* [PATCH v2] mmc: sdhci-of-at91: add presets setup
@ 2016-04-28 12:59 Ludovic Desroches
2016-04-28 13:20 ` Adrian Hunter
2016-05-02 8:40 ` Ulf Hansson
0 siblings, 2 replies; 3+ messages in thread
From: Ludovic Desroches @ 2016-04-28 12:59 UTC (permalink / raw)
To: adrian.hunter, ulf.hansson
Cc: linux-mmc, linux-kernel, nicolas.ferre, Ludovic Desroches
The controller claims to support SDR104. In fact, it only supports a
degraded SDR104 since the maximum frequency of the SD clock is 120 MHz
instead of 208 MHz.
The sdhci core is unaware of it and will compute a wrong clock divider.
We can deal with this specific case by using presets.
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
---
Changes:
- v2:
- use a define for preset_common since it's a constant
drivers/mmc/host/sdhci-of-at91.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
index c1923c0..25f779e 100644
--- a/drivers/mmc/host/sdhci-of-at91.c
+++ b/drivers/mmc/host/sdhci-of-at91.c
@@ -18,6 +18,7 @@
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
+#include <linux/kernel.h>
#include <linux/mmc/host.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/module.h>
@@ -32,6 +33,8 @@
#define SDMMC_CACR_CAPWREN BIT(0)
#define SDMMC_CACR_KEY (0x46 << 8)
+#define SDHCI_AT91_PRESET_COMMON_CONF 0x400 /* drv type B, programmable clock mode */
+
struct sdhci_at91_priv {
struct clk *hclock;
struct clk *gck;
@@ -163,6 +166,7 @@ static int sdhci_at91_probe(struct platform_device *pdev)
unsigned int clk_base, clk_mul;
unsigned int gck_rate, real_gck_rate;
int ret;
+ unsigned int preset_div;
match = of_match_device(sdhci_at91_dt_match, &pdev->dev);
if (!match)
@@ -230,6 +234,28 @@ static int sdhci_at91_probe(struct platform_device *pdev)
clk_mul, real_gck_rate);
}
+ /*
+ * We have to set preset values because it depends on the clk_mul
+ * value. Moreover, SDR104 is supported in a degraded mode since the
+ * maximum sd clock value is 120 MHz instead of 208 MHz. For that
+ * reason, we need to use presets to support SDR104.
+ */
+ preset_div = DIV_ROUND_UP(real_gck_rate, 24000000) - 1;
+ writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
+ host->ioaddr + SDHCI_PRESET_FOR_SDR12);
+ preset_div = DIV_ROUND_UP(real_gck_rate, 50000000) - 1;
+ writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
+ host->ioaddr + SDHCI_PRESET_FOR_SDR25);
+ preset_div = DIV_ROUND_UP(real_gck_rate, 100000000) - 1;
+ writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
+ host->ioaddr + SDHCI_PRESET_FOR_SDR50);
+ preset_div = DIV_ROUND_UP(real_gck_rate, 120000000) - 1;
+ writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
+ host->ioaddr + SDHCI_PRESET_FOR_SDR104);
+ preset_div = DIV_ROUND_UP(real_gck_rate, 50000000) - 1;
+ writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
+ host->ioaddr + SDHCI_PRESET_FOR_DDR50);
+
clk_prepare_enable(priv->mainck);
clk_prepare_enable(priv->gck);
--
2.5.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] mmc: sdhci-of-at91: add presets setup
2016-04-28 12:59 [PATCH v2] mmc: sdhci-of-at91: add presets setup Ludovic Desroches
@ 2016-04-28 13:20 ` Adrian Hunter
2016-05-02 8:40 ` Ulf Hansson
1 sibling, 0 replies; 3+ messages in thread
From: Adrian Hunter @ 2016-04-28 13:20 UTC (permalink / raw)
To: Ludovic Desroches, ulf.hansson; +Cc: linux-mmc, linux-kernel, nicolas.ferre
On 28/04/16 15:59, Ludovic Desroches wrote:
> The controller claims to support SDR104. In fact, it only supports a
> degraded SDR104 since the maximum frequency of the SD clock is 120 MHz
> instead of 208 MHz.
> The sdhci core is unaware of it and will compute a wrong clock divider.
> We can deal with this specific case by using presets.
>
> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
>
> Changes:
> - v2:
> - use a define for preset_common since it's a constant
>
> drivers/mmc/host/sdhci-of-at91.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
> index c1923c0..25f779e 100644
> --- a/drivers/mmc/host/sdhci-of-at91.c
> +++ b/drivers/mmc/host/sdhci-of-at91.c
> @@ -18,6 +18,7 @@
> #include <linux/delay.h>
> #include <linux/err.h>
> #include <linux/io.h>
> +#include <linux/kernel.h>
> #include <linux/mmc/host.h>
> #include <linux/mmc/slot-gpio.h>
> #include <linux/module.h>
> @@ -32,6 +33,8 @@
> #define SDMMC_CACR_CAPWREN BIT(0)
> #define SDMMC_CACR_KEY (0x46 << 8)
>
> +#define SDHCI_AT91_PRESET_COMMON_CONF 0x400 /* drv type B, programmable clock mode */
> +
> struct sdhci_at91_priv {
> struct clk *hclock;
> struct clk *gck;
> @@ -163,6 +166,7 @@ static int sdhci_at91_probe(struct platform_device *pdev)
> unsigned int clk_base, clk_mul;
> unsigned int gck_rate, real_gck_rate;
> int ret;
> + unsigned int preset_div;
>
> match = of_match_device(sdhci_at91_dt_match, &pdev->dev);
> if (!match)
> @@ -230,6 +234,28 @@ static int sdhci_at91_probe(struct platform_device *pdev)
> clk_mul, real_gck_rate);
> }
>
> + /*
> + * We have to set preset values because it depends on the clk_mul
> + * value. Moreover, SDR104 is supported in a degraded mode since the
> + * maximum sd clock value is 120 MHz instead of 208 MHz. For that
> + * reason, we need to use presets to support SDR104.
