[PATCH 1/5] arm: sa1100: add cpu clock

[PATCH 1/5] arm: sa1100: add cpu clock

[Dmitry Eremin-Solenikov]

Both SA1100 framebuffer and PCMCIA drivers require knowledge of cpu
frequency to correctly program timings.  Currently they receive timing
information by calling cpufreq_get(0).  However if cpu frequency driver
is not enabled (e.g. due to unsupported DRAM chip/board on sa1110)
cpufreq_get(0) returns 0, causing incorrect timings to be programmed.

Add cpu clock returning cpu frequency, to be used by sa11x0 fb and
pcmcia drivers.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
---
 arch/arm/mach-sa1100/clock.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/arch/arm/mach-sa1100/clock.c b/arch/arm/mach-sa1100/clock.c
index 172ebd0..abf1dc1 100644
--- a/arch/arm/mach-sa1100/clock.c
+++ b/arch/arm/mach-sa1100/clock.c
@@ -15,10 +15,12 @@
 #include <linux/clkdev.h>
 
 #include <mach/hardware.h>
+#include <mach/generic.h>
 
 struct clkops {
 	void			(*enable)(struct clk *);
 	void			(*disable)(struct clk *);
+	unsigned long		(*get_rate)(struct clk *);
 };
 
 struct clk {
@@ -51,6 +53,19 @@ static void clk_gpio27_disable(struct clk *clk)
 	GAFR &= ~GPIO_32_768kHz;
 }
 
+static void clk_cpu_enable(struct clk *clk)
+{
+}
+
+static void clk_cpu_disable(struct clk *clk)
+{
+}
+
+static unsigned long clk_cpu_get_rate(struct clk *clk)
+{
+	return sa11x0_getspeed(0) * 1000;
+}
+
 int clk_enable(struct clk *clk)
 {
 	unsigned long flags;
@@ -80,16 +95,35 @@ void clk_disable(struct clk *clk)
 }
 EXPORT_SYMBOL(clk_disable);
 
+unsigned long clk_get_rate(struct clk *clk)
+{
+	if (clk && clk->ops && clk->ops->get_rate)
+		return clk->ops->get_rate(clk);
+	else
+		return 0;
+}
+EXPORT_SYMBOL(clk_get_rate);
+
 const struct clkops clk_gpio27_ops = {
 	.enable		= clk_gpio27_enable,
 	.disable	= clk_gpio27_disable,
 };
 
+const struct clkops clk_cpu_ops = {
+	.enable		= clk_cpu_enable,
+	.disable	= clk_cpu_disable,
+	.get_rate	= clk_cpu_get_rate,
+};
+
 static DEFINE_CLK(gpio27, &clk_gpio27_ops);
 
+static DEFINE_CLK(cpu, &clk_cpu_ops);
+
 static struct clk_lookup sa11xx_clkregs[] = {
 	CLKDEV_INIT("sa1111.0", NULL, &clk_gpio27),
 	CLKDEV_INIT("sa1100-rtc", NULL, NULL),
+	CLKDEV_INIT("sa11x0-fb", NULL, &clk_cpu),
+	CLKDEV_INIT("sa11x0-pcmcia", NULL, &clk_cpu),
 };
 
 static int __init sa11xx_clk_init(void)
-- 
1.8.4.2

[PATCH 2/5] fbdev: sa1100fb: make use of device clock

[Dmitry Eremin-Solenikov]

Use per-device clock (instead of calling cpufreq_get(0), which can
return 0 if no cpu frequency driver is selected) to program timings.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
---
 drivers/video/sa1100fb.c | 24 +++++++++++++++++-------
 drivers/video/sa1100fb.h |  1 +
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/video/sa1100fb.c b/drivers/video/sa1100fb.c
index de76da0..05d1b37 100644
--- a/drivers/video/sa1100fb.c
+++ b/drivers/video/sa1100fb.c
@@ -178,6 +178,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/mutex.h>
 #include <linux/io.h>
+#include <linux/clk.h>
 
 #include <video/sa1100fb.h>
 
@@ -413,9 +414,9 @@ sa1100fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
 		var->transp.offset);
 
