mmc: tmio, sh_mobile_sdhi: Add support for variable input clock frequency
Currently tmio_mmc assumes that the input clock frequency is fixed and
only its own clock divider can be changed. This is not true in the
case of sh_mobile_sdhi; we can use the clock API to change it.
In tmio_mmc:
- Delegate setting of f_min from tmio to the clk_enable operation (if
implemented), as it can be smaller than f_max / 512
- Add an optional clk_update operation called from tmio_mmc_set_clock()
that updates the input clock frequency
- Rename tmio_mmc_clk_update() to tmio_mmc_clk_enable(), to avoid
confusion with the clk_update operation
In sh_mobile_sdhi:
- Make the setting of f_max conditional; it should be set through the
max-frequency property in the device tree in future
- Set f_min based on the input clock's minimum frequency
- Implement the clk_update operation, selecting the best input clock
frequency for the bus frequency that's wanted
sh_mobile_sdhi_clk_update() is loosely based on Kuninori Morimoto's work
in sh_mmcif.
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
index e1e5759..ecc16a3 100644
--- a/drivers/mmc/host/tmio_mmc_pio.c
+++ b/drivers/mmc/host/tmio_mmc_pio.c
@@ -160,9 +160,12 @@
u32 clk = 0, clock;
if (new_clock) {
- for (clock = host->mmc->f_min, clk = 0x80000080;
- new_clock >= (clock << 1);
- clk >>= 1)
+ if (host->clk_update)
+ clock = host->clk_update(host, new_clock) / 512;
+ else
+ clock = host->mmc->f_min;
+
+ for (clk = 0x80000080; new_clock >= (clock << 1); clk >>= 1)
clock <<= 1;
/* 1/1 clock is option */
@@ -837,19 +840,12 @@
pm_runtime_put_autosuspend(mmc_dev(mmc));
}
-static int tmio_mmc_clk_update(struct tmio_mmc_host *host)
+static int tmio_mmc_clk_enable(struct tmio_mmc_host *host)
{
- struct mmc_host *mmc = host->mmc;
- int ret;
-
if (!host->clk_enable)
return -ENOTSUPP;
- ret = host->clk_enable(host);
- if (!ret)
- mmc->f_min = mmc->f_max / 512;
-
- return ret;
+ return host->clk_enable(host);
}
static void tmio_mmc_power_on(struct tmio_mmc_host *host, unsigned short vdd)
@@ -1135,7 +1131,7 @@
mmc->caps & MMC_CAP_NONREMOVABLE ||
mmc->slot.cd_irq >= 0);
- if (tmio_mmc_clk_update(_host) < 0) {
+ if (tmio_mmc_clk_enable(_host) < 0) {
mmc->f_max = pdata->hclk;
mmc->f_min = mmc->f_max / 512;
}
@@ -1263,7 +1259,7 @@
struct tmio_mmc_host *host = mmc_priv(mmc);
tmio_mmc_reset(host);
- tmio_mmc_clk_update(host);
+ tmio_mmc_clk_enable(host);
if (host->clk_cache) {
tmio_mmc_set_clock(host, host->clk_cache);