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SubjectRe: [RFC 3/3] mmc: sdhci-pxav3: Add ->voltage_switch callback support
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On 2015/9/2 3:32, Vaibhav Hiremath wrote:
> In case PXA1928 family of devices, there is device/controller specific
> configuration to control voltage/power on the IO pins.
>
> This patch implements and enables the sdhci_ops->voltage_switch()
> callback api.
> Note that IO pad register addresses are fetched as a memory resource.
>
> For example, in case of PXA1928 and family of devices, the DT property
> would look something like,
>
> sdh1: sdh@d4280000 {
> compatible = "mrvl,pxav3-mmc";
> reg-names = "sdhci", "io-pwr", "io-pwr-lock-unlock";
> reg = <0xd4280000 0x120>,
> <0xd401e81c 4>,
> <0xd4015068 8>;
> ...
> };
>
> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
> ---
> drivers/mmc/host/sdhci-pxav3.c | 59 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 59 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
> index 5d26fe0..cebb2f9 100644
> --- a/drivers/mmc/host/sdhci-pxav3.c
> +++ b/drivers/mmc/host/sdhci-pxav3.c
> @@ -63,11 +63,18 @@
> #define IO_PWR_AKEY_ASSAR 0xeb10
> #define IO_PWR_MMC1_PAD_1V8 BIT(2)
>
> +/* IO Power control */
> +#define IO_PWR_AKEY_ASFAR 0xbaba
> +#define IO_PWR_AKEY_ASSAR 0xeb10
> +#define IO_PWR_MMC1_PAD_1V8 BIT(2)
> +
> struct sdhci_pxa {
> struct clk *clk_core;
> struct clk *clk_io;
> u8 power_mode;
> void __iomem *sdio3_conf_reg;
> + void __iomem *io_pwr_reg;
> + void __iomem *io_pwr_lock_reg;
> };
>
> /*
> @@ -307,6 +314,38 @@ static void pxav3_set_uhs_signaling(struct sdhci_host *host, unsigned int uhs)
> __func__, uhs, ctrl_2);
> }
>
> +static void pxav3_voltage_switch(struct sdhci_host *host,
> + u8 signal_voltage)
> +{
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_pxa *pxa = pltfm_host->priv;
> + unsigned int val;
> +
> + if (!pxa->io_pwr_reg || !pxa->io_pwr_lock_reg)
> + return;
> +
> + /* Lock register is 64 bit: First & Second access register */
> + writel(IO_PWR_AKEY_ASFAR, pxa->io_pwr_lock_reg);
> + writel(IO_PWR_AKEY_ASSAR, pxa->io_pwr_lock_reg + 4);
> + val = readl(pxa->io_pwr_reg);
> +
> + switch (signal_voltage) {
> + case MMC_SIGNAL_VOLTAGE_180:
> + case MMC_SIGNAL_VOLTAGE_120:
> + val |= IO_PWR_MMC1_PAD_1V8;
> + break;
> + case MMC_SIGNAL_VOLTAGE_330:
> + default:
> + val &= ~IO_PWR_MMC1_PAD_1V8;
> + break;
> + }
> +
> + writel(IO_PWR_AKEY_ASFAR, pxa->io_pwr_lock_reg);
> + writel(IO_PWR_AKEY_ASSAR, pxa->io_pwr_lock_reg + 4);
> +
> + writel(val, pxa->io_pwr_reg);
> +}
> +
> static const struct sdhci_ops pxav3_sdhci_ops = {
> .set_clock = sdhci_set_clock,
> .platform_send_init_74_clocks = pxav3_gen_init_74_clocks,
> @@ -314,6 +353,7 @@ static const struct sdhci_ops pxav3_sdhci_ops = {
> .set_bus_width = sdhci_set_bus_width,
> .reset = pxav3_reset,
> .set_uhs_signaling = pxav3_set_uhs_signaling,
> + .voltage_switch = pxav3_voltage_switch,
> };
>
> static struct sdhci_pltfm_data sdhci_pxav3_pdata = {
> @@ -368,6 +408,7 @@ static int sdhci_pxav3_probe(struct platform_device *pdev)
> struct sdhci_host *host = NULL;
> struct sdhci_pxa *pxa = NULL;
> const struct of_device_id *match;
> + struct resource *res;
> int ret;
>
> pxa = devm_kzalloc(&pdev->dev, sizeof(struct sdhci_pxa), GFP_KERNEL);
> @@ -408,6 +449,24 @@ static int sdhci_pxav3_probe(struct platform_device *pdev)
> goto err_mbus_win;
> }
>
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "io-pwr-conf");
> + if (res) {
> + pxa->io_pwr_reg = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(pxa->io_pwr_reg)) {
> + ret = PTR_ERR(pxa->io_pwr_reg);
> + goto err_mbus_win;
> + }
> + }

Hi Vaibhav,

Why not get it from syscon and use regmap API to deal with it.
IMO, that's okay, you can find examples from
drivers/mmc/host/dw_mmc-k3.c: dw_mci_hi6220_switch_voltage


> +
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "io-pwr-lock-unlock");
> + if (res) {
> + pxa->io_pwr_lock_reg = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(pxa->io_pwr_lock_reg)) {
> + ret = PTR_ERR(pxa->io_pwr_lock_reg);
> + goto err_mbus_win;
> + }
> + }
> +
> match = of_match_device(of_match_ptr(sdhci_pxav3_of_match), &pdev->dev);
> if (match) {
> ret = mmc_of_parse(host->mmc);
>


--
Best Regards
Shawn Lin



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