 #ifdef CONFIG_CPU_FREQ
-	dev_dbg(fbi->dev, "dma period = %d ps, clock = %d kHz\n",
+	dev_dbg(fbi->dev, "dma period = %d ps, clock = %ld kHz\n",
 		sa1100fb_display_dma_period(var),
-		cpufreq_get(smp_processor_id()));
+		clk_get_rate(fbi->clk) / 1000);
 #endif
 
 	return 0;
@@ -586,9 +587,10 @@ static struct fb_ops sa1100fb_ops = {
  * Calculate the PCD value from the clock rate (in picoseconds).
  * We take account of the PPCR clock setting.
  */
-static inline unsigned int get_pcd(unsigned int pixclock, unsigned int cpuclock)
+static inline unsigned int get_pcd(struct sa1100fb_info *fbi,
+		unsigned int pixclock)
 {
-	unsigned int pcd = cpuclock / 100;
+	unsigned int pcd = clk_get_rate(fbi->clk) / 100 / 1000;
 
 	pcd *= pixclock;
 	pcd /= 10000000;
@@ -667,7 +669,7 @@ static int sa1100fb_activate_var(struct fb_var_screeninfo *var, struct sa1100fb_
 		LCCR2_BegFrmDel(var->upper_margin) +
 		LCCR2_EndFrmDel(var->lower_margin);
 
-	pcd = get_pcd(var->pixclock, cpufreq_get(0));
+	pcd = get_pcd(fbi, var->pixclock);
 	new_regs.lccr3 = LCCR3_PixClkDiv(pcd) | fbi->inf->lccr3 |
 		(var->sync & FB_SYNC_HOR_HIGH_ACT ? LCCR3_HorSnchH : LCCR3_HorSnchL) |
 		(var->sync & FB_SYNC_VERT_HIGH_ACT ? LCCR3_VrtSnchH : LCCR3_VrtSnchL);
@@ -1003,7 +1005,6 @@ sa1100fb_freq_transition(struct notifier_block *nb, unsigned long val,
 			 void *data)
 {
 	struct sa1100fb_info *fbi = TO_INF(nb, freq_transition);
-	struct cpufreq_freqs *f = data;
 	u_int pcd;
 
 	switch (val) {
@@ -1012,7 +1013,7 @@ sa1100fb_freq_transition(struct notifier_block *nb, unsigned long val,
 		break;
 
 	case CPUFREQ_POSTCHANGE:
-		pcd = get_pcd(fbi->fb.var.pixclock, f->new);
+		pcd = get_pcd(fbi, fbi->fb.var.pixclock);
 		fbi->reg_lccr3 = (fbi->reg_lccr3 & ~0xff) | LCCR3_PixClkDiv(pcd);
 		set_ctrlr_state(fbi, C_ENABLE_CLKCHANGE);
 		break;
@@ -1219,6 +1220,13 @@ static int sa1100fb_probe(struct platform_device *pdev)
 	if (!fbi)
 		goto failed;
 
+	fbi->clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(fbi->clk)) {
+		ret = PTR_ERR(fbi->clk);
+		fbi->clk = NULL;
+		goto failed;
+	}
+
 	fbi->base = ioremap(res->start, resource_size(res));
 	if (!fbi->base)
 		goto failed;
@@ -1271,6 +1279,8 @@ static int sa1100fb_probe(struct platform_device *pdev)
  failed:
 	if (fbi)
 		iounmap(fbi->base);
+	if (fbi->clk)
+		clk_put(fbi->clk);
 	kfree(fbi);
 	release_mem_region(res->start, resource_size(res));
 	return ret;
diff --git a/drivers/video/sa1100fb.h b/drivers/video/sa1100fb.h
index fc5d429..0139d13 100644
--- a/drivers/video/sa1100fb.h
+++ b/drivers/video/sa1100fb.h
@@ -68,6 +68,7 @@ struct sa1100fb_info {
 #endif
 
 	const struct sa1100fb_mach_info *inf;
+	struct clk *clk;
 };
 
 #define TO_INF(ptr,member)	container_of(ptr,struct sa1100fb_info,member)
-- 
1.8.4.2

[PATCH 3/5] pcmcia: sa1100: make use of device clock

[Dmitry Eremin-Solenikov]

Use per-device clock (instead of calling cpufreq_get(0), which can
return 0 if no cpu frequency driver is selected) to program timings.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
---
 drivers/pcmcia/sa1100_generic.c |  1 +
 drivers/pcmcia/sa11xx_base.c    | 14 ++++++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/pcmcia/sa1100_generic.c b/drivers/pcmcia/sa1100_generic.c
index ff8a027..d2ab060 100644
--- a/drivers/pcmcia/sa1100_generic.c
+++ b/drivers/pcmcia/sa1100_generic.c
@@ -93,6 +93,7 @@ static int sa11x0_drv_pcmcia_remove(struct platform_device *dev)
 	for (i = 0; i < sinfo->nskt; i++)
 		soc_pcmcia_remove_one(&sinfo->skt[i]);
 
