[PATCH v4] clk: at91: add generated clock driver

[PATCH v4] clk: at91: add generated clock driver

[Nicolas Ferre]

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@atmel.com>
Acked-by: Boris Brezillon <boris.brezillon@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@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

[PATCH v4] clk: at91: add generated clock driver

[Nicolas Ferre]

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@atmel.com>
Acked-by: Boris Brezillon <boris.brezillon@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@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

Re: [PATCH v4] clk: at91: add generated clock driver

[Boris Brezillon]

Hi Nicolas,

On Tue, 28 Jul 2015 18:08:05 +0200
Nicolas Ferre <nicolas.ferre@atmel.com> wrote:


> +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;

Hm, I'm not sure this is correct. Here, you're just faking the
fact that your current parent is the first one in the parent list while
it actually points to the 6th entry. Not only your rate will be false
(the one calculated in ->round_rate()), but you're also changing the
behavior of the clk_set_rate() and clk_set_parent() operation (AFAIR,
if you try to change to the first parent, the core code will think it's
already properly configured and will never call ->set_parent()).

This leaves 2 solutions here:
- implement the missing clk driver and add an entry in the parent
  list
- select the 1st parent clk (I mean, change the register value) if the
  hardware points to the 6th one.

Best Regards,

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[PATCH v4] clk: at91: add generated clock driver

[Boris Brezillon]

Hi Nicolas,

On Tue, 28 Jul 2015 18:08:05 +0200
Nicolas Ferre <nicolas.ferre@atmel.com> wrote:


> +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;

Hm, I'm not sure this is correct. Here, you're just faking the
fact that your current parent is the first one in the parent list while
it actually points to the 6th entry. Not only your rate will be false
(the one calculated in ->round_rate()), but you're also changing the
behavior of the clk_set_rate() and clk_set_parent() operation (AFAIR,
if you try to change to the first parent, the core code will think it's
already properly configured and will never call ->set_parent()).

This leaves 2 solutions here:
- implement the missing clk driver and add an entry in the parent
  list
- select the 1st parent clk (I mean, change the register value) if the
  hardware points to the 6th one.

Best Regards,

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Re: [PATCH v4] clk: at91: add generated clock driver

[Nicolas Ferre]

Le 29/07/2015 09:15, Boris Brezillon a écrit :
> Hi Nicolas,
> 
> On Tue, 28 Jul 2015 18:08:05 +0200
> Nicolas Ferre <nicolas.ferre@atmel.com> wrote:
> 
> 
>> +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;
> 
> Hm, I'm not sure this is correct. Here, you're just faking the
> fact that your current parent is the first one in the parent list while
> it actually points to the 6th entry. Not only your rate will be false
> (the one calculated in ->round_rate()), but you're also changing the
> behavior of the clk_set_rate() and clk_set_parent() operation (AFAIR,
> if you try to change to the first parent, the core code will think it's
> already properly configured and will never call ->set_parent()).

Well, as the values are actually used from the cached local structure
all the way to the "enable" function, I suspect it won't break the core
behavior. And making sure that this clock is not enabled before Linux is
run makes this change work.

But I admit it is somehow weird, as a workaround :-\


> This leaves 2 solutions here:
> - implement the missing clk driver and add an entry in the parent
>   list

Yes, I'll do this.

> - select the 1st parent clk (I mean, change the register value) if the
>   hardware points to the 6th one.

This is not safer than what I proposed hereunder.

So, I remove this change in the v4 and send you a v5 that reverts this
modification and adds a WARN_ON the condition, to ease debugging...

Bye,
-- 
Nicolas Ferre

[PATCH v4] clk: at91: add generated clock driver

[Nicolas Ferre]

Le 29/07/2015 09:15, Boris Brezillon a ?crit :
> Hi Nicolas,
> 
> On Tue, 28 Jul 2015 18:08:05 +0200
> Nicolas Ferre <nicolas.ferre@atmel.com> wrote:
> 
> 
>> +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;
> 
> Hm, I'm not sure this is correct. Here, you're just faking the
> fact that your current parent is the first one in the parent list while
> it actually points to the 6th entry. Not only your rate will be false
> (the one calculated in ->round_rate()), but you're also changing the
> behavior of the clk_set_rate() and clk_set_parent() operation (AFAIR,
> if you try to change to the first parent, the core code will think it's
> already properly configured and will never call ->set_parent()).

Well, as the values are actually used from the cached local structure
all the way to the "enable" function, I suspect it won't break the core
behavior. And making sure that this clock is not enabled before Linux is
run makes this change work.

But I admit it is somehow weird, as a workaround :-\


> This leaves 2 solutions here:
> - implement the missing clk driver and add an entry in the parent
>   list

Yes, I'll do this.

> - select the 1st parent clk (I mean, change the register value) if the
>   hardware points to the 6th one.

This is not safer than what I proposed hereunder.

So, I remove this change in the v4 and send you a v5 that reverts this
modification and adds a WARN_ON the condition, to ease debugging...

Bye,
-- 
Nicolas Ferre