> + */
> + preset_div = DIV_ROUND_UP(real_gck_rate, 24000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_SDR12);
> + preset_div = DIV_ROUND_UP(real_gck_rate, 50000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_SDR25);
> + preset_div = DIV_ROUND_UP(real_gck_rate, 100000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_SDR50);
> + preset_div = DIV_ROUND_UP(real_gck_rate, 120000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_SDR104);
> + preset_div = DIV_ROUND_UP(real_gck_rate, 50000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_DDR50);
> +
> clk_prepare_enable(priv->mainck);
> clk_prepare_enable(priv->gck);
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] mmc: sdhci-of-at91: add presets setup
2016-04-28 12:59 [PATCH v2] mmc: sdhci-of-at91: add presets setup Ludovic Desroches
2016-04-28 13:20 ` Adrian Hunter
@ 2016-05-02 8:40 ` Ulf Hansson
1 sibling, 0 replies; 3+ messages in thread
From: Ulf Hansson @ 2016-05-02 8:40 UTC (permalink / raw)
To: Ludovic Desroches
Cc: Adrian Hunter, linux-mmc, linux-kernel@vger.kernel.org,
Nicolas Ferre
On 28 April 2016 at 14:59, Ludovic Desroches
<ludovic.desroches@atmel.com> wrote:
> The controller claims to support SDR104. In fact, it only supports a
> degraded SDR104 since the maximum frequency of the SD clock is 120 MHz
> instead of 208 MHz.
> The sdhci core is unaware of it and will compute a wrong clock divider.
> We can deal with this specific case by using presets.
>
> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Thanks, applied for next!
Kind regards
Uffe
> ---
>
> Changes:
> - v2:
> - use a define for preset_common since it's a constant
>
> drivers/mmc/host/sdhci-of-at91.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
> index c1923c0..25f779e 100644
> --- a/drivers/mmc/host/sdhci-of-at91.c
> +++ b/drivers/mmc/host/sdhci-of-at91.c
> @@ -18,6 +18,7 @@
> #include <linux/delay.h>
> #include <linux/err.h>
> #include <linux/io.h>
> +#include <linux/kernel.h>
> #include <linux/mmc/host.h>
> #include <linux/mmc/slot-gpio.h>
> #include <linux/module.h>
> @@ -32,6 +33,8 @@
> #define SDMMC_CACR_CAPWREN BIT(0)
> #define SDMMC_CACR_KEY (0x46 << 8)
>
> +#define SDHCI_AT91_PRESET_COMMON_CONF 0x400 /* drv type B, programmable clock mode */
> +
> struct sdhci_at91_priv {
> struct clk *hclock;
> struct clk *gck;
> @@ -163,6 +166,7 @@ static int sdhci_at91_probe(struct platform_device *pdev)
> unsigned int clk_base, clk_mul;
> unsigned int gck_rate, real_gck_rate;
> int ret;
> + unsigned int preset_div;
>
> match = of_match_device(sdhci_at91_dt_match, &pdev->dev);
> if (!match)
> @@ -230,6 +234,28 @@ static int sdhci_at91_probe(struct platform_device *pdev)
> clk_mul, real_gck_rate);
> }
>
> + /*
> + * We have to set preset values because it depends on the clk_mul
> + * value. Moreover, SDR104 is supported in a degraded mode since the
> + * maximum sd clock value is 120 MHz instead of 208 MHz. For that
> + * reason, we need to use presets to support SDR104.
> + */
> + preset_div = DIV_ROUND_UP(real_gck_rate, 24000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_SDR12);
> + preset_div = DIV_ROUND_UP(real_gck_rate, 50000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_SDR25);
> + preset_div = DIV_ROUND_UP(real_gck_rate, 100000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_SDR50);
> + preset_div = DIV_ROUND_UP(real_gck_rate, 120000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_SDR104);
> + preset_div = DIV_ROUND_UP(real_gck_rate, 50000000) - 1;
> + writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
> + host->ioaddr + SDHCI_PRESET_FOR_DDR50);
> +
> clk_prepare_enable(priv->mainck);
> clk_prepare_enable(priv->gck);
>
> --
> 2.5.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-04-28 12:59 [PATCH v2] mmc: sdhci-of-at91: add presets setup Ludovic Desroches
2016-04-28 13:20 ` Adrian Hunter
2016-05-02 8:40 ` Ulf Hansson
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