+	clk_put(sinfo->clk);
 	kfree(sinfo);
 	return 0;
 }
diff --git a/drivers/pcmcia/sa11xx_base.c b/drivers/pcmcia/sa11xx_base.c
index 6eecd7c..aef0e69 100644
--- a/drivers/pcmcia/sa11xx_base.c
+++ b/drivers/pcmcia/sa11xx_base.c
@@ -38,6 +38,7 @@
 #include <linux/spinlock.h>
 #include <linux/io.h>
 #include <linux/slab.h>
+#include <linux/clk.h>
 
 #include <mach/hardware.h>
 #include <asm/irq.h>
@@ -138,14 +139,15 @@ sa1100_pcmcia_frequency_change(struct soc_pcmcia_socket *skt,
 static int
 sa1100_pcmcia_set_timing(struct soc_pcmcia_socket *skt)
 {
-	return sa1100_pcmcia_set_mecr(skt, cpufreq_get(0));
+	unsigned long clk = clk_get_rate(skt->clk);
+	return sa1100_pcmcia_set_mecr(skt, clk / 1000);
 }
 
 static int
 sa1100_pcmcia_show_timing(struct soc_pcmcia_socket *skt, char *buf)
 {
 	struct soc_pcmcia_timing timing;
-	unsigned int clock = cpufreq_get(0);
+	unsigned int clock = clk_get_rate(skt->clk);
 	unsigned long mecr = MECR;
 	char *p = buf;
 
@@ -221,6 +223,11 @@ int sa11xx_drv_pcmcia_probe(struct device *dev, struct pcmcia_low_level *ops,
 	struct skt_dev_info *sinfo;
 	struct soc_pcmcia_socket *skt;
 	int i, ret = 0;
+	struct clk *clk;
+
+	clk = clk_get(dev, NULL);
+	if (IS_ERR(clk))
+		return -ENODEV;
 
 	sa11xx_drv_pcmcia_ops(ops);
 
@@ -229,12 +236,14 @@ int sa11xx_drv_pcmcia_probe(struct device *dev, struct pcmcia_low_level *ops,
 		return -ENOMEM;
 
 	sinfo->nskt = nr;
+	sinfo->clk = clk;
 
 	/* Initialize processor specific parameters */
 	for (i = 0; i < nr; i++) {
 		skt = &sinfo->skt[i];
 
 		skt->nr = first + i;
+		skt->clk = clk;
 		soc_pcmcia_init_one(skt, ops, dev);
 
 		ret = sa11xx_drv_pcmcia_add_one(skt);
@@ -245,6 +254,7 @@ int sa11xx_drv_pcmcia_probe(struct device *dev, struct pcmcia_low_level *ops,
 	if (ret) {
 		while (--i >= 0)
 			soc_pcmcia_remove_one(&sinfo->skt[i]);
+		clk_put(clk);
 		kfree(sinfo);
 	} else {
 		dev_set_drvdata(dev, sinfo);
-- 
1.8.4.2

[PATCH 4/5] arm: sa1100: add a clock alias for sa1111 pcmcia device

[Dmitry Eremin-Solenikov]

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
---
 arch/arm/mach-sa1100/clock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/mach-sa1100/clock.c b/arch/arm/mach-sa1100/clock.c
index abf1dc1..cd4762d 100644
--- a/arch/arm/mach-sa1100/clock.c
+++ b/arch/arm/mach-sa1100/clock.c
@@ -124,6 +124,7 @@ static struct clk_lookup sa11xx_clkregs[] = {
 	CLKDEV_INIT("sa1100-rtc", NULL, NULL),
 	CLKDEV_INIT("sa11x0-fb", NULL, &clk_cpu),
 	CLKDEV_INIT("sa11x0-pcmcia", NULL, &clk_cpu),
+	CLKDEV_INIT("1600", NULL, &clk_cpu), /* sa1111 pcmcia */
 };
 
 static int __init sa11xx_clk_init(void)
-- 
1.8.4.2

[PATCH 5/5] pcmcia: sa1111: make use of device clock

[Dmitry Eremin-Solenikov]

