clk_generated_set_rate,
+};
+
+/**
+ * clk_generated_startup - Initialize a given clock to its default parent and
+ * divisor parameter.
+ *
+ * @gck: Generated clock to set the startup parameters for.
+ *
+ * Take parameters from the hardware and update local clock configuration
+ * accordingly.
+ */
+static void clk_generated_startup(struct clk_generated *gck)
+{
+ struct at91_pmc *pmc = gck->pmc;
+ u32 tmp;
+
+ pmc_lock(pmc);
+ pmc_write(pmc, AT91_PMC_PCR, (gck->id & AT91_PMC_PCR_PID_MASK));
+ tmp = pmc_read(pmc, AT91_PMC_PCR);
+ pmc_unlock(pmc);
+
+ gck->parent_id = (tmp & AT91_PMC_PCR_GCKCSS_MASK)
+ >> AT91_PMC_PCR_GCKCSS_OFFSET;
+ /*
+ * make sure that what we read in hardware is coherent with
+ * what we've just probed
+ */
+ if (gck->parent_id >= __clk_get_num_parents(gck->hw.clk))
+ gck->parent_id = 0;
+
+ gck->gckdiv = (tmp & AT91_PMC_PCR_GCKDIV_MASK)
+ >> AT91_PMC_PCR_GCKDIV_OFFSET;
+}
+
+static struct clk * __init
+at91_clk_register_generated(struct at91_pmc *pmc, const char *name,
+ const char **parent_names, u8 num_parents,
+ u8 id, const struct clk_range *range)
+{
+ struct clk_generated *gck;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ gck = kzalloc(sizeof(*gck), GFP_KERNEL);
+ if (!gck)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &generated_ops;
+ init.parent_names = parent_names;
+ init.num_parents = num_parents;
+ init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
+
+ gck->id = id;
+ gck->hw.init = &init;
+ gck->pmc = pmc;
+ gck->range = *range;
+
+ clk = clk_register(NULL, &gck->hw);
+ if (IS_ERR(clk))
+ kfree(gck);
+ else
+ clk_generated_startup(gck);
+
+ return clk;
+}
+
+void __init of_sama5d2_clk_generated_setup(struct device_node *np,
+ struct at91_pmc *pmc)
+{
+ int num;
+ u32 id;
+ const char *name;
+ struct clk *clk;
+ int num_parents;
+ const char *parent_names[GENERATED_SOURCE_MAX];
+ struct device_node *gcknp;
+ struct clk_range range = CLK_RANGE(0, 0);
+
+ num_parents = of_clk_get_parent_count(np);
+ if (num_parents <= 0 || num_parents > GENERATED_SOURCE_MAX)
+ return;
+
+ of_clk_parent_fill(np, parent_names, num_parents);
+
+ num = of_get_child_count(np);
+ if (!num || num > PERIPHERAL_MAX)
+ return;
+
+ for_each_child_of_node(np, gcknp) {
+ if (of_property_read_u32(gcknp, "reg", &id))
+ continue;
+
+ if (id < PERIPHERAL_ID_MIN || id >= PERIPHERAL_MAX)
+ continue;
+
+ if (of_property_read_string(np, "clock-output-names", &name))
+ name = gcknp->name;
+
+ of_at91_get_clk_range(gcknp, "atmel,clk-output-range",
+ &range);
+
+ clk = at91_clk_register_generated(pmc, name, parent_names,
+ num_parents, id, &range);
+ if (IS_ERR(clk))
+ continue;
+
+ of_clk_add_provider(gcknp, of_clk_src_simple_get, clk);
+ }
+}
diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index 39be2be82b0a..3775d82c213d 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -370,6 +370,12 @@ static const struct of_device_id pmc_clk_ids[] __initconst = {
.data = of_sama5d4_clk_h32mx_setup,
},
#endif
+#if defined(CONFIG_HAVE_AT91_GENERATED_CLK)
+ {
+ .compatible = "atmel,sama5d2-clk-generated",
+ .data = of_sama5d2_clk_generated_setup,
+ },
+#endif
{ /*sentinel*/ }
};
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index 8b87771c69b2..f65739272779 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -118,4 +118,7 @@ void of_at91sam9x5_clk_smd_setup(struct device_node *np,
void of_sama5d4_clk_h32mx_setup(struct device_node *np,
struct at91_pmc *pmc);
+void of_sama5d2_clk_generated_setup(struct device_node *np,
+ struct at91_pmc *pmc);
+
#endif /* __PMC_H_ */
diff --git a/include/linux/clk/at91_pmc.h b/include/linux/clk/at91_pmc.h
index dfc59e2b64fb..ae61860e6892 100644
--- a/include/linux/clk/at91_pmc.h
+++ b/include/linux/clk/at91_pmc.h
@@ -183,10 +183,17 @@ extern void __iomem *at91_pmc_base;
#define AT91_PMC_PCR 0x10c /* Peripheral Control Register [some SAM9 and SAMA5] */
#define AT91_PMC_PCR_PID_MASK 0x3f
+#define AT91_PMC_PCR_GCKCSS_OFFSET 8
+#define AT91_PMC_PCR_GCKCSS_MASK (0x7 << AT91_PMC_PCR_GCKCSS_OFFSET)
+#define AT91_PMC_PCR_GCKCSS(n) ((n) << AT91_PMC_PCR_GCKCSS_OFFSET) /* GCK Clock Source Selection */
#define AT91_PMC_PCR_CMD (0x1 << 12) /* Command (read=0, write=1) */
#define AT91_PMC_PCR_DIV_OFFSET 16
#define AT91_PMC_PCR_DIV_MASK (0x3 << AT91_PMC_PCR_DIV_OFFSET)
#define AT91_PMC_PCR_DIV(n) ((n) << AT91_PMC_PCR_DIV_OFFSET) /* Divisor Value */
+#define AT91_PMC_PCR_GCKDIV_OFFSET 20
+#define AT91_PMC_PCR_GCKDIV_MASK (0xff << AT91_PMC_PCR_GCKDIV_OFFSET)
+#define AT91_PMC_PCR_GCKDIV(n) ((n) << AT91_PMC_PCR_GCKDIV_OFFSET) /* Generated Clock Divisor Value */
#define AT91_PMC_PCR_EN (0x1 << 28) /* Enable */
+#define AT91_PMC_PCR_GCKEN (0x1 << 29) /* GCK Enable */
#endif
--
2.1.3
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