target/linux/s3c24xx/patches-2.6.24/1250-add-glamo-mci-slower-clocking-dynamic-switching.patc.patch

   1 From 6d8e14dc4253f3921aff1bbbeb3caf073aa6a7b2 Mon Sep 17 00:00:00 2001
   2 From: Andy Green <andy@openmoko.com>
   3 Date: Wed, 30 Jul 2008 12:46:44 +0100
   4 Subject: [PATCH] add-glamo-mci-slower-clocking-dynamic-switching.patch
   5
   6 This patch gives glamo-mci a concept of a platform-defined
   7 dynamic clock slowing callback.  It means that platform code
   8 can associate some completely external state to decide if
   9 we run the SD clock at normal rate or a rate divided by a
  10 module parameter "sd_slow_ratio", which you can set on
  11 kernel commandline like this:
  12
  13 glamo_mci.sd_slow_ratio=8
  14
  15 you can also change it at runtime by
  16
  17 echo 8 > /sys/module/glamo_mci/parameters/sd_slow_ratio
  18
  19 If no platform callback is defined, then no slow mode
  20 is used.  If it is defined, then the default division
  21 action is / 8, eg, 16MHz normal -> 2MHz slow mode.
  22
  23 Signed-off-by: Andy Green <andy@openmoko.com>
  24 ---
  25  drivers/mfd/glamo/glamo-core.c |    2 ++
  26  drivers/mfd/glamo/glamo-core.h |    2 ++
  27  drivers/mfd/glamo/glamo-mci.c  |   30 ++++++++++++++++++++++++++++--
  28  include/linux/glamofb.h        |    2 ++
  29  4 files changed, 34 insertions(+), 2 deletions(-)
  30
  31 diff --git a/drivers/mfd/glamo/glamo-core.c b/drivers/mfd/glamo/glamo-core.c
  32 index f411446..c094a8c 100644
  33 --- a/drivers/mfd/glamo/glamo-core.c
  34 +++ b/drivers/mfd/glamo/glamo-core.c
  35 @@ -1114,6 +1114,8 @@ static int __init glamo_probe(struct platform_device *pdev)
  36         /* bring MCI specific stuff over from our MFD platform data */
  37         glamo_mci_def_pdata.glamo_set_mci_power =
  38                                         glamo->pdata->glamo_set_mci_power;
  39 +       glamo_mci_def_pdata.glamo_mci_use_slow =
  40 +                                       glamo->pdata->glamo_mci_use_slow;
  41         glamo_mci_def_pdata.glamo_irq_is_wired =
  42                                         glamo->pdata->glamo_irq_is_wired;
  43         glamo_mci_def_pdata.mci_suspending =
  44 diff --git a/drivers/mfd/glamo/glamo-core.h b/drivers/mfd/glamo/glamo-core.h
  45 index 8d647ec..d3f4309 100644
  46 --- a/drivers/mfd/glamo/glamo-core.h
  47 +++ b/drivers/mfd/glamo/glamo-core.h
  48 @@ -72,6 +72,8 @@ struct glamo_mci_pdata {
  49         unsigned long   ocr_avail;
  50         void            (*glamo_set_mci_power)(unsigned char power_mode,
  51                                      unsigned short vdd);
  52 +       /* glamo-mci asking if it should use the slow clock to card */
  53 +       int             (*glamo_mci_use_slow)(void);
  54         int             (*glamo_irq_is_wired)(void);
  55         void            (*mci_suspending)(struct platform_device *dev);
  56         int             (*mci_all_dependencies_resumed)(struct platform_device
  57 diff --git a/drivers/mfd/glamo/glamo-mci.c b/drivers/mfd/glamo/glamo-mci.c
  58 index 54ba613..577021e 100644
  59 --- a/drivers/mfd/glamo/glamo-mci.c
  60 +++ b/drivers/mfd/glamo/glamo-mci.c
  61 @@ -57,6 +57,23 @@ static int sd_max_clk = 50000000 / 3;
  62  module_param(sd_max_clk, int, 0644);
  63
  64  /*
  65 + * Slow SD clock rate
  66 + *
  67 + * you can override this on kernel commandline using
  68 + *
  69 + *   glamo_mci.sd_slow_ratio=8
  70 + *
  71 + * for example
  72 + *
  73 + * platform callback is used to decide effective clock rate, if not
  74 + * defined then max is used, if defined and returns nonzero, rate is
  75 + * divided by this factor
  76 + */
  77 +
  78 +static int sd_slow_ratio = 8;
  79 +module_param(sd_slow_ratio, int, 0644);
  80 +
  81 +/*
  82   * SD Signal drive strength
  83   *
  84   * you can override this on kernel commandline using
  85 @@ -554,8 +571,17 @@ static void glamo_mci_send_request(struct mmc_host *mmc)
  86                  cmd->opcode, cmd->arg, cmd->data, cmd->mrq->stop,
  87                  cmd->flags);
  88
  89 -       /* resume requested clock rate */
  90 -       __glamo_mci_fix_card_div(host, host->clk_div);
  91 +       /* resume requested clock rate
  92 +        * scale it down by sd_slow_ratio if platform requests it
  93 +        */
  94 +       if (host->pdata->glamo_mci_use_slow)
  95 +               if ((host->pdata->glamo_mci_use_slow)())
  96 +                       __glamo_mci_fix_card_div(host, host->clk_div *
  97 +                                                                sd_slow_ratio);
  98 +               else
  99 +                       __glamo_mci_fix_card_div(host, host->clk_div);
 100 +       else
 101 +               __glamo_mci_fix_card_div(host, host->clk_div);
 102
 103         if (glamo_mci_send_command(host, cmd))
 104                 goto bail;
 105 diff --git a/include/linux/glamofb.h b/include/linux/glamofb.h
 106 index efd315b..b101e9c 100644
 107 --- a/include/linux/glamofb.h
 108 +++ b/include/linux/glamofb.h
 109 @@ -31,6 +31,8 @@ struct glamofb_platform_data {
 110         /* glamo mmc platform specific info */
 111         void            (*glamo_set_mci_power)(unsigned char power_mode,
 112                                      unsigned short vdd);
 113 +       /* glamo-mci asking if it should use the slow clock to card */
 114 +       int             (*glamo_mci_use_slow)(void);
 115         int             (*glamo_irq_is_wired)(void);
 116         void            (*mci_suspending)(struct platform_device *dev);
 117         int             (*mci_all_dependencies_resumed)(struct platform_device
 118 --
 119 1.5.6.5
 120