Use per-device clock (instead of calling cpufreq_get(0), which can
return 0 if no cpu frequency driver is selected) to program timings.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
---
 drivers/pcmcia/sa1111_generic.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pcmcia/sa1111_generic.c b/drivers/pcmcia/sa1111_generic.c
index 65b02c3..c5988be 100644
--- a/drivers/pcmcia/sa1111_generic.c
+++ b/drivers/pcmcia/sa1111_generic.c
@@ -145,6 +145,9 @@ int sa1111_pcmcia_add(struct sa1111_dev *dev, struct pcmcia_low_level *ops,
 			return -ENOMEM;
 
 		s->soc.nr = ops->first + i;
+		s->soc.clk = clk_get(&dev->dev, NULL);
+		if (IS_ERR(s->soc.clk))
+			return -ENODEV;
 		soc_pcmcia_init_one(&s->soc, ops, &dev->dev);
 		s->dev = dev;
 		if (s->soc.nr) {
@@ -220,6 +223,7 @@ static int pcmcia_remove(struct sa1111_dev *dev)
 	for (; s; s = next) {
 		next = s->next;
 		soc_pcmcia_remove_one(&s->soc);
+		clk_put(s->soc.clk);
 		kfree(s);
 	}
 
-- 
1.8.4.2

[PATCH 1/5] arm: sa1100: add cpu clock

[Russell King - ARM Linux]

On Tue, Nov 12, 2013 at 07:32:08AM +0400, Dmitry Eremin-Solenikov wrote:
> Both SA1100 framebuffer and PCMCIA drivers require knowledge of cpu
> frequency to correctly program timings.  Currently they receive timing
> information by calling cpufreq_get(0).  However if cpu frequency driver
> is not enabled (e.g. due to unsupported DRAM chip/board on sa1110)
> cpufreq_get(0) returns 0, causing incorrect timings to be programmed.

I added a select statement back in 1937f5b91833e2e8e53bcc821fc7a5fbe6ccb9b5
which avoids this problem.  Does this not work?

[PATCH 1/5] arm: sa1100: add cpu clock

[Dmitry Eremin-Solenikov]

On 11/12/2013 01:57 PM, Russell King - ARM Linux wrote:
> On Tue, Nov 12, 2013 at 07:32:08AM +0400, Dmitry Eremin-Solenikov wrote:
>> Both SA1100 framebuffer and PCMCIA drivers require knowledge of cpu
>> frequency to correctly program timings.  Currently they receive timing
>> information by calling cpufreq_get(0).  However if cpu frequency driver
>> is not enabled (e.g. due to unsupported DRAM chip/board on sa1110)
>> cpufreq_get(0) returns 0, causing incorrect timings to be programmed.
>
> I added a select statement back in 1937f5b91833e2e8e53bcc821fc7a5fbe6ccb9b5
> which avoids this problem.  Does this not work?

No, it does not.

1) For collie (sa1110) we don't have dram chip timings in table, so the 
cpufreq driver is not registered and cpufreq_get() returns 0

2) What if I want to build a kernel w/o cpu freq? We have clocks exactly 
for this reasons - to let drivers get frequency information.

3) And last but not least - PXA uses clocks in this place.


-- 
With best wishes
Dmitry

[PATCH 4/5] arm: sa1100: add a clock alias for sa1111 pcmcia device

[Dmitry Artamonow]

12.11.2013 07:32, Dmitry Eremin-Solenikov wrote:
> Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
> ---
>   arch/arm/mach-sa1100/clock.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm/mach-sa1100/clock.c b/arch/arm/mach-sa1100/clock.c
> index abf1dc1..cd4762d 100644
> --- a/arch/arm/mach-sa1100/clock.c
> +++ b/arch/arm/mach-sa1100/clock.c
> @@ -124,6 +124,7 @@ static struct clk_lookup sa11xx_clkregs[] = {
>   	CLKDEV_INIT("sa1100-rtc", NULL, NULL),
>   	CLKDEV_INIT("sa11x0-fb", NULL, &clk_cpu),
>   	CLKDEV_INIT("sa11x0-pcmcia", NULL, &clk_cpu),
> +	CLKDEV_INIT("1600", NULL, &clk_cpu), /* sa1111 pcmcia */

Shouldn't it be "1800" here? As I can see device name for sa1111 devices is
initialized from offset in sa1111_init_one_child():
         dev_set_name(&dev->dev, "%4.4lx", info->offset);

And the offset for SA1111_PCMCIA is 0x1800:

         {
                 .offset         = 0x1800,
                 .skpcr_mask     = 0,
                 .devid          = SA1111_DEVID_PCMCIA,
                 .irq = {
                         IRQ_S0_READY_NINT,
                         IRQ_S0_CD_VALID,
                         IRQ_S0_BVD1_STSCHG,
                         IRQ_S1_READY_NINT,
                         IRQ_S1_CD_VALID,
                         IRQ_S1_BVD1_STSCHG,
                 },
         },

Also it would be nice if you could add some words about this strange 
sa1111 device
naming convention in commit changelog. It's really puzzling to see 
string like
"1600" in clock's devid.

--
Best regards,
Dmitry